Symptomatic and hemodynamic recovery following dobutamine stress echo: benefit of low-dose esmolol administration.

OBJECTIVES: We studied the use of esmolol in patients experiencing minor side effects of palpitations, anxiety, nervousness, and tremors associated with dobutamine stress echocardiography.
BACKGROUND: Dobutamine stress echocardiography is frequently used in the assessment of coronary artery disease. Esmolol administration may enhance patient comfort.
METHODS: Sixty consecutive patients who experienced minor side-effects during dobutamine stress echocardiography were given 0.3 mg/kg esmolol intravenously in the recovery period and compared retrospectively to sixty consecutive controls who underwent dobutamine stress echocardiography, who did not receive esmolol, during the same time period. Both groups were matched for age, ejection fraction, and peak dose of dobutamine. Heart rate and blood pressure were assessed during and after dobutamine administration.
RESULTS: Both groups had similar baseline blood pressure (mmHg) (142 +/- 19/72 +/- 14 vs 139 +/- 20/72 +/- 14) and heart rate (beats per minute) (75 +/- 14 vs 75 +/- 17) (esmolol and control respectively, p = ns), but peak heart rate was higher in the esmolol group (126 +/- 14 vs. 116 +/- 14, p < 0.01). In the group who received esmolol, symptomatic relief paralleled the statistically significant decrease in heart rate which occurred within 1 minute of esmolol administration (99.7 +/- 15.3 vs 108.5 +/- 13.1 p < 0.0001); the heart rate in the esmolol group remained significantly lower than the control group for 5 minutes following esmolol administration (92.0 +/- 10.3 vs 96.7 +/- 11.8 p < 0.05). As a percentage of peak heart rate the esmolol group remained significantly lower than the control for 7 minutes (74% vs 80% p < 0.05). Esmolol induced a significant reversal of dobutamine-induced diastolic hypotension (diastolic blood pressure at peak 66 +/- 17 vs 8 min recovery 70 +/- 12, p < 0.03) that was not seen in controls (diastolic blood pressure at peak 64 +/- 18 vs 8 min recovery 65 +/- 14, p = ns). Systolic blood pressure and heart rate remained elevated in both groups 8 min into recovery compared to baseline, suggesting persistent dobutamine effect beyond the expected 2 min pharmacologic half-life of dobutamine. No side-effects from esmolol were seen despite it being used in 9 patients with EF < 35%.
CONCLUSIONS: Esmolol is effective and well tolerated for the management of dobutamine-related minor side-effects. The mechanism of benefit, in addition to heart rate reduction, may involve a reversal of dobutamine-induced diastolic hypotension. Blood pressure and heart rate recovery are slower than expected from previously published pharmacokinetic data.