Troponin elevation after radiofrequency catheter ablation of atrial fibrillation: Relevance to AF substrate, procedural outcomes, and reverse structural remodeling

Bilirubin Elevation During Hospitalization Post Radiofrequency Catheter Ablation of Persistent Atrial Fibrillation: Variation Trend, Related Factors, and Relevance to 1-Year Recurrence

Background

The role of total bilirubin (TBIL) in cardiovascular disease has been increasingly recognized in recent decades. Studies have shown a correlation between total bilirubin levels and the prognosis of patients after heart surgery. This study aimed to investigate the clinical significance of bilirubin elevation in persistent atrial fibrillation (PAF) patients who received radiofrequency catheter ablation (RFCA).

Methods and Results

A total of 184 patients with PAF who received RFCA were retrospectively studied. Laboratory examinations and demographic data were analyzed to identify independent predictors of TBIL elevation. The relationship between TBIL and prognosis was further investigated. Our results indicated that TBIL increased significantly after RFCA. Multiple linear regression analysis showed that TBIL elevation owned a negative correlation with the percentile of low voltage areas (LVAs) in left atria (β=-0.490, P<0.001). In contrast, a positive correlation was observed with the white blood cell (WBC) ratio (β=0.153, P=0.042) and left atrial diameter (LAD) (β=0.232, P=0.025). It was found that postoperative TBIL levels increased and then gradually decreased to baseline within 5 days without intervention. The bilirubin ratio <1.211 indicated the possibility of 1-year AF recurrence after ablation with a predictive value of 0.743 (specificity = 75.00%, sensitivity = 66.67%).

Conclusion

Bilirubin elevation post PAF RFCA was a common phenomenon and was associated with 1-year recurrence of AF in PAF patients after RFCA.

The association between the effective apnea-hypopnea index and blood pressure reduction efficacy following CPAP/oxygen treatment

BACKGROUND

The effect of sleep apnea treatment on reducing cardiovascular disease risk remains inconclusive. This study aims to assess if the effective apnea hypopnea index (eAHI), a measure of residual sleep apnea burden post-treatment, is a factor in determining blood pressure (BP) response to continuous positive airway pressure therapy. The eAHI integrates time on therapy, residual apnea, and % of sleep time untreated.

METHODS

A secondary analysis of the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a randomized, controlled, parallel group assessment of continuous positive airway pressure (CPAP), oxygen and sleep hygiene. The Delta-AHI (▲AHI) was defined as the difference between baseline AHI and effective AHI at 12 weeks. Logistic and linear regression models estimated the predictors for nocturnal systolic BP change following sleep apnea therapy.

RESULTS

One hundred and sixty-nine subjects with a mean age of 62.82 ± 6.99 years were included in the final analysis. Fifty subjects had ▲AHI ≤8/hour of sleep and 119 subjects were higher. After adjustment, baseline mean nighttime systolic blood pressure (OR 1.036, 95% CI 1.015-1.058, p: 0.001) and ▲AHI ≥8/hour (OR 2.406, 95% CI 1.116-5.185, p:0.025) were independent predictors for mean nighttime systolic blood pressure change >3 mm Hg. The higher effective AHI was negatively related with BNP (β: -2.564, SE: 1.167, p: 0.029) and positively related with troponin change (β: 0.703, SE: 0.256, p: 0.007).

CONCLUSION

The ▲AHI was an independent predictor of the blood pressure response to sleep apnea treatment.

REGISTER NUMBER

NCT01086800.

Surgical ablation, left atrial appendage occlusion or both? Nationwide registry analysis of cardiac surgery patients with underlying atrial fibrillation

OBJECTIVES

The aim of this study was to evaluate in-hospital outcomes and long-term survival of patients undergoing cardiac surgery with preoperative atrial fibrillation (AF). We compared different strategies, including no-AF treatment, left atrial appendage occlusion (LAAO) alone, concomitant surgical ablation (SA) alone or both.

METHODS

A retrospective analysis using the KROK registry included all patients with preoperative diagnosis of AF who underwent cardiac surgery in Poland between between January 2012 and December 2022. Risk adjustment was performed using regression analysis with inverse probability weighting of propensity scores. We assessed 6-year survival with Cox proportional hazards models. Sensitivity analysis was performed based on index cardiac procedure.

RESULTS

Initially, 42 510 patients with preoperative AF were identified, and, after exclusion, 33 949 included in the final analysis. A total of 1107 (3.26%) received both SA and LAAO, 1484 (4.37%) received LAAO alone, 3921 (11.55%) SA alone and the remaining 27 437 (80.82%) had no AF-directed treatment. As compared to no treatment, all strategies were associated with survival benefit over 6-year follow-up. A gradient of treatment was observed with the highest benefit associated with SA + LAAO followed by SA alone and LAAO alone (log-rank P < 0.001). Mortality benefits were reflected when stratified by surgery type with the exception of aortic valve surgery where LAAO alone fare worse than no treatment.

CONCLUSIONS

Among patients with preoperative AF undergoing cardiac surgery, surgical management of AF, particularly SA + LAAO, was associated with lower 6-year mortality. These findings support the benefits of incorporating SA and LAAO in the management of AF during cardiac surgery.

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Myocardial injury and inflammation following pulsed-field ablation and very high-power short-duration ablation for atrial fibrillation

INTRODUCTION

Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) is an established treatment strategy for atrial fibrillation (AF). To improve PVI efficacy and safety, high-power short-duration (HPSD) ablation and pulsed-field ablation (PFA) were recently introduced into clinical practice. This study aimed to determine the extent of myocardial injury and systemic inflammation following PFA, HPSD, and standard RFA using established biomarkers.

METHODS

We included 179 patients with paroxysmal AF receiving first-time PVI with different ablation technologies: standard RFA (30-40 W/20-30 s, n = 52), power-controlled HPSD (70 W/5-7 s, n = 60), temperature-controlled HPSD (90 W/4 s, n = 32), and PFA (biphasic, bipolar waveform, n = 35). High-sensitivity cardiac troponin T (hs-cTnT), creatine kinase (CK), CK MB isoform (CK-MB), and white blood cell (WBC) count were determined before and after ablation.

RESULTS

Baseline characteristics were well-balanced between groups (age 63.1 ± 10.3 years, 61.5% male). Postablation hs-cTnT release was significantly higher with PFA (1469.3 ± 495.0 ng/L), HPSD-70W (1322.3 ± 510.6 ng/L), and HPSD-90W (1441.2 ± 409.9 ng/L) than with standard RFA (1045.9 ± 369.7 ng/L; p < .001). CK and CK-MB release was increased with PFA by 3.4-fold and 5.8-fold, respectively, as compared to standard RFA (p < .001). PFA was associated with the lowest elevation in WBC (Δ1.5 ± 1.5 × 109 /L), as compared to standard RFA (Δ3.8 ± 2.5 × 109 /L, p < .001), HPSD-70W (Δ2.7 ± 1.7 × 109 /L, p = .037), and HPSD-90W (Δ3.6 ± 2.5 × 109 /L, p < .001).

CONCLUSION

Among the four investigated ablation technologies, PFA was associated with the highest myocardial injury and the lowest inflammatory reaction.

Comparison of myocardial injury and inflammation between ablation index-guided and conventional contact force-guided ablation in atrial fibrillation patients

PURPOSE

Ablation index (AI)-guided ablation improves the incidence of arrhythmia recurrence as compared to conventional contact force (CF)-guided ablation. The aim of this study was to elucidate the differences in the biomarkers associated with myocardial injury and inflammation between conventional CF-guided and AI-guided ablation.

METHODS

Atrial fibrillation (AF) patients who underwent pulmonary vein isolation (PVI) from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry were enrolled. We divided the patients into two groups: conventional CF-guided PVI (CF group) and AI-guided PVI (AI group). The differences in biomarkers associated with myocardial injury and inflammation, and long-term durability of PVI between the two groups were evaluated.

RESULTS

This study population included a total of 794 patients (CF-guided, 241 patients; AI-guided, 553 patients). Total application time was significantly shorter, and total application number was significantly smaller in AI than CF group. High-sensitive troponin I (hs-TnI) post-ablation was significantly higher in AI than CF group (p < 0.001), even after taking the total application number and total application time into consideration. No significant differences in inflammatory markers changes from pre- to post-ablation were observed between the two groups. AI-guided ablation was significantly associated with the hs-TnI post-ablation by multiple regression analysis. The PV reconnection ratio was significantly smaller in AI than CF group (p = 0.037).

CONCLUSIONS

AI-guided ablation had the ability to create larger lesions than CF-guided ablation despite no increase in inflammation and achieved the better PVI durability than that of CF-guided.

The Role of Biochemical Cardiac Markers in Atrial Fibrillation

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Proteins are a component of cardiac biomarkers containing cell structures that are released into the circulation when a myocardial injury occurs. They are essential in the diagnosis, risk assessment, and treatment of patients who have chest pain, are thought to have acute coronary syndrome, or are experiencing acute heart failure exacerbations. There are numerous biochemical cardiac markers, but this article summarizes the basic role of major biochemical cardiac markers, including cardiac natriuretic peptides, cardiac troponins, C-reactive protein (CRP), creatine kinase-MB, heart-type fatty acid-binding protein, ischemia-modified albumin, lipoprotein (a), osteopontin (OPN), and soluble suppression of tumorigenicity 2 (sST2), in AF. Atrial natriuretic peptide may serve as an indicator of atrial integrity, which may help to select appropriate treatment approaches for AF. Higher levels of N-terminal pro-B-type natriuretic peptide and brain natriuretic peptide are predictive of incidental AF. Increased troponin T release may indicate better clinical results following AF ablation. Similarly, CRP increases the risk of the AF-increasing calcium (Ca) influx in atrial myocytes, but not because of atrial fibrosis. Patients with postoperative AF have lower FABP3 gene expression in the atrium. Lipoprotein (a) (Lp[a]) may play a causative role in the onset of AF and impact various cardiac tissues. Clinical trials for Lp(a)-lowering drugs should assess their impact on preventing AF. Also, OPN was highly expressed in the circulation of AF patients and further increased with the progression of AF. sST2 was a reliable predictor of new-onset AF and can improve the accuracy of the AF risk model. There is a greater chance that these cardiac biomarkers might be employed to enhance clinical risk stratification in AF.

Subclinical Dysfunction of Left Atrial Compliance after Cryoballoon versus Radiofrequency Ablation for Paroxysmal Atrial Fibrillation

It has been suggested that cryoballoon (CB) ablation for paroxysmal atrial fibrillation (PAF) may lead to more extensive left atrial (LA) injury than radiofrequency (RF) ablation; however, results are conflicting. We sought to address this issue using modern echocardiographic techniques estimating the LA function after successful CB and RF ablation for PAF. A total of 90 patients (66% males, mean age 57 ± 10 years) successfully treated (no AF recurrences confirmed in serial 4-7 day ECG Holter monitoring) with RF (51%) or CB (49%) ablation for PAF were retrospectively studied. Echocardiography with speckle tracking (STE) was performed before and 12 months after the procedure. The peak longitudinal LA strain (LAS) and strain rate (LASR) during the reservoir (r), conduit (cd), and contraction (ct) phases were measured in sinus rhythm. Analysis of covariance was applied to compare changes in the echocardiographic parameters over time with the baseline measurements as covariance and the type of ablation as the factor. The parallelism of the slopes of the covariance was tested. The LA diameter decreased (38.3 ± 4.1 mm vs. 36.8 ± 3.6 mm, p < 0.001) in the whole study group at 12 months after ablation. The LASRr and LASRcd increased (1.1 ± 0.3 s-¹ vs. 1.3 ± 0.3 s-¹, p < 0.001 and 1.1 ± 0.3 s-¹ vs. 1.2 ± 0.3 s-¹, p < 0.001, respectively) whereas other LA strain parameters remained unchanged in the whole study group at 12 months after ablation. In the analysis of LA function at 12 months after the procedure regarding the mode of ablation, the worsening of parameters reflecting LA compliance was observed in patients with better pre-served baseline values in the CB ablation subgroup. For baseline LAScd >28%, the difference ΔCB - ΔRF was -7.6 (11.7; -3.4), p < 0.001, and for baseline LAScd >16%, ΔCB - ΔRF was -1.8 (-3.2; -0.4), p = 0.014. The traditional Doppler-derived parameter e' showed the same trend-for baseline e' ≥12 cm/s, ΔCB - ΔRF was -1.7 (-2.8; -0.6), p = 0.003. We conclude that worsening of parameters reflecting LA compliance was observed 12 months after CB ablation compared to RF ablation for PAF in patients who underwent a successful procedure and had better-preserved baseline LA function. This might suggest subclinical dysfunction of LA after the CB ablation procedure. The clinical significance of these findings warrants further investigations.

The Atrium in Atrial Fibrillation - A Clinical Review on How to Manage Atrial Fibrotic Substrates

Atrial fibrillation (AF) is the most common sustained arrhythmia in the population and is associated with a significant clinical and economic burden. Rigorous assessment of the presence and degree of an atrial arrhythmic substrate is essential for determining treatment options, predicting long-term success after catheter ablation, and as a substrate critical in the pathophysiology of atrial thrombogenesis. Catheter ablation of AF has developed into an essential rhythm-control strategy. Nowadays is one of the most common cardiac ablation procedures performed worldwide, with its success inversely related to the extent of atrial structural disease. Although atrial substrate evaluation remains complex, several diagnostic resources allow for a more comprehensive assessment and quantification of the extent of left atrial structural remodeling and the presence of atrial fibrosis. In this review, we summarize the current knowledge on the pathophysiology, etiology, and electrophysiological aspects of atrial substrates promoting the development of AF. We also describe the risk factors for its development and how to diagnose its presence using imaging, electrocardiograms, and electroanatomic voltage mapping. Finally, we discuss recent data regarding fibrosis biomarkers that could help diagnose atrial fibrotic substrates.

High-sensitivity Troponin I and Ablation Effectiveness Quotient after Ablation Index-guided pulmonary vein isolation-markers of arrhythmia recurrence?

BACKGROUND

There are conflicting data regarding the relationship between high-sensitivity cardiac Troponin I (Hs-cTnI) and the ablation effectiveness quotient (AEQ) with arrhythmia recurrence following atrial fibrillation (AF) ablation. Our goals were to evaluate the impact of the Ablation Index (AI) software on Hs-cTnI and AEQ levels and to assess whether these markers are predictors of arrhythmia recurrence.

METHODS

Prospective single-center study of 75 consecutive patients referred for paroxysmal AF ablation from October 2017 to January 2019. Procedural endpoints and 2-year outcomes were assessed and compared to those of 75 propensity score-matched patients submitted to non-AI-guided pulmonary vein isolation (PVI) [control group].

RESULTS

Compared to the control group, patients having AI-guided PVI had lower Hs-cTnI values (1580 [IQR 1180-2140] ng/L vs. 2600 [IQR 1840 - 3900], p < 0.001) and a lower AEQ (0.9 [IQR 0.6-1.2] ng/L/s vs. 1.4 [0.8-1.6] ng/L/s, p < 0.001). After a median follow-up of 26 (IQR 20-32) months, there was a significant reduction in arrhythmia recurrence in the AI group (15% vs. 31%, HR 0.67 [95% CI, 0.32-1.40], p = 0.02). However, neither Hs-cTnI nor AEQ was predictors of arrhythmia recurrence in AI-guided PVI.

CONCLUSIONS

The use of the AI software led to reduced levels of Hs-cTnI and lower AEQ in AF patients submitted to PVI. However, none of these markers predicted arrhythmia recurrence.

Catheter Ablation for Hospitalized Atrial Fibrillation Patients with Reduced Systolic Function: Analysis of Inpatient Mortality, Resource Utilization and Complications

Background

Randomized trials have shown improvement in hard clinical end points when catheter ablation (CA) is employed as a management strategy for certain atrial fibrillation (AF) patients with heart failure and reduced ejection fraction (HFrEF). Limited data, however, exist in this realm outside the controlled clinical trial settings. We sought to determine real-world data on mortality and complications after utilization of CA in such patients.

Methods and Results

Data were derived from National Inpatient Sample from January 2008 to August 2015. Patients were identified using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. Baseline characteristics and outcomes were compared among HFrEF and AF patients undergoing CA or not. Propensity matching was done to mitigate selection bias and balance confounding variables. Various CA related complications were assessed. Logistic regression was done to determine predictors of mortality in our study cohort. A total of 2,569,919 patients were analyzed and a total of 7773 patients underwent CA. Mortality was significantly better in CA group in both unmatched (1.2% vs. 4.9%, p < 0.01) and propensity matched cohorts (1.2% vs. 3.6%, p < 0.01). Overall complication rate was 10.2% in CA cohort and primarily driven by cardiac and neurological etiologies. In regression analysis, CA remained a strong predictor of reduced mortality (OR 0.301, 95% CI 0.184-0.494).

Conclusions

CA is associated with improved mortality in admitted AF patients with concomitant HFrEF. Overall complication rate after CA was modest at 10.2%. Consideration can be given to the utilization of this therapeutic modality in hospitalized AF patients with concomitant HFrEF.

Relationship between ablation index and myocardial biomarkers after radiofrequency catheter ablation for atrial fibrillation

Background

Further in-vivo evidence is needed to support the usefulness of ablation index (AI) in guiding atrial fibrillation (AF) ablation. We aimed at evaluating the relationship between AI and other lesion indicators and the release of myocardial-specific biomarkers following radiofrequency AF ablation.

Methods

Forty-six patients underwent a first-time radiofrequency AF ablation and were prospectively enrolled in this study. Pulmonary vein isolation was performed by six experienced electrophysiologists with a point-by-point approach, guided by strict Visitag criteria and consistent AI target values. Myocardial-specific biomarkers troponin T and creatine kinase myocardial band were measured after 6 (TnT6 and CKMB6) and 20 h (TnT20 and CKMB20) following sheath removal. Ablation duration, impedance drop (ID), force-time integral (FTI) and AI were registered automatically and analyzed offline.

Results

TnT release was 985 ± 495 ng/L and 1038 ± 461 ng/L (p = ns) while CKMB release was 7.3 ± 2.7 μg/L and 6.5 ± 2.1 μg/L (p < 0.001) at 6 and 20 h respectively. Ablation duration, ID, FTI and AI were all significantly correlated with the release of myocardial-specific biomarkers both at 6 and 20 h. Ablation index showed the highest degree of correlation with TnT6, TnT20, CKMB6 and CKMB20 (Pearson's R 0.69, 0.69, 0.61, 0.64 respectively, p < 0.001). Multiple regression analysis demonstrated that AI had the strongest association with TnT6, TnT20, CKMB6 and CKMB20 (β 0.43, β 0.71, β 0.44 and β 0.43 respectively).

Conclusion

Ablation index appears as the strongest lesion indicator as measured by the release of myocardial-specific biomarkers following radiofrequency catheter ablation for AF.

Acute myocardial injury after radiofrequency catheter ablation: impact on pulmonary vein reconnection and relevant factors

Radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) causes myocardial injury and induces high-sensitive cardiac troponin I (hs-TnI) release into the systemic circulation. Several factors are considered to be associated with myocardial injury after ablation, but few studies showed the relationship between the value of myocardial injury marker after the RFCA and relevant factors. AF patients who underwent primary RFCA were enrolled from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry. The relationship between hs-TnI after the RFCA and PV reconnection (PVR) was evaluated. The impact of relevant factors, including baseline patient characteristics, detail of procedure on myocardial injury was investigated. This study included 407 patients (median age was 71 years, the ratio of female was 30.7%). Late arrhythmia recurrence was observed in 111 patients (27.3%) and 66 patients were underwent repeated ablation. PVR was observed in 33 patients (50.0%). The hs-TnI level was significantly lower in the patients with PVR than those without PVR (1.150 ng/ml vs 1.921 ng/ml, p = 0.040). Paroxysmal AF and age were significantly associated with acute myocardial injury after the RFCA (standardized beta coefficient = 0.206 and p < 0.001, standardized beta coefficient = - 0.114 and p = 0.043, respectively). The hs-TnI after RFCA was significantly higher in PAF patients than PerAF (p < 0.001), even if application number and total application time were taken into consideration. Acute myocardial injury after RFCA was significantly lower in the patients with PVR than those without PVR. Age and AF type were significantly and strongly associated with acute myocardial injury after the RFCA.

Troponin T Elevation After Percutaneous Left Atrial Appendage Occlusion

Background: Cardiac troponin T (cTNT) has been widely used in detecting cardiac damage. Elevated cTNT level has been reported to be associated with increased mortality in multiple cardiac conditions. It is not uncommon to observe an increased level of cTNT in patients after left atrial appendage occlusion (LAAO). The objective of the study is to study the incidence, significance, and factors associated with cTNT elevation after LAAO.

Methods: We prospectively included patients who underwent LAAO from January 2019 to July 2020 in Fudan Zhongshan Hospital. Patients were divided into those with elevated cTNT after procedure and those with normal postprocedure cTNT. All individuals were followed up for 1 year. The primary outcome is major adverse cardiovascular events, which include myocardial infarction, heart failure, cardiac death, and stroke. The second outcome is periprocedure complication, including chest pain, tachycardia, cardiac tamponade, change of electrocardiograph, and atrial thrombus.

Results: A total of 190 patients were enrolled. Of the patients, 85.3% had elevated cTNT after LAAO, while 14.7% of them did not. Exposure time, dosage of contrast, types of devices, shapes, and sizes of LAA could contribute to elevated postprocedure cTNT. We found that patients with a Watchman device were more likely to have elevated postprocedure cTNT than those with a Lambre device (89.2 vs. 76.7%, p = 0.029). LAAO shapes were associated with cTNT levels in patients with a Watchman device, while the diameter of the outer disc and LAA depth mattered for the Lambre device. There was no significant difference in the primary and second outcome between the two groups (p-value: 0.619, 0.674).

Conclusion: LAAO was found to be commonly accompanied with cTNT elevation, which might not to be related to the complications and adverse cardiac outcomes within 1 year of follow-up. Moreover, eGFR at baseline, exposure time, dosage of contrast, types of LAAO device, and LAA morphology could contribute to cTNT elevation.

The Blinding Period Following Ablation Therapy for Atrial Fibrillation: Proarrhythmic and Antiarrhythmic Pathophysiological Mechanisms

Atrial fibrillation (AF) causes heart failure, ischemic strokes, and poor quality of life. The number of patients with AF is estimated to increase to 18 million in Europe in 2050. Pharmacological therapy does not cure AF in all patients. Ablative pulmonary vein isolation is recommended for patients with drug-resistant symptomatic paroxysmal AF but is successful in only about 60%. In patients in whom ablative therapy is successful on the long term, recurrence of AF may occur in the first weeks to months after pulmonary vein ablation. The early recurrence (or delayed cure) of AF is not understood but forms the basis for the generally accepted 3-month blinding (or blanking) period after ablation therapy, which is not included in the evaluation of the eventual success rate of the procedures. The underlying pathophysiological processes responsible for early recurrence and the delayed cure are unknown. The implicit assumption of the blinding period is that the AF mechanism in this period is different from the ablation-targeted AF mechanism (ectopy from the pulmonary veins). In this review, we evaluate the temporary and long-lasting pro- and antiarrhythmic effects of each of the pathophysiological processes and interventions (necrosis, ischemia, oxidative stress, edema, inflammation, autonomic nervous activity, tissue repair, mechanical remodeling, and use of antiarrhythmic drugs) occurring in the blinding period that can modulate AF mechanisms. We propose that stretch-reducing ablation scar is a permanent antiarrhythmic mechanism that develops during the blinding period and is the reason for delayed cure.

Post-ablation left atrial function impacts long-term recurrence of atrial fibrillation after ablation

Left atrial (LA) function can help predict various cardiovascular events. Catheter ablation for atrial fibrillation (AF) modifies baseline LA function through the maintenance of sinus rhythm and myocardial injury. We investigated the impact of post-ablation LA function on recurrence of AF after ablation and identified the predictors of reduced post-ablation LA function. A total of 616 patients who underwent AF ablation (paroxysmal, N = 310; non-paroxysmal, N = 306) were retrospectively examined with cardiac computed tomography at baseline and 3 months after the final ablation procedure. Post-ablation LA emptying fraction (LAEF_post) was calculated. We evaluated the association between LAEF_post and recurrence of AF after the final ablation procedure. Further, we assessed the predictors of reduced LAEF_post. The recurrence rate of AF was 72.7% after the final ablation procedure [median follow-up 48 months (48.0, 48.0), total number of ablation sessions: 1.4 ± 0.7]. Multivariate analysis revealed that LAEF_post was associated with the recurrence of AF (hazard ratio/10% increase: 0.62, 95% confidence interval: 0.51-0.75, P < 0.0001). LAEF_post had a mild predictive power for recurrence of AF (c-statistics: 0.670, optimal cutoff: 26.36%, P < 0.0001). The recurrence-free proportion among patients with reduced LAEF_post (< 26.36%, N = 100) and those with preserved LAEF_post (≥ 26.36%, N = 516) was 40% and 79%, respectively (P < 0.0001). The predictors of reduced LAEF_post were low pre-ablation LAEF, high pre-ablation LA volume, low body mass index (BMI), and female sex. Further, reduced LAEF_post was associated with the total number of ablation sessions and extra-pulmonary vein LA ablation. In conclusion, reduced LAEF_post was associated with recurrence of AF after ablation. Advanced LA remodeling, low BMI, and female sex could predict reduced LAEF_post. Although additional ablation was associated with reduced LAEF_post, it remains unclear whether reduced LAEF_post resulted from the additional ablation. Reduced LAEF_post might help stratify patients with ablation-refractory AF.

Effect of catheter ablation on pre-existing abnormalities of left atrial systolic, diastolic, and neurohormonal functions in patients with chronic heart failure and atrial fibrillation

The critical role of the left atrium (LA) in cardiovascular homoeostasis is mediated by its reservoir, conduit, systolic, and neurohormonal functions. Atrial fibrillation is generally a reflection of underlying disease of the LA, especially in patients with heart failure. Disease-related LA remodelling leads to a decline in both atrial contractility and distensibility along with an impairment in the control of neurohormonal systems that regulate intravascular volume. Catheter ablation can lead to further injury to the atrial myocardium, as evidenced by post-procedural troponin release and tissue oedema. The cardiomyocyte loss leads to replacement fibrosis, which may affect up to 30-35% of the LA wall. These alterations further impair atrial force generation and neurohormonal functions; the additional loss of atrial distensibility can lead to a 'stiff LA syndrome', and the fibrotic response predisposes to recurrence of the atrial arrhythmia. Although it intends to restore LA systole, catheter ablation often decreases the chamber's transport functions. This is particularly likely in patients with long-standing atrial fibrillation and pre-existing LA fibrosis, especially those with increased epicardial adipose tissue (e.g. patients with obesity, diabetes and/or heart failure with a preserved ejection fraction). Although the fibrotic LA in these individuals is an ideal substrate for the development of atrial fibrillation, it may be a suboptimal substrate for catheter ablation. Such patients are not likely to experience long-term restoration of sinus rhythm, and catheter ablation has the potential to worsen their haemodynamic and clinical status. Further studies in this vulnerable group of patients are needed.

Exercise-induced release of troponin

It is well established that regular physical activity reduces cardiovascular disease risk; however, numerous studies have demonstrated postexercise elevations in cardiac troponin (cTn), indicative of cardiac injury in apparently healthy individuals. The prevalence of these findings in different exercise settings and population groups, as well as potential underlying mechanisms and clinical significance of exercise-induced cTn release are not yet quite determined. The present review will discuss the cTn response to exercise in light of developing cTn assays and the correlation between postexercise cTn release and cardiac function. Additionally, recent data regarding the potential link between strenuous endurance exercise and its relationship with unfavorable cardiac effects in athletes, as well as the management of patients presenting at emergency care after sport events will be briefly reviewed.

Myocardial Injury in the Era of High-Sensitivity Cardiac Troponin Assays: A Practical Approach for Clinicians

Importance

Traditionally, elevated troponin concentrations were synonymous with myocardial infarction. But with improvements in troponin assays, elevated concentrations without overt myocardial ischemia are now more common; this is referred to as myocardial injury. Physicians may be falsely reassured by the absence of myocardial ischemia; however, recent evidence suggests that myocardial injury is associated with even more detrimental outcomes. Accordingly, this article reviews the definition, epidemiology, differential diagnosis, diagnostic evaluation, and management of myocardial injury.

Observations

Current epidemiological evidence suggests that myocardial injury without overt ischemia represents about 60% of cases of abnormal troponin concentrations when obtained for clinical indications, and 1 in 8 patients presenting to the hospital will have evidence of myocardial injury. Myocardial injury is a concerning prognosis; the 5-year mortality rate is approximately 70%, with a major adverse cardiovascular event rate of 30% in the same period. The differential diagnosis is broad and can be divided into acute and chronic precipitants. The initial workup involves an assessment for myocardial ischemia. If infarction is ruled out, further evaluation includes a detailed history, physical examination, laboratory testing, a 12-lead electrocardiogram, and (if there is no known history of structural or valvular heart disease) an echocardiogram. Unfortunately, no consensus exists on routine management of patients with myocardial injury. Identifying and treating the underlying precipitant is the most practical approach.

Conclusion and Relevance

Myocardial injury is the most common cause of abnormal troponin results, and its incidence will likely increase with an aging population, increasing prevalence of cardiovascular comorbidities, and greater sensitivity of troponin assays. Myocardial injury represents a challenge to clinicians; however, given its serious prognosis, it warrants a thorough evaluation of its underlying precipitant. Future strategies to prevent and/or manage myocardial injury are needed.

A Compelling Case for Less Aggressive Arrhythmia Management in Patients With Chronic Heart Failure and Long-Standing Atrial Fibrillation

BACKGROUND AND METHODS

Atrial fibrillation (AF) is common in chronic heart failure, and some have advocated intensive rate and/or rhythm control strategies for these patients. However, the loss of atrial systole and irregularity of the ventricular response has not been shown to contribute to the progression of heart failure, and the presence or rate of long-standing AF in patients with chronic heart failure does not have prognostic significance.

RESULTS

In randomized clinical trials, pharmacological rhythm control has not been shown to be superior to rate-control in influencing long-term outcomes, but the use of membrane-active antiarrhythmic drugs can increase the risk of both pump failure and arrhythmic deaths in patients with heart failure. Additionally, intensive efforts to slow the ventricular rate in AF can potentially cause clinically inapparent bradyarrhythmias, which can trigger rate-dependent lethal rhythm disturbances or hemodynamic abnormalities. In patients with AF, a more stringent approach to rate control (target rate <80/min) is not superior to a more lenient strategy (target rate <110/min) on the risk of major events. Little is known about the effects of catheter ablation of long-standing AF in established heart failure, particularly in patients with a preserved or a meaningfully reduced ejection fraction, but ablation can add to the fibrotic burden of the left atrium and impair its capacitance functions.

CONCLUSIONS

For all of these reasons, the management of heart failure and long-standing AF should be primarily directed to slowing of the progression of their underlying cardiomyopathic process rather than the treatment of the arrhythmia. In addition, patients should receive long-term oral anticoagulation with non-vitamin K-antagonist oral anticoagulants to reduce the risk of thromboembolic events. The utility of intensive rate and rhythm control interventions for long-standing AF in patients with established heart failure requires further study.

Atrial ectopy after pulmonary vein isolation and left heart reverse remodeling in patients with atrial fibrillation

BACKGROUND

Maintenance of sinus rhythm after pulmonary vein isolation (PVI) for atrial fibrillation (AF) is associated with left atrial (LA) and ventricular (LV) reverse remodeling, although the degree varies among individuals. We hypothesized that frequent premature atrial complex (PAC) after PVI may attenuate the left heart reverse remodeling benefited from maintenance of sinus rhythm.

METHODS

We included 82 AF patients who underwent first-time PVI and 24-h Holter recordings at 6 months after PVI. All patients had no AF recurrence before this time. The number of PAC was categorized into tertiles: <90, 90-488 and >488 PACs/day. All patients underwent two-dimensional echocardiography and serum plasma B-type natriuretic peptide (BNP) measurement before and 6 months after PVI. LA reverse remodeling was defined as ≥15% decrease in LA volume index.

RESULTS

There was no significant difference in the baseline characteristics among the PAC tertiles except for sex. Six months after PVI, LA volume index, LV mass index, and serum BNP levels were significantly decreased in lower and middle PAC tertiles (all P < .05), whereas no significant changes were observed in upper PAC tertile. Frequency of LA reverse remodeling was significantly lower in upper tertile of PAC compared with middle and lower tertiles (22.2%, 57.1%, and 59.3%, P < .001). Baseline LA volume index, changes in LV mass index, and the frequency of PAC were independently associated with LA reverse remodeling (all P < .05).

CONCLUSIONS

Frequent PAC after PVI was associated with less left heart reverse remodeling in AF patients even without AF recurrence.

Mechanistic implication of decreased plasma atrial natriuretic peptide level for transient rise in the atrial capture threshold early after ICD or CRT-D implantation

PURPOSE

Despite the use of steroid-eluting leads, a transient but not persistent rise in the atrial/ventricular capture threshold (TRACT/TRVCT) can occur early after pacemaker implantation in patients with sick sinus syndrome. This study aimed to assess the prevalence, predictors, and mechanisms of TRACT/TRVCT in patients with heart failure undergoing implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT) implantation.

METHOD

One hundred twenty consecutive patients underwent ICD (N = 70) or CRT (N = 50) implantation. Capture threshold was measured at implantation, 7-day, 1-month, and 6-month post-implantation. TRACT/TRVCT was defined as a threshold rise at 7 days by more than twice the height of the threshold at implantation, with full recovery during follow-up. Atrial and brain natriuretic peptide (ANP and BNP) levels were measured before implantation.

RESULTS

TRACT and TRVCT were observed in 13 (11%) and 10 (8%) patients, respectively. Patients with TRACT had lower ANP level (median 72 [42-105] vs. 99 [49-198] pg/mL, P = 0.06), lower ANP/BNP ratio (0.29 [0.20-0.36] vs. 0.50 [0.33-0.70], P < 0.01), lower atrial sensing amplitude (2.0 ± 0.8 vs. 2.7 ± 1.3 mV, P = 0.02), and lower left ventricular ejection fraction (32 ± 12 vs. 40 ± 14%, P = 0.04) than those without TRACT. TRACT recovered within 1 month, whereas TRVCT recovered within 6 months. In multivariable analysis, ANP/BNP ratio was the only independent predictor of TRACT (OR, 0.018; 95% CI, 0.001-0.734; P = 0.034).

CONCLUSIONS

Atrial degenerative change characterized by lower ANP/BNP ratio was associated with the occurrence of TRACT in patients with heart failure. TRVCT could also occur, but it required a longer recovery time than TRACT.

Comparison of Pulmonary Venous and Left Atrial Remodeling in Patients With Atrial Fibrillation With Hypertrophic Cardiomyopathy Versus With Hypertensive Heart Disease

Left ventricular diastolic dysfunction in hypertrophic cardiomyopathy (HC) increases susceptibility to atrial fibrillation. Although phenotypical characteristics of the hypertrophied left ventricle are clear, left atrial (LA) and pulmonary venous (PV) remodeling has rarely been investigated. This study aimed to identify differences in LA and PV remodeling between HC and hypertensive heart disease (HHD) using 3-dimensional computed tomography. Included were 33 consecutive patients with HC, 25 with HHD, and 29 without any co-morbidities who were referred for catheter ablation of atrial fibrillation. Pre-ablation plasma atrial and brain natriuretic peptide levels, post-ablation troponin T level, and LA pressure were measured, and LA and PV diameters were determined 3 dimensionally. LA transverse diameter in the control group was smaller than that in the HHD or HC group (55 ± 6 vs 63 ± 9 vs 65 ± 12 mm, p = 0.0003). PV diameter in all 4 PVs was greatest in the HC group and second greatest in the HHD group (21.0 ± 3.1 vs 23.8 ± 2.8 vs 26.8 ± 4.1 mm, p <0.0001 for left superior PV). Differences in PV size between the HHD and HC groups were enhanced by indexing to the body surface area (12.4 ± 1.9 vs 13.1 ± 1.4 vs 16.1 ± 3.3 mm/m², p <0.0001). The PV/LA diameter ratio was greater in the HC than in the other groups (0.38 ± 0.06 vs 0.38 ± 0.05 vs 0.42 ± 0.07, p = 0.01). Atrial natriuretic peptide, brain natriuretic peptide, troponin T levels, and LA pressure were highest in the HC group (all p <0.05). In conclusion, the stiff LA caused from atrial hypertrophy may account for higher levels of biomarkers, higher LA pressure, and PV-dominant remodeling in HC.

Pre-Procedural Serum Atrial Natriuretic Peptide Levels Predict Left Atrial Reverse Remodeling After Catheter Ablation in Patients With Atrial Fibrillation

OBJECTIVES

This study aimed to investigate the role of atrial natriuretic peptide (ANP) levels to predict left atrial (LA) reverse remodeling in atrial fibrillation (AF) patients.

BACKGROUND

Although LA reverse remodeling after radiofrequency catheter ablation (RFCA) for AF was reported to be associated with favorable outcomes and improvement of LA and left ventricular function, the predictor has not been extensively evaluated.

METHODS

This study included 104 consecutive patients who underwent RFCA for AF. All patients underwent multidetector computed tomography examination and laboratory tests, including measurement of ANP, plasma B-type natriuretic peptide (BNP), and high-sensitivity C-reactive protein (hs-CRP) levels before and 6 months after RFCA. The study population was divided according to the extent of the decrease in the LA volume index at follow-up; responders were defined as patients who exhibited a ≥15% decrease in the LA volume index.

RESULTS

At follow-up, 49 patients (47%) were classified as responders. Pre-procedural serum ANP and BNP levels were significantly higher in the responders than in the nonresponders (both p < 0.01). In the responders, a significant decrease was observed in the log ANP, log BNP, and log hs-CRP levels from baseline to follow-up (all p < 0.01). Multivariate linear regression analysis revealed that log ANP levels before RFCA and maintenance of sinus rhythm during follow-up were independent predictors of LA reverse remodeling (both p < 0.01).

CONCLUSIONS

In this study, 47% of the patients exhibited LA reverse remodeling after RFCA for AF, with a concomitant improvement in serum ANP, BNP, and hs-CRP levels. The pre-procedural ANP level and maintenance of sinus rhythm were independently associated with LA reverse remodeling.

The ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em) predicts improvement in left ventricular systolic and diastolic function 1 year after catheter ablation for atrial fibrillation

AIMS

Successful rhythm control after atrial fibrillation catheter ablation is known to induce left atrial reverse remodelling and improve left ventricular (LV) function. We explored the clinical factors affecting LV systolic and diastolic function 1-year after catheter ablation for atrial fibrillation.

METHODS AND RESULTS

We compared pre-procedural and 1-year follow-up echocardiograms in 521 patients with atrial fibrillation who underwent catheter ablation. Left ventricular systolic function was estimated by the ejection fraction (EF); diastolic function was estimated by the ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em). (i) Catheter ablation of atrial fibrillation significantly reduced left atrium volume index (P < 0.001) and improved LV EF both in patients with recurrent atrial fibrillation (n = 133, P = 0.008) and those without recurrence (n = 388, P < 0.001). (ii) Follow-up EF was significantly improved in patients with baseline E/Em < 15 (n = 454, P < 0.001), whereas E/Em was significantly reduced in patients with pre-procedural E/Em ≥ 15 (n = 67, P = 0.008). (iii) Baseline E/Em < 15 (β = -3.854, 95% CI -5.99 to -1.72, P < 0.001), baseline EF <50% (β = 10.586, 95% CI 7.55 to 13.63, P < 0.001), and female (β = -1.726, 95% CI -3.36 to -0.10, P = 0.038) were independently associated with improved EF. Baseline E/Em ≥ 15 (β = 4.896, 95% CI 3.45 to 6.34, P < 0.001) and younger age (β = -0.066, 95% CI -0.11 to -0.02, P = 0.003) were independent factors associated with improved E/Em.

CONCLUSION

Pre-procedural E/Em predicted improvement in LV systolic and diastolic functions 1 year after catheter ablation for atrial fibrillation. Low baseline E/Em was independently associated with improved EF, while high E/Em predicted improvement in LV diastolic function.