Late ventricular potentials in risk assessment of the occurrence of complex ventricular arrhythmia in patients with myocardial infarction and heart failure.

AIM: To determine the prognostic significance of late ventricular potentials on signal-averaged electrocardiogram and left ventricular ejection fraction for the occurrence of complex ventricular arrhythmia in patients treated with accelerated tissue-type plasminogen activator, using the rapid protocol, within six months of acute myocardial infarction.

METHODS: In this analytic observational prospective study patients were divided into four groups: patients with left ventricular ejection fraction bellow 40% and late ventricular potentials, patients with left ventricular ejection fraction bellow 40% and without late ventricular potentials, patients with left ventricular ejection fraction over 40% and late ventricular potentials, and patients with left ventricular ejection fraction over 40% and without late ventricular potentials. Complex ventricular arrhythmias (Lown grade IVa, IVb, and V) were recorded using standard electrocardiography and 24-hour Holter monitoring 21, 60, and 90 days after acute myocardial infarction, respectively. Serial recordings of signal-averaged electrocardiogram were obtained 30, 90, and 180 days after acute myocardial infarction. Left ventricular ejection fraction was determined by echocardiography between 15 and 21 days after acute myocardial infarction. Multivariant logistic regression analysis was used to evaluate the relation between late ventricular potentials and left ventricular ejection fraction with the occurrence of complex ventricular arrhythmias. Sensitivity, specificity, positive and negative predictive values of late ventricular potentials and left ventricular ejection fraction for the occurrence of complex ventricular arrhythmias were determined.

RESULTS: The prospective study included 80 patients (73% men), mean age 64 +/- 3.5 years. Complex ventricular arrhythmias were recorded in 34 (42.5%) of patients, all 17 (50%) of which were from the first group (p < 0.01). Complex ventricular arrhythmias were recorded in 25 (73.5%) patients with late ventricular potentials, and in 23 (67.6%) patients with left ventricular ejection fraction bellow 40%. Left ventricular ejection fraction bellow 40% and late ventricular potentials represented independent predictors for the occurrence of complex ventricular arrhythmias (RR = 14.33, p < 0.01). When combined with left ventricular ejection fraction bellow 40%, late ventricular potentials had sensitivity (0.50), specificity (0.93), and positive predictive accuracy (0.85) higher than late ventricular potentials alone (0.44, 0.67, and 0.37, respectively) for the occurrence of complex ventricular arrhythmias following acute myocardial infarction.

CONCLUSION: In this study, late ventricular potentials in patients with left ventricular ejection fraction bellow 40% represented the independent predictor for the occurrence of complex ventricular arrhythmias in the first six months after the first myocardial infarction treated with accelerated tissue-type plasminogen activator, using the rapid protocol.