Cardiac Resynchronization in Women: A Substudy of the Resynchronization-Defibrillation for Ambulatory Heart Failure
Dominique de Waard1, Jaimie Manlucu2, Anne M Gillis3
1Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
Insights
Cardiac resynchronization therapy with defibrillator (CRT-D) significantly reduced mortality and heart failure hospitalizations in women compared to men. Women also experienced fewer ventricular arrhythmias with CRT-D.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy with defibrillator (CRT-D) is known to reduce mortality and heart failure hospitalizations.
- Previous studies indicated a potentially greater benefit in women compared to men, but data on ventricular arrhythmias were unclear.
Purpose of the Study:
- To evaluate the comparative effectiveness of CRT-D versus implantable cardioverter-defibrillator (ICD) in women and men regarding mortality, heart failure hospitalization, and ventricular arrhythmia.
- To investigate potential sex-based differences in response to CRT-D therapy.
Main Methods:
- A post hoc analysis of the RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure Trial) study.
- 1,798 patients randomized to ICD or CRT-D were analyzed, comparing outcomes between women and men using multivariable models.
- Outcomes assessed included death, heart failure hospitalization, and incidence of ventricular arrhythmia.
Main Results:
- Women receiving CRT-D showed significantly reduced rates of death and heart failure hospitalization compared to men receiving CRT-D (HR 0.52).
- Women with a primary prevention indication and CRT-D had the lowest incidence of ventricular arrhythmia compared to men (HR 0.59).
- The analysis included 308 women (17%) and 1,490 men (83%).
Conclusions:
- Women experience improved outcomes (reduced mortality and heart failure hospitalizations) with CRT-D compared to men.
- Women treated with CRT-D are less likely to experience ventricular arrhythmia than men.
- Further research is needed to understand the underlying sex differences contributing to enhanced CRT-D response.
Objectives:
This study sought to evaluate the effect of cardiac resynchronization therapy with defibrillator (CRT-D) as compared with implantable cardioverter-defibrillator (ICD) on mortality, heart failure (HF) hospitalization, and ventricular arrhythmia in women versus men.
Background:
CRT-D has demonstrated reduced mortality and HF hospitalizations with greater benefit observed in women compared with men. However, whether CRT-D prevented ventricular arrhythmias in women compared with men was unclear.
Methods:
The RAFT (Resynchronization-Defibrillation for Ambulatory Heart Failure Trial) study randomized 1,798 patients to an ICD or CRT-D. In this post hoc analysis, women and men were compared by randomized group. By using a multivariable model, the outcomes of death and HF hospitalization and incidence of ventricular arrhythmia were compared between men and women.
Results:
There were 1,490 (83%) men (732, ICD; 758, CRT-D) and 308 (17%) women (172, ICD; 136, CRT-D) included in the analysis. Women with CRT-D had a significantly reduced incidence of death and HF hospitalization compared with men with CRT-D (hazard ratio: 0.52; 95% confidence interval: 0.33 to 0.81; p < 0.001) on multivariable analysis. Women with a primary prevention indication and CRT-D had the lowest rate of ventricular arrhythmia compared with men (hazard ratio: 0.59; 95% confidence interval: 0.39 to 0.91; p = 0.016).
Conclusions:
Women have improved rates of death and HF hospitalization with CRT-D and were less likely to experience ventricular arrhythmia when compared with men, after adjusting for differences in baseline characteristics over a prolonged follow-up. Whether these improved outcomes reflect inherent sex differences in the underlying myocardial substrate resulting in an enhanced response to CRT-D requires further research.
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