Studies utilizing the portable electromagnetic ballistocardiograph. III. The ballistocardiogram in bundle branch block

Ballistocardiographic studies were done on 28 subjects with left bundle branch block and on 18 subjects with right bundle branch block. The influence of ventricular asynchronism, and the predominance of left or right ventricular disease, upon the derivation and interpretation of the ballistocardiogram, is discussed. The ballistocardiogram was found to be a valuable objective guide in the detection of subjects whose bundle branch block was not associated with significant heart disease. The ballistocardiogram also provided helpful confirmatory evidence of coronary artery or hypertensive heart disease when this was the suspected or certain diagnosis in subjects with bundle branch block.

The Syndrome of Short P-R Interval Normal QRS Complex and Paroxysmal Rapid Heart Action

A short A-V conduction time, whether present with normal or with abnormal QRS complex, is associated with an increased incidence of paroxysmal rapid heart action. There are a considerable number of patients who have a short P-R interval, normal QRS complex and bouts of tachycardia. They are usually females, in middle life, devoid of organic heart disease and exhibit a snapping apical first heart sound. They do not demonstrate any of the features of anomalous A-V conduction. Evidence is presented suggesting the operation of endocrine and autonomic nervous system factors in the genesis both of the short P-R interval and the tachycardia.

Venous System of the Myocardium with Special Reference to the Conduction System

Myocardial veins and sinusoids of the right atrioventricular junction of the heart were studied in serial section, and their relations to the common conduction bundle and nodal tissues were anatomically demonstrated by wax model reconstructions. It is suggested these venous channels may well explain the complete, but transient, bundle block of children observed in certain toxic diseases. On the other hand, the same sinusoids functioning as capillaries may nourish the bundle tissues in older decades, thus explaining the low incidence of bundle block in cases of gradual coronary occlusion. The possible role of these vessels to the intercoronary circulation is discussed.