Prevalence of left bundle branch block in women with ischemic heart disease.

The controversy about the sex distribution in Left Bundie Branch Block (LBBB) led us to study what occurred in 56 hospitalized patient~s affected by LBBB and ischemic heart disease (IHD). In the group of acute myocardial infarction (AMI), 26 patients, with a high incidence of pump faiture (73%) an a mortality of 33%, the male/female (M/F) ratio was clearly reduced in relation to the global AMI M/F ratio (1.9:1 against 3.5:1). In the group without AMI, there was a female predosninance and, namely in cases with unstable angina, the M/F ratio was reversed (1:2 against 2:1 in the general group with unstable angina). Hypertension did not seem responsible for the absence of male prevalence in patients with IHD. The reasons of this phenomenon — the relative female prevalence of LBBB in patients with AMI, and the absolute female predominance in cases without AMI — seem to be obscure at the moment. It is possible that, for the majority of patients with JHD and LBBB, LBBB does not have a simple etiology. The hypothesis of the coexistence of IHD with a prirnary degenerative disease of the conduction system is admitted.