Gender difference in coronary sinus anatomy and left ventricular lead pacing parameters in patients with cardiac resynchronization therapy

Background: Recent studies have suggested better outcomes from cardiac resynchronization therapy (CRT) in women. Gender differences in coronary sinus (CS) anatomy and left ventricular (LV) lead parameters in patients undergoing CRT, however, have not been well studied. Methods and Results: Two hundred and twenty-three consecutive patients, undergoing CRT at the University of California in San Diego Medical Center from 2003 to 2011 were included in this study. The location of the LV lead was assessed on coronary venography and chest X-ray recorded at the time of device implantation. Optimal LV lead position was defined as either mid-lateral or posterolateral LV wall. The relationship between LV lead position (optimal or non-optimal position) and LV lead parameters at completion of implant were compared between genders. No statistically significant gender differences were noted in baseline characteristics. LV lead implantation was successful in 217 patients (97.3%). Lateral or posterolateral CS branches were unavailable in more women than men (26.3% vs. 10.8%, P=0.011). Women had a higher LV lead pacing threshold than men (P=0.003) and gender was an independent risk factor of high LV lead pacing threshold (P=0.008). Conclusions: Women had an anatomical disadvantage for LV lead placement and had higher LV lead pacing threshold compared to men. Implanting physicians should be aware of gender differences during LV lead placement in order to maximize CRT benefits.