Augmentation of Left Ventricular Contraction Pattern in Coronary Artery Disease by an Inotropic Catecholamine

Abstract

In order to assess potential improvement in abnormal left ventricular (LV) wall motion, eighteen subjects — sixteen with obstructive coronary artery disease and LV asynergy and two with no evidence of organic heart disease — were studied by cardiac catheterization and cineangiography. Ventriculograms were performed at rest and during a constant infusion of l-epinephrine (EPI) at 1-4 µg/min after an average of nine minutes steady state. EPI infusion induced augmentation of LV contraction pattern in both normal subjects and in all normal zones in the sixteen subjects with asynergy, and in no instance was contraction in a normal zone rendered abnormal. Eleven of sixteen patients showed improved contraction in previously asynergic areas, two of whom also demonstrated paradoxical motion in an abnormal zone. Of a total of forty-four resting asynergic zones, twenty-three exhibited an improved contraction pattern with EPI, one showed depressed contraction, two demonstrated both an increase and deterioration in the same zone (paradoxical motion), and eighteen showed no change. Quantitative motion analysis generally corroborated these qualitative ventriculographic observations. Heart rate, LV systolic pressure and LV end-diastolic pressure increased slightly with EPI, but were not significantly changed from control values. While there was wide variation in end-diastolic volume in the subjects with asynergy, EPI resulted in an increase in both stroke volume and ejection fraction, the latter significantly ( P < 0.05). In the four subjects who subsequently underwent aneurysmectomy, preoperative lack of improvement with EPI correlated with a pathologic diagnosis of fibrosis. Other than angina pectoris of brief duration in two subjects, EPI provoked no untoward reactions, arrhythmias or complications. It is concluded that LV motion abnormalities can be improved or changed in certain cases by the inotropic stimulus of EPI, suggesting residual contractile ability; the agent may differentiate between zones of potentially functional cardiac muscle and frank fibrosis.