October 10, 2014Circulation183 citations
View Full PaperLeft Ventricular Ejection Fraction Normalization in Cardiac Resynchronization Therapy and Risk of Ventricular Arrhythmias and Clinical Outcomes
Key Result
LVEF normalization (>50%) following CRT-defibrillator implantation significantly reduced the risk of ventricular tachyarrhythmias compared to LVEF ≤35% (HR 0.24; 95% CI 0.07-0.82; P=0.023).
Study Design
Type
RCT (n=752)
Randomization
randomized
Multicenter
Yes
Structured PICO
Does LVEF normalization (>50%) reduce the risk of ventricular tachyarrhythmias and clinical outcomes in patients treated with CRT-defibrillator?
P
Population
752 patients from the MADIT-CRT trial randomized to CRT-defibrillator who survived and had paired echocardiograms at enrollment and at 12 months
I
Intervention
LVEF recovery to >50% or 36%-50% at 12 months post-CRT-D implantation
C
Comparator
LVEF ≤35% at 12 months (reference group)
O
Outcome
Ventricular tachyarrhythmias (VTAs)hard clinical
Patients achieving LVEF normalization (>50%) after CRT-D implantation have a significantly reduced risk of ventricular tachyarrhythmias and may be candidates for downgrade to CRT-P at battery depletion.
Main Result
Effect estimate: HR 0.24 (95% CI 0.07-0.82)
p-value: p=0.023
Abstract
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 Implantation Trial 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. The risk of VTA was reduced in patients with LVEF >50% (hazard ratio HR, 0.24; 95% confidence interval CI, 0.07-0.82; P=0.023) and LVEF of 36% to 50% (HR, 0.44; 95% CI, 0.28-0.68; P50%, only 1 patient had VTA ≥200 bpm (HR, 0.16; 95% CI, 0.02-1.51), none were shocked by the ICD, and 2 died of nonarrhythmic causes. The risk of HF or death was reduced with improvements in LVEF (LVEF >50%: HR, 0.29; 95% CI, 0.09-0.97; P=0.045; and LVEF of 36%-50%: HR, 0.44; 95% CI, 0.28-0.69; P50% was seen compared with an LVEF of 36% to 50%. A total of 6 factors were associated with LVEF normalization, and patients with all factors present (n=42) did not experience VTAs (positive predictive value, 100%). CONCLUSIONS: Patients who achieve LVEF normalization (>50%) have very low absolute and relative risk of VTAs and a favorable clinical course within 2.2 years of follow-up. Risk of inappropriate ICD therapy is still present, and these patients could be considered for downgrade from CRT-defibrillator to CRT-pacemaker at the time of battery depletion if no VTAs have occurred. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00180271.