Cardiac resynchronization therapy: potential for arrhythmic risk modification

• Published in: Kardiovaskuli͡a︡rnai͡a︡ terapii͡a︡ i profilaktika Vol. 22; no. 5; p. 3555
• Main Authors: Ilov, N. N., Boitsov, S. A., Krivosheev, Yu. S., Nechepurenko, A. A.
• Format: Journal Article
• Language: English; Russian
• Published: SILICEA-POLIGRAF» LLC 08.06.2023
• Subjects: cardiac resynchronization therapy; heart failure; implantable cardioverter-defibrillator; ventricular tachyarrhythmias
• ISSN: 1728-8800; 2619-0125
• DOI: 10.15829/1728-8800-2023-3555

Aim . To evaluate the impact of cardiac resynchronization therapy (CRT) on the risk of sustained ventricular tachyarrhythmias (VT) in patients with heart failure (HF) with a implantable cardioverter-defibrillator (ICD) for the primary prevention of sudden cardiac death. Material and methods . This single-center prospective clinical study included 470 patients (men, 84%) with HF at the age of 57 (51-62) years with a left ventricular ejection fraction (LVEF) of 29 (25-33)%. There were following exclusion criteria: indications for cardiac surgery, known channelopathies, previously registered VT. Depending on intraventricular conduction disorders, dual-chamber ICDs (42%) or CRT-D (58%) were implanted. After ICD implantation, patients were followed up for 24 months to register the end point — a first-time sustained paroxysm of VT detected by the ICD. A positive response to CRT was established in the case of an increase in LVEF by ≥5% of the initial level. Results . A total of 388 patients underwent full postoperative follow-up. The studied arrhythmic endpoint occurred on average 21 (0,6) months after implantation in 104 patients (27%) with higher frequency in the ICD group. However, the differences in the VT rate in the study groups were statistically unreliable (30% in the ICD group versus 24% in the CRT-D group, p=0,142). It was found that the VT rate was reliably lower in CRT-responders (118 patients, 53%): 15% compared to 32% in the group of inefficient CRT. A 5% increase in the LFEF reduced the probability of VT occurrence by 3 times (odds ratio [OR]=0,34; 95% of CI: 0,13-0,86; p=002). Significant modification of arrhythmic risk was verified by increasing LFEF to 36-40% (OR=0,72; 95% CI: 0,63-0,82; p=0,04). Conclusion . The results obtained indicate that effective CRT has the potential to modify arrhythmic risk in patients with HF, especially with an increase in LVEF to the level of 36-40%.