Abstract 2503: Emerging Roles of Coronary Vasospasm and Ventricular Fibrillation in the Pathogenesis of Out-of-Hospital Cardiac Arrest
Background: The prevalence of sudden death in the absence of structural heart disease (termed as Pokkuri disease in Japan) is high in Asian males. However, the pathogenesis of such out-of-hospital cardiac arrest (OHCA) remains to be elucidated. It is conceivable that both coronary vasospasm and ventricular fibrillation (VF) play key roles in this disorder.
Methods: Between December 2004 and March 2009, we enrolled consecutive 15 patients (male/female, 14/1; age, 42±13 [SD] years) who survived from OHCA but had no structural heart disease. In those patients, we performed the dual induction tests for coronary vasospasm with intracoronary acetylcholine and VF with electrophysiological study after their full recovery from OHCA event. We first performed the induction test for coronary spasm and when positive, we performed the induction test for VF 1~2 weeks after initiation of Ca channel blocker. We also performed a drug challenge test using sodium channel blockers for the diagnosis of Brugada syndrome.
Results: In all patients, VF had been documented as an initial rhythm during resuscitation for OHCA. Left ventricular ejection fraction was well preserved (66±7%). Importantly, all patients were positive for either test; coronary spasm alone in 3, VF alone in 3, and both of them in 9. ECG changes typical for Brugada syndrome was induced in 2 patients with VF alone and in 2 with both coronary spasm and VF. All patients subsequently underwent implantable cardioverter defibrillator (ICD) implantation for secondary prevention of OHCA. During the follow-up period of 18±13 months, appropriate ICD shocks for VF were documented in 2 patients with both coronary spasm and VF and in 1 with VF alone. VF-free survival rate at 1- and 2-year was 82% and 70%, respectively. All patients were free of recurrence of OHCA or any other cardiovascular events except the recurrence of VF with appropriate ICD shocks.
Conclusions: All patients survived from OHCA without structural heart diseases were positive for either coronary vasospasm or VF, suggesting the heterogeneous causes of OHCA as well as the importance of the dual induction tests for the therapeutic strategy of the disorder. It remains to be examined whether ICD therapy could improve the prognosis of OHCA patients with coronary spasm.