Variability of inotropic and chronotropic response during dobutamine stress echocardiography and possible implications for diagnostic accuracy.

Chronotropic and inotropic response patterns were assessed during dobutamine stress echocardiography. Three heart rate response patterns were noted: nonresponders (48% of patients), slow responders (30% of patients), and fast responders (21% of patients). There was no relation between heart rate and contractile response.