Sex Differences in Long-Term Outcomes With Cardiac Resynchronization Therapy in Mild Heart Failure Patients With Left
Yitschak Biton1, Wojciech Zareba1, Ilan Goldenberg1
1Heart Research Follow-up Program, Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY (Y.B., W.Z., I.G., H.K., S.M.N., B.P., A.J.M., V.K.).
Insights
Cardiac resynchronization therapy with a defibrillator (CRT-D) significantly benefits both men and women with left bundle-branch block. Women experienced greater reductions in heart failure events compared to men, regardless of QRS duration.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Conflicting data exists on cardiac resynchronization therapy (CRT) efficacy stratified by sex and QRS duration.
- Left bundle-branch block (LBBB) is a key indicator for CRT consideration.
Purpose of the Study:
- To evaluate the long-term clinical outcomes of CRT with defibrillator backup (CRT-D) versus implantable cardioverter-defibrillator (ICD) only in LBBB patients.
- To analyze the differential benefit of CRT-D based on patient sex and QRS duration.
Main Methods:
- Analysis of data from the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT).
- Comparison of CRT-D versus ICD-only in 394 women and 887 men with LBBB.
- Long-term follow-up assessing heart failure (HF) or death, death alone, and HF alone, with QRS duration dichotomized at 150 ms.
Main Results:
- Women showed a significantly greater reduction in HF or death (71%) and HF alone (77%) with CRT-D compared to men (41% and 50%, respectively).
- Both sexes experienced similar reductions in long-term all-cause mortality with CRT-D.
- The incremental benefit of CRT-D in women was consistent across QRS durations (<150 ms or >150 ms).
Conclusions:
- CRT-D provides sustained long-term benefits for both men and women with LBBB and mild heart failure.
- Women derive a greater incremental benefit from CRT-D for reducing heart failure events.
- The benefits of CRT-D are evident regardless of QRS duration in this patient population.
Background:
Previous studies have shown conflicting results regarding the benefit of cardiac resynchronization therapy (CRT) by sex and QRS duration.
Methods And Results:
In the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), we evaluated long-term clinical outcome of heart failure (HF) or death, death, and HF alone by sex and QRS duration (dichotomized at 150 ms) in left bundle-branch block patients with CRT with defibrillator backup (CRT-D) versus implantable cardioverter-defibrillator (ICD) only. There were 394 women (31%) and 887 men with left bundle-branch block. During the median follow-up of 5.6 years, women derived greater clinical benefit from CRT-D compared with implantable cardioverter-defibrillator only, with a significant 71% reduction in HF or death (hazard ratio [HR] 0.29, P<0.001) and a 77% reduction in HF alone (HR 0.23, P<0.001) compared with men, who had a 41% reduction in HF or death (HR 0.59, P<0.001) and a 50% reduction in HF alone (HR 0.50, P<0.001) (all sex-by-treatment interaction P<0.05). Men and women had similar reduction in long-term mortality with CRT-D versus implantable cardioverter-defibrillator only (men: HR 0.70, P=0.03; women: HR 0.59, P=0.04). The incremental benefit of CRT-D in women for HF or death and HF alone was consistent with QRS <150 or >150 ms.
Conclusions:
During long-term follow-up of mild HF patients with left ventricular dysfunction and wide QRS, both women and men with left bundle-branch block derived sustained benefit from CRT-D versus implantable cardioverter-defibrillator only, with significant reduction in HF or death, HF alone, and all-cause mortality regardless of QRS duration. There is an incremental benefit with CRT-D in women for the end points of HF or death and HF alone.
Clinical Trial Registration:
URL: https://clinicaltrials.gov/. Unique identifiers: NCT00180271, NCT01294449, and NCT02060110.
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