SYMPTOMATIC AND HEMODYNAMIC RECOVERY FOLLOWING DOBUTAMINE STRESS ECHO- BENEFIT OF LOW-DOSE ESMOLOL ADMINISTRATION

Objectives: We studied the use of esmolol in patients experiencing min or side effects of palpitations, anxiety, nervousness, and tremors ass ociated with dobutamine stress echocardiography. Background: Dobutamin e stress echocardiography is frequently used in the assessment of coro nary artery disease. Esmolol administration may enhance patient comfor t. Methods: Sixty consecutive patients who experienced minor side-effe cts during dobutamine stress echocardiography were given 0.3 mg/kg esm olol intravenously in the recovery period and compared retrospectively to sixty consecutive controls who underwent dobutamine stress echocar diography, who did not receive esmolol, during the same time period. B oth groups were matched for age, ejection fraction, and peak dose of d obutamine. Heart rate and blood pressure were assessed during and afte r 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 an d control respectively, p=ns), but peak heart rate was higher in the e smolol group (126 +/- 14 vs. 116 +/- 14, p<0.01). In the group who rec eived esmolol, symptomatic relief paralleled the statistically signifi cant 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 r ate in the esmolol group remained significantly lower than the control group for 5 minutes following esmolol administration (92.0 +/- 10.3 v s 96.7 +/- 11.8 p<0.05). As a percentage of peak heart rate the esmolo l group remained significantly lower than the control for 7 minutes (7 4% vs 80% p<0.05). Esmolol induced a significant reversal of dobutamin e-induced diastolic hypotension (diastolic blood pressure at peak 66 /- 17 vs 8 min recovery 70 +/- 12, p<0.03) that was not seen in contro ls (diastolic blood pressure at peak 64 +/- 18 vs 8 min recovery 65 +/ - 14, p=ns). Systolic blood pressure and heart rare remained elevated in both groups 8 min into recovery compared to baseline, suggesting pe rsistent dobutamine effect beyond the expected 2 min pharmacologic hal f-life of dobutamine. No side-effects from esmolol were seen despite i t being used in 9 patients with EF < 35%. Conclusions: Esmolol is effe ctive and well tolerated for the management of dobutamine-related mino r side-effects. The mechanism of benefit, in addition to heart rate re duction, may involve a reversal of dobutamine-induced diastolic hypote nsion. Blood pressure and heart rate recovery are slower than expected from previously published pharmacokinetic data.