[Diagnosis of coronary disease using echocardiography with inotropic dobutamine stimulation]

To evaluate dobutamine echocardiography capacity to diagnose coronary artery disease.

Prospective clinical study.

Cardiology Department of Hospital Santa Marta.

32 patients with suspected coronary artery disease, without myocardial infarction, have been studied.

An intravenous perfusion of dobutamine with gradual doses, from 5 to 40 micrograms/kg/min, and increments of 5 to 10 micrograms/kg/min, in 3 minute stages, except the last stage which lasted only 1 minute with 40 micrograms/kg, was performed. Twelve-lead ECG were registered to detect ST changes and symptoms, namely chest pain. Basal and dobutamine bidimensional echocardiograms, in the end of each stage and during recovery, were registered in video. The segmental analysis was performed considering the left ventricle divided in 16 segments. It was considered positive the occurrence or aggravation of the contractility asynergy of the left ventricle with inotropic stress. All the patients were submitted to coronary arteriography.

Due to the bad quality of the echocardiographic images 2 patients were excluded. The stress dobutamine echocardiograms were positive in 14 P and negative in 16 P. The coronary arteriography showed coronary disease in 18 cases and absence of significant lesions in 12 cases. The values for sensitivity, specificity positive predictive value and negative predictive value obtained with dobutamine echocardiography were, 78% and 100% and 75% respectively. In Dobutamine-ECG, 7P had ST segment changes, 2 of them with chest pain values for sensitivity, specificity, positive and negative predictive value with dobutamine-ECG were, 39%, 100% and 52%, respectively. The occurrence of side-effects was observed in 8 P (27%): ventricular tachycardia (2 P-7%), complex ventricular ectopy (4 P-13%), chest pain (2 P-7%), headache (1 P-3%), nausea (1 P-3%) and palpitations (2 P-7%). There was no significant difference in the occurrence of side-effects in the two groups of patients, with and without coronary artery disease (33% vs 17%, respectively; p = ns). The reasons for early discontinuation of dobutamine infusion were: ventricular tachycardia (2 P), complex ventricular ectopy (2 P) and chest pain (1 P). Heart rate, systolic blood pressure and double-product did not differ significantly in patients with and without coronary artery disease. In dobutamine electrocardiography 7 P had ST segment changes, 2 of them with chest pain.

Dobutamine echocardiography showed in this study elevated values for sensitivity and specificity, however sensitivity can be increased with better technical conditions.