Influence of haemodynamics and myocardial ischaemia on Doppler transmitral flow in patients undergoing dobutamine echocardiography.

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)