Abstract 9885: Progressive Worsening of Left Ventricular Size and Function is Associated with Increased Ventricular Arrhythmia Burden Among Patients Undergoing Cardiac Resynchronization Therapy

Background Ventricular tachycardia and fibrillation (VT/VF) may increase as systolic heart failure worsens. The effect of progressive decline in LV function despite cardiac resynchronization therapy (CRT) on the incidence of VT/VF has not been described. Methods The relationships between changes in LV size and function and incident VT/VF were analyzed in 115 patients who underwent CRT implant. Baseline and 6 month post-CRT echocardiograms were used to determine LV remodeling. Progressors were defined by both increase in LV end-systolic dimension (LVESD) and decrease in left ventricular ejection fraction (LVEF) after CRT. Responders were defined as >5% absolute increase in LVEF or 10% decrease in LVESD, and all other patients were defined as Non-Progressors. The primary endpoint was time to VT/VF requiring device therapy for 5 years after CRT implant. Results At 6 months, 67% of patients were Responders, 22% were Non-Progressors and 11% were Progressors. There were no baseline differences between the 3 groups in medications, comorbidities, LVEF, LVESD, cardiomyopathy type, NYHA class, prior VT/VF, or renal function. Progressors were at significantly increased risk of VT/VF compared to either Non- Progressors (p=0.0431) or Responders (p = 0.0018)(figure). There was no significant difference in VT/VF comparing Non-Progressors to Responders (p=0.4151). Conclusions CRT patients with worsening in both LV size and function 6 months after CRT placement have a significantly increased incidence of VT/VF compared to patients with no change or improvements in these parameters. “Progressors” despite CRT thus represent a high-risk population for VT/VF who warrant close follow-up.