Relation Between Amplitude of First Heart Sound and Duration of P-Q Interval in Dogs With Atrioventricular Block

Publisher Website
Google Scholar
Abstract
Curves that relate the amplitude of the first heart sound to the P-Q interval have been obtained in 13 dogs with complete atrioventricular (AV) heart block. The amplitude was highest at a P-Q interval of approximately 0.05 second, became lowest at a P-Q interval of 0.13 second and continued low for intervals up to 0.25 second or longer and then increased again to some extent with further prolongation of the P-Q interval. Cardiac failure or infusions into peripheral or pulmonary veins caused an earlier and higher rise of the amplitude with very long P-Q intervals, whereas exsanguination had the opposite effect. These factors probably alter reopening of the AV valves during atrial diastole and thereby change the intensity of the first heart sound.

This publication has 2 references indexed in Scilit: