Endogenous catecholamine levels and function of the systemic right ventricle following atrial switch.

Background: As a result of successful surgery there is a large cohort of young adults with systemic right ventricles, suffering from progressive right ventricular dysfunction. Beta-blockers are successfully used in left ventricular failure. We assessed catecholamine levels and related it to cardiac function late following atrial switch, to provide the pathophysiologic basis for pharmacotherapy in patients with systemic right ventricles.

Methods: It was a prospective study of 23 consecutive adult patients with the complete transposition of the great arteries, following atrial switch. Epinephrine and norepinephrine concentrations were measured with high performance liquid chromatography.

Results: Mean+/-SD epinephrine and norepinephrine levels were 54.5+/-29.0 pg/mL and 389.6+/-134.2 pg/mL, respectively. In multivariate stepwise regression models, sex (B=-0.455, 95% CI for B of -0.887 to -0.023, P=0.04), age (B=-1.328, 95% CI for B of -2.402 to -0.254, P=0.018), and cardiothoracic ratio (B=2.302, 95% CI for B of 0.120-4.484, P=0.04) were significant predictors of epinephrine levels. Diastolic right ventricular cavity area (B=0.024, 95% CI for B of 0.009-0.038, P=0.003) was a significant predictor of norepinephrine levels. Significantly higher levels of epinephrine were observed in patients with vs without left ventricular tract obstruction (88.0+/-15.5 vs 47.4+/-26.2 pg/mL, P=0.008).

Conclusions: We have demonstrated a significant correlation between right ventricular enlargement and epinephrine as well as norepinephrine levels. Elevated catecholamine levels were observed in patients with left ventricular tract obstruction. This supports the use of beta-blockers in the selected patients with systemic right ventricles following atrial switch.