Heart Rate Dynamics During A Treadmill Cardiopulmonary Exercise Test in Optimized Beta-Blocked Heart Failure Patients

Abstract

Carvalho VO, Guimarães GV, Ciolac EG, Bocchi EA. Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients. Clinics. 2008;63:479-82. BACKGROUND:Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49±11 years, 76% male), with an average LVEF of 30±7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57±3 bpm) compared to controls (89±14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4±11.1%) compared to controls (98.6±2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2±0.5 for controls and 1.15±1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48±9%) and control (53±8%) was not different (p=0.157). CONCLUSION: No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required.

Heart rate dynamic during an exercise test in heart failure patients with different sensibilities of the carvedilol therapy

“…Carvalho et al [9] found a peak heart rate by 65% of the maximum age-predicted heart rate in an optimized hear failure group (heart rate between 50 and 60 bpm and Carvedilol dose of 50 mg/day or more). This is in agreement with our optimized group, which reached 60% of the maximum heart rate predicted for age and with our optimized high-sensible group that reached 62%.…”

The relationship between heart rate and oxygen consumption in heart transplant recipients during a cardiopulmonary exercise test

“…Resting oxygen consumption and heart rate were computed as the mean of the final 30 s of the resting period, while peak effort (peak of oxygen consumption) and peak heart rate were the mean values of the final 30 s of effort before exhaustion. The respiratory exchange ratios were recorded as the averaged samples obtained during each stage of the protocol used (modified Naughton protocol) [11]. A satisfactory cardiopulmonary exercise test was characterized by a peak of respiratory exchange ratio N 1.05 and symptoms of maximum effort.…”

The Borg Scale as an Important Tool of Self-Monitoring and Self-Regulation of Exercise Prescription in Heart Failure Patients During Hydrotherapy

“…1 Despite there being no consensus about which exercise intensity is the best for heart failure patients, a submaximal level (between the anaerobic threshold and respiratory compensation point) seems to have the best security-efficacy relationship. 15 The HR is a good tool to use as a guide for exercise training because of the close relation with oxygen consumption, 27 especially when considering the percentage of HR reserve in heart failure patients on optimized carvedilol therapy. 28 In our study, the land and water exercises were well tolerated without any complications such as dizziness, breathlessness or muscular pain.…”