Ourania Papazachou

Effects of exercise rehabilitation program on heart rate recovery in patients with chronic heart failure

Background Heart rate recovery (HRR1) immediately after exercise reflects parasympathetic activity, which is markedly attenuated in chronic heart failure (CHF) patients. The aim of our study was to examine both continuous and interval exercise training effects on HRR1 in these patients. Design The population study consisted of 29 stable CHF patients that participated at a rehabilitation program of 36 sessions, three times per week. Of the 29 patients, 24 completed the program. Patients were randomly assigned to interval {n = 10 [100% peak work rate (WRp) for 30 s, alternating with rest for 30 s]} and to continuous training [n = 14 (50%WRp)]. Methods All patients performed a symptom-limited cardiopulmonary exercise test on a cycle ergometer before and after the completion of the program. Measurements included peak oxygen uptake (VO2p), anaerobic threshold (AT), WRp, first degree slope of VO2 during the first minute of recovery (VO2/t-slope), chronotropic response [% chronotropic reserve (CR) = (peak HR - resting HR) × 100/(220 - age - resting HR)], HRR1 (HR difference from peak exercise to one minute after). Results After the completion of the rehabilitation program there was a significant increase of WRp, VO2p, AT and VO2/t-slope (by 30%, P=0.01; 6%, P=0.01; 10%, P=0.02; and 27%, P=0.03 respectively for continuous training and by 21%, P≤0.05; 8%, P=0.01; 6%, P=NS; and 48%, P=0.02 respectively for interval training). However, only patients exercised under the continuous training regime had a significant increase in HRR1 (15.0±9.0 to 24.0±12bpm; P=0.02) and CR (57±19 to 72±21%, P=0.02), in contrast with those assigned to interval training (HRR1: 21 ± 11 to 21 ± 8 bpm; P=NS and CR: 57 ± 18 to 59 ± 21%, P=NS). Conclusions Both continuous and interval exercise training program improves exercise capacity in CHF patients. However, continuous rather than interval exercise training improves early HRR1, a marker of parasympathetic activity, suggesting a greater contribution to the autonomic nervous system.

Early recovery of oxygen kinetics after submaximal exercise test predicts functional capacity in patients with chronic heart failure

Oxygen (O2) uptake at peak exercise (VO2 peak) is an objective measurement of functional capacity in patients with chronic heart failure (CHF). The significance of recovery O2 kinetics parameters in predicting exercise capacity, and the parameters of submaximal exercise testing have not been thoroughly examined.

VE/VCO2 slope is associated with abnormal resting haemodynamics and is a predictor of long-term survival in chronic heart failure.

Patients with chronic heart failure (CHF) present with exercise‐induced hyperpnea, but its pathophysiological mechanism has not been thoroughly investigated. We aimed to determine the relationship between exercise‐induced hyperpnea, resting haemodynamic measurements and the validity of ventilatory response (VE/VCO2 slope) as a mortality predictor in CHF patients.

Association of passive smoking with masked hypertension in clinically normotensive nonsmokers.

BACKGROUND We investigated ambulatory blood pressure (BP) levels among clinically normotensive nonsmokers exposed (PS) and not exposed (SF) to passive smoking aiming to evaluate the relative prevalence of masked hypertension (MH). METHODS From 790 consecutive never-treated subjects who were self-referred to an outpatient hypertensive clinic, we excluded active smokers and those having a mean clinic BP >140/90 mm Hg. In the remaining population, echocardiography and routine biochemical profile assessment was performed, whereas by the implementation of additional exclusion criteria, all clinically normotensive subjects eligible to participate (i.e., 154 PS and 100 SF) underwent to ambulatory BP monitoring. RESULTS PS with respect to SF subjects were younger, followed a less hygienic diet and consumed more alcohol (all P < 0.05). Moreover, PS in comparison with SF showed higher 24-h systolic BP, standing diastolic BP, and clinic heart rate (126 +/- 6 mm Hg vs. 122 +/- 5 mm Hg, 89 +/- 4 mm Hg vs. 84 +/- 4 mm Hg and 79 +/- 5 beats/min vs. 73 +/- 4 beats/min, respectively, P < 0.05 for all) and higher prevalence of MH (23% vs. 8%, P < 0.01). After adjustment for confounders determinants of MH remained passive smoking, weekly duration and intensity of passive smoke exposure, younger age, clinic heart rate, low physical activity score, and standing/sitting difference of diastolic BP and heart rate (P < 0.05 for all). CONCLUSIONS MH is associated with passive smoking in a dose-related manner and low physical activity, increased heart rate and postural hemodynamic reaction may represent potential accelerators of that phenomenon.

Impairment of Autonomic Nervous System Activity in Patients With Pulmonary Arterial Hypertension: A Case Control Study

BACKGROUND Chronotropic response to exercise (CR) and heart rate recovery (HRR) immediately after exercise are indirect indices of sympathetic and parasympathetic activity, respectively. The aim of this study was to evaluate CR and HRR in patients with pulmonary arterial hypertension (PAH) in relation to disease severity. METHODS AND RESULTS Ten PAH patients (6 females/4 males, mean age: 48+/-12 years) and 10 control subjects matched for age, gender, and body mass index (6 females/4 males, mean age: 46+/-6 years) performed a ramp incremental symptom-limited cardiopulmonary exercise test on a cycle ergometer. Main measurements included heart rate at rest (HR), CR=[(peak HR-resting HR/220-age-resting HR)x100, %], HRR(1)=HR difference from peak exercise to 1minute after, ventilatory efficiency during exercise (VE/VCO(2) slope), peak oxygen uptake (VO(2)p), and the first-degree slope of VO(2) for the first minute of the recovery period (VO(2)/t-slope). PAH patients had a significantly decreased CR (58+/-31 vs 92+/-13, %, P < .001) and HRR(1) (10+/-5 vs 29+/-6, beats/min, P < .001) as well as VO(2)p (11.9+/-3.5 vs 26.9+/-6.6, mL.kg.min) and VO(2)/t-slope (0.2+/-0.1 vs. 0.9+/-0.2, mL.kg.min(2)) compared with controls. CR and HRR(1) correlated well with VO(2)p (r=0.7; P < .001 and r=0.85; P < .001, respectively) and VO(2)/t-slope (r=0.66; P < .001 and r=0.85; P < .001, respectively) and had a significant inverse correlation with VE/VCO(2) slope (r=-0.47; P < .01 and r=-0.77; P < .001, respectively). CONCLUSIONS PAH patients present a significant impairment of CR and HRR(1) in relation to disease severity, indicating profound autonomic nervous system abnormalities.

Free Leptin Is Associated With Masked Hypertension in Nonobese Subjects: A Cross-Sectional Study

Abstract—The aim of the study was to investigate whether diverse clinical blood pressure phenotypes are associated with free leptin surrogates, as reflected by plasma leptin, human soluble leptin receptor, and their ratio (ie, free leptin index) in nonobese normoglycemic subjects. Three separate clinic blood pressure measurements and ambulatory blood pressure monitoring were implemented to divide 494 subjects (aged 44±5 years; 272 men; body mass index: <30 kg/m2) into hypertensives (n=166), white-coat hypertensives (n=82), masked hypertensives (n=66), and normotensives (n=180). Participants underwent echocardiography, while, from fasting venous blood samples, metabolic profile, plasma leptin, and its receptor levels were assessed. Hypertensives and masked hypertensives demonstrated higher levels of log (10)(leptin) and log (10)(free leptin index), as well as lower levels of log (10)(human soluble leptin receptor) with respect to normotensives. White-coat hypertensives had similar free leptin surrogates compared with normotensives. Younger age, 24-hour systolic and diastolic blood pressures, 24-hour heart rate, and left ventricle mass index were common correlates of free leptin surrogates. After adjustment for confounders, masked hypertensive and hypertensive with respect to normotensive phenotype were associated with log (10)(leptin) with odds ratios (95% CIs) of 1.31 (1.12 to 3.80) and 1.26 (1.09 to 2.24), respectively, log (10)(human soluble leptin receptor) with 0.65 (0.53 to 0.78) and 0.69 (0.57 to 0.84), respectively, and log (10)(free leptin index) with 2.46 (1.32 to 7.23) and 1.84 (1.26 to 3.73), respectively (P<0.05 for all of the cases). Free leptin surrogates are associated with masked hypertension in nonobese normoglycemic subjects. Free leptin is almost equally increased in masked and sustained hypertension, suggesting a similar leptin-related vascular impairment.

Effects of interval exercise training on respiratory drive in patients with chronic heart failure

BACKGROUND Patients with chronic heart failure (CHF) suffer from ventilatory abnormalities. This study examined the effects of interval exercise training on the respiratory drive in CHF patients. METHODS Forty-six clinically stable CHF patients (38 males/8 women, mean age = 53 +/- 11 years) participated in an exercise rehabilitation program (ERP) 3 times/week, for 12 weeks by interval training modality with or without the addition of resistance training. All patients underwent symptom-limited cardiopulmonary exercise testing (CPET), and measurements of mouth occlusion pressure at 100 ms (P(0.1)) and maximum inspiratory muscle strength (P(Imax)) before and after ERP. Respiratory drive was estimated by mouth occlusion pressure P(0.1) and P(0.1)/P(Imax) ratio at rest, and the ventilatory pattern by resting mean inspiratory flow (V(T)/T(I)) and by V(T)/T(I) at identical CPET workloads, before and after ERP. We also studied a control non exercising group of 11 patients (8 men and 3 women). RESULTS P(0.1) at rest decreased from 3.04 +/- 1.52 to 2.62 +/- 0.9 cmH(2)O (p = 0.015), P(0.1)/P(Imax) % at rest from 4.56 +/- 3.73 to 3.69 +/- 2.03 (p = 0.006), resting V(T)/T(I) from 0.44 +/- 0.10 to 0.41 +/- 0.10 l/s (p = 0.014), and V(T)/T(I) at identical work rate from 2.13 +/- 0.59 to 1.93 +/- 0.58 l/s (p = 0.001) after ERP. VO(2) at peak exercise increased from 16.3 +/- 4.8 to 18.5 +/- 5.3 ml/kg/min (p < 0.001) in the exercise group. No improvement was noted in the control group. CONCLUSIONS ERP by interval training improves the respiratory drive and ventilatory pattern at rest and during exercise in CHF patients.

Cardiopulmonary Rehabilitation Enhances Heart Rate Recovery in Patients With COPD

BACKGROUND: Autonomic dysfunction is present early in the course of COPD, and is associated with adverse outcomes. We utilized heart rate recovery, a simple and validated index of autonomic balance, to investigate the effects of exercise training on autonomic dysfunction in patients with COPD. METHODS: We evaluated 45 stable subjects with COPD who participated in a 36-session exercise-based cardiopulmonary rehabilitation program. Subjects underwent maximal cardiopulmonary exercise testing at baseline and after completion of the rehabilitation program. We recorded exercise testing parameters and heart rate during rest, exercise, and recovery. Heart rate recovery was calculated as heart rate at peak exercise minus heart rate at the first minute of recovery. RESULTS: Thirty-nine subjects (age 66.3 ± 7.8 y, 90% male, body mass index 27.1 ± 4.1 kg/m2, FEV1 45.7 ± 18.7%) completed the program. In these subjects, heart rate recovery increased from 16.2 ± 8.0 beats/min to 18.4 ± 8.4 beats/min (P = .01), resting heart rate decreased from 88.0 ± 10.7 beats/min to 83.3 ± 10.5 beats/min (P = .004), and heart rate at anaerobic threshold decreased from 109.0 ± 12.5 beats/min to 105.5 ± 11.7 beats/min (P = .040). In addition, oxygen consumption (V̇O2) increased from 14.3 ± 3.7 mL/kg/min to 15.2 ± 3.8 mL/kg/min at peak exercise, and from 9.7 ± 2.4 mL/kg/min to 10.4 ± 2.6 mL/kg/min at anaerobic threshold (both P = .02), while the V̇O2/t slope increased from –0.32 ± 0.16 mL/kg/min2 to –0.38 ± 0.19 mL/kg/min2 (P = .003). Parameters of ventilatory performance improved also. CONCLUSIONS: In subjects with COPD, exercise-based rehabilitation improves heart rate recovery, modestly though, which indicates a degree of attenuated autonomic dysfunction. Exercise and muscular oxidative capacity, as expressed by V̇O2/t slope, is also improved.

New insights into the exercise intolerance of β‐thalassemia major patients

The purpose of our study was assessment of the relative contribution of the systems involved in blood gas exchange to the limited exercise capacity in patients with β‐thalassemia major (TM) using integrative cardiopulmonary exercise testing (CPET) with estimation of oxygen kinetics. The study consisted of 15 consecutive TM patients and 15 matched controls who performed spirometric evaluation, measurement of maximum inspiratory pressure (Pimax) and an incremental symptom‐limited CPET on a cycle ergometer. Exercise capacity was markedly reduced in TM patients as assessed by peak oxygen uptake (pVO2, mL/kg/min: 22.1±6.6 vs 33.8±8.3; P<0.001) and anaerobic threshold (mL/kg/min: 13.0±3.0 vs 18.7±4.6; P<0.001) compared with controls. No ventilatory limitation to exercise was noted in TM patients (VE/VCO2 slope: 23.4±3.2 vs 27.8±2.6; P<0.001 and breathing reserve, %: 42.9±17.0 vs 29.5±12.0; P<0.005) and no difference in oxygen cost of work (peak VO2/WR, mL/min W: 12.2±1.7 vs 12.2±1.5; P=NS). Delayed recovery oxygen kinetics after exercise was observed in TM patients (VO2/t slope, mL/kg/min2: 0.67±0.27 vs 0.93±0.23; P<0.05) that was significantly correlated with Pimax at rest (r: 0.81; P<0.001). The latter was also significantly correlated to pVO2 (r: 0.84; P<0.001) and inversely correlated to ferritin levels (r: −0.6; P<0.02). Exercise capacity is markedly reduced in TM patients and this reduction is highly associated with the limited functional status of peripheral muscles.

Respiratory drive and breathing pattern abnormalities are related to exercise intolerance in chronic heart failure patients

BACKGROUND Patients with chronic heart failure (CHF) are characterized by exercise intolerance and ventilatory abnormalities that are related to poor prognosis. We hypothesized that CHF patients have increased respiratory drive and abnormal breathing pattern during exercise in relation to disease severity. MATERIALS AND METHODS The study population consisted of 219 stable CHF patients and 30 healthy control subjects. All subjects underwent a symptom-limited cardiopulmonary exercise testing (CPET), pulmonary function tests, measurement of the maximal inspiratory pressure (PImax) and respiratory drive (P0.1). Measurements included peak oxygen uptake ( [Formula: see text] peak, ml/kg/min). Respiratory drive was measured by mouth occlusion pressure P0.1 and P0.1/PImax ratio at rest, and by mean inspiratory flow (VT/TI) at rest and during exercise. CHF patients were divided into 3 groups according to [Formula: see text] peak (Group A: >20, Group B: 20-16 and Group C: <16ml/kg/min). RESULTS CHF patients presented higher P0.1/PImax (4.1±3.6 vs 3.0±1.5, p=0.007) and VT/TI at rest (0.48±0.14 vs 0.41±0.10, L/s respectively, p=0.004) and lower VT/TI at peak exercise (2.17±0.66 vs 2.56±0.73, L/s, p=0.009) compared to controls. P0.1/PImax was higher in CHF Group C vs B vs A (4.9±2.9 vs 3.6±1.8 vs 3.1±1.8, respectively, p<0.001), while VT/TI at peak exercise was lower (1.71±0.43 vs 2.15±0.52 vs 2.65±0.64, L/s, respectively, p<0.001). CONCLUSIONS CHF patients present increased respiratory drive at rest and abnormal breathing pattern during exercise in relation to CHF severity.