Abstract 17060: Implantable Cardioverter Defibrillator Events and Mortality in Unexplained Cardiac Arrest Subjects in the Cardiac Arrest Survivors With Preserved Ejection Fraction Registry (CASPER)
Background: Implantable cardioverter defibrillators (ICDs) have been shown to reduce mortality in survivors of life-threatening arrhythmias. It is important to understand the rate of ICD events and mortality among subjects with unexplained cardiac arrest.
Methods: Patients with unexplained cardiac arrest and normal cardiac function enrolled in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER) were evaluated for ICD events and mortality. A systematic evaluation including coronary angiogram, signal averaged ECG, cardiac magnetic resonance imaging, exercise testing, adrenaline and procainamide challenge, electrophysiological study and phenotype-directed genetic testing were performed in attempt to establish diagnosis.
Results: Two hundred and fourteen patients from 12 Canadian sites were studied (age 47 ± 16 years, 128 males). Two hundred and four patients (95%) received an implantable cardioverter defibrillator. One hundred and thirty-five patients (63%) had at least one follow-up visit after enrollment. After 32 months of follow-up, 27 patients (20%) had appropriate ICD shocks, 26 (19%) had anti-tachycardia pacing and 2 patients (1.5%) died. A diagnosis was obtained in 108 patients (50%): long QT syndrome in 39, catecholaminergic polymorphic ventricular tachycardia in 15, arrhythmogenic right ventricular cardiomyopathy in 14, early repolarization syndrome in 14, coronary spasm in 10, Brugada’s syndrome in 7, myocarditis in 3, dilated cardiomyopathy in 2, short QT in 1, sarcoidosis in 1, mitral annular ventricular tachycardia in 1 and congenital absence of pericardium in 1. Eighty-nine patients had ECG or clinical features suggestive of idiopathic ventricular fibrillation and the diagnosis of 17 patients remained unclear.
Conclusions: In patients with unexplained cardiac arrest, recurrent ventricular arrhythmia requiring ICD therapies were common. Systematic evaluation of these patients unmasked the cause in 50% of cases.
- Sudden cardiac death
- Ventricular arrhythmia
- Implantable cardioconvert defibrillator
- © 2013 by American Heart Association, Inc.