Orthostatic Factors in Pulsus Alternans

Abstract

Ventricular alternans was present in three cardiac patients only in the erect or semierect position and disappeared with recumbency. The phenomenon which was regularly reproduced in the standing posture was prevented or minimized by exercise, digitalis, infusions of blood and norepinephrine and by application of external vascular support. Ventricular alternation in the supine patient was noted only after phlebotomy, or venous pooling combined with Valsalva maneuvers. The observations suggest that in the mechanism of this type of pulsus alternans there is an important peripheral hemodynamic factor which exerts its effect by changes in diastolic length of an injured ventricular muscle.