value of pulse-wave doppler tissue imaging during dobutamine stress echocardiography in detection of right coronary artery narrowing

ABSTRACT

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