Role of ischemia and infarction in late right ventricular dysfunction after atrial repair of transposition of the great arteries

OBJECTIVES This study was conducted to assess whether myocardial ischemia a nd/or infarction are involved in the pathogenesis of late right ventricular dysfunction in adult survivors of atrial baffle repair for transposition o f the great arteries in infancy. BACKGROUND The medium-term success of intraatrial baffle repair for transpo sition of the great arteries is good, with many patients surviving into adu lt life, but prognosis can be limited by progressive right ventricular dysf unction. We hypothesized that ongoing myocardial ischemia and/or infarction are important factors in the pathogenesis of this complication. Radionucli de techniques offer an opportunity to study both myocardial perfusion and c oncomitant ventricular wall motion. METHODS Dipyridamole sestamibi single-photon emission computed tomography f ollowed by rest sestamibi single-photon emission computed tomography was us ed to assess right ventricular myocardial perfusion, wall motion, wall thic kening and ejection fraction in 22 adolescents/ young adults who had underg one atrial baffle repair for simple transposition of the great arteries at median 6.7 (range 0.5 to 54) months of age. The patients were aged 10 to 25 (median 15.5) years; 19 in New York Heart Association class I, 2 in class II and 1 in class III. All were in a regular cardiac rhythm during the stud ies. The right ventricular tomographic images were examined in three parall el and two orthogonal planes, analyzed in 12 segments. RESULTS Perfusion defects were evident in all patients in at least one segm ent, in either the rest or stress images. Twelve patients (55%) demonstrate d fixed defects only, nine (41%) had fixed and reversible defects and one ( 4.5%) had reversible defects only. Concomitant wall-thickening abnormalitie s occurred in 83% of segments with fixed perfusion defects, mirrored by a r eduction in wall motion in 91% of segments analyzed. Right ventricular ejec tion fraction was correlated with age (R = 0.62; p = 0.002), and with wall- thickening abnormalities (R = 0.60; p < 0.005). CONCLUSIONS Reversible and fixed perfusion defects with concordant regional wall motion abnormalities occur in the right (systemic) ventricle 10 to 20 years after Mustard repair for transposition of the great arteries; this m ay be important in the pathogenesis of late right ventricular dysfunction i n this group. (C) 2000 by the American College of Cardiology.