Improvement of alveolar-capillary membrane diffusing capacity with exercise training in chronic heart failure

Abstract

Chronic heart failure (CHF) may impair lung gas diffusion, an effect that contributes to exercise limitation. We investigated whether diffusion improvement is a mechanism whereby physical training increases aerobic efficiency in CHF. Patients with CHF (n = 16) were trained (40 min of stationary cycling, 4 times/wk) for 8 wk; similar sedentary patients (n = 15) were used as controls. Training increased lung diffusion (DlCO, +25%), alveolar-capillary conductance (DM, +15%), pulmonary capillary blood volume (VC, +10%), peak exercise O2 uptake (peak VO2, +13%), and VO2 at anaerobic threshold (AT, +20%) and decreased the slope of exercise ventilation to CO2 output (VE/VCO2, -14%). It also improved the flow-mediated brachial artery dilation (BAD, from 4.8 +/- 0.4 to 8.2 +/- 0.4%). These changes were significant compared with baseline and controls. Hemodynamics were obtained in the last 10 patients in each group. Training did not affect hemodynamics at rest and enhanced the increase of cardiac output (+226 vs. +187%) and stroke volume (+59 vs. +49%) and the decrease of pulmonary arteriolar resistance (-28 vs. -13%) at peak exercise. Hemodynamics were unchanged in controls after 8 wk. Increases in DlCO and DM correlated with increases in peak VO2 (r = 0.58, P = 0.019 and r = 0.51, P = 0.04, respectively) and in BAD (r = 0.57, P < 0.021 and r = 0.50, P = 0.04, respectively). After detraining (8 wk), DlCO, DM, VC, peak VO2, VO2 at AT, VE/VCO2 slope, cardiac output, stroke volume, pulmonary arteriolar resistance at peak exercise, and BAD reverted to levels similar to baseline and to levels similar to controls. Results document, for the first time, that training improves DlCO in CHF, and this effect may contribute to enhancement of exercise performance.

Abnormal Ventilatory Response to Exercise in Adults With Congenital Heart Disease Relates to Cyanosis and Predicts Survival

“…43 The beneficial effect of exercise training on exercise capacity in acquired heart failure is now widely accepted and has also been shown to reduce the V E/V CO 2 slope. 44,45 Studies of systematic training in ACHD have shown that exercise training in specific cohorts of ACHD patients is safe and might be beneficial. 46 Regular low-grade physical exercise should be discussed and encouraged in contemporary ACHD practice, even though there are still limited data on its beneficial effects.…”

A clinician's guide to cardiopulmonary exercise testing 2: test interpretation

“…A number of treatments have been shown to effectively lower VE/ CO2 slope including exercise training (Guazzi et al, 2004), angiotensin converting enzyme (ACE) inhibitors (Guazzi et al, 1999), cardiac resynchronisation therapy (Malfatto et al, 2005) and heart transplantation (Carter et al, 2006). Serial CPET may be advantageous in assessing the efficacy of such therapeutic interventions.…”

The combined exercise stress echocardiography and cardiopulmonary exercise test for identification of masked heart failure with preserved ejection fraction in patients with hypertension

“…Exercise training may improve the effort tolerance with the decrease of the VE/VCO2 slope. 31,32 Drugs like ACEIs, angiotensin II receptor antagonists and beta-blockers may also improve the VE/VCO2 slope in patients with HF. [33][34][35] Likewise, the reduction in the VE/VCO2 slope was obtained by cardiac resynchronization therapy.…”