Q. Investigation of Tricuspid regurgitation by Echo Doppler?
Investigations
ECG in secondary TR shows evidence of right atrial overload and right ventricular hypertrophy with right axis QRS deviation. Chest X-ray shows evidence of right atrial enlargement and right ventricular type of cardiomegaly.
Echo Doppler Evaluation
Echocardiographic examination clarifies the diagnosis, etiology and severity of tricuspid regurgitation. Right atrial and ventricular dilatation depend upon severity of TR. High pressure TR may be associated with near normal size of RA and RV. Severe organic TR may be present with normal RV systolic pressure. In volume overload of RV, IVS shows a paradoxical motion in late systole while in pressure overload of RV, IVS motion is paradoxical in early systole. Inter atrial septum may be pushed to left side. There is no simple and reliable formula to calculate right ventricular ejection fraction and one has to depend upon suggestive visual impression. Color flow imaging shows the severity of TR and continuous wave Doppler imaging measures the TR jet velocity from which RV-RA systolic pressure gradient is calculated. Addition of estimated RA pressure to this gradient gives right ventricular systolic pressure. The following criteria suggest severe tricuspid regurgitation: A color flow regurgitant jet area > 30 per cent RA area, dense continuous wave Doppler signal annulus dilatation with incomplete leaflet coaptation, increased tricuspid inflow velocity [E-wave >1.0 m/sec], systolic flow reversal in the hepatic vein. Trivial
to mild TR may be seen in echocardiogram of up to 65 per cent of normal subjects and these are of no clinical significance.