Long-term risk of ventricular arrhythmia in dilated cardiomyopathy by response to cardiac resynchronization therapy.

BACKGROUND

Improvements in pharmacological treatments and cardiac resynchronization therapy (CRT) raise questions about the benefit of implantable cardioverter defibrillators (ICDs) in non-ischaemic dilated cardiomyopathy (NI-DCM). In this context, the long-term incidence of ventricular arrhythmia events (VAEs) by response to CRT remains under-reported.

AIMS

To assess the long-term risk of VAE by response to CRT in patients with NI-DCM.

METHODS

Patients who underwent CRT-defibrillator (CRT-D) implantation for primary prevention of NI-DCM (left ventricular ejection fraction [LVEF]≤35%, bundle branch block>130ms) from February 2002 to January 2020 were retrospectively included. CRT response was defined as an increase in LVEF≥10%, with LVEF≥35% at first transthoracic echocardiography (TTE) evaluation. VAE was defined as a sudden arrhythmic death, sustained ventricular arrhythmia or device-treated ventricular arrhythmia, occurring after the first TTE evaluation.

RESULTS

A total of 192 patients (mean age 61years, 68% female, mean LVEF 25%) were included and followed for a median of 91months. Median time to first TTE evaluation after CRT-D implantation was 14months. The overall incidence of VAE was 18.8% (annual rate of 2.9%). CRT response was associated with a reduced risk of VAE (hazard ratio [HR]: 0.27, 95% CI: 0.14-0.55; P<0.001). Super responders to CRT had a lower risk of VAE compared to partial responders (HR: 0.06, 95% CI: 0.02-0.17; P<0.001). Among responders who were VAE free before generator replacement, super responders exhibited a lower incidence of VAE compared to partial responders (HR: 0.13, 95% CI: 0.02-0.82; P=0.04) after generator replacement.

CONCLUSION

In patients with NI-DCM undergoing CRT-D implantation for primary prevention, the CRT response was associated with a 73% decrease in the risk of VAE. Partial responders present a higher rate of VAE compared to super responders, persisting after generator replacement.