The prevalence and outcome of ventricular arrhythmias in acute myocardial infarction

One hundred and seventy-two consecutive cases of acute myocardial infarction (MI) admitted to a coronary care unit were studied with regard to ventricular arrhythmias - pre-mature ventricular contractions (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF). Sixty-seven (39%) patients had ventricular arrhythmias (PCC-VT-VF), of whom 17 (9.8%) had VT and 11 (6.4%) VF. VT and VF, but not total arrhythmias, were more common in anterior infarctions. Fifty-six out of 67 (83.5%) of these patients arrived at Accident & Emergency (A&E) within the first six hours of onset of chest pain. Ten out of 11 (91 %) patients who had VF did so in the first six hours. PVCs were poor predictors of the occurrence of VF (positive predictive value 5.9%). Forty-three patients (84%) who had PVCs did not develop any further arrhythmias. Spontaneous heart rate had no influence on the occurrence of ventricular arrhythmias. Frequent PVCs were more commonly associated with progression to VT and VF. In 30 cases (88%) lignocaine was effective. There was no death due to VT/VF and all responded to drugs and/or cardioversion.