Impaired left ventricular postischemic function and metabolism in chronic right ventricular hypertrophy

Chronic right ventricular hypertrophy (RVH) has been shown to produce changes in left ventricular diastolic properties but minimal effects on left ventricular systolic function. We studied the effects of chronic pressure overload RVH on left ventricular systolic function before and after reversible hypothermic global ischemia. RVH was induced by pulmonary artery banding (PAB) in newborn piglets (5 to 7 days). At 2 months of age the PAB group (n = 6) and a control group (n = 8) were subjected to cardiac arrest on cardiopulmonary bypass with cold crystalloid cardioplegia (10 degrees C) for 2 hr and were reperfused for 1 hr. Left ventricular function was assessed by a conductance catheter in the left ventricle measuring the end-systolic pressure-volume relationship (Emax). Preischemic and postischemic Emax were the same in the control group (4.1 +/- 0.4 mm Hg/ml before vs 4.1 +/- 0.4 mm Hg/ml after ischemia), but significantly different in the PAB group (4.7 +/- 0.5 mm Hg/ml before vs 2.97 +/- 0.7 mm Hg/ml after ischemia, p less than .05). There also was a marked drop in ATP and phosphocreatine (CP) content in the PAB group during ischemia (ATP, 20 +/- 2 mmol/kg dry wt before vs 10 +/- 2 mmol/kg dry wt after ischemia, p less than .05; PC, 26 +/- 3 mmol/kg dry wt before vs 11 +/- 1 mmol/kg dry wt after ischemia, p less than .05). In the control group there was no change in ATP content and, although CP did drop by end-ischemia, there was complete recovery by 1 hr of reperfusion but minimal CP recovery in the PAB group.(ABSTRACT TRUNCATED AT 250 WORDS)