Abstract
The relationship between heart sounds S3 and S4 in PCG on one hand and vibrations in lateral BCG on the other were studied referring to the clinical data. According to the author the protodiastolic lateral wave in BCG is clinically useful, while the presystolic lateral wave is not. The conclusions on protodiastolic waves are as follows. 1) S3 decreased its amplitude with aging in normal cases. 2 ) Vibrations always originated in the heart, and decrease in amplitude of S3 showed only the decrease in the capabillity of transmission. 3) Almost all cases with accentuated S3 were accompanited by accentuated protodiastolic lateral wave and their clinical conditions were very severe. 4) The cases with accentuated protodiastolic lateral wave, without accentuated S3, were considered to be the pre-stage of protodiastolic gallop rhythm and they had clinical significance. 5) Accentuated S3 without accentuated protodiastolic lateral wave was not clinically significant. 6) Protodiastolic lateral wave originated from right ventricle was accompanied by accentuated S3, only when its amplitude became very large.
