Key result
Adding ivabradine to dobutamine in post-ischaemia hearts reduced heart rate and increased stroke volume from 30 to 36 mL with a neutral effect on cardiac efficiency.
Why the study?
Does the addition of ivabradine to dobutamine improve stroke volume and cardiac energetics in a preclinical model of left ventricular post-ischaemia dysfunction?
Does the addition of ivabradine to dobutamine improve stroke volume and cardiac energetics in a preclinical model of left ventricular post-ischaemia dysfunction?
In a preclinical model of post-ischemic LV dysfunction, adding ivabradine to dobutamine reversed dobutamine-induced tachycardia and increased stroke volume without compromising cardiac efficiency.
Answers are grounded in this paper and cite their sources.
Hypothesis-generating for ivabradine with dobutamine in post-ischaemic LV dysfunction; prospective human trials needed before clinical consideration.
AIM: Compensatory tachycardia can potentially be deleterious in acute heart failure. In this study, we tested a therapeutic strategy of combined inotropic support (dobutamine) and selective heart rate (HR) reduction through administration of ivabradine. METHODS: In an open-chest pig model (n = 12) with left ventricular (LV) post-ischaemia dysfunction, cardiac function was assessed by LV pressure catheter and sonometric crystals. Coronary flow and blood samples from the coronary sinus were used to measure myocardial oxygen consumption (MVO2 ). LV energetics was assessed by comparing MVO2 with cardiac work at a wide range of workloads. RESULTS: In the post-ischaemia heart, dobutamine (5 μg kg(-1) min(-1) ) increased cardiac output (CO) by increasing HR from 102 ± 21 to 131 ± 16 bpm (beats per min; P < 0.05). Adding ivabradine (0.5 mg kg(-1) ) slowed HR back to 100 ± 9 bpm and increased stroke volume from 30 ± 5 to 36 ± 5 mL (P < 0.05) by prolonging diastolic filling time and increasing end-diastolic dimensions. Adding ivabradine had no adverse effects on CO, mean arterial pressure and cardiac efficiency. Similar findings on efficiency and LV function were also seen using an ex vivo working mouse heart protocol. CONCLUSIONS: A combined infusion of dobutamine and ivabradine had a neutral effect on post-ischaemia LV efficiency and increased left ventricular output without an increase in HR.
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Bakkehaug et al. (2016) studied left ventricular post-ischaemia dysfunction (n=12). ivabradine added to dobutamine vs. dobutamine alone was evaluated on stroke volume (mL) (p=<0.05). Adding ivabradine to dobutamine in post-ischaemia hearts reduced heart rate and increased stroke volume from 30 to 36 mL with a neutral effect on cardiac efficiency.
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