Complete right bundle branch block with left axis deviations: significance of vectorcardiographic morphology

Sixty-five patients with a VCG pattern of complete right bundle branch block and left axis deviation (> ?30 degrees) were studied. There were 46 patients with counterclockwise rotation (Group A) and 19 patients with clockwise rotation (Group B) in the horizontal plane. His bundle electrograms were recorded in 24 Group A patients and in four Group B patients.The Group A patients were slightly younger (average age 69 years) than the Group B patients (average age 75 years). The incidence of previous myocardial infarction (Group A $\text{12}\text{46}$, Group B $\text{4}\text{19}$) and hypertension (Group A $\text{13}\text{46}$, Group B $\text{4}\text{19}$) were similar. Diabetes mellitus was slightly more common in Group B (Group A $\text{7}\text{46}$, Group B $\text{5}\text{19}$). Cardiomegaly (Group A $\text{16}\text{46}$, Group B $\text{12}\text{19}$) and congestive heart failure (Group A $\text{13}\text{46}$, Group B $\text{9}\text{19}$) were more common in Group B. Episodes of syncope (Group A $\text{19}\text{46}$, Group B $\text{4}\text{19}$) and prolonged H-Q interval (55 msec. or greater) (Group A $\text{19}\text{24}$, Group B $\text{2}\text{4}$) were more frequent in Group A patients. However, in individual cases there was no definite relationship between prolonged H-Q interval and syncope.It is concluded that this pattern represents a wide spectrum of disease and anatomical defects. The relationship of VCG morphology to clinical course does not appear to be close enough to predict the course of an individual patient or aid in clinical management.