Stroke volume changes during dobutamine-atropine stress echocardiography: the influence of heart rate and ischaemia.
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BACKGROUND
A decrease in stroke volume during dobutamine-atropine stress echocardiography heralds ischaemia and possible hypotension. Hypotension results from worsening of LV-function (as a result of ischaemia) left ventricular outflow tract obstruction or hypovolemia, while an increase of stroke volume indicates the preservation of myocardial contractile reserve.
OBJECTIVE
To assess stroke volume changes during dobutamine stress echocardiography in relation to heart rate and occurrence of ischaemia and to validate a new automated cardiac output measurement device.
METHODS
In fifty patients, the stroke volume was assessed using the echocardiographic biplane discs method during a stress echocardiography. These data were reference values for the validation of a new automated cardiac output measurement using the first method as a reference.
RESULTS
Stroke volume measured by the biplane discs method and automated cardiac output device decreased from rest to peak stress, respectively, from 54+/-16 to 34+/-9 (63%) ml and 63+/-17 to 38+/-15 (60%) ml (p < 0.001). Stroke volume decreased with increased heart rate and stress-induced ischaemia when assessed by the biplane discs method, but with the automated device it decreased only with increased heart rate.
CONCLUSIONS
Both increased heart rate and myocardial ischaemia during dobutamine stress echocardiography cause a reduction of stroke volume. However, the automated device did not detect the effects of stress-induced ischaemia on stroke volume. It appears that the biplane discs method is more sensitive for evaluating the effect of ischaemia.
