Anna De Lorenzo

Long-term effects of cardiac rehabilitation on end-exercise heart rate recovery after myocardial infarction.

Background Heart rate recovery (HRR) is a marker of vagal tone that is a powerful predictor of mortality in patients with coronary artery disease. Design This study aims at evaluating the effects of long-term exercise training on HRR after acute myocardial infarction (AMI), in order to clarify whether prolonged exercise training could maintain a long-term improvement of HRR. Methods Forty-four patients after AMI were enrolled in a 3-month hospital-based exercise training programme. At the end, patients were subdivided into two groups: group A (n = 22), patients discharged with a specific home-based exercise training programme and instructions for improving leisure-time physical activity; group B (n = 22), patients discharged with generic instructions to maintain physical activity. All patients underwent a cardiopulmonary exercise test before, at the end of 3 months exercise training and at 6 months follow-up. Results At the end of the hospital-based exercise training programme we observed an increase in peak oxygen consumption [VO2peak; from 13.9 ± 3.6 to 18 ± 2.7 ml/kg per min (A) and from 14.1 ± 3.9 to 17.9 ± 2.1 ml/kg per min (B), P<0.001] and in HRR [from 17.1 ± 1.8 to 23.4 ± 1.4 beats/min (A), and from 18.8 ± 2.1 to 24.3 ± 1.9 beats/min (B), P<0.001]. At 6 months’ follow-up we observed a further improvement in VO2peak (from 18.0 ± 2.7 to 20.3 ± 2.7 ml/kg per min, P<0.001) and in HRR (from 23.4 ± 1.4 to 27.8 ± 2.1 beats/min, P<0.001) in group A, but a significant decrease in VO2peak and in HRR in group B (P<0.001). Conclusion Long-term exercise training is useful for maintaining or improving the beneficial results of the standard 3-month exercise training programme on cardiovascular capacity and HRR. This observation may bear beneficial prognostic effects on patients after AMI.

Left ventricular remodelling in patients with moderate systolic dysfunction after myocardial infarction: favourable effects of exercise training and predictive role of N-terminal pro-brain natriuretic peptide.

Aims To investigate the effects of exercise training (ET) on left ventricular (LV) volumes, cardiopulmonary functional capacity and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in postinfarction patients with moderate LV dysfunction. Methods Sixty-one postinfarction patients were randomized into two groups: group T [n = 30, LV ejection fraction (EF) 41.6 ± 11.3%, mean ± SD] entered a 6-month ET programme, whereas group C (n = 31, EF 42.0 ± 7.6%, P=NS) did not. NT-proBNP assay, Doppler-echocardiography and cardiopulmonary exercise test were performed upon enrolment and at sixth months. Results At sixth months, trained patients showed an improvement in workload (+26%, P<0.001), Vo2peak (+31%, P<0.001), LV end-diastolic volume index (LVEDVI; −9%, P<0.001), a reduction in NT-proBNP (−71%, P<0.001) and a significant correlation between changes in NT-proBNP and in LVEDVI (r=0.858, P<0.001). Baseline NT-proBNP correlated with changes in LVEDVI in both trained (r=0.673, P<0.001) and untrained (r=0.623, P<0.001) patients. Group C showed unfavourable LVEDVI dilation (+8%, P<0.001; T vs. C group, P<0.001) and a smaller reduction in NT-proBNP (−40%, P<0.001; T vs. C group, P<0.001). Conclusions Six month ET induced a favourable LV remodelling and a marked fall in NT-proBNP that could predict LV remodelling in postinfarction patients with moderate LV dysfunction.

Reduction of N terminal-pro-brain (B-type) natriuretic peptide levels with exercise-based cardiac rehabilitation in patients with left ventricular dysfunction after myocardial infarction.

Introduction N-terminal-pro-brain (B-type) natriuretic peptide (NT-pro-BNP) is a peptide hormone released from ventricles in response to myocyte stretch. The aim of the study was to investigate the influence of exercise training on plasma NT-pro-BNP to verify if this parameter could be used as a biological marker of left ventricular remodelling in myocardial infarction patients undergoing an exercise training programme. Methods Forty-four patients after myocardial infarction were enrolled into a cardiac rehabilitation programme, and were randomized in two groups of 22 patients each. Group A patients followed a 3-month exercise training programme, while group B patients received only routine recommendations. All patients underwent NT-pro-BNP assay, and cardiopulmonary exercise test before hospital discharge and after 3 months. Results In Group A, exercise training reduced NT-pro-BNP levels (from 1498 ± 438 to 470 ± 375 pg/ml, P = 0.0026), increased maximal (V O2peak + 4.3 ± 2.9 ml/kg per min, P<0.001; Powermax + 38 ± 7, P<0.001) exercise parameters and work efficiency (Powermax/V O2peak + 1.3 ± 0.4 Power/ml per kg per min, P<0.001); there was also an inverse correlation between changes in NT-pro-BNP levels and in V O2peak (r = −0.72, P<0.001), E-wave (r = −0.51, P<0.001) and E/A ratio (r = 0.59, P<0.001). In group B, at 3 months, no changes were observed in NT-pro-BNP levels, exercise and echocardiographic parameters. Conclusion Three months exercise training in patients with moderate left ventricular systolic dysfunction after myocardial infarction induced a reduction in NT-pro-BNP levels, an improvement of exercise capacity and early left ventricular diastolic filling, without negative left ventricular remodelling. Whether the reduction of NT-pro-BNP levels could be useful as a surrogate marker of favourable left ventricular remodelling at a later follow-up remains to be further explored.