Right and left ventricular volume characteristics in common atrioventricular canal

Right (RV) and left (LV) ventricular volume characteristics were determined from biplane cineangiography in 29 patients with atrioventricular canal (AVC). The patients were classified into two groups: group I (N = 19), uncomplicated AVC; group II (N = 10), AVC associated with RV obstruction. In group I, LV end-diastolic volume (EDV) [177 +/- 9 (SEM)% of normal] and RVEDV (125 +/- 9%) both were greater than normal (P is less than 0.001 and less than 0.01, respectively). LV ejection fraction (EF) was decreased (0.59 +/- 0.02, P is less than 0.001) but RVEF was normal (0.58 +/- 0.03). LV stroke volume index (SVI) was increased (48 +/- 3 ml/m2, P is less than 0.005), and RVSVI was normal (34 +/- 3 ml/m2). One patient had a markedly small RVEDV (45%). In group II, LVEDV and RVEDV were not different from normal (119 +/- 11% and 97 +/- 15%, respectively). LVEF was depressed (0.52 +/- 0.04, P is less than 0.001) and RVEF was normal (0.55 +/- 0.05). LVSVI was normal (38 +/- 5 ml/m2) and RVSVI was slightly decreased (29 +/- 4 ml/m2, P is less than 0.025). Two patients had a markedly small RVEDV (31%, 55%). EDV correlated with the pulmonary-to-systemic flow ratio (LV, r = 0.71; RV, r = 0.68). The data show that in most patients with AVC, LV and RV are enlarged in the uncomplicated form but not in the form with RV obstruction. LV function is more compromised than RV in both groups. RV hypoplasia is rare but was documented in both uncomplicated forms and forms with RV obstruction.