[Normal values for dobutamine stress echocardiography]

Dobutamine stress echocardiography having established itself as a sensitive method for diagnosing coronary heart disease, even in the absence of normative values, the physiological haemodynamics as well as the physiological values for global and regional left ventricular myocardial function were measured.

14 healthy subjects (ten men, four women; median age 25 [range 21-32] years) underwent dobutamine stress echocardiography according to an internationally practised dosage steps protocol (5-40 micrograms/kg/min with additional 0.5 mg atropine at 40 micrograms).

Maximal infusion rate achieved a serum dobutamine level of 1.67 micrograms/ml with minimal quartiles; it did not influence serum electrolytes (especially potassium). Heart rate increased from 64 to 150/min (P < 0.0001), blood pressure from 111/66 to 158/88 mmHg (systolic: P < 0.0001; diastolic P < 0.001) and the double product of systolic pressure and heart rate from 6714 to 24571 (P < 0.001). While the end-diastolic volume index decreased from 50 to 37 ml/m2 (P < 0.05), the end-systolic volume index fell from 20 to 7 ml/m2 (P < 0.0001). Regional wall motion analysis indicated an increase in left ventricular circumferential contractility with little scatter.

The usual protocol for dobutamine stress echocardiography is a sensible one, because the haemodynamic effect occurs already at low dosage and can then be increased significantly with further dosage steps. High serum dobutamine concentrations can be achieved without arrhythmogenic hypokalaemia. Volume index and ejection fraction are especially discriminatory variables. Quantitative analysis of wall motion is justified because of the low scatter of values.