Cardiopulmonary Exercise Testing in Heart Failure

Exercise and cardiac rehabilitation after LVAD implantation

Left ventricular assist devices (LVAD) have improved mortality and quality of life for patients with end-stage heart failure by providing an alternative to cardiac transplant or as a bridge to transplantation. The improvement in functional capacity however is minimal to modest depending on the right ventricular function, optimal hemodynamics on LVAD therapy, and comorbidities. There is improvement in submaximal exercise capacity but improvement in peak aerobic capacity is limited. Exercise capacity can be improved by referral to cardiac rehabilitation after LVAD implantation. Cardiac rehabilitation is safe and effective with improvement in functional capacity, and decrease in mortality and heart failure hospitalizations. Cardiopulmonary exercise testing (CPET) is a specialized exercise stress test that measures gas exchange during exercise to determine a variety of variables that have been shown to be predictive of mortality in patients undergoing cardiac transplant. CPET is valuable for prognostication and is a predictor of adverse outcomes, including right heart failure in the immediate post-LVAD implantation period, long-term mortality. CPET is an additional testing that can aid in the decision making for LVAD explantation or decommissioning.

Unveiling the limitations of non-metabolic thresholds in assessing maximal effort: The role of cardiopulmonary exercise testing

INTRODUCTION

Maximal effort, defined by a respiratory exchange ratio (RER) ≥ 1.10, is crucial for accurate interpretation of cardiopulmonary exercise testing (CPET). Standard tests rely on non-metabolic thresholds, such as peak predicted heart rate (ppHR) ≥ 85 %, double product (DP) ≥ 20,000 bpm*mmHg and peak metabolic equivalent of task (MET) ≥ 5.0. This study aimed to assess the effectiveness of non-metabolic thresholds in detecting maximal effort, compared with the RER ≥ 1.10 criterion.

METHODS

We retrospectively analyzed stable patients who underwent CPET from 2022 to 2023, regardless of test indication, history of heart failure (HF), or medication use. All patients also performed transthoracic echocardiography.

RESULTS

Among 239 middle-aged patients (53 ± 14 years, 67 % male), 86 % achieved a RER ≥ 1.10, and 65 % had a diagnosis of HF. Non-metabolic thresholds correctly identified maximal efforts (RER ≥ 1.10) in 75 % of the cases (AUC < 0.600). Misclassified cases were more likely to have a history of atrial fibrillation (AF), paced rhythm, HF, and beta-blockers or RAAS inhibitors use. These patients exhibited lower VO2 peak and higher VE/VCO2 slope. Multivariable analysis identified HF history (OR 4.8, CI 95 % 1.6-15.6, p: 0.005), low resting DP (≤ 7500 mmHg*bpm), and ramp protocol as independent predictors of discordant tests.

CONCLUSION

Non-metabolic thresholds misclassified up to 25 % of tests with RER ≥ 1.10 as non-maximal, potentially leading to inaccurate interpretation. In patients with HF, poor expected functional capacity and low DP, direct referral to CPET-equipped facilities may provide more accurate assessment than relying on non-metabolic thresholds.

The contribution of cardiopulmonary exercise testing in the familial screening for dilated and non-dilated left ventricular cardiomyopathies: case series

Background

The importance of family screening in relatives of patients affected by cardiomyopathies is highlighted in the international guidelines. Although electrocardiogram (ECG) and echocardiogram represent cornerstones of family screening, they may not always be sufficient to detect subtle abnormalities, especially in genotype-positive/phenotype-negative relatives. The role of cardiopulmonary exercise testing (CPET) in providing additional clinical information during family screening, remains to be fully elucidated.

Case summary

Ten asymptomatic genotype-positive/phenotype-negative first-degree relatives of probands affected by dilated cardiomyopathy (DCM) and non-dilated left ventricular cardiomyopathy (NDLVC) were evaluated in the context of family screening. Cardiopulmonary exercise testing was integrated into the initial diagnostic evaluation. Two out of 10 relatives showed an abnormal CPET, with alteration in O2 kinetic.

Discussion

Family screening in relatives of DCM and NDLVC patients, particularly in genotype-positive/phenotype-negative subjects, remains challenging due to difficulties in assessing the subtle abnormalities that may represent an initial clinical manifestation of the disease and support early treatment initiation. A more accurate and comprehensive familial screening may be achieved by integrating ECG and echocardiogram-the current first-line assessments-with data from additional tools, such as global longitudinal strain on echocardiogram, cardiac magnetic resonance, Holter ECG, and CPET.

The Impact of Exercise Training in a Hypobaric/Normobaric Hypoxic Environment on Cardiometabolic Health in Adults with Overweight or Obesity: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aims to comprehensively evaluate the effects of hypoxic training (HT) versus normoxic training (NT) on cardiometabolic health parameters in overweight or obese adults. Searches were performed in PubMed, Web of Science, Embase, Scopus, and the Cochrane Library. A meta-analysis was performed using Stata 18 and RevMan 5.4 software. Seventeen randomized controlled studies involving 517 participants were included. HT significantly improved cardiorespiratory fitness (CRF) and reduced systolic blood pressure (SBP) and diastolic blood pressure (DBP). Compared with NT, HT demonstrated a significant difference in CRF, but no significant differences were observed in SBP and DBP. The subgroup analysis of CRF revealed that HT significantly outperformed NT in six aspects: participants aged < 45 years (Hedges' g = 0.50), an intervention duration of 8 weeks (Hedges' g = 0.43), three sessions per week (Hedges' g = 0.40), each session lasting < 45 min (Hedges' g = 0.23), FiO2 levels > 15% (Hedges' g = 0.69), and high-load-intensity exercise (Hedges' g = 0.57). HT demonstrated favorable effects in improving cardiometabolic health among overweight or obese adults. Compared with NT, this advantage was primarily reflected in CRF while the impacts on SBP and DBP were similar.

Machine Learning-Based VO2 Estimation Using a Wearable Multiwavelength Photoplethysmography Device

The rate of oxygen consumption, which is measured as the volume of oxygen consumed per mass per minute (VO2) mL/kg/min, is a critical metric for evaluating cardiovascular health, metabolic status, and respiratory function. Specifically, VO2 is a powerful prognostic predictor of survival in patients with heart failure (HF) because it provides an indirect assessment of a patient's ability to increase cardiac output (CO). In addition, VO2 measurements, particularly VO2 max, are significant because they provide a reliable indicator of your cardiovascular fitness and aerobic endurance. However, traditional VO2 assessment requires bulky, breath-by-breath gas analysis systems, limiting frequent and continuous monitoring to specialized settings. This study presents a novel wrist-worn multiwavelength photoplethysmography (PPG) device and machine learning algorithm designed to estimate VO2 continuously. Unlike conventional wearables that rely on static formulas for VO2 max estimation, our algorithm leverages the data from the PPG wearable and uses the Beer-Lambert Law with inputs from five wavelengths (670 nm, 770 nm, 810 nm, 850 nm, and 950 nm), incorporating the isosbestic point at 810 nm to differentiate oxy- and deoxy-hemoglobin. A validation study was conducted with eight subjects using a modified Bruce protocol, comparing the PPG-based estimates to the gold-standard Parvo Medics gas analysis system. The results demonstrated a mean absolute error of 1.66 mL/kg/min and an R2 of 0.94. By providing precise, individualized VO2 estimates using direct tissue oxygenation data, this wearable solution offers significant clinical and practical advantages over traditional methods, making continuous and accurate cardiovascular assessment readily available beyond clinical environments.

Transition to Advanced Heart Failure: From Identification to Improving Prognosis

Advanced heart failure (AHF) represents the terminal stage of heart failure (HF), characterized by persistent symptoms and functional limitations despite optimal guideline-directed medical therapy (GDMT). This review explores the clinical definition, pathophysiology, and therapeutic approaches for AHF. Characterized by severe symptoms, New York Heart Association (NYHA) class III-IV, significant cardiac dysfunction, and frequent hospitalizations, AHF presents substantial challenges in prognosis and management. Pathophysiological mechanisms include neurohormonal activation, ventricular remodeling, and systemic inflammation, leading to reduced cardiac output and organ dysfunction. Therapeutic strategies for AHF involve a multidisciplinary approach, including pharmacological treatments, device-based interventions like ventricular assisted devices, and advanced options such as heart transplantation. Despite progress, AHF management faces limitations, including disparities in access to care and the need for personalized approaches. Novel therapies, artificial intelligence, and remote monitoring technologies offer future opportunities to improve outcomes. Palliative care, which focuses on symptom relief and quality of life, remains crucial for patients ineligible for invasive interventions. Early identification and timely intervention are pivotal for enhancing survival and functional outcomes in this vulnerable population. This review underscores the necessity of integrating innovative technologies, personalized medicine, and robust palliative strategies into AHF management to address its high morbidity and mortality.

Cardiopulmonary exercise test with bicycle stress echocardiography for predicting adverse cardiac events in patients with stage A or B heart failure

Background

Given the high prevalence of stage A or B heart failure (HF), comprehensive screening for new-onset HF is cost-prohibitive. Therefore, further risk stratification is warranted to identify at-risk patients. This study aimed to evaluate the prognostic utility of cardiopulmonary exercise test (CPET) with bicycle stress echocardiography (BSE) in patients with stage A or B HF.

Methods

Among 687 consecutive patients who underwent CPET-BSE, 410 with stage A or B HF were analyzed. The association between the CPET-BSE parameters and adverse cardiac events (hospitalization for HF or cardiac-related death) was analyzed using the Cox proportional hazard model under univariate and multivariate analyses.

Results

After a median 9 years of follow-up, 47 (11.5 %) of the 410 patients had events. In the univariable analysis, age, diuretics, BUN, creatinine, peak oxygen uptake (VO2), ventilatory efficiency (VE/VCO2), time to VT and peak exercise, left atrial volume index, rest and exercise E/e', and tricuspid regurgitation velocity demonstrated significant parameters. In multivariate analysis, VE/VCO2 (hazard ratio [HR] 1.205, 95 % CI 1.095-1.327) and VO2 at peak exercise (HR 1.164, 95 % CI 1.022-1.325), time to VT (HR 0.993, 95 % CI 0.989-0.997), and exercise E/e' (HR 1.582, 95 % CI 1.199-2.087) were only independent predictors for events.

Conclusions

In patients with stage A or B HF, four parameters of CPET-BSE were good predictors of future development of HF or cardiac death. If patients are unable to perform complete exercise, the time to VT may serve as a sufficiently predictive parameter for clinical events.

Right ventricular coupling predicts cardiopulmonary fitness in cardiac transthyretin amyloidosis

BACKGROUND

Wild-type transthyretin cardiac amyloidosis (ATTRwt) is an infiltrative disease leading to restrictive cardiomyopathy. We aimed to characterise exercise capacity in ATTRwt and to identify predictors of cardiopulmonary fitness, focusing on echocardiographic and clinical parameters.

METHODS

We studied 110 ATTRwt patients from a prospective single-centre registry (2020-2024) by cardiopulmonary exercise testing (CPET). Besides CPET, all patients underwent comprehensive clinical assessment including follow-up for mortality. In 32 patients follow-up CPET after 1 year was available.

RESULTS

In ATTRwt, reduced aerobic capacity (pVO2 16 [13-18] ml/kg/min), and ventilatory inefficiency (VE/VCO2 slope 35 [30-43]) were common. In the multivariable regression analysis, we identified TAPSE/sPAP ratio as predictive for pVO2 (p = 0.019) and ventilatory efficiency (p = 0.004), while left ventricular ejection fraction or measures of left ventricular hypertrophy were not predictive. Concordantly, TAPSE/sPAP ratio assessed at baseline predicted pVO2 at 1-year follow-up (p = 0.009). Furthermore, patients with a TAPSE/sPAP ratio below the median of 0.38 mm/mmHg presented a higher risk of all-cause death (p = 0.009).

CONCLUSION

In ATTRwt the TAPSE/sPAP ratio, a marker of right ventricular coupling, was an independent predictor of aerobic capacity assessed by CPET, at baseline and after 1 year, highlighting the importance of right ventricular assessment for risk stratification.

Circulating neuropeptide Y dynamics and performance during exercise in heart failure patients with contemporary medical and device therapy

High cardiac sympathetic drive and release of the sympathetic cotransmitter neuropeptide Y (NPY) are significant features of congestive heart failure (CHF), in which resting venous NPY levels are known to be associated with mortality. However, whether circulating NPY levels increase during exercise in CHF when they are already elevated is controversial. We sought to establish the dynamics of circulating NPY levels in CHF patients treated with contemporary medical therapy and devices in relationship to indices of performance linked to long-term prognosis. CHF patients (n = 15) underwent cardiopulmonary exercise testing with venous blood sampling at rest, peak exercise and recovery. These patients had significantly higher resting venous NPY levels compared with an age- and sex-matched control group of patients (n = 16) with normal left ventricular function (40 ± 6.9 vs. 9.0 ± 4.6 pg/mL, respectively; P < 0.0001). In CHF patients, NPY levels increased significantly from baseline to peak exercise (to 93.5 ± 42.1 pg/mL; P = 0.0004) and remained elevated during recovery (86.8 ± 44.6 pg/mL; P = 0.0018). The peak (r = 0.58, P = 0.0222) and recovery (r = 0.56, P = 0.0304) NPY levels and the ability to increase NPY from baseline (r = 0.53, P = 0.0427) showed significant positive correlations with heart rate recovery at 1 min, but not with peak oxygen consumption. In CHF patients, the ability to increase NPY levels on exertion is correlated with heart rate recovery, a known prognostic indicator for mortality. These findings suggest that NPY dynamics during exercise might provide valuable insights into sympathetic responses and prognosis in CHF patients.

Association of Physiological Reserve Obtained from Cardiopulmonary Exercise Testing and Frailty with All-Cause Mortality in Patients on Hemodialysis

Key Points

This study analyzed the prognostic value of reserves obtained from cardiopulmonary exercise testing in patients on hemodialysis. Each reserve (cardiac, autonomic, and muscular) was associated with mortality, with muscle reserve having the highest prognostic accuracy. Patients with physical frailty also had a fairly good prognosis if their physiological reserve is preserved by exercise testing.

Background

Potential impairment of exercise capacity is prevalent even in patients undergoing hemodialysis without frailty. Cardiopulmonary exercise testing (CPET) can detect physiological reserves, such as cardiopulmonary, muscle, and autonomic function. We hypothesized that these indices could accurately determine the prognosis of patients on hemodialysis and analyzed them on the basis of their relationship to frailty.

Methods

In this two-center prospective cohort study of patients on hemodialysis from Japan, patients underwent CPET and physical assessment to evaluate peak oxygen uptake (peak VO2, indicator of exercise capacity), peak work rate (WR, indicator of muscle function), ventilatory equivalent for carbon dioxide (VE/VCO2) slope (indicator of cardiac reserve), heart rate reserve (indicator of chronotropic incompetence), and frailty phenotype. Survival was followed up for up to 5 years.

Results

Data from 189 patients (median [interquartile range] age: 71 [62–77] years) were analyzed. All CPET indicators showed a consistent nonlinear relationship with all-cause mortality after adjustment: for peak VO2, hazard ratio (HR), 0.79 (95% confidence interval [CI], 0.71 to 0.88), P < 0.001; for peak WR, HR, 0.95 (95% CI, 0.93 to 0.97), P < 0.001; for VE/VCO2 slope, HR, 1.09 (95% CI, 1.05 to 1.13), P < 0.001; and for heart rate reserve, HR, 0.96 (95% CI, 0.93 to 0.99), P = 0.02. Frailty phenotype was associated with mortality after adjustment (HR, 1.73 [95% CI, 1.06 to 2.81], P = 0.03); however, this association was not statistically significant in the model after adding peak VO2 (P = 0.41). Furthermore, in both subgroups with and without frailty, CPET measures were significantly associated with mortality risk (peak VO2, peak WR, and VE/VCO2 slope: P < 0.05). The peak VO2 (Δ area under the curve, 0.09; 95% CI, 0.02 to 0.16) or the peak WR (Δ area under the curve, 0.09; 95% CI, 0.02 to 0.15) most significantly improved the prognostic accuracy.

Conclusions

Results showed the fragile aspect of the frailty phenotype in the hemodialysis population and the superior ability of CPET to indicate death risk complementing that aspect.

Correlations Between Body Composition and Aerobic Fitness in Elite Female Youth Water Polo Players

Body composition and cardiopulmonary exercise testing (CPET) are vital for optimizing sports performance, but the correlations between them are still underexplored. Our study aimed to investigate the relationships between body composition and specific CPET variables describing physical fitness in young athletes, also adjusting for age and height, in a less-studied, female population. Seventy players participated in our study (age: 16.10 ± 1.63 y). After determining body composition using dual-energy X-ray absorptiometry, we conducted treadmill-based maximal-intensity CPET. Data were analyzed in R using multivariate linear regression, accounting for age and height as confounders. Lean body mass (LBM), body fat mass (BFM), and bone mineral content (BMC) showed no effect on resting, maximum, or recovery heart rates and no correlation with resting or maximal lactate values. LBM positively correlated with maximum ventilation (VE-max) (Est: 1.3 × 10-3; SE: 6.1 × 10-4; p < 0.05) and maximum absolute oxygen consumption (VO2abs-max) (Est: 7.710-5; SE: 6.9 × 10-6; p < 0.001)-with age as an influencing factor for VE-max and height as an influencing factor for VO2abs-max. Conversely, BFM showed a negative correlation with maximum relative oxygen consumption (VO2rel-max) (Est: -4.8 × 10-4; SE: 1.2 × 10-4; p < 0.001). Moreover, BFM and BMC were also negatively correlated with maximal exercise duration (Est: -2.2 × 10-4; SE: 8.0 × 10-5; p < 0.01; Est: -3.2 × 10-3; SE: 1.4 × 10-3; p < 0.05) with height as an influencing factor. Our findings indicate complex correlations between body composition and CPET parameters, providing important information for the analysis of individual ergospirometric data. Our results draw attention to the fact that body composition is more precise than weight and height in the evaluation of athletes' physical fitness.

Prognostic Value of Submaximal Cardiopulmonary Exercise Testing in Patients With Cardiac Amyloidosis

Background

This study assessed the prognostic value of submaximal cardiopulmonary exercise testing (CPET) in cardiac amyloidosis and explored CPET as an alternative to the 6-min walk test (6MWT).

Methods and Results

In this single-center prospective observational study, 160 patients with cardiac amyloidosis (87% male; mean age 78±7 years) were evaluated. A total of 145 performed maximum symptom limited CPET. The V̇E/V̇CO2 slope was 39±8, submaximal power output (SPO) was 24.75±11.50 W, and V̇O2 at anaerobic threshold (AT) was 8.13±2.29 mL/min/kg. During follow up, 34 (21.25%) patients died, and another 34 (21.25%) experienced heart failure (HF)-related hospitalization, with 15 (9.38%) patients experiencing both events. Univariate analysis showed that V̇E/V̇CO2 slope (hazard ratio [HR] 0.89; 95% confidence interval [CI] 0.86-0.93; P<0.001) and SPO (HR 0.91; 95% CI 0.87-0.96; P<0.001) were predictors of mortality. In multivariate analysis, V̇E/V̇CO2 slope remained a significant predictor (HR 0.92; 95% CI 0.88-0.97; P<0.001) for both all-cause mortality and HF-related hospitalization independently. A SPO cut-off of <28 W predicted a worse outcome for both measures independently. Moderate correlations for V̇E/V̇CO2 slope (-0.56 [CI -0.67, -0.42]) and SPO (0.55 [CI 0.42, 0.67]) with 6MWT distance have been found.

Conclusions

These findings highlight CPET parameters, particularly V̇E/V̇CO2 slope and SPO with a cut-off <28 W, as predictors of survival and HF-related hospitalization in cardiac amyloidosis.

Prediction of left ventricular reverse remodeling in patients with heart failure with reduced ejection fraction using cardiopulmonary exercise testing

BACKGROUND

With advances in the treatment of heart failure with reduced ejection fraction (HFrEF), the prediction of left ventricular reverse remodeling (LVRR) has become increasingly important. Cardiopulmonary exercise testing (CPET) is a non-invasive test recommended for prognostic risk assessment in HFrEF; however, it is not known whether it predicts LVRR. We aimed to investigate whether the parameters obtained from CPET are useful in predicting LVRR in HFrEF.

METHODS

We retrospectively evaluated 230 consecutive patients with HFrEF [left ventricular ejection fraction (LVEF) ≤40 %] hospitalized for acute heart failure (59 ± 14 years, 78 % males) who underwent CPET before discharge. We investigated whether the CPET parameters, peak oxygen consumption (VO2), and the minute ventilation (VE) vs. carbon dioxide production (VCO2) slope could predict LVRR within 1 year (LVEF >50 %).

RESULTS

Among 230 patients, 89 (39 %) exhibited LVRR. In multivariable logistic analysis, higher peak VO2 [odds ratio (OR): 1.13, 95 % confidence interval (CI): 1.05-1.22, p < 0.001] and lower VE vs. VCO2 slope (OR: 0.95, 95 % CI: 0.91-0.98, p < 0.001) were independently associated with LVRR. In receiver operating characteristic curve analysis, peak VO2 [area under the curve (AUC): 0.657, p < 0.001, optimal cut-off: 15.5 mL/min/kg] and VE vs. VCO2 slope (AUC: 0.663, p < 0.001, optimal cut-off: 35.8) were significant predictors of LVRR. Moreover, combining the peak VO2 and VE vs. VCO2 slope improved the predictive value (AUC: 0.682).

CONCLUSIONS

CPET is a valuable test for the non-invasive detection of LVRR. The combination of peak VO2 and the VE vs. VCO2 slope is useful for predicting LVRR among hospitalized patients with HFrEF receiving pharmacological treatment.

Risk Stratification with Haemodynamic Gain Index and Peak Rate-Pressure Product in Patients with Chronic Heart Failure Undergoing Treadmill Exercise Testing

AIMS

We recently demonstrated the combined prognostic value of two simple non-invasive parameters obtained from treadmill exercise testing in patients with heart failure (HF) with reduced ejection fraction, the haemodynamic gain index (HGI) and peak rate-pressure product (RPP). However, their prognostic value is yet to be validated in patients with undifferentiated HF syndrome.

METHODS

We identified consecutive HF patients undergoing treadmill exercise testing for symptom evaluation between 1/1991-2/2015. HGI was calculated from [(SBPpeak x heart ratepeak) - (SBPrest x heart raterest)]/(SBPrest x heart raterest), and peak RPP was calculated from SBPpeak x heart ratepeak. Hazard ratios per doubling of HGI and peak RPP for all-cause mortality were estimated using multivariable Cox regression models with adjustment for traditional cardiovascular risk factors and exercise testing parameters (chronotropic reserve index, estimated metabolic equivalents, abnormal heart rate recovery, and total exercise time).

RESULTS

In our cohort of 5,940 patients with symptomatic HF diagnosis with median follow up of 7.1 years, 2,222 (37.4%) patients died. Higher both HGI and peak RPP were associated with a lower risk of mortality (adjusted hazard ratio per standard deviation increase 0.80 [0.73-0.88] and 0.85 [0.78-0.91], respectively, all p<0.001). Optimal cut-off values for HGI and peak RPP for discriminating all-cause mortality were 1.06 and 18,966, respectively.

CONCLUSION

Both HGI and peak RPP are predictors of mortality in patients with chronic HF and may be tools to signal need for advanced HF therapy evaluation.

Left Atrial Strain Predicts Poor Exercise Capacity in Patients With Indeterminate Diastolic Function

BACKGROUND AND OBJECTIVES

The 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines report that approximately 20% of diastolic dysfunction is indeterminate and has limited diagnostic accuracy. Left atrial strain may help accurately categorize diastolic dysfunction; however, its exact roles remain unclear. This study investigated the impact of left atrial reservoir strain (LARS) and its association with exercise capacity in patients with indeterminate diastolic function.

METHODS

Among 687 patients who underwent cardiopulmonary exercise tests and supine bicycle stress echocardiography for symptoms including dyspnea, chest pain, valvular heart disease, and other cardiovascular problems, 118 with indeterminate diastolic function were analyzed after excluding those with atrial fibrillation and significant valvular heart disease. Poor exercise tolerance was defined as peak oxygen consumption (pVO₂) <14 mL/kg/min.

RESULTS

Key diastolic dysfunction indices showed no statistical differences between patients with pVO₂ <14 mL/kg/min and ≥14 mL/kg/min. Only LARS was independently associated with pVO₂ (β=0.12 [0.09-0.15], p<0.001) in patients with indeterminate diastolic function. Receiver-operating characteristic curves highlighted LARS as a strong predictor of impaired pVO₂ among all echocardiographic variables (area under the curve: 0.871 [0.776-0.966]), with an optimal cut-off value of 21% after adjusting for clinical variables. Logistic analysis showed that patients with ≤21% LARS had significantly reduced exercise capacity (odds ratio, 12.77; 95% confidence interval, 3.83-48.65; p<0.001).

CONCLUSIONS

LARS is significantly associated with pVO₂ in patients with indeterminate diastolic function. Impaired LARS is a robust predictor of exercise intolerance; measuring LARS enhances diastolic-function assessment accuracy, potentially improving individualized diastolic-dysfunction management and treatment.

Exercise testing in patients with tricuspid regurgitation undergoing transcatheter tricuspid valve intervention

BACKGROUND

Transcatheter tricuspid valve intervention (TTVI) has shown promising results with persistent reduction of tricuspid regurgitation (TR) and improvements in functional class and quality of life (QOL).

OBJECTIVES

To analyze the impact of TTVI on maximal and submaximal exercise capacity (SEC).

METHODS

Constant work-rate exercise-time (CWRET) testing reflects SEC, which is more likely to be relevant for daily life activities and provides more differentiated physiological insight into the nature of exercise intolerance. Thus, 30 patients undergoing TTVI (21 direct annuloplasty and 9 edge-to-edge repair) received cardiopulmonary exercise testing (CPET) and CWRET (at 75% of maximum work rate in the initial CPET) before and 3 months after TTVI.

RESULTS

Patients' age was 80.5 [74.8-82.3] years and 53.3% were female. TR reduction ≥ 2 grades was achieved in 93.3% (TR grade ≤ moderate in 83.3%). Echocardiography revealed improved right ventricular (RV) characteristics with decreased RV basal diameter (47.0 mm [43.0-54.3] vs. 41.5 mm [36.8-48.0]; p < 0.001) and decreased inferior caval vein diameter. CWRET testing showed a significantly improved SEC (246.5 s [153.8-416.8] vs. 338.5 s [238.8-611.8] p = 0.001). Maximum oxygen uptake showed a positive trend without statistically significant differences (9.9 ml/min/kg [8.6-12.4] vs. 11.7 ml/min/kg [9.7-13.3]; p = 0.31). In contrast to the six-minute-walking distance (6MWD), SEC correlated moderately with effective regurgitation orifice area reduction (r = 0.385; p = 0.036), increased cardiac output (r = 0.378; p = 0.039), and improved QOL (r = 387; p = 0.035).

CONCLUSION

Improvements in exercise capacity after TTVI mainly occur in the submaximal rather than in the maximal exercise range and correlate with hemodynamic effects and QOL. This may have a methodological impact on assessment of exercise capacity in these patients.

Exercise, cancer, and the cardiovascular system: clinical effects and mechanistic insights

Cardiovascular diseases and cancer are the leading causes of death in the Western world and share common risk factors. Reduced cardiorespiratory fitness (CRF) is a major determinant of cardiovascular morbidity and cancer survival. In this review we discuss cancer- induced disturbances of parenchymal, cellular, and mitochondrial function, which limit CRF and may be antagonized and attenuated through exercise training. We show the impact of CRF on cancer survival and its attenuating effects on cardiotoxicity of cancer-related treatment. Tailored exercise programs are not yet available for each tumor entity as several trials were performed in heterogeneous populations without adequate cardiopulmonary exercise testing (CPET) prior to exercise prescription and with a wide variation of exercise modalities. There is emerging evidence that exercise may be a crucial pillar in cancer treatment and a tool to mitigate cardiotoxic treatment effects. We discuss modalities of aerobic exercise and resistance training and their potential to improve CRF in cancer patients and provide an example of a periodization model for exercise training in cancer.

Bibliometrics of the current state of application of teletechnology in the rehabilitation of patients with heart and large blood vessel disease

The first publication on the use of teletechnology in heart and large blood vessels dates back to 1961. Since then, the study of teletechnology in heart and large blood vessels has become popular, and the number of publications has drastically increased. Hence, it is imperative to establish a comprehensive research framework that enables researchers and other stakeholders to understand the use of remote technologies in heart and large blood vessels. To bridge this gap, bibliometrics was used, a novel approach to determine the most prolific countries, institutions, journals, authors, source topics, funding agencies, and the most popular category of remote technologies and solutions for disease rehabilitation. The corpus was extracted from the WOS core database and analyzed using CiteSpace 6.2R7 and VOS Viewer 1.6.18 versions. The number of publications has grown since the start of the 21st century, with the United States, the United Kingdom, and Italy being the most productive nations. The most commonly used remote technology was a 24 h dynamic electrocardiogram (ECG) and ambulatory blood pressure monitoring. The most researched objective indicators were heart rate, blood pressure, and cardiac output. The primary research focused on daily life, physical activity, exercise endurance, and quality of life. Moreover, heart failure and coronary artery disease were the most extensively researched diseases.

Effect of Exercise-Based Cardiac Rehabilitation on Patients With Chronic Heart Failure After Transcatheter Aortic Valve Replacement: A Randomized Controlled Trial

PURPOSE

The objective of this study was to assess the effect of exercise-based cardiac rehabilitation (CR) with individualized exercise prescription in patients with chronic heart failure (HF) undergoing transcatheter aortic valve replacement (TAVR) in a randomized controlled trial.

METHODS

A total of 60 patients with chronic HF who received TAVR treatment were randomly divided into the control group (n = 30) and exercise training (ET) group (n = 30). The control group was treated with conventional rehabilitation, and the ET group was given personalized exercise-based CR based on a cardiopulmonary exercise test (CPX). The CPX parameters, echocardiography, 6-minute walk test distance, and quality of life were evaluated in the two groups.

RESULTS

All patients who completed symptom-restricted CPX showed no complications. After the 12-week rehabilitation period, the levels of anaerobic threshold, peak oxygen uptake, peak oxygen pulse, peak power, left ventricular ejection fraction, and 6-minute walk test distance in the ET group were significantly higher than those in the control group ( P  < .05). Scores on the Minnesota Life with Heart Failure Questionnaire in the ET group were lower than those in the control group ( P < .05).

CONCLUSION

Exercise-based CR significantly improves cardiopulmonary function, exercise tolerance, and quality of life in patients with chronic HF who undergo TAVR.

Cardiopulmonary Exercise Testing in Advanced Heart Failure Management

Cardiopulmonary exercise testing (CPET) permits the assessment of gas exchange, electrocardiogram, and hemodynamic patterns throughout exercise, providing a window into multi-organ physiologic reserve during exercise. CPET provides risk stratification and informs management of advanced heart failure (HF). Increasingly, CPET is combined with echocardiography, or invasive right heart catheterization, which enables high-resolution assessment of cardiac and extracardiac limitations to exercise. CPET also represents a cornerstone in the evaluation process for advanced HF interventions. This review underscores the importance and utility of CPET in managing patients with advanced HF.

Cardiopulmonary Exercise Testing, Rehabilitation, and Exercise Training in Postpulmonary Embolism

Long-term exercise intolerance and functional limitations are common after an episode of acute pulmonary embolism (PE), despite 3 to 6 months of anticoagulation. These persistent symptoms are reported in more than half of the patients with acute PE and are referred as "post-PE syndrome." Although these functional limitations can occur from persistent pulmonary vascular occlusion or pulmonary vascular remodeling, significant deconditioning can be a major contributing factor. Herein, the authors review the role of exercise testing to elucidate the mechanisms of exercise limitations to guide next steps in management and exercise training for musculoskeletal deconditioning.

Chest wall muscle area, ventilatory efficiency and exercise capacity in systemic sclerosis

To investigate the potential contribution of chest wall muscle area (CWMA) to the ventilatory efficiency and exercise capacity in patients with Systemic Sclerosis (SSc) without interstitial lung disease (ILD). Forty-four consecutive SSc patients [F = 37, median age 53.5 years (IQR 43.5-58)] were examined using chest high-resolution computed tomography (HRCT), pulmonary function tests and cardiopulmonary exercise testing (CPET). The CWMA was evaluated at the level of the ninth thoracic vertebra on CT images by two independent evaluators blinded to the patient information. CPET parameters analyzed were maximum oxygen uptake (VO2 max) and VO2 at anaerobic threshold (VO2@AT); minute ventilation (VE); maximum tidal volume (VT). A statistically significant positive correlation was found between CWMA and maximum workload (r = 0.470, p < 0.01), VO2 max ml/min (r = 0.380, p < 0.01), VO2@AT (r = 0.343, p < 0.05), VE (r = 0.308, p < 0.05), VT (r = 0.410, p < 0.01) and VO2/heart rate (r = 0.399, p < 0.01). In multiple regression analysis, VO2 max (ml/min) was significantly associated with CWMA [β coefficient = 5.226 (95% CI 2.824, 7.628); p < 0.001], diffusing capacity for carbon monoxide (DLco) [β coefficient = 6.749 (95% CI 1.460, 12.039); p < 0.05] and body mass index (BMI) [β coefficient = 41.481 (95% CI 8.802, 74.161); p < 0.05]. In multiple regression analysis, maximum workload was significantly associated with CWMA [β coefficient = 0.490 (95% CI 0.289, 0.691); p < 0.001], DLco [β coefficient = 0.645 (95% CI 0.202, 1.088); p < 0.01] and BMI [β coefficient = 3.747 (95% CI 1.013, 6.842); p < 0.01]. In SSc-patients without ILD, CWMA represents an important variable in exercise capacity and can be evaluated by the mediastinal window available in the HRCT images required for lung disease staging.

Utility of Frailty Index in Predicting Adverse Outcomes in Patients With the Same American Society of Anesthesiologists Class in Video-assisted Thoracoscopic Surgery

OBJECTIVES

To investigate the utility of the five-item Modified Frailty Index (MFI-5) as a preoperative risk-stratification tool in video-assisted thoracoscopic surgery (VATS) for patients with the same American Society of Anesthesiologists (ASA) class.

DESIGN

This was a retrospective cohort study utilizing data from The American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) database from 2008 to 2021.

SETTING

The NSQIP includes 685 participating hospitals in all 50 states, the majority being large, academic medical centers.

PARTICIPANTS

All patients undergoing VATS were identified via CPT codes in the deidentified NSQIP dataset. Patients with invalid values for any variables of interest or significant covariates were excluded.

INTERVENTIONS

No interventions were applied to any patients in this retrospective cohort study.

MEASUREMENTS AND MAIN RESULTS

69,145 patients undergoing VATS were included, with the largest number having single lobectomy (32%) or unilateral wedge resection (26%). A total of 1,277 (1.8%) had unplanned reintubation, and 1,155 (1.7%) had ventilator dependence (VentDep) >48 hours after surgery. Of these patients, 66% were ASA class 3. Overall, ASA classification had a stronger correlation with both VentDep rates (adjusted R2 difference: +6.1%) and reintubation rates (adjusted R2 difference: +1.5%) than the MFI-5 score. However, combining ASA class with MFI-5 score was a stronger predictor for both primary outcomes than the ASA class alone (adjusted R2 difference: +1.5%, p < 0.001). The MFI-5 had the strongest correlation with both outcomes among ASA class 3 patients, demonstrating exponentially increasing odds of VentDep and reintubation (MFI 3 v MFI 0: odds ratio = 5.1 [3.7, 7], p = 0.002). MFI-5 also helped classify risk within ASA class 2 patients but not as reliably as for ASA class 3 (ASA class 2 reintubation: increased probability from MFI 0-1 and 1-2; VentDep: increased probability from MFI 0-1 only, p = 0.005).

CONCLUSIONS

The MFI-5 is a comorbidity-based scale that can be calculated preoperatively and considers distinct, but complementary information to the ASA class. Among VATS patients with identical ASA classes 2 and 3, the MFI-5 further stratified risk for reintubation and ventilator dependence >48 hours postsurgery.

High-Intensity Interval Training Programs Versus Moderate-Intensity Continuous Training for Individuals With Heart Failure: A Systematic Review and Meta-analysis

OBJECTIVE

To explore the effect sizes of different high-intensity interval training (HIIT) protocols on cardiorespiratory parameters when compared with moderate-intensity continuous training (MICT) in different heart failure (HF) subtypes.

DATA SOURCES

Electronic databases were searched from their inception date until January 23, 2023.

STUDY SELECTION

Randomized controlled trials (RCTs) were included if they compared HIIT with MICT in patients with HF. The primary outcome was peak oxygen consumption (Vo2peak). Two reviewers independently evaluated 99 initially identified studies, resulting in the selection of 15 RCTs that met the eligibility criteria.

DATA EXTRACTION

Data were extracted independently by 2 observers using a data extraction form drafted based on the CONSORT statement and the Template for Intervention Description and Replication; the methodological quality of the studies was analyzed individually based on the Tool for the Assessment of Study Quality in Exercise scale.

DATA SYNTHESIS

Fifteen RCTs with 553 patients with HF were included in the systematic review. The included studies had moderate to good overall methodological quality. The results showed that HIIT was generally more effective than MICT at improving Vo2peak in patients with HF (n=541, 15 RCTs; MD: 1.49 mL/kg/min; I2=66%; P<.001). However, the effect size varied depending on the HF subtype and HIIT protocol used. For patients with HF with reduced ejection fraction (HFrEF), the long-interval (high-intensity interval lasting ≥4 min) and high-volume HIIT (high-intensity efforts in total ≥15 min) showed the largest benefits over the MICT (n=261, 6 RCTs; MD: 2.11 mL/kg/min; P<.001); followed by the short-interval (≤1 min) and high-volume HIIT (≥15 min; n=71, 3 RCTs; MD: 0.91 mL/kg/min; P=.12), and the short-interval and low-volume HIIT showed the least superiority over MICT (n=68, 3 RCTs; MD: 0.54 mL/kg/min; P=.05). For patients with HF with perceived ejection fraction, there was a modest beneficial effect from HIIT over MICT (n=141, 3 RCTs; MD: 0.55 mL/kg/min; P=.32).

CONCLUSIONS

The long-interval and high-volume HIIT protocol may produce greater benefits than MICT for improving cardiopulmonary fitness in patients with HFrEF. Further research is needed to determine the optimal HIIT protocol for different HF subtypes and to provide definitive recommendations for clinical practice.

The Usefulness of Soluble ST2 Concentration in Heart Failure with Reduced Ejection Fraction to Predict Severe Impairment in Exercise Capacity Assessed in Cardiopulmonary Exercise Testing

Background/Objectives: Heart failure (HF) constitutes a complex clinical syndrome that is highly prevalent worldwide, comprises a serious prognosis, and results in a reduced quality of life. Exercise capacity is one of the most significant parameters involved in the prognosis in HF patients. Our objective was to evaluate the relationship between the selected cardiopulmonary exercise testing (CPET) parameters and the concentration of novel biomarker sST2 in a group of patients with heart failure with reduced ejection fraction (HFrEF). Methods: A group of 135 patients with HFrEF was enrolled in this prospective cohort study. Patients were in the stable phase of the disease in the prior 4 weeks and received optimal medical treatment. Clinical and biochemical parameters were investigated. All patients performed maximal CPET. Results: The mean (SD) concentration of sST2 was 45.5 ± 39.2 ng/mL. Based on the CPET results, the cut-off value (52.377 ng/mL) was established, optimal for the discrimination of relative peakVO2 < 12 mL/kg/min. Patients were divided into two groups according to sST2 cut-off values determined with an ROC curve (AUC 0.692, 95% CI: 0.567-0.816). The mean relative peakVO2 in patients with higher sST2 was 14.5 ± 4.6 mL/kg/min, while in the second group, it was 17.6 ± 5.2 (p = 0.002). In the sST2 ≥ 52.377 ng/mL group, 55.6% of patients achieved VO2 < 50%. Subjects with lower sST2 values obtained higher values of PETCO2 (p < 0.001) and higher values of pulse O2 (p = 0.01). VE/VCO2slope (p = 0.002) was higher in patients with increased sST2 concentration. Conclusions: The concentration of sST2 protein is substantially associated with the clinical severity of heart failure with reduced left ventricular ejection fraction assessed by functional capacity through CPET.

Impairment of Cardiovascular Functional Capacity in Mild-to-Moderate Kidney Dysfunction

Key Points

Mild-to-moderate CKD is associated with impairment in cardiovascular functional capacity as assessed by oxygen uptake at peak exercise (VO2Peak). Cardiac output is significantly reduced in patients with mild-to-moderate CKD and is associated with impaired VO2Peak. Assessment of VO2Peak by cardiopulmonary exercise testing can detect decrements in cardiovascular function during early stages of kidney function decline that may not be captured using resting left ventricular geometric indices alone.

Background

Traditional diagnostic tools that assess resting cardiac function and structure fail to accurately reflect cardiovascular alterations in patients with CKD. This study sought to determine whether multidimensional exercise response patterns related to cardiovascular functional capacity can detect abnormalities in mild-to-moderate CKD.

Methods

In a cross-sectional study, we examined 3075 participants from the Framingham Heart Study (FHS) and 451 participants from the Massachusetts General Hospital Exercise Study (MGH-ExS) who underwent cardiopulmonary exercise testing. Participants were stratified by eGFR: eGFR ≥90, eGFR 60–89, and eGFR 30–59. Our primary outcomes of interest were peak oxygen uptake (VO2Peak), VO2 at anaerobic threshold (VO2AT), and ratio of minute ventilation to carbon dioxide production (VE/VCO2). Multiple linear regression models were fitted to evaluate the associations between eGFR group and each outcome variable adjusted for covariates.

Results

In the FHS cohort, 1712 participants (56%) had an eGFR ≥90 ml/min per 1.73 m2, 1271 (41%) had an eGFR of 60–89 ml/min per 1.73 m2, and 92 (3%) had an eGFR of 30–59 ml/min per 1.73 m2. In the MGH-ExS cohort, 247 participants (55%) had an eGFR ≥90 ml/min per 1.73 m2, 154 (34%) had an eGFR of 60–89 ml/min per 1.73 m2, and 50 (11%) had an eGFR of 30–59 ml/min per 1.73 m2. In FHS, VO2Peak and VO2AT were incrementally impaired with declining kidney function (P < 0.001); however, this pattern was attenuated after adjustment for age. Percent-predicted VO2Peak at AT was higher in the lower eGFR groups (P < 0.001). In MGH-ExS, VO2Peak and VO2AT were incrementally impaired with declining kidney function in unadjusted and adjusted models (P < 0.05). VO2Peak was associated with eGFR (P < 0.05) in all models even after adjusting for age. On further mechanistic analysis, we directly measured cardiac output (CO) at peak exercise by right heart catheterization and found impaired CO in the lower eGFR groups (P ≤ 0.007).

Conclusions

Cardiopulmonary exercise testing–derived indices may detect impairment in cardiovascular functional capacity and track CO declines in mild-to-moderate CKD.

Functional Capacity Assessment in Adults After Fontan Palliation: A Cardiopulmonary Exercise Test-Invasive Exercise Hemodynamics Correlation Study

Although cardiopulmonary exercise testing (CPET) parameters have known prognostic value in adults after Fontan palliation, there are limited data correlating treadmill CPET with invasive exercise hemodynamics. Furthermore, the invasive hemodynamic underpinnings of exercise limitations have not been thoroughly investigated. This is a retrospective analysis of 55 adults (age ≥18 years) with prior Fontan palliation who underwent treadmill CPET before invasive exercise hemodynamic testing using a supine cycle protocol between November 2018 and April 2023. The median age was 32.2 (IQR 24.1; 37.2) years. The peak heart rate (HR) was 139.7 ± 28.1 beats per minute and the peak oxygen consumption (VO2) was 19.1 ± 5.7 ml/kg/min (47.4 ± 13.5% predicted). VO2/HR was directly related to exercise stroke volume index (r = 0.50, p = 0.0002), whereas no association was seen with exercise arterio-mixed venous O2 content difference (r = 0.14, p = 0.32). Peak HR was inversely related to exercise pulmonary artery (PA) pressures (r = -0.61, p <0.0001) and PA wedge pressures (PAWP) (r = -0.61, p <0.0001). Moreover, %predicted VO2 was inversely related to exercise PA pressures (r = -0.50, p <0.0001) and PAWP (r = -0.55, p <0.0001). Peak VO2 ≤19.1 ml/kg/min had a sensitivity of 81% and a specificity of 76% (area under the curve 0.82) for predicting a ΔPAWP/ΔQs ratio >2 mmHg/L/min and/or a ΔPA/ΔQp >3 mmHg/L/min, whereas a predicted peak VO2 ≤48% had a sensitivity of 74% and a specificity of 81% (area under the curve 0.79) for the same parameters. In summary, lower peak HR and peak VO2 were associated with higher exercise PAWP and PA pressure. Peak VO2 ≤48% predicted provided the optimal cutoff for predicting increased indexed exercise PAWP or PA pressures; therefore, low peak VO2 should alert clinicians of abnormal underlying hemodynamics.

Advancing Cardiac Amyloidosis Care Through Insights from Cardiopulmonary Exercise Testing

Cardiac amyloidosis, encompassing both transthyretin (ATTR) and light-chain (AL) types, poses considerable challenges in patient management due to its intricate pathophysiology and progressive course. This narrative review elucidates the pivotal role of cardiopulmonary exercise testing (CPET) in the assessment of these patients. CPET is essential for evaluating disease progression by measuring cardio-respiratory performance and providing prognostic insights. This functional test is crucial not only for tracking the disease trajectory, but also for assessing the effectiveness of disease-modifying therapies. Moreover, CPET facilitates the customization of therapeutic strategies based on individual patient performance, enhancing personalized care. By objectively measuring parameters such as peak oxygen uptake (VO2 peak), ventilatory efficiency, and exercise capacity, clinicians can gain a deeper understanding of the degree of functional impairment and make informed decisions regarding treatment initiation, adjustment, and anticipated outcomes. This review emphasizes the importance of CPET in advancing personalized medicine approaches, ultimately striving to improve the quality of life and clinical outcomes for patients with cardiac amyloidosis.

Prognostic value of heart rate and oxygen pulse response in heart failure with left ventricular ejection fraction over 40

BACKGROUNDS

Heart rate (HR) and stroke volume (SV)-the components of cardiac output-have a complementary relationship. Poor HR increase during exercise is associated with poor exercise tolerance in heart failure (HF) with preserved ejection fraction (HFpEF), but its prognostic impact remains unclear. Furthermore, whether the compensation for poor HR increase with SV during exercise is associated with prognosis remains unknown.

METHODS

We evaluated 129 consecutive hospitalized HF patients with sinus rhythm and left ventricular ejection fractions > 40% who underwent cardiopulmonary exercise testing before discharge from the index hospitalization.

RESULTS

Patients (age: 66 [55-74] years; 73% male) were divided into four groups by median HR reserve (HRR; peak-rest HR: 34 bpm) and O2 pulse, a surrogate for SV, reserve (peak-rest O2 pulse: 4.8 mL/beat). During a mean follow-up of 562 [294-961] days, cardiovascular events (cardiovascular death and/or HF rehospitalizations) occurred in 24 patients. Kaplan-Meier analysis identified significant differences in outcomes among the four groups (χ2 = 27.3, p < 0.001). Using the preserved HRR/preserved O2 pulse reserve group (n = 33) as a reference, the impaired HRR/impaired O2 pulse reserve group (n = 37) was associated with poor outcomes (adjusted hazard ratio: 5.66, 95% CI 1.15-27.74, p = 0.033), whereas the impaired HRR/preserved O2 pulse reserve group (n = 31) was not (adjusted hazard ratio: 0.38, 95% CI 0.03 to 4.76, p = 0.455).

CONCLUSION

The overlap of lower increases in HR and O2 pulse, a surrogate for SV, during exercise was associated with an extremely poor prognosis in HFpEF.

Minute Ventilation/Carbon Dioxide Production Slope Could Predict Short- and Long-Term Prognosis of Patients After Acute Decompensated Heart Failure

(1) Background: Heart failure (HF) leads to functional disability and major cardiovascular events (MACEs). Cardiopulmonary exercise testing (CPET) is the gold standard for assessing aerobic capacity and prognostic stratification. This study aimed to evaluate the predischarge CPET variables in patients with acute decompensated HF and identify the submaximal CPET variables with prognostic value. (2) Methods: A retrospective cohort study was conducted at a tertiary center in Taiwan. Patients surviving their first episode of decompensated HF and undergoing predischarge CPET (February 2017 to January 2023) were analyzed. Follow-up was conducted until a MACE or administrative censoring (up to 5 years). Cox regression identified the significant predictors of MACE. (3) Results: The study included 553, 485, and 267 patients at the 3-month, 1-year, and 5-year follow-ups, respectively. MACE rates were 15.0%, 34.2%, and 50.9%. The VE/VCO2 slope was a significant predictor of MACE at all intervals. A VE/VCO2 slope >38.95 increased the risk of MACE by 2.49-fold at 3 months and 1.81-fold at 1 year (both p < 0.001). A slope > 37.35 increased the 5-year MACE risk by 1.75-fold (p = 0.002). (4) Conclusions: The VE/VCO2 slope is a significant submaximal CPET predictor of MACE in patients post-acute decompensated HF for both short- and long-term outcomes.

Impact of right ventricular function on cardiopulmonary exercise capacity in mitral regurgitation patients undergoing transcatheter mitral valve intervention

OBJECTIVE

Transcatheter mitral valve interventions (TMVI) have been proven to reduce symptom burden and improve outcomes in patients with severe mitral regurgitation (MR). However, the impact of right ventricular function (RVF) on exercise capacity in MR patients is less well understood.

METHODS

Cardiopulmonary exercise testing (CPET) is the most comprehensive approach to assess maximum exercise capacity. Submaximal exercise capacity (SEC), assessed by constant work rate exercise time testing (CWRET), is presumed to be relevant in daily life activities and gives a more differentiated physiological insight into the nature of exercise intolerance. Thus, 28 MR patients underwent CPET and CWRET (at 75% of the maximum work rate in the initial incremental exercise test) prior to TMVI and 3 months post-procedurally.

RESULTS

Patients' mean age was 75.0 ± 8.7 years and 32.1% were female. One patient presented with an MR reduction of less than two grades. RVF was at least moderately impaired in 25% of the patients. SEC of these patients was lower but did not significantly differ (416.4s ± 359.6 vs. 296.1 ± 216.5s; p=) from patients without RVF-deterioration. At follow-up, the SEC improved significantly (from 337.4 ± 262.2s to 517.4 ± 393.5s; p = 0.006). Maximum oxygen uptake (peakVO2) showed a positive trend, but no statistically significant difference (10.3 ± 3.1 ml/min/kg vs. 11.3 ± 3.4 ml/min/kg; p = 0.06). RVF improved in 35.7% of the patients and these patients showed a significantly higher SEC increase (471.7 ± 153.9s vs. 82.7 ± 47.0s, p = 0.003).

CONCLUSION

SEC is significantly increased in MR patients undergoing TMVI, reflecting an improvement, especially regarding daily life activities. This may be related to TMVIś beneficial effect on right ventricular remodeling.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Cardiopulmonary exercise testing following acute pulmonary embolism: Systematic review and pooled analysis of global studies

Recent reports have revealed a substantial morbidity burden associated with "post-PE syndrome" (PPES). Cardiopulmonary exercise testing (CPET) has shown promise in better characterizing these patients. In this systematic review and pooled analysis, we aim to use CPET data from PE survivors to understand PPES better. A literature search was conducted in PubMed, EMBASE, and Cochrane for studies reporting CPET results in post-PE patients without known pulmonary hypertension published before August 1, 2023. Studies were independently reviewed by two authors. CPET findings were subcategorized into (1) exercise capacity (percent predicted pVO2 and pVO2) and (2) ventilatory efficiency (VE/VCO2 slope and VD/VT). We identified 14 studies (n = 804), 9 prospective observational studies, 4 prospective case-control studies, and 1 randomized trial. Pooled analysis demonstrated a weighted mean percent predicted pVO2 of 76.09 ± 20.21% (n = 184), with no difference between patients tested <6 months (n = 76, 81.69±26.06%) compared to ≥6 months post-acute PE (n = 88, 82.55 ± 21.47%; p = 0.817). No difference was seen in pVO2 in those tested <6 months (n = 76, 1.67 ± 0.51 L/min) compared to ≥6 months post-acute PE occurrence (n = 144, 1.75 ± 0.57 L/min; p = 0.306). The weighted mean VE/VCO2 slope was 32.72 ± 6.02 (n = 244), with a significant difference noted between those tested <6 months (n = 91, 36.52 ± 6.64) compared to ≥6 months post-acute PE (n = 191, 31.99 ± 5.7; p < 0.001). In conclusion, this study, which was limited by small sample sizes and few multicenter studies, found no significant difference in exercise capacity between individuals tested <6 months versus ≥6 months after acute PE. However, ventilatory efficiency was significantly improved in patients undergoing CPET ≥ 6 months compared to those <6 months from the index PE.

Exercise as a modality to improve heart transplantation-related functional impairments: An article review

Heart transplantation (HT), the treatment choice of advanced heart failure patients, is proven effective in increasing the survival and functional status of the recipients. However, compared to normal controls, functional status is lower in HT recipients. Exercise given in cardiac rehabilitation has been shown to improve exercise capacity as measured with peak oxygen uptake (VO2 peak) and muscle strength after completion of the program and cessation of exercise results in loss of exercise benefits. Several factors related to cardiac denervation and the use of immunosuppressive agents in HT recipients result in functional impairments including cardiovascular, pulmonary, exercise capacity, psychological, and quality of life (QoL) problems. High-intensity interval training (HIIT) is the most common type of exercise used in HT recipients and given as a hospital-based program. Improvement of functional impairments was found to have occurred due to primarily musculoskeletal adaptations through improvement of muscle structure and aerobic capacity and cardiovascular adaptations. In general, exercise given after transplantation improved VO2 peak significantly and improvement was better in the HIIT group compared to moderate intensity continuous training or no-exercise groups. Improvement of QoL was ascribed to improvement of exercise capacity, symptoms, pulmonary function, physical capacity improvement, anxiety, and depression.

Predicting impaired cardiopulmonary exercise capacity in patients with atrial fibrillation using a simple echocardiographic marker

BACKGROUND

Exercise intolerance is a common symptom associated with atrial fibrillation (AF). However, echocardiographic markers that can predict impaired exercise capacity are lacking.

OBJECTIVE

This study aimed to investigate the association between echocardiographic parameters and exercise capacity assessed by cardiopulmonary exercise testing in patients with AF.

METHODS

This single-center prospective study enrolled patients with AF who underwent echocardiography and cardiopulmonary exercise testing to evaluate exercise capacity at a tertiary center for AF management from 2020 to 2022. Patients with valvular heart disease, reduced left ventricular ejection fraction, or documented cardiomyopathy were excluded.

RESULTS

Of the 188 patients, 134 (71.2%) exhibited impaired exercise capacity (peak oxygen consumption ≤85%), including 4 (2.1%) having poor exercise capacity (peak oxygen consumption <50%). Echocardiographic findings revealed that these patients had an enlarged left atrial end-systolic diameter (LA); smaller left ventricular end-diastolic diameter (LVEDD); and increased relative wall thickness, tricuspid regurgitation velocity, and LA/LVEDD and E/e' ratios. In addition, they exhibited lower peak systolic velocity of the mitral annulus and LA reservoir strain. In the multivariate regression model, LA/LVEDD remained the only significant echocardiographic parameter after adjustment for age, sex, and body mass index (P = .020). This significance persisted even after incorporation of heart rate reserve, N-terminal pro-B-type natriuretic peptide level, and beta-blocker use into the model.

CONCLUSION

In patients with AF, LA/LVEDD is strongly associated with exercise capacity. Further follow-up and validation are necessary to clarify its clinical implications in patient care.

Left ventricular global longitudinal strain and cardiorespiratory fitness in patients with heart failure: Systematic review and meta-analysis

BACKGROUND

There is no definition for strain deformation values in relation to cardiorespiratory fitness (CRF) in different heart failure (HF) phenotypes.

AIM

To identify the relationship between echocardiographic systolic function measurements and CRF in HF patients.

METHODS

Systematic review and meta-analysis following the PRISMA recommendations. Studies reporting echocardiographic assessments of left ventricular global longitudinal strain (LVGLS), left ventricular ejection fraction (LVEF), and direct measurement of peak oxygen uptake (VO2peak) in HF patients with reduced or preserved LVEF (HFrEF, HFpEF) were included. The patients were divided into Weber classes according to VO2peak.

RESULTS

A total of 25 studies involving of 2,136 patients (70.5% with HFpEF) were included. Mean LVEF and LVGLS were similar in HFpEF patients in Weber Class A/B and Class C/D. In HFrEF patients, a non-significant difference was found in LVEF between Weber Class A/B (30.2% [95%CI: 29.6 to 30.9%]) and Class C/D (25.2% [95%CI: 20.5 to 29.9%]). In HFrEF patients, mean LVGLS was significantly lower in Class C/D compared to Class A/B (6.5% [95%CI: 6.0 to 7.1%] and 10.3% [95%CI: 9.0 to 11.5%], respectively). The correlation between VO2peak and LVGLS (r2 = 0.245) was nearly twofold stronger than that between VO2peak and LVEF (r2 = 0.137).

CONCLUSIONS

Low LVGLS values were associated with low CRF in HFrEF patients. Although a weak correlation was found between systolic function at rest and CRF, the correlation between VO2peak and LVGLS was nearly twofold stronger than that with LVEF, indicating that LVGLS may be a better predictor of CRF in patients with HFrEF.

Percent Predicted Peak Exercise Oxygen Pulse Provides Insights Into Ventricular-Vascular Response and Prognosticates HFpEF

Background

Peak oxygen consumption and oxygen pulse along with their respective percent predicted measures are gold standards of exercise capacity. To date, no studies have investigated the relationship between percent predicted peak oxygen pulse (%PredO2P) and ventricular-vascular response (VVR) and the association of %PredO2P with all-cause mortality in heart failure with preserved ejection fraction (HFpEF) patients.

Objectives

The authors investigated the association between: 1) CPET measures of %PredO2P and VVR; and 2) %PredO2P and all-cause mortality in HFpEF patients.

Methods

Our cohort of 154 HFpEF patients underwent invasive CPET and were grouped into %PredO2P tertiles. The association between percent predicted Fick components and markers of VVR (ie, proportionate pulse pressure, effective arterial elastance) was determined with correlation analysis. The Cox proportional hazards model was used to identify predictors of mortality.

Results

The participants' mean age was 57 ± 15 years. Higher %PredO2P correlated with higher exercise capacity. In terms of VVR, higher %PredO2P correlated with a lower pressure for a given preload (effective arterial elastance r = -0.45, P < 0.001 and proportionate pulse pressure r = -0.22, P = 0.008). %PredO2P distinguished normal and abnormal percent predicted peak stroke volume and correlated positively with %PredVO2 (r = 0.61, P < 0.001). Participants had a median follow-up time of 5.6 years and 15% death. Adjusted for age and body mass index, there was a 5% relative reduction in mortality (HR: 0.95, 95% CI: 0.92-0.98, P = 0.003) for every percent increase in %PredO2P.

Conclusions

In HFpEF, %PredO2P is a VVR marker that can stratify invasive parameters such as percent predicted peak stroke volume. %PredO2P is an independent prognostic marker for all-cause mortality and those with higher %PredO2P exhibited longer survival.

CA125 outperforms NT-proBNP in the prediction of maximum aerobic capacity in heart failure with preserved ejection fraction and kidney dysfunction

Background

Heart failure with preserved ejection fraction (HFpEF) often coexists with chronic kidney disease (CKD). Exercise intolerance is a major determinant of quality of life and morbidity in both scenarios. We aimed to evaluate the associations between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and carbohydrate antigen 125 (CA125) with maximal aerobic capacity (peak VO2) in ambulatory HFpEF and whether these associations were influenced by kidney function.

Methods

This single-centre study prospectively enrolled 133 patients with HFpEF who performed maximal cardiopulmonary exercise testing. Patients were stratified across estimated glomerular filtration rate (eGFR) categories (<60 ml/min/1.73 m2 versus ≥60 ml/min/1.73 m2).

Results

The mean age of the sample was 73.2 ± 10.5 years and 56.4% were female. The median of peak VO2 was 11.0 ml/kg/min (interquartile range 9.0-13.0). A total of 67 (50.4%) patients had an eGFR <60 ml/min/1.73 m2. Those patients had higher levels of NT-proBNP and lower peak VO2, without differences in CA125. In the whole sample, NT-proBNP and CA125 were inversely correlated with peak VO2 (r = -0.43, P < .001 and r = -0.22, P = .010, respectively). After multivariate analysis, we found a differential association between NT-proBNP and peak VO2 across eGFR strata (P for interaction = .045). In patients with an eGFR ≥60 ml/min/1.73 m2, higher NT-proBNP identified patients with poorer maximal functional capacity. In individuals with eGFR <60 ml/min/1.73 m2, NT-proBNP was not significantly associated with peak VO2 [β = 0.02 (95% confidence interval -0.19-0.23), P = .834]. Higher CA125 was linear and significantly associated with worse functional capacity without evidence of heterogeneity across eGFR strata (P for interaction = .620).

Conclusions

In patients with stable HFpEF, NT-proBNP was not associated with maximal functional capacity when CKD was present. CA125 emerged as a useful biomarker for estimating effort intolerance in HFpEF irrespective of the presence of CKD.

Development of a Pediatric Cardiology Cardiopulmonary Exercise Testing Database

Cardiopulmonary exercise testing (CPET) provides clinicians with information vital to the management of pediatric cardiology patients. CPET can also be used to measure cardiorespiratory fitness (CRF) in these patients. CRF is a robust marker of overall health in children. However, a complete understanding of CRF in pediatric cardiology patients is limited by lack of large, standardized CPET databases. Our purpose was to develop a standardized CPET database, describe available data at our institution, and discuss challenges and opportunities associated with this project. CPETs performed from 1993 to present in an urban pediatric hospital were collected and compiled into a research database. Historical data included demographic and clinical variables and CPET outcomes, and additional variables were calculated and coded to facilitate analyses in these cohorts. Patient diagnoses were coded to facilitate sub-analyses of specific cohorts. Quality assurance protocols were established to ensure future database contributions and promote inter-institutional collaborations. This database includes 10,319 CPETs (56.1% male), predominantly using the Bruce Protocol. Patients ranging from ages 6 to 18 years comprise 86.8% of available CPETs. Diagnosis classification scheme includes patients with structurally normal hearts (n = 3,454), congenital heart disease (n = 3,614), electrophysiological abnormalities (n = 2,082), heart transplant or cardiomyopathy (n = 833), and other diagnoses (n = 336). Historically, clinicians were provided with suboptimal interpretive resources for CPET, often generalizing inferences from these resources to non-representative clinical populations. This database supports representative CRF comparisons and establishes a framework for future CRF-based registries in pediatric patients referred for CPET, ultimately improving clinical decision-making regarding fitness in these populations.

The 30-second chair stand test (CS30) as a predictor of exercise tolerance in elderly individuals (≥75 years) with stage A/B heart failure

Background

In Japan, the number of very elderly individuals with heart failure (HF) is on the rise. One indicator of HF stage progression is a decrease in exercise tolerance (ET). While peak oxygen uptake (peak VO₂) determined by cardiopulmonary exercise testing (CPX) is the gold standard for ET assessment, the wide-scale applicability of CPX is constrained owing to expensive equipment and challenges in this population. The 30-second chair stand test (CS30), a simple and quick alternative, is widely used among community-dwelling elderly individuals. The objective of this study was to investigate whether CS30 is a predictor of ET in elderly individuals with stage A/B HF.

Methods

Of 748 outpatients aged 75 years and over who visited our center between March 2021 and December 2022, 493 patients (296 males and 197 females) were included in this study. CS30 was measured using a seat height of 40 cm, and peak VO₂ was assessed using CPX.

Results

The findings showed a statistically significant positive association between CS30 and peak VO₂ for both males and females (males: β = 0.255, 95 % CI = 0.102-0.407; females: β = 0.282, 95 % CI = 0.043-0.521). Receiver operating characteristic (ROC) analyses showed moderate accuracy of CS30 in predicting low ET in both sexes (males AUC = 0.740, 95 % CI = 0.640-0.841, p < 0.001; females AUC = 0.725, 95 % CI = 0.644-0.807, p < 0.001). The cut-off values of CS30 were established as 18 times for males and 16 times for females.

Conclusions

CS30 is a potentially convenient method for estimating current ET in older adults, providing a feasible alternative to CPX.

Feasibility of a Novel Augmented 6-Minute Incremental Step Test: A Simplified Cardiorespiratory Fitness Assessment Tool

Background

The cardiopulmonary exercise test (CPET) is considered a gold standard in assessing cardiorespiratory fitness (CRF) but has limited accessibility due to competency requirements and cost. Incorporating portable sensor devices into a simple bedside test of CRF could improve diagnostic and prognostic value.

Objectives

The authors sought to evaluate the association of an augmented 6-minute incremental step test (6MIST) with standard CPET.

Methods

We enrolled patients undergoing clinically indicated supine cycle ergometry CPET with invasive hemodynamics (iCPET) for the same-day 6MIST. CRF-related variables were simultaneously recorded using a signal morphology-based impedance cardiograph (PhysioFlow Enduro) and a portable metabolic analyzer (VO2 Master Pro) during incremental pace stationary stepping. The correlation between CPET and hemodynamic parameters from both tests was assessed using the intraclass correlation coefficient (ICC).

Results

Fifteen patients (mean age 60 ± 14 years, 40% female, 27% Black) were included. All patients who agreed to undergo 6MIST completed the study without any test-related adverse events. We observed good to excellent correlation between iCPET- and 6MIST-measured CPET parameters: peak heart rate (ICC = 0.60; 95% CI: 0.15-0.85), absolute peak O2 consumption (VO2) (ICC = 0.77; 95% CI: 0.44-0.92), relative peak VO2 (ICC = 0.64; 95% CI: 0.20-0.86), maximum ventilation (ICC = 0.59; 95% CI: 0.13-0.84), O2 pulse (ICC = 0.71; 95% CI: 0.33-0.89), and cardiorespiratory optimal point (ICC = 0.82; 95% CI: 0.52-0.94). No significant correlation was determined between iCPET and 6MIST in measuring cardiac index at rest (ICC = 0.19; 95% CI: -0.34 to 0.63) or at peak exercise (ICC = 0.36; 95% CI: -0.17 to 0.73).

Conclusions

We demonstrate the feasibility of a novel augmented 6MIST with wearable devices for simultaneous CPET and hemodynamic assessment. 6MIST-measured CPET parameters were strongly correlated with the iCPET-derived measurements. Additional studies are needed to confirm the validity of the 6MIST compared to standard upright CPET.

Estimation of ventilatory thresholds during exercise using respiratory wearable sensors

Ventilatory thresholds (VTs) are key physiological parameters used to evaluate physical performance and determine aerobic and anaerobic transitions during exercise. Current assessment of these parameters requires ergospirometry, limiting evaluation to laboratory or clinical settings. In this work, we introduce a wearable respiratory system that continuously tracks breathing during exercise and estimates VTs during ramp tests. We validate the respiratory rate and VTs predictions in 17 healthy adults using ergospirometry analysis. In addition, we use the wearable system to evaluate VTs in 107 recreational athletes during ramp tests outside the laboratory and show that the mean population values agree with physiological variables traditionally used to exercise prescription. We envision that respiratory wearables can be useful in determining aerobic and anaerobic parameters with promising applications in health telemonitoring and human performance.

Effect of Left Ventricular Diastolic Dysfunction on the Cardiopulmonary Exercise Test in Patients With Cardiovascular Disease

Left ventricular diastolic dysfunction exists in patients with heart failure with reduced ejection fraction and causes activity restriction and a poor prognosis, but there have been few reports about exercise tolerance in patients with diastolic dysfunction, regardless of left ventricular ejection fraction (LVEF). In this study, 294 cardiovascular disease patients who performed a cardiopulmonary exercise test (CPX) with an adequate examination by echocardiography at Fukuoka University Hospital from 2011 to 2020 were investigated. Patients were divided into groups with grade I and grade II or III diastolic dysfunction according to diagnostic criteria, regardless of LVEF, by echocardiography. After adjusting for age, gender, body mass index, smoking, and LVEF by propensity score matching, we compared the results of CPX between the grade I and grade II/III groups. There were no significant differences in hemodynamic parameters, or in the respiratory exchange ratio, oxygen uptake per body weight, oxygen uptake per heart rate, or parameters of ventilatory volume. Ventilatory equivalents per oxygen uptake and per carbon dioxide output were significantly worse in the grade II/III group from the rest to peak periods during CPX. In conclusion, left ventricular diastolic dysfunction worsens ventilatory efficacy during CPX. This effect potentially contributes to a poor prognosis in left ventricular diastolic dysfunction.

Association of Sarcopenia and Oxygen Uptake Efficiency Slope in Male Patients With Heart Failure

PURPOSE

Sarcopenia, the loss of muscle mass and function, is a common comorbidity in patients with heart failure (HF). The skeletal muscle modulates the respiratory response during exercise. However, whether ventilatory behavior is affected by sarcopenia is still unknown.

METHODS

We enrolled 169 male patients with HF. Muscle strength was measured by a handgrip dynamometer. Body composition was measured with dual-energy X-ray absorptiometry. Sarcopenia was defined by handgrip strength <27 kg and appendicular lean mass divided by height squared (ALM/height 2 ) <7.0 kg/m 2 . Oxygen uptake efficiency slope (OUES), ventilation (VE), oxygen uptake (VO 2 ), and carbon dioxide output (VCO 2 ) were measured by a cardiopulmonary exercise test.

RESULTS

Sarcopenia was identified in 29 patients (17%). At the first ventilatory threshold, VE/VO 2 (36.9 ± 5.9 vs 32.7 ± 6.5; P = .003) and VE/VCO 2 (39.8 ± 7.2 vs 35.3 ± 6.9; P = .004) were higher in patients with sarcopenia compared to those without sarcopenia. At the exercise peak, compared to patients without sarcopenia, patients with sarcopenia had lower OUES (1186 ± 295 vs 1634 ± 564; P < .001), relative VO 2 (16.2 ± 5.0 vs 19.5 ± 6.5 mL/kg/min; P = .01), and VE (47.3 ± 10.1 vs 63.0 ± 18.2 L/min; P < .0001), while VE/VCO 2 (42.9 ± 8.9 vs 38.7 ± 8.4; P = .025) was increased. OUES was positively correlated with ALM/height 2 ( r = 0.36; P < .0001) and handgrip strength ( r = 0.31; P < .001). Hemoglobin (OR = 1.149; 95% CI, 0.842-1.570; P = .038), ALM/height 2 (OR = 2.166; 95% CI, 1.338-3.504; P = .002), and VO 2peak (OR = 1.377; 95% CI, 1.218-1.557; P < .001) were independently associated with OUES adjusted by cofounders.

CONCLUSIONS

Our results suggest that sarcopenia is related to impaired ventilatory response during exercise in patients with HF.

Accuracy of the 6-Minute Walk Test for Assessing Functional Capacity in Patients With Heart Failure With Preserved Ejection Fraction and Other Chronic Cardiac Pathologies: Results of the ExIC-FEp Trial and a Meta-Analysis

BACKGROUND

Heart diseases, particularly heart failure, significantly impact patient quality of life and mortality rates. Functional capacity assessment is vital for predicting prognosis and risk in these patients. While the cardiopulmonary exercise test is considered the gold standard, the 6-minute walk test has emerged as a more accessible alternative. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity in cardiac pathologies, including heart failure with preserved ejection fraction, are unclear. The study aimed to analyse the diagnostic accuracy of the 6-minute walk test for detecting reduced functional capacity, defined as VO2max < 14 ml/kg/min, compared with the cardiopulmonary exercise test in participants with heart failure with preserved ejection fraction using data from the "Ejercicio en Insuficiencia Cardiaca con Fracción de Eyección Preservada" (ExIC-FEp) trial; and to compare these results with previous studies investigating the screening accuracy for assessing functional capacity of the 6-minute walk test in participants with other chronic cardiac pathologies through a meta-analysis.

RESULTS

The ExIC-FEp trial involved 22 participants with heart failure with preserved ejection fraction, who were not treated with beta-blockers, using the cardiopulmonary exercise test, specifically VO2max, as the reference test. The 6-minute walk test had a sensitivity of 70%, a specificity of 80%, and an area under the curve of 76% in the ExIC-FEp trial. Five studies were included in the meta-analysis showing a sensitivity of 79%, a specificity of 78%, and an area under the curve of 85%.

CONCLUSION

In conclusion, the 6-minute walk test holds promise as a screening tool for assessing functional capacity in heart failure with preserved ejection fraction and chronic heart diseases, with a VO2max < 14 ml/kg/min as a reference point. It demonstrates moderate to good screening accuracy. However, the screening accuracy and optimal cut-off points of the 6-minute walk test for detecting severely reduced functional capacity, regardless of aetiology, are unclear.

TRIAL REGISTRATION

NCT05726474. Registered 16 February 2023, https://clinicaltrials.gov/study/NCT05726474 .

Application of the Six-Minute Walk Test in Assessment of the Cardiopulmonary Function of Children With Idiopathic Scoliosis

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

To assess whether the six-minute walk test (6MWT) can predict cardiopulmonary function in children with idiopathic scoliosis (IS) as an alternative to the cardiopulmonary exercise test (CPET).

SUMMARY OF BACKGROUND DATA

Cardiopulmonary functional impairment in the setting of IS is a common health problem. A simple and convenient assessment method is needed.

MATERIALS AND METHODS

We recruited 65 children (eight male, 57 female) aged 10.70 to 14.84 years old with IS. Radiographic characteristics of the cohort were measured, including Risser's sign and Cobb angle. We measured cardiopulmonary exercise tolerance using both the 6MWT and CPET and their corresponding indicators, including six-minute walking distance (6MWD) and peak oxygen uptake (peak VO 2 ), respectively. Pearson correlation analysis was used to determine the relationship between 6MWT indicators and IS parameters. Linear regression models were used to explore the relationship between 6MWT and CPET response indicators.

RESULTS

Over a third of the cohort (35.4%) had a Risser's sign grade of 0, with 21.5% in grade 2 and 3, respectively. The cohort's mean Cobb angle was 26.02°. 6MWD was significantly positively correlated with Risser's sign ( R =0.258; P =0.038) and change in respiratory rate positively correlated with vertebral rotation ( R =0.264; P =0.034). 6MWD positively correlated with peak VO 2 , peak VO 2 /heart rate (HR), and metabolic equivalents, and negatively correlated with the ventilation equivalent of the carbon dioxide slope (VE/VCO 2 slope) ( P <0.05). These four CPET indicators were found to be predicted from 6MWD in the linear regression model ( P <0.05).

CONCLUSIONS

CPET response indicators, especially peak VO 2 , can be predicted using 6MWD, among other factors. The 6MWT can therefore be used to rapidly and efficiently predict the cardiorespiratory tolerance of children with IS.

LEVEL OF EVIDENCE

3.

Clinical Impact of Preoperative Symptoms of Aortic Stenosis on Prognosis After Transcatheter Aortic Valve Replacement

Background: The prognostic significance of different presentations of aortic stenosis (AS) remains unclear. Our aim was to analyze outcomes after transcatheter aortic valve replacement (TAVR) according to preoperative AS symptoms. Methods and Results: We retrospectively enrolled 369 consecutive patients (age 84.3±5.0 years, and 64% females) who underwent TAVR from 2014 to 2021. We divided them into 4 groups by the main preoperative symptom: asymptomatic (n=50), chest pain (n=46), heart failure (HF; n=240), and syncope (n=33). Post-TAVR rates of HF readmission, all-cause death and cardiac death were compared among the 4 groups. The 4 groups showed no significant trends in age, sex, stroke volume index, or echocardiography indices of AS severity. During a follow-up, the overall survival rate at 1 and 5 years after TAVR was 97% and 90% in the asymptomatic group, 96% and 69% in the chest pain group, 93% and 69% in the HF group, and 90% and 72% in the syncope group, respectively. HF and syncope symptom had significantly lower HF readmission or cardiac death-free survival at 5 years after TAVR (log-rank test P=0.038). In the Cox hazard multivariate analysis, preoperative syncope was an independent predictor of future HF readmission or cardiac death after TAVR (HR=9.87; 95% CI 1.67-97.2; P=0.035). Conclusions: AS patients with preoperative syncope or HF had worse outcomes after TAVR than those with angina or no symptoms.