SOME OBSERVATIONS ON THE BALLISTOCARDIOGRAPHIC PATTERN, WITH SPECIAL REFERENCE TO THE H AND K WAVES 1

Abstract

Ballistocardiograph records of clinical cases and of the ejection behavior of a simple model heart are presented. Evidence to support the origin of the K-wave is found in records of coarctation of the aorta and of reactive hyperemia. Characteristic patterns of pre- and post-operative cases of coarctation of the aorta, of constrictive pericarditis and of an iliac arteriovenous fistula are also presented. The form of records with extremely large and small stroke volumes are shown as found respectively in the special conditions of aortic insufficiency and of shock. Data have been presented from the observations made in cases of heart block. This material illustrates the contribution of the auricular ejection to the ballistocardio-gram and shows that in cases with normal P-R intervals the auricular beat may produce an apparent delay in the development of the I-J wave, a delay attributed by some workers to faulty behavior of the ballistocardiograph.