Is dobutamine stress echocardiography useful for noninvasive differentiation of ischemic from idiopathic dilated cardiomyopathy?

Dobutamine stress echocardiography was performed in 56 consecutive patients, mean age: sixty-two +/- twelve years. Twenty-two patients had an idiopathic dilated cardiomyopathy (group 1) and 34 had angiographically proven ischemic dilated cardiomyopathy (group 2). Wall motion score index and left ventricular ejection fraction were determined at baseline, 5 micrograms/kg/min, peak, and ten minutes after stepwise dobutamine infusion. Worsening or no change in global wall motion score was observed in 9 group 2 patients (26%) and 1 group 1 patient (5%, P = .07). No significant difference was observed with regard to wall motion score index decrease between baseline and peak dose. Left ventricular ejection fraction increase during dobutamine infusion was comparable in both groups. Thus, an ischemic response was observed more often in the coronary artery disease group, yielding a good specificity and positive predictive value although sensitivity was low. However, left ventricular function improvement did not help to discriminate patients with or without significant CAD.

[Dobutamine stress echocardiography; a monocentric experience on 600 consecutive patients. Effect of age]. / Echocardiographie sous dobutamine; expérience monocentrique portant sur 600 patients consécutifs. Influence de l'âge.

The increasing indications of dobutamine stress echo in the investigation of myocardial ischaemia, viability and evaluation of the prognosis of coronary artery disease has made this technique a tool of everyday clinical practice. The authors reviewed the results of 600 investigations in consecutive unselected including patients aged over 75. No significant difference was observed with respect to the causes of interruption of the test between patients aged less than 75 (521 patients) and those older than 75 (79 patients). Attaining the target theoretical maximal heart rate was the commonest reason for stopping the test (47 and 48% respectively). Ventricular arrhythmias were not more common (12 and 10% respectively). Twelve cases of ventricular tachycardia were observed, 8 of which were non-sustained; 9 led to interruption of the test. No cases of ventricular fibrillation were observed. A previous history of cardiac arrhythmias was not associated with a higher frequency of arrhythmia during the test (8% in those with a previous history, 4% in those patients without). Supraventricular arrhythmias were significantly more common in patients over 75 years of age (15 versus 8%, p = 0.046). Dobutamine stress echocardiography' is feasible in a population of unselected patients, including those over 75. Therefore, age does not represent a limitation to the extension of this investigation.