Comparison of modified short axis view and apical four chamber view in evaluating right ventricular function after repair of tetralogy of Fallot

BACKGROUND: In clinical settings an easy and reliable method for following up right ventricular (RV) function in patients after repair of tetralogy of Fallot (TOF) is needed. It is, however, unclear whether the novel modified short axis view from echocardiography is superior to the apical four chamber view in this aspect. MATERIALS AND METHODS: Thirty postoperative TOF patients with median age 17 years (range 6-45 years) and follow up period of 10 years (range 0.5-40 years) were examined echocardiographically using the apical four chamber view and the novel modified short axis view. RV areas in end-systole (Amin) and end-diastole (Amax) were measured and an area fraction [(Amax - Amin)/Amax * 100%] was calculated from the respective view. RV ejection fraction was assessed through magnetic resonance imaging (MRI). The RV area fractions from echocardiography were compared to the RV ejection fraction. RESULTS: The right ventricular area fraction derived from the modified short axis view was significantly lower than that from the apical four chamber view (34.3+/-9.1% vs. 42.5+/-10.2%, p=0.007). Both the RV area fractions obtained from the modified short axis view (r=0.674, p<0.001) and from the apical four chamber view (r=0.512, p=0.025) correlated significantly with the MRI derived RV ejection fraction. CONCLUSION: The novel modified short axis view from echocardiography may be superior to the apical four chamber view for routine follow up of patients after TOF repair, in whom the right ventricular outflow tract plays an important role in the right ventricular systolic function.