Relation of Heart Rate Variability with Clinical and Echocardiographic Parameters After Acute Myocardial Infarction

Heart rate variability (HRV) is one of the independent prognostic criteria after acute myocardial infaretion (AMI). The aim of this study is to evaluate the changes in HRV after AMI in patients w ith and without left ventricular (LV) dysfunction and to determine the relation of these HRV changes with elinical and echocardiographic parameters. Twenty patients ( 1 8 males, 2 females; m ean age 49.2±8.2) with preserved LV systolic function after AMI (Group I), twenty patients (I 8 males, 2 females; mean age 5 1.5±7.7) with impaired LV (systolic) function and heart failure (functional class NYHA II-III) (Group II) and 20 healthy subjects (18 males, 2 females; mean age 50.5±7.9) (control group) were studied. In patients with and without LV dys function high frequency power (HFP), low frequency power (LFP), very low frequency power (VLFP) and LFP/HFP ratio which reflects sympathetic activity increased when compared with the control group (p<0.05). In patients with LV sys tolic dysfun ction, HFP/LFP ratio was s ignificantly higher than in patients without systolic dysfunction. In the latter group, HFP was found to be negatively correlated with end-diastolic volume and, pos itively correlated with stroke volume whereas VLFP was negatively correlated with heart rate and NYHA stage. We concluded that, parasympathetic activity which is a elinical and prognostic parameter after AMI is decreased, the other parameter sympathetic activity is increased, and HRV is depressed. These changes are fo und to be mo re prominent in patients w ith LV systolic dysfunction. HFP, reflecting parasympathetic activ ity of HRV parameter, is rel ated significantly to LV systolic functions.