Heart rate variability for risk stratification after acute myocardial infarction in the thrombolytic era

Investigations involving large populations of post myocardial infarction (MI) patients from the pre-thrombolytic era have demonstrated that a reduced heart rare variability (HRV) is an important factor for the prediction of cardiac mortality. However, little is known whether this prognostic value will persist in an era where thrombolytic therapy and other interventions such as PTCA are available. Therefore, 322 patients of less than 75 years were studied prospectively in a study of consecutively included post MI patients with a total follow-up of 12 months each. Thrombolytic therapy was applied in 69% of the cases. 24-hour ambulatory ECG monitoring included an analysis of arrhythmias and ST segment changes as well as the calculation of 12 HRV parameters in time domain. In addition, the ejection fraction (EF) was determined using radionuclide ventriculography at hospital discharge. Furthermore data from the medical history and the clinical course were recorded. Univariate as well as multivariate analysis revealed an independent prognostic value of HRV parameters from the low frequency range for cardiac mortality in the first year after acute MI. However, the most important factor was older age and an impaired left ventricular function.<>