Impact of Various Doses of Dobutamine on Myocardial Viability and the Effects of β-Blockers in Patients With Ischemic Cardiomyopathy: An Assessment Using Stress Echocardiography

Background

This study aimed to investigate the predictive value of dobutamine stress echocardiography (DSE) at varying doses for myocardial viability, with a particular emphasis on the impact of β-adrenergic blockers on myocardial viability in patients with ischemic cardiomyopathy (ICM).

Material and Methods

A total of 189 patients with ICM underwent DSE. Based on the dosage of dobutamine, patients were randomly divided into three groups: low-dose group (LD, 10 µg/kg/min, n = 63), medium-dose group (CD, 20 µg/kg/min, n = 63), and high-dose group (HD, 30 µg/kg/min, n = 63). All patients received β-blockers 1 min after the DSE examination. Changes in heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), radial strain (RS), and radial strain rate (RSr) during left ventricular systole (LVS) were analyzed, along with secondary effects and myocardial viability in the LD-β, CD-β, and HD-β groups.

Results

During the postoperative dobutamine injection, HR, SBP, and DBP in the LD, CD, and HD groups were significantly higher compared to pre-injection levels (p < 0.05), with DBP in the HD group being notably higher than in the LD and CD groups (p < 0.05). After intravenous injection of metoprolol, all indicators significantly decreased in the LD and CD groups (p < 0.05). The rates of RS and RSr in the CD and HD groups were significantly lower than those in the LD group (p < 0.05). The proportion of normal wall motion viability (VWM) post-injection was significantly higher than pre-injection levels (p < 0.05), with the CD group surpassing the LD group (p < 0.05). The use of β-adrenergic blockers demonstrated that the sensitivity, specificity, and accuracy of myocardial viability in the LD, CD, and HD groups were all superior to those of the control group (p < 0.05), with the CD group exhibiting the highest diagnostic performance (p < 0.05). The incidence of arrhythmias in the HD group was 20.3%, compared to 7.9% in the LD group (χ² = 6.78, p = 0.034). Additionally, the occurrence of cardiovascular events in the HD group was 17.2%, significantly higher than the 6.3% observed in the LD group (χ² = 6.21, p = 0.045).

Conclusion

Moderate-dose DSE exhibited the optimal diagnostic performance in assessing myocardial viability in patients with ICM. Furthermore, the use of β-blockers effectively enhances the sensitivity and accuracy of the diagnosis, providing important practical guidance for the clinical evaluation of myocardial viability.