Tricuspid Regurgitation (TR)
Tricuspid regurgitation (TR) can be either low pressure TR or high pressure TR depending on the right ventricular (RV) systolic pressure. High pressure TR occurs when the RV pressure is elevated as in pulmonary hypertension or RV outflow obstruction. Since the pressure gradient between RV and right atrium (RA) is high in this situation, the murmur is high pitched and pansystolic. TR murmur increases with inspiration (Carvallo’s sign) and also on passive leg elevation. Carvallo’s sign is absent in tricuspid regurgitation if there is associated tricuspid stenosis which prevents the increase in right ventricular volume with inspiration. Severe TR is associated with prominent v wave (also called cv wave or venous Corrigan) in the jugular venous pulse and systolic hepatic pulsations.
Low pressure TR occurs in Ebstein’s anomaly and other structural defects of tricuspid valve. Due to the low pressure gradient between RV and RA, the murmur is of relatively lower pitch.
TR can be assessed well by Doppler and Colour Doppler Echocardiography. The best view to visualise TR is apical four chamber view. TR gradient measured by Doppler gives a good estimate of the RV systolic pressure. RV systolic pressure will be equal to TR gradient plus right atrial pressure. Due allowance should be given to elevated jugular venous pressure will estimating RA pressure.