Heart rate variability and left ventricular dilatation early after myocardial infarction

To assess clinically whether alterations of autonomic tone precede left ven tricular dilatation, heart rate variability and early left ventricular dila lation after a first myocardial infarction were assessed. Low-frequency pow er (LF), high-frequency power (HF), and total power (TP) were obtained by a mbulatory electrocardiogram on day 1 in 53 patients with a first acute myoc ardial infarction. Left ventricular end-diastolic volume determined by echo cardiography was obtained on day 1 and day 14. Stepwise linear regression a nalysis was used to assess the associations of early left ventricular dilat ation with heart rate variability adjusted for clinical variables. Higher L F and TP were significantly associated with early left ventricular dilatati on after adjustment for age, sex, site of myocardial infarction, acute reva sucularization, peak creatine kinase level, history of hypertension, and us e of angiotensin-converting enzyme inhibitors and beta-blockers. Higher LF and TP preceded early left ventricular dilatation after myocardial infarcti on.