Abstract 3803: Influence of Autopsy Records on Classification of Sudden Unexpected Death in Patients With Myocardial Infarction and Left Ventricular Dysfunction, Heart Failure or Both
Background: Sudden unexpected death (SD) is highest in the early post-myocardial infarction (MI) period, yet the DINAMIT and the IRIS trials showed no improvement in mortality with early ICD placement after MI.
Methods: To better understand the causes of SD following MI, we assessed how autopsy records influenced classification of SD events in patients from the Valsartan in Acute Myocardial Infarction Trial (VALIANT). Of 398 patients with autopsy results (14% of deaths), 105 had clinical circumstances consistent with SD, yet final adjudication in the trial took into account autopsy records if available. We evaluated the influence of autopsy on death classification and the influence of timing following MI on specific cause of death.
Results: Of 105 SD events based on clinical circumstances, autopsy-based cause of death were: 28 (27%), recurrent MI; 13 (12%), cardiac rupture; 3 (3%), index MI in the first 7 days; 4 (4%), pump failure; 2 (2%), other cardiovascular (stroke or pulmonary embolism); 3 (3%), non-cardiovascular. 52 (50%) had no specific autopsy evidence other than the index MI and were thus presumed arrhythmic. The rate of SD due to recurrent MI and/or rupture was highest in the first 3 months after the index MI. By contrast, after 3 months, the rate of presumed arrhythmic death was higher than recurrent MI until 18 months when both events were equivalently low.
Conclusion: Recurrent MI or cardiac rupture accounts for a high proportion of death in patients dying suddenly and unexpectedly in the early period following acute MI, while arrhythmic death may be more likely subsequently. These findings may help explain the lack of benefit of early ICD therapy.