Background Cardiac implantable electronic devices (CIEDs) include pacemakers, cardioverter defibrillators, and resynchronization therapy. This study aimed to assess CIED implantation and outcomes by sex and indication. Methods and Results This was a retrospective cohort study of adults with cardiovascular hospitalizations in New South Wales, Australia (2008 to 2018). CIED implantation in patients with arrhythmia, cardiomyopathy, and syncope were examined. Subcategories (complete heart block, atrial fibrillation/atrial flutter, ventricular tachycardia/ventricular fibrillation/cardiac arrest, sick sinus syndrome, and ischemic and nonischemic cardiomyopathy) were investigated. Primary outcome was implantation of CIEDs in men versus women adjusted for age and comorbidities. Secondary outcomes were trends over time, time to implant, length of stay, emergency status, and 30-day survival. Of 1 291 258 patients with cardiovascular admissions, 287 563 had arrhythmia, cardiomyopathy, or syncope and 29 080 (2.3%) received a CIED (22 472 pacemakers, 6808 defibrillators, 3207 resynchronization therapy). Women with arrhythmia, cardiomyopathy, or syncope were less likely to have pacemakers (adjusted odds ratio [aOR], 0.78 [95% CI, 0.76-0.80]), defibrillators (aOR, 0.4, [95% CI, 0.40-0.45]) and resynchronization therapy (aOR, 0.66 [95% CI, 0.61-0.71]). Differences persisted across subcategories, including fewer pacemakers in complete heart block (aOR, 0.89 [95% CI, 0.80-0.98]) and syncope (aOR, 0.70 [95% CI, 0.63-0.79]); fewer defibrillators in ventricular tachycardia/ventricular fibrillation/cardiac arrest (aOR, 0.69 [95% CI, 0.61-0.77]); and less resynchronization therapy in cardiomyopathy (aOR, 0.62 [95% CI, 0.51-0.75]). Men and women receiving devices had higher 30-day survival compared with those who did not receive a device, and 30-day survival was similar between men and women receiving devices. Conclusions Lower CIED implantation was seen in women versus men, across nearly all indications, including complete heart block and ventricular tachycardia/ventricular fibrillation/cardiac arrest. The underuse of cardiac devices among women may arguably reflect a sex bias and requires further research.
Keywords: cardiac implantable electronic devices; cardiac resynchronization therapy; implantable cardioverter defibrillator; pacemaker; sex.