Myocardial perfusion and function of the systemic right ventricle in patients after atrial switch procedure for complete transposition: Long-term follow-up

OBJECTIVES Our purpose was to assess the right ventricular (RV) function an d identify patients with RV impairment long after the Mustard or Senning op eration. BACKGROUND Systemic Ventricular failure can cause myocardial perfusion abno rmalities in thallium scintigraphy correlating with hemodynamic deteriorati on. METHODS Myocardial perfusion at rest and at peak exercise was assessed in 6 1 patients, aged 7 to 23 years in mean time 10.0 +/- 2.9 years after surger y using technetium-99m methoxyisobutyl isonitrile single-photon emission co mputed tomography. Ventricular function was assessed by first-pass radionuc lide angiography at rest. Exercise capacity was determined with a modified Bruce protocol. RESULTS The mean RV ejection fraction was 36.1 +/- 7.7%, and left ventricul ar (LV) ejection fraction was 52.1 +/- 9.4%. Moderate or severe perfusion a bnormalities on the rest scan were observed in 20 patients (33%). On exerci se perfusion worsened in another 13 patients (21.3%). Patients with perfusi on defects on stress scan had significantly lower RV and LV ejection fracti on (33.2 vs. 39.4%; p = 0.002 and 49.2 vs. 55.5%; p = 0.01, respectively). They were also older (16.6 vs.13.0 years; p = 0.002), operated on at an old er age (4.0 vs. 2.4 years; p = 0.05) and had longer follow-up (12.5 vs. 10. 5 years; p = 0.003). CONCLUSIONS Myocardial perfusion defects are common findings in patients in long-term follow-up after atrial switch operation. Despite excellent exerc ise tolerance, the extent of myocardial perfusion abnormalities correlated well with impaired RV and LV function, and greater perfusion defects were s een more frequently in older patients with longer follow-up. It is likely t hat myocardial perfusion defects could be a sensitive predictor of systemic ventricular impairment. (J Am Coll Cardiol 2000;36:1365-70) (C) 2000 by th e American College of Cardiology.