Regurgitation of Radiopaque Contrast Material Through Normal Mitral Valves in Cinefluorographic Studies of Dogs

¹ From the Departments of Radiology and Physiology, Temple University Hospital and School of Medicine, Philadelphia, Pennsylvania

Radiopaque contrast medium was introduced into the left ventricle by way of a retrograde catheter passed through carotid and aorta. Regurgitation through normal mitral valves takes place during asystole, bradycardia, sinus arrhythmia and compensatory pauses after an extrasystole. Such regurgitations are diastolic and depend on the presence of a long period of ventricular diastasis. Ventricular tachycardias which shorten or eliminate diastasis prevent regurgitation through normal mitral valves. In these experiments presence or absence of atrial systole plays a negligible role. Regurgitations associated with mitral valve lesions are systolic in time and present in every cycle.