Ventricular electrical delay as a predictor of arrhythmias in patients with cardiac resynchronization implantable cardioverter defibrillator.

BACKGROUND: Left ventricular (LV) remodeling and clinical response to cardiac resynchronization therapy (CRT) is inversely related to electrical dyssynchrony, measured as LV lead electrical delay (QLV). Presence of atrial or ventricular arrhythmia is correlated with worsening heart failure and LV remodeling.

OBJECTIVE: We sought to assess the association of QLV with arrhythmic events in CRT recipients.

METHODS: We identified patients implanted with a CRT device at our center. QLV interval was measured and corrected for baseline QRS (cQLV). We performed multivariable Logistic regression to assess the effect of cQLV on the occurrence of atrial/ventricular arrhythmic events.

RESULTS: Sixty-nine patients were included in analyses. The cQLV was significantly shorter in patients with atria tachycardia/supraventricular tachycardia (AT/SVT) events compared to patients without AT/SVT events (43.4 ± 22% vs. 60.3 ± 26.7%, P = 0.006). In contrast, no significant difference in cQLV was observed between patients with and without ventricular tachycardia/fibrillation (VT/VF) events (46.2 ± 25.4% vs. 56 ± 25.7%, P = 0.13). cQLV was significantly shorter in patients with new onset AT/SVT events compared to those without (38.3 ± 22.2% vs. 55.7 ± 25.7%, P = 0.028). In contrast, no significant difference in cQLV was observed between patients with and without new onset VT/VF events (44.2 ± 25.2% vs. 56.3 ± 25.5%, P = 0.069). Following adjusted analyses, cQLV was a significant predictor of AT/SVT, but not for VT/VF.

CONCLUSION: cQLV is a simple measure that can identify a vulnerable cohort of CRT patients at increased risk for atrial tachyarrhythmias, and hence can predict reverse remodeling and clinical response to CRT treatment.