Deleterious effects of cardiac pacing in a patient with mitral insufficiency

A 70-year-old, artificially paced women with dizziness and extremely low physical capacity exhibited a systolic BP varying from one moment to another; in standing position it was not measurable. With the aid of a strain gauge technique, the amplitude of the pulse wave of her left thumb was recorded and shown to vary widely. The variations were correlated to synchrony or asynchrony between atrial and ventricular activity. Pronounced decreases in stroke volume and peripheral pulse volume were recorded with pacemaker-induced beats compared with idioventricular beats. With artifical stimulation at a rate of 45/min, thus avoiding competition but still protecting her from syncopes, she was free from symptoms.