Left Ventricular Ejection Fraction Normalization in Cardiac Resynchronization Therapy and Risk of Ventricular Arrhythmias and Clinical Outcomes

Abstract

C onsiderable clinical decision making revolves around the use of left ventricular ejection fraction (LVEF) for prognosis and for indications for use of both implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT). Guidelines support implantation for CRT for heart failure (HF) patients with LVEF ≤30% with left bundle-branch block (LBBB), sinus rhythm, and New York Heart Association (NYHA) class II, class III, and ambulatory class IV HF symptoms (Class IA recommendation). Similarly, guidelines support implantation of an ICD in postmyocardial infarction patients with LVEF ≤35% (Class IA recommendation) and in nonischemic cardiomyopathy HF Background-Appropriate guideline criteria for use of implantable cardioverter-defibrillators (ICDs) do not take into account potential recovery of left ventricular ejection fraction (LVEF) in patients treated with CRT-defibrillator. Methods and Results-Patients randomized to CRT-defibrillator from the Multicenter Automatic Defibrillator ImplantationTrial With Cardiac Resynchronization Therapy (MADIT-CRT) trial who survived and had paired echocardiograms at enrollment and at 12 months (n=752) were included. Patients were evaluated by LVEF recovery in 3 groups (LVEF ≤35% [reference], 36%-50%, and >50%) on outcomes of ventricular tachyarrhythmias (VTAs), VTA ≥200 bpm, ICD shock, heart failure or death, and inappropriate ICD therapy by multivariable Cox models. A total of 7.3% achieved LVEF normalization (>50%). The average follow-up was 2.2±0.8 years.

Patients upgraded to cardiac resynchronization therapy due to pacing-induced cardiomyopathy are at low risk of life-threatening ventricular arrhythmias: a long-term cause-of-death analysis

“…However, it remains unknown whether these patients are at high risk of life-threatening ventricular arrhythmias thus requiring defibrillator back-up. Responders and super-responders to CRT have annual appropriate device therapy incidences of 1.7% to 5.4%, with most studies reporting incidences <2.4%/year (17)(18)(19)(20)(21). In the Mona Lisa cohort study, a 4.3% risk of sustained VT in the first 12 months of follow-up was seen in chronic heart failure patients implanted with CRT-P (9).…”

Heart Failure with Recovered Ejection Fraction in a Cohort of Elderly Patients with Chronic Heart Failure

“…Other studies have shown that the cessation of medical therapy is associated with the recurrence of left ventricular dysfunction in patients who had previously improved or recovered their LVEF [7,8,9]. In addition, a better prognosis has been described among patients who achieve LVEF normalization after cardiac resynchronization [10]. Recently, a small retrospective study has proven that an early improvement in different echocardiographic parameters (left ventricular end-systolic dimension, right ventricular function and mitral regurgitation) are independent predictors of 5-year survival, suggesting that serial echocardiograms may aid in stratifying patient care [11].…”

Ventricular arrhythmias and survival of patients after cardiac resynchronization therapy in the setting of real-life clinical practice

“…Возможными механизмами подавления ЖТ / ФЖ при СРТ являются как снижение электрической нестабиль-ности вследствие уменьшения электрической и механи-ческой диссинхронии, так и такие факторы, как улучше-ние сократительной способности миокарда и подавле-ние аритмий, провоцируемых паузами [8]. Наибольшее снижение риска аритмий отмечается при нормализа-ции ФВ ЛЖ на фоне СРТ [9]. По данным нашей кли-ники, анализ выживаемости без достижения конечной точки первое мотивированное срабатывание функции кардиовертера-дефибрилятора также позволяет пола-гать, что ЖТ и ФЖ чаще возникали в группе больных с имплантированным ИКД, чем в группе пациентов с имплантированными системами СРТ-Д.…”