Tissue Doppler imaging of the tricuspid annulus and myocardial performance index in the evaluation of right ventricular involvement in the acute and late phase of a first inferior myocardial infarction.

BACKGROUND: Ischemic involvement of the right ventricle (RV) can complicate the early course of inferior ST elevation myocardial infarction (IMI) and has significant management implications but its diagnosis is difficult. This study assessed RV involvement in the acute and late phase of IMI by pulse-wave tissue Doppler (PW-TDI) and RV myocardial performance index (RVMPI).

METHODS: We prospectively evaluated 38 patients with first IMI, of whom 14 had RV involvement and 24 no RV involvement, as defined by ST segment elevation ≥0.1 mV in lead V4R. Thirty age-matched healthy subjects served as controls. Echocardiographic assessment included PW-TDI measurements from the lateral tricuspid annulus with MPI evaluation and was repeated at 6-month follow-up.

RESULTS: Peak systolic velocity of the tricuspid annulus, S', was significantly lower and RVMPI higher in patients with RVMI compared to patients without RVMI and controls. Patients with proximal RCA lesion had lower S' and higher RVMPI than patients with distal RCA or left coronary lesion. In the acute setting, the index S'/MPI < 17 was perfectly discriminatory for RV involvement and had moderate sensitivity and specificity (85%, 87%) for identifying proximal RCA disease. S'/MPI < 23 at 6 months had moderate-to-good sensitivity and specificity in identifying patients with previous RVMI.

CONCLUSIONS: Echocardiographic assessment of the RV by PW-TDI of the lateral tricuspid annulus, with derivation of MPI is a sensitive and specific marker of RV involvement in first IMI and remains so 6 months after the ischemic event. The novel index of S'/MPI appears to have potentially improved diagnostic accuracy in identifying RV involvement and proximal RCA lesion.