The importance of rate controlling medication in the performance and outcome of dobutamine stress echocardiogram in assessing patients with suspected angina

Stress echocardiography (SE) had been recommended by the professional Societies in assessing patients with suspected angina. SE protocols are variable across hospitals and countries in the recommendation of the cessation of rate controlling medication (RCMx) prior to SE. Some expert opinion paper recommends the cessation of beta-receptor blockers (BB) and rate controlling calcium channel blockers 48 hrs prior to SE to improve diagnostic accuracy of the test. This can impact on the efficient management of SE waiting list in addition can result in haemodynamic rebound effect leading to accelerated angina or hypertension.

To investigate the efficacy of Dobutamine SE in a cohort of patients where the cessation of rate controlling medication has not been mandated, we reviewed our results over one year period in patients investigated for suspected coronary artery disease (CAD).

Two hundred and twenty-seven consecutive patients underwent Dobutamine SE between January 2022 and January 2023 in a single centre. In addition to dobutamine the protocol allowed the administration of intravenous Atropine (maximum dose of 1.2mg), and "top up" handgrip exercise at the discretion of the performing cardiologist. We assessed the DSE outcome (positive vs negative), target (85% of maximum age predicted) heart rate (THR) and the achieved peak HR, in the two groups with RCMx and without (No-RCMx). We analysed the patients’ characteristics and 12 months outcome of a combined MACE of death, non-fatal MI, stroke, admission with angina, unplanned revascularisation.

Of the 227 patients 59% were on No-RCMx (male 49%). 88% of the patients in the RCMx group were on BB and 12 % on other RCMx. The THR was achieved in 74% of the RCMx and 90% in No-RCMx groups p=0.001. Positive Dobutamine SE was observed in 49% (46/93) of patients on RCMx vs 28% (38/134) on No-RCMx (p=0.001). Patients who did not reach THR 41% (15/37) had positive Dobutamine SE compared to 36% (69/190) who reached THR (p=0.626). There was no difference between groups in the peak WMSI. Logistic regression analysis showed that THR is not an independent determinant of positive Dobutamine SE (OR: 1.3, 95% CI 0.47-3.59, p=0.611), but being on RCMx was (OR 2.03, 95% CI 1.06-3.91, p=0.034). The MACE rate was higher in patients where the THR was not achieved (10/37, 27.0%) vs those with THR achieved (12/190, 6.3%) p<0.0001; in both the RCMx (8/24, 33% vs 8/69, 12%, p=0.015) and No-RCMx (2/12, 15% vs 4/121, 3%; p=0.045) groups respectively. RCMx was a determinant of MACE (OR 3.67, 95% CI 1.04-13.02, p=0.043)

This retrospective analysis of Dobutamine SE data proved same efficacy in patients with and without RCMx investigated for suspected CAD. The use of RCMx proved to be a predictor of both SE and MACE outcome irrespective the achieved THR. Our data show that patients referred for Dobutamine SE on RCMx can continue without impact on the test accuracy.