Impact of β-Blockers on Heart Rate and Oxygen Uptake During Exercise and Recovery in Older Patients With Heart Failure With Preserved Ejection Fraction

Clinical effect of recombinant human brain natriuretic peptide in the treatment of heart failure in elderly patients

BACKGROUND

Heart failure in elderly individuals poses significant challenges due to the decline in cardiac function associated with aging. This study aimed to investigate the clinical efficacy of recombinant human brain natriuretic peptide (rhBNP) for the treatment of heart failure, especially in elderly patients.

METHODS

This was a retrospective case control study of the medical records of 60 elderly patients with heart failure admitted to our hospital between December 2020 and December 2023. Patients were divided into two groups based on treatment. The control group (n = 30) received diuretics, digitalis, and β receptor blockers, while the observation group (n = 30) received lyophilized rhBNP in addition to the control group treatment. Changes in BNP levels and clinical outcomes were compared between the two groups.

RESULTS

Posttreatment BNP levels were significantly lower in the observation group than in the control group (p < 0.05), and the total clinical effective rate was greater in the observation group (p < 0.05). Additionally, the left ventricular diameter, left atrial diameter, left ventricular shortening fraction, diastolic flow signal and cardiac output in the observation group were lower than those in the control group (p < 0.05), while the thickness of the aortic root diameter in the observation group was greater than that in the control group (p < 0.05).

CONCLUSION

RhBNP demonstrated ideal clinical efficacy in elderly patients with heart failure, improving symptoms and indicating potential for widespread use in the future.

Heart Rate Recovery: Up to Date in Heart Failure-A Literature Review

The rising prevalence of cardiovascular disease underscores the growing significance of heart failure (HF). Pathophysiological insights into HF highlight the dysregulation of the autonomic nervous system (ANS), characterized by sympathetic overactivity and diminished vagal tone, impacting cardiovascular function. Heart rate recovery (HRR), a metric measuring the heart's ability to return to its baseline rate post-exertion, plays a crucial role in assessing cardiovascular health. Widely applied across various cardiovascular conditions including HF, coronary artery disease (CAD), and arterial hypertension (HTN), HRR quantifies the difference between peak and recovery heart rates. Given its association with elevated sympathetic tone and exercise, HRR provides valuable insights into the perspective of HF, beyond effort tolerance, reaching toward prognostic and mortality indicators. Incorporating HRR into cardiovascular evaluations enhances our understanding of autonomic regulation in HF, offering potential implications for prognostication and patient management. This review addresses the significance of HRR in HF assessment, analyzing recently conducted studies, and providing a foundation for further research and clinical application.

Revisiting Beta-Blocker Therapy in Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a heterogenous disorder and tends to be predominant in elderly, female, and obese patients. HFpEF has been classified using various cut-offs of left ventricular ejection fraction in the published studies with a current cut-off of ≥50%. The evidence of beta-blocker therapy in HFpEF patients showed conflicting findings with variably reported efficacy. This review aims to examine the published studies on the use of beta blockers for the treatment of patients with HFpEF.

The Impact of beta blockade on the cardio-respiratory system and symptoms during exercise

Background

Beta blockers prolong life in patients with cardiovascular diseases. Negative chronotropic and inotropic effects carry the potential to adversely effect peripheral skeletal and airway smooth muscle contributing to further fatigue, dyspnea and exercise intolerance.

Research questions

Do beta-blockers reduce maximal power output (MPO), VO2 max, cardiorespiratory responses, increase the perceived effort required to cycle and breath during cardiopulmonary exercise tests (CPET) and limit the capacity to exercise?

Methods

Retrospective observational study of subjects performing CPET to capacity from 1988 to 2012. Subjects with and without beta-blockers were compared: baseline physiological characteristics, MPO, VO₂ max, heart rate max, ventilation responses and perceived exertion required to cycle and breathe (modified Borg scale). Forward stepwise linear additive regression was performed with MPO as the dependent factor with height, age, gender, muscle strength, FEV1 and DLCO as independent contributors.

Results

42,771 subjects were included 7,787 were receiving beta-blocker [mean age 61 yrs, BMI 28.40 kg/m², 9% airflow obstruction (FEV1/FVC<0.7)] and 34,984 were not [mean age 51yrs, BMI 27.40 kg/m², 11% airflow obstruction]. Heart rate was lower by 18.2% (95% C.I. 18.15–18.38) (p<0.0001) while Oxygen pulse (VO₂/HR) was higher by 19.5% (95% C.I. 19.3–19.7) in those receiving beta blockers. Maximum power output (MPO) was 3.3% lower in those taking beta-blockers. The perceived effort required to cycle and breathe (mBorg) was 8% lower in those taking beta-blockers.

Interpretation

Increases in oxygen pulse minimize the reduction in exercise intolerance and symptom handicap associated with beta-blockers.

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Comprehensive set of exercise physiology measurements in a large cohort, to delineate any hazardous effects of beta blockade.

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Beta-blockers attenuate the heart rate at rest and during exercise.

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Beta-blockade has no meaningful effects on muscle strength, breathing capacity or exercise induced bronchoconstriction.

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Beta Blockers were not associated with a reduction in Maximal power output.

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Increases in Oxygen pulse minimize the reduction in exercise intolerance and symptom handicap associated with beta-blockers.

Prognostic Value of NT-Pro Brain Natriuretic Peptide During Exercise Recovery in Ischemic Heart Failure of Reduced, Midrange, and Preserved Ejection Fraction

BACKGROUND

Ischemic heart disease is a leading cause of heart failure (HF), which continues to carry a high mortality despite considerable improvements in diagnosis and treatment. N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) measured at rest is a recognized diagnostic and prognostic marker of HF of reduced ejection fraction (HFrEF); however, its value in patients with HF of midranged/preserved ejection fraction (HFmrEF/HFpEF) is not well established. We examined the prognostic value of NT-pro-BNP during recovery from exercise in patients with ischemic HF (IHF) of any ejection fraction.

METHODS

Patients (n = 213) with HF (123 HFrEF, 90 HFmrEF/HFpEF) underwent cardiopulmonary exercise testing. Doppler echocardiography was used to estimate resting pulmonary artery systolic pressure (PASP) and tricuspid annular plane systolic excursion (TAPSE). NT-pro-BNP was determined at rest, peak exercise, and after 1 min of exercise recovery.

RESULTS

Patients with HFrEF had higher plasma levels of NT-pro-BNP at rest, peak exercise, and recovery than those with HFmrEF/HFpEF (984 ± 865 vs 780 ± 805; 1012 ± 956 vs 845 ± 895; 990 ± 1013 vs 808 ± 884 pg/mL; P < .01, respectively), whereas ΔNT-pro-BNP peak/rest and ΔNT-pro-BNP recovery/peak were similar (60 ± 100 vs 50 ± 96; -25 ± 38 vs -20 ± 41 pg/mL, P > .05). During the tracking period (22.4 ± 20.3 mo), 34 patients died, 2 underwent cardiac transplantation, and 3 had left ventricular assist device implantation. In a multivariate regression model, only NT-pro-BNP during exercise recovery and TAPSE/PASP were retained in the regression for the prediction of adverse events (χ2 = 11.4, P <.001).

CONCLUSIONS

NT-pro-BNP value during exercise recovery may be a robust predictor of adverse events in patients with IHF across a wide range of ejection fraction.

Chronotropic Responses to Exercise and Recovery in Myocardial Infarction Patients Taking β-Blockers Following Aerobic High-Intensity Interval Training: AN INTERFARCT STUDY

PURPOSE

The objectives of this study were to compare the effects of two different high-intensity interval training (HIIT) programs (low-volume vs high-volume) on chronotropic responses during exercise and recovery, and to contrast the results of the HIIT groups together to only physical activity recommendations in post-myocardial infarction (MI) patients taking β-blockers.

METHODS

Resting heart rate (HRrest), peak HR (HRpeak), HR reserve (HRreserve = HRpeak-HRrest), HR recovery (HRR) as the difference between HRpeak and post-exercise HR, and chronotropic incompetence were assessed in 70 patients (58 ± 8 yr) following MI with a cardiopulmonary exercise test to peak exertion before and after a 16-wk exercise intervention period. All participants were randomized to either attention control (AC) (physical activity recommendations) or one of the two supervised HIIT groups (2 d/wk).

RESULTS

After the intervention, no significant between-HIIT group differences were observed. The HRpeak increased (P < .05) in low- (Δ= 8 ± 18%) and high-volume HIIT (Δ= 6 ± 9%), with a small decrease in AC (Δ=- 2 ± 12%, P > .05) resulting in large differences (P < .05) between HIIT and AC. The HRreserve increased (P < .05) in high-volume HIIT. The HRR slightly increased (P < .05) in low-volume (5th min, Δ= 19 ± 31%) and high-volume HIIT (2nd min, Δ= 15 ± 29%, and 5th min, Δ= 19 ± 28%).

CONCLUSION

These findings suggest that both low- and high-volume HIIT elicit similar improvements in chronotropic responses after MI, independent of β-blocker treatment. Supervised HIIT was more effective than giving physical activity recommendations alone. Low-volume HIIT is presented as a potent and time-efficient exercise strategy that could enhance the sympathovagal balance in this population.

Multimodality assessment of heart failure with preserved ejection fraction skeletal muscle reveals differences in the machinery of energy fuel metabolism

AIMS

Skeletal muscle (SkM) abnormalities may impact exercise capacity in patients with heart failure with preserved ejection fraction (HFpEF). We sought to quantify differences in SkM oxidative phosphorylation capacity (OxPhos), fibre composition, and the SkM proteome between HFpEF, hypertensive (HTN), and healthy participants.

METHODS AND RESULTS

Fifty-nine subjects (20 healthy, 19 HTN, and 20 HFpEF) performed a maximal-effort cardiopulmonary exercise test to define peak oxygen consumption (VO_{2, peak} ), ventilatory threshold (VT), and VO₂ efficiency (ratio of total work performed to O₂ consumed). SkM OxPhos was assessed using Creatine Chemical-Exchange Saturation Transfer (CrCEST, n = 51), which quantifies unphosphorylated Cr, before and after plantar flexion exercise. The half-time of Cr recovery (t_{1/2, Cr} ) was taken as a metric of in vivo SkM OxPhos. In a subset of subjects (healthy = 13, HTN = 9, and HFpEF = 12), percutaneous biopsy of the vastus lateralis was performed for myofibre typing, mitochondrial morphology, and proteomic and phosphoproteomic analysis. HFpEF subjects demonstrated lower VO_2,peak , VT, and VO₂ efficiency than either control group (all P < 0.05). The t_{1/2, Cr} was significantly longer in HFpEF (P = 0.005), indicative of impaired SkM OxPhos, and correlated with cycle ergometry exercise parameters. HFpEF SkM contained fewer Type I myofibres (P = 0.003). Proteomic analyses demonstrated (a) reduced levels of proteins related to OxPhos that correlated with exercise capacity and (b) reduced ERK signalling in HFpEF.

CONCLUSIONS

Heart failure with preserved ejection fraction patients demonstrate impaired functional capacity and SkM OxPhos. Reductions in the proportions of Type I myofibres, proteins required for OxPhos, and altered phosphorylation signalling in the SkM may contribute to exercise intolerance in HFpEF.