Clinical Studies on the Mechanism for the Production of the H-wave in the Ballistocardiogram

　It is interesting and important for the　analysis of the ballistic wave to determine　whether or not the　　H-wave is produced　by auricular contraction.

　Nickerson⁴⁾　has reported that the produ—ction of the　H-wave may be relateed　to auricular contraction.

　Hamilton⁶⁾ has described that the　H-wave　is initiated by the apex thrust which oc—curs during isometric contraction.

　Brown¹⁾　said shat the apex thrust and　the right auricular systole play, a role in　the production of the H peak, and it has　been suggested by　Schaffer²⁾　that some of　the factors which are thought to be res—ponsible for the H-wave are:　auricular　contraction, apical thrust, and downward　displacement of blood in the inferior vena　cava.

　Using a high-frequency table, Shimizu　and　Akita⁷⁾　have reported as follows:　the　H-wave consists of two upward　deflections.　which are approximately the same in　magnitude but the initial deflection is not　as sharp as the 2nd deflection.

　The initial deflection may be due to the　abrupt deceleration of the inflowing blood　and the occulsion of the semilunar valve,　while the 2nd deflection may be caused　by the apex thrust which　occurs during　isometric contraction.

　We conclude that the　H-wave may not　be due to auricular contraction but to the　apical trust during ventricular contraction,　since it was possible for us to obsecve the　　H wave in the auricular fibrillation in　which effective auricular contraction is　absent, and in the ventricular premature　beat and the isofrequent　auriculo-ventri　cular dissociaiion, in which the preceeding　auricular contractions are absent.