Normokinesia Adjacent to Left Ventricular Aneurysm: A Differential Risk for Sudden Cardiac Death

BACKGROUND: Following myocardial infarction, the ejection fraction (EF) is an indiscriminate predictor of both non-sudden cardiac death (NSCD) and sudden cardiac death (SCD). However, development of a left ventricular aneurysm (LVA) confers independent risk only for SCD. Thus, we tested the hypothesis that mechanical factors, other than the global left ventricular performance, are causally related to SCD in the presence of LVA. METHODS: A secondary analysis was conducted from a longitudinal, prospective, long-term follow-up cohort study of 66 patients with LVA (diastolic eccentricity and systolic dyskinesia) diagnosed by ventriculography. The left ventricular contour was divided into five segments and contractility scores for the residual myocardium and the segments adjacent to the aneurysm were allocated along with assessment of the EF. A normal adjacent segment was considered present when at least one segment adjacent to the aneurysm exhibited normokinesia. Presence of ventricular tachycardia was documented by Holter recording. RESULTS: At a 5.2-year median follow-up, there were 12 NSCD and 8 SCD. The EF was lower among patients who died vs. survivors (31.5% vs. 39.7%, P=0.01). Patients with NSCD and SCD, exhibited similar EF but disparate residual contractility scores (3.0 vs. 4.1, P<0.004). Among cardiac deaths, a decreasing residual contractility score differentially predicted NSCD (odds ratio=17.06, P<0.03), while a normokinetic adjacent segment differentially predicted SCD (odds ratio=21, P<0.02). Albeit a predictor of both NSCD and SCD, ventricular tachycardia increased markedly the model significance (P<0.004) only when tested with a normokinetic adjacent segment vis-a'-vis SCD. CONCLUSIONS: In the presence of LVA, the contractility of the non-aneurysmal myocardium is a differential predictor of death from pump failure. In contrast, a normal segment adjacent to LVA constitutes an independent and discriminate predictor of SCD, possibly through an arrhythmic substrate linked to the motion discordance between the expanding aneurysm and a normokinetic adjacent myocardium.