Differentiation of normal and ischemic right ventricular myocardium with quantitative two-dimensional integrated...

We have previously shown that ultrasonic tissue characterization with two-dimensional (2D) guided M-Mode acquisition of integrated backscatter (IB) identifies ischemic and infarcted myocardium. However, there is no information regarding the applicability of IB in assessment of right ventricular (RV) myocardial acoustic properties. Thus, we performed IB imaging of the RV in a group of 45 consecutive patients and were successful in 16, all of whom had normal RV wall motion. This group was compared to 8 additional patients studied acutely with clinical criteria of RV infarction. Real-time IB from RV was obtained from parasternal long axis or subcostal views. Diastolic-to-systolic cyclic variation of IB in normals was 4.8 +/- 0.9 dB (+/- SD). No significant difference was observed between parasternal and subcostal views (5.2 +/- 0.8 and 4.5 +/- 0.9 dB). Mean value of delay (R wave to nadir of backscatter normalized to the electrocardiographic Q-T interval) was 0.85 +/- 0.07. Patients with RV infarction had significantly lower values averaging 3.2 +/- 0.8 dB (p less than 0.001 vs. normals); cyclic variation of IB was present in all despite severe hypokinesis in 4/8. Mean value of normalized delay was 0.80 +/- 0.04 and was not different from normals. Thus, tissue characterization provides quantitative information regarding RV myocardial structure and function. Preservation of IB cyclic variation in patients with RV infarction suggests residual RV myocardial viability.