Echocardiographic analysis of the subtypes of right ventricular restrictive physiology in surgically treated patients with tetralogy of Fallot

Abstract

Our study focuses on echocardiographic assessment of the right ventricular diastolic function and adaptive right ventricular response to volume overload resulting from pulmonary and tricuspid regurgitation in surgically treated patients with tetralogy of Fallot. We included 60 patients subsequent to surgical correction of tetralogy of Fallot, dividing them into two groups - a group of 18 patients with restrictive physiology, having antegrade flow to the pulmonary arteries greater than 30 centimetres per second in late diastole in five consecutive beats, and a group of 42 patients with non-restrictive physiology. Based on the cardiothoracic ratio, being more or equal to, or less than 0.55, we further divided those with restrictive physiology into a group of 14 patients deemed to have primary restriction, and the other 4 patients considered to have secondary or acquired restriction. Those with non-restrictive physiology were divided into groups of 16 patients with a small heart, and 26 patients with a large heart. A fraction of the venous retrograde diastolic flow in the hepatic vein greater or equal to 30 centimetres is important for distinguishing between the subgroup with primary restriction and the other subgroups. In the four patients with secondary restriction, anterograde diastolic flow in the pulmonary artery greater than 30 centimetres per second was recorded after the average period of follow-up of 2.4 years. The mean value of the pulmonary regurgitant jet pressure half-time was higher in the subgroup with the secondary restriction in comparison to the nonrestrictive subgroup with large hearts at 152 milliseconds with standard deviation of 36 milliseconds versus 85 milliseconds with standard deviation of 11 milliseconds, p less than 0.05. This was significantly lower in comparison to those with primary restriction, where the value was 238 milliseconds, with standard deviation of 42 milliseconds, p less than 0.02. Echocardiographic analysis offers great possibilities for assessment of right ventricular diastolic function, identifying in particular those with restrictive physiology, its interrelation with pulmonary and tricuspid regurgitation, as well as timing and selection of patients for re-intervention.