Abstract Body (Do not enter title and authors here): Introduction: Cardiac Resynchronization Therapy-Defibrillator (CRT-D) use has increased over the past two decades. As this procedure often also involves patients with a prior history of myocardial infarction(MI), we aim to evaluate potential sex-based disparities in short-term complications among the elderly.

Methods: Our sample consisted of patients ages >60 years with a prior history of myocardial infarction undergoing CRT-D. The data was extracted via the 2016-2021 National Inpatient Sample(NIS). Adjusted odds ratios(aOR) of in-hospital complications between Females and Males were estimated using multivariable regression analyses, taking into account potential confounders.

Results: Out of 13695 CRT-D procedures among older patients (ages >60 years), 2880(21.0%) were Females, with 10815(79.0%) Males. The median age of all patients was 74.0 years(mean of 73.99 years). Females were at higher odds of experiencing cardiogenic shock (aOR 1.231, 95% CI 1.013-1.495, p=0.036), cardiac arrest(aOR 1.413, 95% CI 1.150-1.737, p=0.001), pericardial effusion(aOR 2.334, 95% CI 1.704-3.198,p=0.000), and pneumothorax(aOR 2.107, 95%CI 1.089-4.075, p=0.027) than Males. No differences were reported in events of acute kidney injury (AKI)(aOR 0.923,95%CI 0.832-1.024, p=0.132), acute ischemic stroke (AIS)(aOR 1.166, 95%CI 0.585-2.324,p=0.662), pleural effusion(aOR 0.827,95%CI 0.618-1.107, p=0.203), and sepsis(aOR 0.743,95%CI 0.506-1.092,p=0.130) between the two sexes. Furthermore, we found sex-based disparities in mortality as 1.6% of Females (vs. 1.0% of Males, aOR 1.729, 95% CI 1.161-2.576, p<0.01) did not survive their hospitalization.
Finally, our analysis noted that Males and Females did not have any differences in mean lengths of stay(LOS)(Males: 6.06 days vs. Females: 6.26 days, p=0.056).

Conclusion: Our results confirm that among the elderly with a prior history of MI, Females are prone to a poor prognosis with multiple complications during CRT-D implantations, including pericardial effusion, cardiac arrest, cardiogenic shock, and all-cause mortality. It is vital to advocate for additional studies to understand the various factors predisposing females to these complications and bring forward adequate measures to prevent them.