Non-invasive Assessment of Right Ventricular Function in Patients With Tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease (CHD). Surgical treatment (total repair) has been available for 50 years, with favorable outcome in most patients. We are now, however, faced with an increasing number of patients presenting with right ventricular (RV) failure. Furthermore, because of geometric limitations, there is currently no generally accepted echocardiographic standard for assessment of right ventricular function. Speckle tracking echocardiography (STE) is a new method for angle-independent assessment of regional myocardial deformation properties (strain rate, strain and torsion). To test the hypothesis that right ventricular function can be assessed by speckle tracking echocardiography in patient s after repair of tetralogy of Fallot, we will perform two studies: Study 1: Correlation between RV function by STE and physical exercise capacity. 50 patients followed at the Toronto Congenital Cardiac Center for Adults previously undergoing repair for TOF, will be recruited for echocardiography and cardiopulmonary exercise test. This population will invariably have a wide range of RV dysfunction and we will correlate RV function by STE to physical exercise capacity. We will use magnetic resonance imag ing (MRI) tagging as reference method. Study 2: Alteration in RV function during surgical interventions. It is well known that extensive cardiac surgery reduces myocardial function temporarily (stunning). To investigate if STE can identify changes in RV-function over time, we will perform per- and postoperative STE in 30 TOF patients admitted for surgical intervention. MRI tagging will be performed preoperatively and 2 months postoperatively. Per- and postoperative central venous oxygen saturation wil l be recorded to assess cardiac output.