Right Bundle Branch Block and Cardiac Infarction

Right bundle branch block is not rare in healthy subjects and was found 7 times when 1445 healthy persons were examined by Wood, Jeffers, and Wolferth (1935).The present analysis is based on 20 cases (see Fig. 1 and Table, Cases 1-20).In 7 cases Q deflections were shown in lead I; they were less frequent and never large in lead IL.The upstroke of the main deflection and the beginning of the downstroke were slender and steep as in normal curves.The R-T segment showed no significant depression or elevation except for a gradual rise if the following T was high and set close to the QRS complex.The T waves were upright in leads I and II in all cases.The chest lead cardiogram of right branch block, made famiLiar through the work of Wilson and his collaborators (1934, 1944), was examined in 14 cases, and it included leads from the right precordial area in 11.Lead CR1 or VI showed a bifid QRS complex, with two peaks above the isoelectric line; in some records the initial peak was of low voltage (see Fig. 1D); there were no Q waves; the R-T segment was either level with the TABLE OF CASES CLINICAL DIAGNOSIS Healthy subject.Retinal arteriosclerosis, normal heart.Healthy subject.Bronchitis.Bronchitis.Healthy subject.Healthy subject