The purpose of this study was to determine the potential value of a novel marker for the severity of structural heart disease and the risk of arrhythmia.
Background
The ventricular ectopic QRS interval (VEQSI) has been shown to identify structural heart disease and predict mortality in an unselected population. In ischemic heart disease (IHD), risk stratification for sudden death is imperfect. We hypothesized that VEQSI would identify patients with prior myocardial infarction (MI) compared with healthy subjects and distinguish IHD patients who have suffered life-threatening events from those without prior significant ventricular arrhythmia.
Methods
The 12-lead Holter recordings from 189 patients with previous MI were analyzed: 38 with prior ventricular tachycardia/ventricular fibrillation (MI-VT/VF) (66 ± 9 years; 92% male); 151 without prior significant ventricular arrhythmia (MI-no VT/VF) (64 ± 11 years; 74% male). These were compared with 60 healthy controls (62 ± 7 years; 70% male). All ventricular ectopic beats were reviewed and maximal VEQSI duration (VESQI max) was recorded as the duration of the longest ventricular ectopic beat.
Results
VEQSI max was longer in post-MI patients compared with normal controls (185 ± 26 ms vs. 164 ± 16 ms; p < 0.001) and in MI-VT/VF patients with prior life-threatening events compared with MI-no VT/VF patients without prior life-threatening events (214 ± 20 ms vs. 177 ± 22 ms; p < 0.001). Multivariate analysis established VEQSI max as the strongest independent marker for prior serious ventricular arrhythmia. VEQSI max >198 ms had 86% sensitivity, 85% specificity, 62% positive predictive value, and 96% negative predictive value for identifying patients with prior life-threatening events (odds ratio: 37.4; 95% confidence interval: 13.0 to 107.5).
Conclusions
VEQSI max >198 ms distinguishes post-MI patients with prior life-threatening events from those without prior significant ventricular arrhythmia. This may be a useful additional index for risk stratification in IHD.
