Original ArticlesEffects of Cardiac Rehabilitation and Beta-Blocker Therapy on Heart Rate Variability After First Acute Myocardial Infarction
Section snippets
Study Population and Protocol
Fifty-three patients (6 women and 47 men, aged 40 to 66 years) were referred to our center for outpatient cardiac rehabilitation after a first noncomplicated AMI. Most had an inferior AMI (37 of 53, 70%), and most (34 of 53, 64%) had undergone fibrinolysis; in this regard, it is important to notice that HRV retains its prognostic value even when thrombolytic drugs are given.[18]Mean left ventricular ejection fraction was 56 ± 3%. Exclusion criteria were: age >70 years, diabetes, severe
Effect of Therapies on Baseline HRV (Table IB)
When baseline values of HRV indexes were compared 1 month after AMI, patients in group 1 (no β blockade) had signs of a greater sympathetic activation than patients in groups 2 and 3 (i.e., those taking β-blocking therapy).
Effects of Exercise Training on Clinical Variables (Table II)
At the evaluation performed 3 months after AMI at the end of rehabilitation, an increase in exercise duration and final workload was observed in groups 1 and 2, whereas no change was observed in group 3. The rate-pressure product at the same workload was reduced by exercise
Discussion
This study examined the influence of 8 weeks of exercise training with β-blocker therapy on HRV in patients with a recent AMI and preserved systolic function. These interventions seem to share similar effects on prognosis after infarction, reducing mortality from all causes and particularly from sudden death.15, 16, 17Such a favorable outcome could be related to the shift that both therapies induce in cardiovascular autonomic tone toward increased parasympathetic activity.11, 14Our
Acknowledgements
We are grateful to Barbara Avezzù, MS, Maria Teresa Femminis, MS, Alberto Gandolfo, MS, Ada Spiezia, RN, and Paola Zanni, RN, for their valuable and effortless caring of patients undergoing rehabilitation at our institution.
References (30)
- et al.
Decreased heart rate variability and its association with increased mortality after acute myocardial infarction
Am J Cardiol
(1987) - et al.
Heart rate variability as an index of sympatho-vagal interaction after acute myocardial infarction
Am J Cardiol
(1987) - et al.
Baroreflex sensitivity and its evolution during the first year after myocardial infarction
J Am Coll Cardiol
(1988) - et al.
Time course of recovery of heart period variability after myocardial infarction
J Am Coll Cardiol
(1991) - et al.
Risk stratification for arrhythmic events in post-infarction patients based on heart rate variability, ambulatory electrocardiographic variables and the signal-averaged electrocardiogram
J Am Coll Cardiol
(1991) - et al.
Effects of beta blockers (atenolol or metoprolol) on heart rate variability after acute myocardial infarction
Am J Cardiol
(1994) - et al.
Effect of atenolol and diltiazem on heart period variability in normal persons
J Am Coll Cardiol
(1991) - et al.
Effect of quinapril or metoprolol on heart rate variability in post-myocardial infarction patients
Am J Cardiol
(1996) - et al.
Frequency domain measures of heart period variability and mortality after myocardial infarction
Circulation
(1992) - et al.
Baroreflex sensitivity, clinical correlates and cardiovascular mortality among patients with a first myocardial infarction
Circulation
(1988)