Résumé
The importance of right ventricalar function in acute and chronic cardiac affection is well established. Is to assess the value of pulse wave Doppler tissue imaging [PWTDI] during dobutamine stress echocardiography in detection of right coronary artery narrowing. 40 subjects were divided into two groups according to the presence [patient group] or absence [control group] of significant > 70% isolated right coronary artery narrowing proved by coronary angiography. All patients studied had right coronary artery dominance, they were subjected to the following: complete history taking and thorough clinical examination, 12 leads resting surface electrocardiography, resting standard echo Doppler study, coronary angiography, doubtamine-atropine stress echocardiography with pluse-wave Doppler tissue sampling. There was no statistically significant difference between the two groups as regard to early [E] and late diastolic [A] velocity in cm/sec by pulse wave tissue Doppler at rest, low dose and high dose dobutamine. p > 0.05. Regarding the ejection phase velocity in cm/sec. [EJ] by pulse-wave Doppler tissue there was no statistically significant difference between the control and the patient groups at rest and low dose dobutamine p > 0.05., however at higdose dubutamine there was a highly statistically significant difference [p < 0.01] and it was found that a progressive increase of the ejection phase velocity [EJ], expressed by a more than 25% increase from 10 microg/kg/min [low dose] to peak dobutamine stress was predictive of normal or insignificantly narrowed right coronary artery [RCA]. Whereas a blunted increase, expressed by < 25% increase of velocity, was predictive of a significantly narrowed RCA. The sensitivity, specificity, negative predictive value, positive predictive value and accuracy of pulse-wave Doppler tissue sampling in detection of right coronary artery narrowing was 80%, 75%, 79.2%, 76.9% and 78% respectively. Analysis of the right ventricular wall was accessible using the pulsed wave tissue Doppler sampling in all cases while visual assessment was not. Pulsed wave tissue Doppler sampling is a valuable tool to detect right coronary artery narrowing when combined with dobuta-mine-atropine stress echocardiography