New findings suggest women have a significantly lower risk of first and recurrent fatalities ventricular tachyarrhythmia burden compared to male patients, but no difference in all-cause mortality risk.
Gender differences in AVT risk were found to be significantly higher in non-ischemic cardiomyopathies than in patients with ischemic cardiomyopathy, highlighting the need for gender-specific risk assessment for implantable cardioverter defibrillation therapy. (INN) primary prevention, according to the investigators.
“Nevertheless, in women, the risk of AVT remains higher than the risk of non-arrhythmic mortality, suggesting that women with both MCI and NICM benefit from ICD implantation in primary prevention,” wrote corresponding author Ilan Goldenberg, MD, Clinical Cardiovascular Research Center, Division of Cardiology, Department of Medicine, University of Rochester Medical Center.
Gender differences often have correlations between development and disease progression in patients with heart failure. Previous results have suggested a lower mortality risk in women and less benefit from CIM compared to men. However, the investigators noted that these results can be attributed to the under-representation of women in all major randomized clinical trials of ICDs, at less than 30% of enrolled patients.
The current study assessed the association between gender and the risk of first occurrence of sustained AVT, total AVT, and shock load during follow-up in an analysis of recurrent events and nonarrhythmic mortality in patients enrolled in the reference multicenter automatic defibrillator implantation trials (MADIT) from July 1997 – December 2011.
Primary endpoints were first occurrence of AVT, defined as sustained ventricular tachycardia, recorded, treated, or monitored by an ICD ≥ 170/min or ventricular fibrillation. Investigators used multivariate Cox proportional hazards regression analysis to identify and assess the association between gender and risk of VTE.
Of a total of 4506 study participants, 1075 were women (24%) with an average age of 64 years. Comparing women and men, left ventricular ejection fraction (24% versus 25%) was similar, but women had a lower frequency of ischemic cardiomyopathy (454 of 1075 women [42%] vs 2535 men out of 3431 [74%]).
Over an average follow-up of 3 years, researchers found that women had a significantly lower cumulative likelihood of sustained AVT (16% versus 26%), rapid AVT (9% versus 17%), and appropriate ICD shocks (7% vs. 15%), compared to men (P <.001 for all).
Additionally, Cox multivariate modeling showed a significantly lower risk of female gender-associated first AVV event (P <.001 for all):
- 40% less risk of sustained AVT
- 45% less risk of rapid AVT ≥ 200/min
- 44% less risk of proper ICD shock
- 39% less risk of antitachycardia pacing
Investigators further observed that the lower AVT risk associated with female gender was consistent across risk subsets. However, it was significantly more pronounced in patients with non-ischemic cardiomyopathy (female vs male in ischemic group: hazard ratio [HR}, 0.73 [95% CI, 0.56 – 0.95], P = 0.02; non-ischemic group: hazard ratio, 0.50 [95% CI, 0.38 – 0.66], P <.001; P = 0.03 for the interaction between female sex and cardiomyopathy).
“To our knowledge, this is the first study to examine gender differences not only in the initial onset of AVT or first appropriate CDI treatment, but also in the overall burden of each of these endpoints. evaluation in patients undergoing ICD implantation for primary prevention,” noted Goldenberg.
The study, “Sex Differences in the Risk of First and Recurrent Ventricular Tachyarrhythmias Among Patients Receiving an Implantable Cardioverter-Defibrillator for Primary Prevention,” was published in Open JAMA Network.
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