Abstract 17529: Incidence of Appropriate Implantable Cardioverter-Defibrillator Therapy in Patients with Ventricular Fibrillation Out of Hospital Cardiac Arrest Secondary to Myocardial Ischemia
Introduction: Current guidelines based on studies prior to the advent of PCI indicate that patients with ventricular fibrillation (VF) out of hospital cardiac arrest (OHCA) due to myocardial ischemia (MI) are not at increased risk of recurrent arrhythmias if revascularized. The outcomes of these patients in the contemporary era of PCI and ICD are not available.
Methods: We examined the incidence of recurrent ventricular arrhythmias in 114 consecutive survivors of VF OHCA during acute MI (age 64±11y, 82% male) in Olmsted County, MN from 1991 to 2010.
Results: An ICD was implanted in 46/114 patients (pts) within 40d of OHCA. Pts with an ICD had lower ejection fraction (EF) (40±18 vs 47±15%, p=0.03). During a mean follow-up of 4.4(±4.8)y, one or more appropriate ICD therapies were delivered in 19(41%), with 21 & 47% of pts experiencing events within 3 & 6 months respectively. Pts who received ICD therapy were older (66±9 vs 60±12y, p=0.05), had lower EF (27±11 vs 49±16%, p<0.0001) and less likely to be revascularized (32 vs 67%, p=0.02). EF was an independent predictor of ICD therapy [HR 0.96 (0.92-0.99), p=0.01] after adjusting for revascularization and age. Only 3 pts with EF>35% received ICD therapy, all within 1y. Amongst those who did not receive an ICD, recurrent OHCA occurred in 6/68 - 5 were either not revascularized or had EF<35%. Death occurred in 52/114 (35% cardiac death) patients during a mean follow-up of 7.8±5.4y. ICD implantation was not a significant predictor of mortality (33 vs 47%, p=0.1).
Conclusions: In the era of PCI, pts with OHCA in the setting of MI and a pre-dismissal EF<35% remain at high risk of recurrent ventricular arrhythmias, and pre-discharge ICD implantation should be considered. Patients with preserved EF have a significant early risk, which then stabilizes; the role for temporary defibrillator support such as a life-vest should be investigated.
- Cardiac arrest
- Implantable cardioconvert defibrillator
- Ventricular fibrillation
- Ejection fraction
- Myocardial infarction
- © 2012 by American Heart Association, Inc.