Accuracy of Clinical Symptoms, Electrocardiographic and Echocardiographic Parameters for Diagnosis of Significant Proximal Right Coronary Artery Lesion in Acute Inferior Wall Myocardial Infarction

Aim: Tissue Doppler (TDI) systolic annular velocity (S') and myocardial performance index may be useful predictors of proximal right coronary artery (RCA) stenosis as a culprit lesion in Inferior wall myocardial infaection in association with clinical symptoms and ECG changes. Methods: In a prospective study, patients with first episode of acute IWMI underwent early conventional and tissue Doppler echocardiographic assessment (within 24 h) of symptom onset and RV indices ; Tricuspid annular systolic plane excursion(TAPSE), myocardial performance index (MPI) and tissue Doppler velocities from RV free wall were measured. Patients underwent coronary angiogram within one month, our Patients divided into two groups(A,B) according to angiographic findings based on the presence or absence of a significant proximal RCA stenosis. Results: There were 35 patients with first episode of IWMI, group A includes (n 14 patient) and group B includes (n 21patient), There was significant difference between groups in TAPSE (1.28cm vs 1.98 p < 0.001) ,MPI-TDI (0.69±0.12 vs 0.38±0.05 p < 0.001), and in S'velocity from RV free wall ( 0.09m/s±0.02 vs 0.12m/s ±0.02 p < 0.001). It was found that S'<10cm/s is apredictor of proximal RCA lesion with sensitivity of 92.86% and specificity of 85.71%ppv 81.25, npv 94.74 , MPI-TDI>0.55 with a sensitivity of 92.86 % and specificity of 100% ,100% PPV and 95.45% NPv, and TAPSE<16mm (sensitivity93%, specificity100%). Conclusion; RV indices (S' velocity, MPI-TDI and TAPSE ) are useful in predicting proximal RCA as infarct related artery in IWMI.