Victims of Sudden Cardiac Death with Ambiguous Autopsies: Potential for Erroneous Interpretation

1148, either, cat. 46

VICTIMS OF SUDDEN CARDIAC DEATH WITH AMBIGUOUS AUTOPSIES: POTENTIAL FOR ERRONEOUS INTERPRETATION?

H. Raju1, M. Papadakis1,2, M. Govindan1, R. Bastiaenen1, N. Chandra1,2,

N. Edwards1, A. O'Sullivan2,3, M.N. Sheppard4, E. Behr1, S. Sharma1,2

1St George's University of London, 2University Hospital of Lewisham, 3King's College Hospital, 4Royal Brompton Hospital, London, UK

Background: The term sudden arrhythmic death syndrome (SADS) is used for victims of sudden cardiac death (SCD) without identifiable cardiac pathology at autopsy and is commonly attributed to inherited ion-channelopathies. Ambiguous autopsy findings, such as ventricular hypertrophy or dilatation, myocardial fibrosis, floppy mitral valve and minor coronary artery disease result in uncertainty regarding their causal effect. We explored the hypothesis that a proportion of such deaths may represent SADS.

Methods: Between 2003 and 2009, we evaluated 1st-degree relatives of 340 victims of SCD who had undergone post-mortem evaluation. Forty (12%) families, comprising of 149 relatives, in whom the deceased exhibited non-specific histopathological findings were included in the study. Relatives underwent comprehensive cardiovascular evaluation with 12-lead ECG, echocardiogram, exercise testing, Holter monitor, Ajmaline provocation test and cardiac MRI, as appropriate.

Results: Following cardiovascular evaluation of 1st-degree relatives, 20 out of the 40 families (50%) received a diagnosis: 13, Brugada syndrome (BS); 4, long QT syndrome (LQT); 1 catecholaminergic polymorphic ventricular tachycardia (CPVT); 1, dilated cardiomyopathy; and 1, hypertrophic cardiomyopathy. Thirty-nine (26%) relatives received a diagnosis of a previously unsuspected condition.

Discussion: An ion-channelopathy was identified following comprehensive cardiovascular assessment of 1st-degree relatives in 18 (45%) cases of SCD with non-specific features at autopsy, raising the possibility that a proportion of ambiguous post-mortem findings may represent innocent bystanders or a trigger for arrhythmia in an individual with a pre-existing ion-channelopathy. Sudden cardiac deaths with inconclusive histopathological findings should be regarded as SADS deaths and comprehensive evaluation of family relatives is recommended.