High-resolution ECG in assessment of myocardial functional state in patients with ischemic heart disease and resultant cardiac dilatation

High resolution signal-averaged ECG (SAECG), echocardiography and 24-hour Holter ECG monitoring were used in the study of 30 patients (mean age 56+/-2 years) with coronary heart disease and stable class II-IV angina (group 1) and 66 patients (mean age 45:0 years) with dilated cardiomyopathy of ischemic origin (group II). SAECG was used for detection of late ventricular potentials and calculation of time-voltage and velocity parameters of P-waves. Disturbances of myocardial de- and repolarization indicative of pronounced hemodynamic left atrial overload associated with elevated left ventricular end diastolic pressure were revealed. These disturbances were more pronounced in patients of group II. Late ventricular potentials and arrhythmias were more frequent in patients with more severe cardiac failure. Sensitivity of SAECG for detection of arrhythmogenic substrate in the myocardium was 70 and 90% in groups I and II, respectively. Positive predictive power of ventricular late potentials for occurrence of ventricular arrhythmias in these groups was 86 and 91%, respectively.