The relationship between electrical and mechanical events in the cardiac cycle of man.

In studying the dynamics of the heart beat, the relationship between electrical and mechanical events in the cardiac cycle has been of fundamental importance. The basic concepts of this relationship have been defined by Lewis (1925) and Wiggers (1923) and their co-workers. Sir Thomas Lewis provided indirect information on these events in the right auricle of man. Animal experiments, supplemented by such indirect information as could be obtained from venous and arterial pulse wave tracings, recording of heart sounds, etc., in man were used .by Wiggers to anticipate the probable normal sequence of events in the cardiac cycle. More precise information may now be obtaiped using the method of right heart catheterization. With direct measurements from within the right heart chambers and pulmonary artery, coupled with peripheral arterial pulse wave and electrocardiographic recordings, the nqrmal course of electrical and mechanical events may be more clearly defined in man and abnormalities in contraction and conduction of the diseased heart may be further elucidated. The data thus obtained will supplement the results obtained by many other investigators and will be analysed and discussed in the light of their studies.