Prognostic implications of complicated ventricular arrhythmias early after hospital discharge in acute myocardial infarction: A serial ambulatory electrocardiography study

Abstract

To assess the prevalence and prognostic implications of complicated ventricular ectopic depolarizations (VEDs) after hospital discharge in patients with acute myocardial infarction (AMI), we obtained serial 24-hour Holter recordings in 85 patients during the first 6 weeks after AMI. Recordings were obtained during two coronary care unit time intervals, two hospital ward time intervals, and during four weekly time intervals after discharge. Complicated VEDs were defined as unifocal VEDs ≥ 10 1000 beats for 24 hours, multiform VEDs, pairs, or ventricular tachycardia. At 1 year follow-up, there were nine cardiac deaths (six sudden deaths and three deaths from recurrent AMI). The mean left ventricular ejection fraction at discharge in the cardiac death patients was 29 ± 12% (sudden death patients 24 ± 11% and AMI death patients 40 ± 6%) compared to 49 ± 13% in the survivors ( p < 0.001). Patients with complicated VEDs at discharge (2 weeks after AMI) or during the first 4 weeks after discharge (3 to 6 weeks after AMI) were significantly more likely to have sudden death at follow-up compared to patients without complicated VEDs. Of the six sudden death patients, four (66%) had complicated VEDs at discharge compared to 18 of 68 survivors (26%) ( p < 0.05). One of there patients who died of recurrent AMI had complicated VEDs. No Holter data were obtained at hospital discharge in eight of the survivors. Of the six patients with sudden death at follow up, six (100%) had complicated VEDs on three or more 24-hour Holter recordings during the first 4 weeks after discharge compared to 21 of 76 survivors (28%) ( p < 0.001). We conclude that AMI patients with complicated VEDs at discharge or during the first 4 weeks after discharge are at increased risk for sudden death at follow-up. Moreover, the persistence or appearance of complicated VEDs early after discharge in AMI patients may be a marker of continued or acquired myocardial electrical instability and for increased risk of sudden death at follow-up.