Persistent ventricular adaptations in postoperative coarctation of the aorta

Abstract

To evaluate ventricular performance and myocardial contractility after surgical correction of congenital coarctation of the aorta, we studied 25 patients (16 men and 9 women, mean age 26.1 years [range 19 to 34]), an average of 10.6 years (range 2 to 25) after repair. Radionuclide ventriculography at rest and exercise and digitized, quantitative two-dimensional echocardiography were performed. Data from derived, high resolution time-activity curves by radionuclide ventriculography, combined with noninvasive hemodynamic/ventricular volume data, were compared with values in an age- and sex-matched normal population. Despite essentially identical baseline and exercise hemodynamics, postoperative coarctation subjects demonstrated enhanced ventricular contraction, as determined by the peak ejection rate at rest (-3.79 versus -3.20 stroke volume/s, p less than 0.01) and exercise (-3.00 versus -2.90 stroke volume/s, p = NS), and overall ejection fraction at rest (56.4 versus 48.0%, p less than 0.01) and exercise (70.8 versus 59.3%, p less than 0.01). An intrinsic activation-contraction delay was observed, as illustrated by a prolonged time to peak ejection rate at rest (27.7 versus 21.5% of the RR interval, p less than 0.01) and exercise (28.4 versus 21.2% of the RR interval, p less than 0.01), and total systolic time at rest (50.2 versus 43.4% of the RR interval, p less than 0.01) and exercise (56.8 versus 50.4% of the RR interval, p less than 0.01). Although left ventricular meridinal wall stress was statistically indistinguishable (62 versus 74 mm Hg/mm2, p = NS), intrinsic myocardial contractility, as assessed by the peak systolic pressure/volume ratio, was increased in the postoperative coarctation group (1.88 versus 2.87 mm Hg/ml, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)