EFFECT OF EXERCISE REHABILITATION ON HEART-RATE-VARIABILITY IN HYPERTENSIVES AFTER MYOCARDIAL-INFARCTION

Objective The aim of the study was to find out whether the presence of hypertension affects heart rate variability in patients rehabilitated after myocardial infarction. Design Echocardiography, exercise testin g and 24 h Holter monitoring were performed before and after 27 days o f early postdischarge cardiac rehabilitation. Patients The study popul ation consisted of 64 patients aged 34-65 years (mean +/- SD 51.6 +/- 6.6) discharged from hospital after a first myocardial infarction who were subdivided into two groups, group A comprising 34 patients with a rterial hypertension which had lasted 4.8 +/- 2.1 years and group B co mprising 30 normotensives. Main outcome We expected exercise rehabilit ation to affect heart rate variability, exercise tolerance and myocard ial ischemia in patients after myocardial infarction with and without arterial hypertension. Results At baseline no intergroup differences w ere seen in the duration of exercise, workload and heart rate variabil ity parameters. All parameters increased significantly after cardiac r ehabilitation (P < 0.01): SD of all normal RR intervals 123.4 +/- 30.0 versus 123.8 +/- 30.0 ms; SD of the averages of normal RR intervals i n all 5-min segments of the entire recording 115.1 +/- 30.5 versus 116 .3 +/- 28.3 ms; mean of the SD of all normal RR intervals for all 5-mi n segments of the entire recording 49.0 +/- 12.5 versus 48.3 +/- 11.8 ms; square root of the mean of the sum of the squares of differences b etween adjacent RR intervals 29.7 +/- 9.1 versus 28.0 +/- 8.5 ms; perc entage of differences between adjacent RR intervals > 50 ms 7.9 +/- 6. 0 versus 7.1 +/- 6.1% (group A versus group B, respectively, NS). The duration of exercise and the workload were significantly increased (th e rise was higher in normotensives). No differences were seen in the f requency and severity of silent myocardial ischemia. Conclusions Early stationary exercise rehabilitation after myocardial infarction improv es heart rate variability parameters and exercise tolerance both in hy pertensives and in normotensives. (C) Rapid Science Publishers ISSN 02 63-6352.