Differential effect of right ventricular dilatation on myocardial deformation in patients with atrial septal defects and patients after tetralogy of Fallot repair

Background

Right ventricular (RV) volume overload results in RV dilatation in patients with atrial septal defect (ASD) and after tetralogy of Fallot (ToF) repair with pulmonary regurgitation.

Aim

Study the differential effects of chronic RV volume loading on regional and global RV deformation in patients with ASD and after TOF repair.

Methods

We studied 85 subjects: 50 patients after ToF repair, 15 patients with unrepaired ASD and 20 age-matched controls. The ToF patients and controls underwent an echocardiography at the time of a clinically indicated MRI. The ASD patients had a routine echocardiogram including RV volume calculations. Longitudinal deformation was analyzed using 2-D speckle tracking echocardiography.

Results

RV free wall global and segmental longitudinal deformation was significantly lower in ToF patients compared with ASD and controls (p < 0.001). In ToF patients, there was a progressive decrease in strain values from base to apex (p < 0.001), while in the ASD group there was a progressive increase (p = 0.04). We found strong negative correlations between RV size and RV longitudinal strain measurements, strongest with RV length (R = 0.72). When corrected for RV size, all ASD patients had normal or higher deformation values while half of the TOF patients had significantly lower values.

Conclusion

Global and regional myocardial RV deformation is differently affected by chronic volume loading in ASD versus TOF patients, especially regarding the apical function. This suggests a different adaptation mechanism in both diseases. Our data also suggest that strain measurements are strongly influenced by ventricular size, which should be taken into consideration when interpreting strain values.