SUMMARY In studies of the right ventricle the complexities of chamber shape may be overcome by use ofmultiple tomographic imaging planes. An established protocol for the echocardiographic description of the heart was used to examine the right ventricle in an ordered series of transducer locations and orientations. Diastolic measurements were made ofthe right ventricular inflow tract, outflow tract, and right ventricular body, and the range and reproducibility of normal values for cavity size and right ventricular free wall thickness were established. These measurements of cavity size in 41 normal subjects were highly reproducible and the views that were used correctly described the truncated and ellipsoidal shape of the right ventricular inflow tract and body with a separately aligned outflow tract. Cavity trabeculation prevented measurement of the free wall thickness in some areas; however, values of nearly twice the previously reported upper limit of normal for anterior regions were measured from the apex or lateral right ventricular wall.These normal data provide a basis for future echocardiographic studies of the right ventricle.

Stress echocardiography with dobutamine infusion for detection of coronary artery disease is a potential alternative to exercise stress testing with some theoretic advantages. Fifty patients who were not receiving cardioactive medication were prospectively studied with two-dimensional echocardiography and 12-lead electrocardiography (ECG) during incremental dobutamine infusion (5, 10, 15 and 20 micrograms/kg body weight per min, each dose for 8 min). Images were analyzed by using an 11-segment left ventricular model. All patients underwent correlative exercise ECG and coronary angiography, which revealed normal coronary arteries in 14 and significant disease (greater than or equal to 70% diameter stenosis) in 36. Peak rate-pressure product during dobutamine infusion was 18,845 +/- 4,156 versus 23,740 +/- 6,158 mm Hg/min on exercise (p less than 0.01). Interobserver concordance for wall motion analysis was good (kappa coefficient = 0.77). The use of baseline (n = 14) or reversible (n = 24) regional asynergy to define an abnormal dobutamine echocardiogram resulted in a sensitivity for detecting coronary artery disease of 78% and a specificity of 93%. Corresponding data for the dobutamine ECG were 47% and 71% and for the exercise ECG were 72% and 71%, respectively. The development of new mitral regurgitation on Doppler color flow imaging (n = 4) improved sensitivity to 81% without loss of specificity. Inducible asynergy or new mitral regurgitation was observed in 6 (50%) of 12 patients with single-, 6 (60%) of 10 with double- and 12 (86%) of 14 with triple-vessel disease. The site of transient asynergy provided additional localizing information. Exercise duration and time to diagnostic ST segment shift were shorter in patients with coronary artery disease with versus those without echocardiographic evidence of ischemia (both p less than 0.05). Side effects during dobutamine infusion were mild and short-lived. Dobutamine stress echocardiography is well tolerated, is useful for detection and assessment of coronary artery disease and is applicable to patients unable to exercise.

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To examine whether pulsed Doppler left ventricular filling indices can reliably detect myocardial ischaemia in patients with coronary artery disease undergoing dobutamine stress echocardiography we studied three groups matched for age and global indices of left ventricular function. Group I patients (n = 10) had normal coronary arteries whereas those in Groups 2 (n = 12) and 3 (n = 15) had significant coronary disease (> or = 70% diameter stenosis) at angiography. After stopping cardioactive treatment, patients underwent incremental dobutamine stress (5, 10, 15 and 20 micrograms.kg-1.min-1) during pulsed Doppler interrogation of diastolic filling with simultaneous heart rate and blood pressure measurements. Only Group 3 patients developed myocardial ischaemia using electrocardiographic and cross sectional echocardiographic criteria; subset 3A (n = 4) comprised those with inducible mitral regurgitation on colour Doppler. Electrocardiographic R-R interval decreased (-311 +/- 123 ms, P < 0.001) and mean blood pressure altered (5 +/- 17 mmHg, P = ns) uniformly across groups. The respective changes in peak early velocity, peak atrial velocity and their ratio for Groups 1 (0.08 +/- 0.09 m.s-1, 0.26 +/- 0.18 m.s-1 and -0.32 +/- 0.36), 2 (0.07 +/- 0.07 m.s-1, 0.18 +/- 0.15 m.s-1 and -0.13 +/- 0.21) and 3 (0.09 +/- 0.12 m.s-1, 0.20 +/- 0.13 m.s-1 and -0.17 +/- 0.21) were similar (all P = ns between groups). Corresponding data for subset 3A (0.23 +/- 0.04 m.s-1, 0.20 +/- 0.10 m.s-1 and 0.00 +/- 0.16) revealed a significantly greater increase in peak early velocity and normalized velocity ratio in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)