engleski

Coronary artery bypass grafting reduces heart rate variability more than myocardial infarction does

Heart rate variability (HRV) was compared between 262 consecutive cardiac rehabilitation in-patients with myocardial infarction (MI) and 99 patients who passed coronary artery bypass grafting (CABG), with left ventricular ejection fraction <40% (150 pts) or >50% (211 pts). HRV was obtained from 24-hour Holter ECG recordings. CABG patients had slightly faster heart rate (p<.05), but much lower HRV (p<.01) than MI patients, irrespective to EF. Two groups differed neither by age and sex, incidence of hypertension, diabetes, rhythm disturbances, left ventricle diameter and ejection fraction, exercise level and course of rehabilitation, nor by medication except nitrates, which were used more frequently in MI group (p<.001). MI group had slightly higher incidence of angina (p<0.05). In conclusion, CABG reduced HRV more that MI did, but prognostic significance of that finding is still doubtful.

heart rate; autonomic nervous system; cardiac surgery

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