AGE-RELATED TRANSMURAL PEAK MEAN VELOCITIES AND PEAK VELOCITY-GRADIENTS BY DOPPLER MYOCARDIAL IMAGING IN NORMAL SUBJECTS

Doppler myocardial imaging is a new cardiac ultrasound technique based on the principles of colour Doppler imaging which call determine myoc ardial velocities by detecting the changes of phase-shift of the ultra sound signal returning directly from the myocardium. To determine the normal range of transmural velocities in healthy hearts a prospective study was carried out involving 42 normal subjects (age from 21 to 78, mean 47 +/- 16 years). Using M-mode Doppler myocardial imaging the pe ak values of the mean velocity and velocity gradient across the left v entricular posterior wall were measured during standardized phases of the cardiac velocities had the following values cycle: isovolumic cont raction -1.3 +/- 1.2cm.s(-1), early ventricular ejection 4.2 +/- 1.2cm .s(-1), late ventricular ejection 1.8 +/- 1.1cm.s(-1), isovolumic rela xation -2.0 +/- 0.8 cm.s(-1), rapid ventricular filling -6.6 +/- 2.2cm .s(-1). atrial contraction -2.8 +/- 1.8cm.s(-1), atrial relaxation 1.3 +/- 1.1cm.s(-1). Peak velocity gradients were: isovolumic contraction 1.3 +/- 1.9s(-1), early ventricular contraction 4.7 +/- 1.9s(-1), lat e ventricular contraction 1.1 +/- 1.0s(-1), isovolumic relaxation -0.6 +/- 0.5s(-1), rapid ventricular filling 6.1 +/- 3.4s(-1), atrial cont raction 2.6 +/- 1.7s(-1), atrial relaxation 0.0 +/- 0.3s(-1). Linear r egression analysis showed that with the increase of age, peak velocity gradient decreases during rapid ventricular filling (r = 0.83: P < 0. 0001) and increases during atrial contraction (r = 0.86; P < 0.0001) w hile peak mean velocity increases only during atrial contraction (r = 0.80, P < 0.0001). Thus, there was no correlation between increasing a ge and systolic peak mean velocity and peak velocity gradient but both diastolic filling phases rapid ventricular filling and atrial contrac tion demonstrated age-related changes. In summary, this study has dete rmined the age-related range of normal transmural myocardial velocitie s-within the left ventricular posterior wall in healthy hearts during the cardiac cycle. We conclude that these measurements of peak mean ve locities and peak velocity gradients, should from the baseline for sub sequent Doppler myocardial imaging clinical studies on myocardial dise ases processes.