Myocardial tissue velocities in the normal left and right ventricle: relationships and predictors

(1) To document, using tissue Doppler echocardiography (TDE), the regional variations in myocardial velocities (MV) in the left and right ventricles (LV and RV) in healthy young adults. (2) To determine the factors predicting MV.

The pattern of tissue velocities within the right ventricle have yet to be determined and their patterns compared to the left ventricular velocities have not yet been described.

Forty healthy subjects, mean age 29+/-6 years, were studied using TDE. Left ventricular long-axis velocities (V(LV-LX)) were obtained by sampling from anteroseptal, anterior, lateral, posterior, inferior and inferoseptal LV walls, and long-axis RV velocities (V(RV-LX)) from the free wall of the RV, in standard apical views. LV radial velocities (V(LV-RAD)) and RV radial velocities (V(RV-RAD)) were assessed from the parasternal long and short-axis views. Regression analyses were performed to assess for correlations of MV with the variables: age, sex, QRS duration, heart rate, systolic and diastolic blood pressure, LV mass, width, LV or RV lengths, LA or RA areas.

There were marked but consistent regional variations in systolic and diastolic tissue velocities in the LV and RV. Systolic (S') and early diastolic (E') velocities differed significantly around the left ventricular base, the highest velocities being located within the free wall at 6.4+/-2.2cm/s and 11.3+/-3.1cm/s, respectively. The E'/S'ratio remained constant and independent of position. V(LV-LX) were significantly higher than V(LV-RAD) (p<0.001). V(LV-LX)S' velocities were consistently lower than V(RV-LX)S' velocities (p<0.001). Age, heart rate, LV mass, width and length were significantly and independently associated with V(LV-LX)S' and V(LV-LX)E' values (p<0.01 for each).

In healthy young adults, there is a consistent pattern of non-uniform MV throughout the heart, including differences in longitudinal and radial axis velocities both within the LV and between the LV and RV. Age, heart rate and LV structure are important determinants of MV.

The patterns of left and right ventricular myocardial velocities and their relationships to each other are not well characterized. Furthermore, the determinants of myocardial velocities are not known. This study evaluated the myocardial longitudinal and radial axis tissue velocities in both the left (LV) and right (RV) ventricles and found that a consistent but non-uniform relationship exists between the LV and RV in both longitudinal and radial axes. Furthermore, age, heart rate and LV dimensions account for between 20% and 70% of the variability seen in LV systolic and diastolic velocities.