Tamara Colette Baynham

Ischemia/reperfusion induced intracellular calcium oscillations in the intact heart: Relation to arrhythmogenesis

Ca rd ia c Ar rh yt hm ia s DCM who were treated with ICDs were enrolled in this study. Their left ventricular ejection fraction (LVEF) was 25±9%. During a regular followup period of up to 60 months (median 21 months), these patients received frequent appropriate (34%) and inappropriate (36%) ICD therapies. The first appropriate ICD therapy occurred at 7 months (median). Approximately 2/3 of these ICD therapies occurred within one year after implantation. There was no significant difference between patients on (n=81) and off ACE inhibitors in age (51±16 vs 52±15 years, p>0.05), LVEF (25.5±8.8% vs 23.2±9.2%, p>0.05), or incidence of documented spontaneous or inducible sustained ventricular tachycardia / fibrillation before implantation (36% vs 48%, p>0.05). Fewer patients on ACE inhibitors were treated with amiodarone (21% vs 48%, p<0.05). After adjustment of age, gender, LVEF, use of antiarrhythmic drugs, and incidence of pre-implant documented spontaneous or inducible sustained ventricular arrhythmias, the incidence of appropriate ICD therapy was significantly lower in patients on ACE inhibitors than those off ACE inhibitors (log rank p<0.05). At one year after implantation, ACE inhibitor therapy was associated with an 80% reduction in appropriate ICD therapy in these patients (18% vs 33%, log rank p<0.05). Conclusion: ACE inhibitor therapy may substantially reduce the incidence of appropriate ICD therapy in patients with CHF secondary to idiopathic DCM. These observations suggest that ACE inhibitors may have important direct and/or indirect antiarrhythmic actions.