Warning arrhythmias occurred in an equal percentage of patients with or without primary ventricular fibrillation, indicating they are poor criteria for initiating antiarrhythmic therapy.
Observational (n=262)
Are warning arrhythmias and specific ventricular ectopic beat characteristics predictive of primary ventricular fibrillation in patients with acute myocardial infarction?
Warning arrhythmias, coupling intervals, and ectopic beat configurations are not reliable predictors for the onset of primary ventricular fibrillation in acute myocardial infarction, challenging their use as criteria for initiating prophylactic antiarrhythmic therapy.
UNLABELLED: In order to evaluate the events preceding primary ventricular fibrillation (PVF), continuous tape recording was performed in 262 patients consecutively admitted to the hospital within six hours of infarction in whom antiarrhythmic therapy was withheld. Warning arrhythmias (defined as ventricular ectopic beats occurring with a frequency of more than five beats per minute, in runs, falling in the vulnerable phase of the cardiac cycle or being multiformed) were registered in an equal percentage in patients who did or did not develop PVF. Immediately prior to PVF seven patients showed sinus tachycardia, 10 a sinus rate ranging from 60 to 100 beats per minute and two bradycardia due to complete atrioventricular block. The ventricular ectopic beat initiating PVF had a late coupling interval (QR'/QT larger than or equal to 0.85) in 11 patients and a left bundle branch block configuration as frequent as a right bundle branch block. CONCLUSIONS: 1) Warning arrhythmias are not considered good criteria for institution of antiarrhythmic therapy in order to prevent PVF. 2) In patients with sinus rhythm there may be an association between heart rate and onset of PVF. 3) The malignancy of a ventricular ectopic beat is not determined by its coupling interval or its configuration.
Lie et al. (1975) conducted an observational in Acute myocardial infarction (n=262). Warning arrhythmias vs. Absence of warning arrhythmias was evaluated on Primary ventricular fibrillation (PVF). Warning arrhythmias occurred in an equal percentage of patients with or without primary ventricular fibrillation, indicating they are poor criteria for initiating antiarrhythmic therapy.