Persistent improvement of ejection fraction in patients with a cardiac resynchronisation therapy defibrillator correlates with fewer appropriate ICD interventions and lower mortality

• Published in: Swiss medical weekly 2016, Vol.146 (1314), p.w14300-w14300
• Main Authors: Schaer, Beat, Frey, Simon, Sticherling, Christian, Osswald, Stefan, Reichlin, Tobias, Kühne, Michael
• Format: Article
• Language: English
• Subjects: Aged; Arrhythmias, Cardiac - epidemiology; Arrhythmias, Cardiac - physiopathology; Cardiac Resynchronization Therapy (CRT); Cardiac Resynchronization Therapy - methods; Cardiac Resynchronization Therapy Devices; Cardiac Resynchronization Therapy Pacemaker (CRT-P); Cardiac Resynchronization Therapy plus Defibrillator (CRT-D); Defibrillators, Implantable; Disease Progression; Female; Heart Failure - etiology; Heart Failure - mortality; Heart Failure - physiopathology; Heart Failure - therapy; Humans; Implantable Cardioverter Defibrillator (ICD); Left Ventricular Ejection Fraction (LVEF); Long-term follow-up; Male; Middle Aged; Mortality; Myocardial Ischemia - complications; Retrospective Studies; Stroke Volume; Treatment Outcome
• ISSN: 1424-7860; 1424-3997
• DOI: 10.4414/smw.2016.14300

Cardiac resynchronisation therapy with defibrillator back-up (CRT-D) is a well-established treatment option for selected heart failure patients. Left ventricular ejection fraction (LVEF), an important risk determinant of life-threatening arrhythmias, can substantially ameliorate with CRT. Our hypothesis was that patients with LVEF improvement to >40% have a lower arrhythmic risk and fewer appropriate defibrillator therapies beyond year one. In this retrospective analysis, all 175 patients with CRT-D implanted from February 2000 to June 2011 and follow-up of >2 years were identified. Every available echocardiography recording was collected. LVEF measurements were grouped to baseline and yearly intervals (±6 months). All appropriate defibrillator therapies were considered events. Age at implant was 65 ± 10 years, 86% were male, and 45% patients had ischemic cardiomyopathy. Follow-up was 5.5 ± 2.6 years. LVEF at implant was 25 ± 6%, increased to 34 ± 12% after one year and remained stable thereafter. 39% (69) of patients experienced a sustained increase of LVEF to ≥40%, 14% of them had tachyarrhythmic events (versus 42.5% in those without such increase). Independent predictors for increase were higher baseline LVEF (HR 1.08 (95%-CI 1.04-1.28) per 1% increase) and lack of amiodarone (HR 0.37, 95%-CI 0.16-0.84). With cut-off values of >40%, >45% and >50%, the study hypothesis was refuted in 7%, 2.5% and 5%, respectively. Cumulative 5-year survival was 95% in improvers versus 73% in non-improvers (p 40% in 1/3 of patients. These patients experienced significantly fewer arrhythmias during long-term follow-up when compared to patients with persisting LVEF