What is the clinical evidence from this study?

Study design: Other. Population: Acute myocardial ischemic injury (n=22). Intervention: Dobutamine vs. Control occlusion. Primary outcome: Increase in intramural carbon dioxide tension (delta PmCO2) in the ischemic zone (p=<0.01).

What question did this study set out to answer?

To determine whether inotropic or chronotropic stimulation induced by intravenous dobutamine augments the severity of acute myocardial ischemic injury during coronary occlusion.

June 1, 1982CirculationOpen Access

Effects of inotropic and chronotropic stimuli on acute myocardial ischemic injury. I. Studies with dobutamine in the anesthetized dog.

Q: What are the key findings of this study?

Inotropic stimulation with dobutamine during coronary occlusion increased acute myocardial ischemic injury (delta PmCO2 76 vs 56 mm Hg, p<0.01) only when heart rate was simultaneously increased.

Q: What question did this study set out to answer?

To determine whether inotropic or chronotropic stimulation induced by intravenous dobutamine augments the severity of acute myocardial ischemic injury during coronary occlusion.

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Key result

Inotropic stimulation with dobutamine during coronary occlusion increased acute myocardial ischemic injury (delta PmCO2 76 vs 56 mm Hg, p<0.01) only when heart rate was simultaneously increased.

Why the study?

Does intravenous dobutamine exacerbate acute myocardial ischemic injury in an anesthetized dog model of coronary occlusion?

Population

22 anesthetized dogs subjected to serial 10-minute occlusions of the left anterior descending coronary artery

Comparison

Intravenous dobutamine at varying doses vs Control occlusion without dobutamine, with or…

Design

Preclinical

Authors

RRRobert E. RudeUniversity of Southern California CICarlos IzquierdoInstituto Nacional de Cancerología LBL. Maximilian BujaGeneral Cardiology

Discussion

Member takes

Implication

Dobutamine with concurrent tachycardia may worsen acute ischemic injury; leaves open whether isolated inotropy is neutral.

Key Points

To determine whether inotropic or chronotropic stimulation induced by intravenous dobutamine augments the severity of acute myocardial ischemic injury during coronary occlusion.
Studied 22 anesthetized dogs undergoing serial 10-minute occlusions of the left anterior descending coronary artery.
Quantified ischemic injury severity by mass spectrometric recording of intramural carbon dioxide tension elevation (delta PmCO2).
Tested three infusion protocols: high-dose dobutamine (20 mcg/kg/min), heart rate-matched dobutamine via atrial pacing (n=9), and low-dose dobutamine (5.6 ± 3.2 mcg/kg/min, n=4) designed to increase contractility without elevating heart rate.
High-dose dobutamine increased both heart rate and left ventricular dP/dt, resulting in a significantly higher delta PmCO2 compared to control occlusion (76 ± 21 vs 56 ± 13 mm Hg, p < 0.01).
In atrially paced dogs with matched heart rates (mean 149–154 beats/min), delta PmCO2 did not differ between occlusions despite higher left ventricular dP/dt with dobutamine.
Low-dose dobutamine increased left ventricular dP/dt without altering baseline heart rate, maintaining similar delta PmCO2 values between control and intervention occlusions.

Structured PICO

Does intravenous dobutamine exacerbate acute myocardial ischemic injury in an anesthetized dog model of coronary occlusion?

Population

22 anesthetized dogs subjected to serial 10-minute occlusions of the left anterior descending coronary artery to assess the effect of dobutamine on ischemic injury.

Intervention

Intravenous dobutamine at varying doses (5.6 to 20 micrograms/kg/min)

Comparator

Control occlusion without dobutamine, with or without atrial pacing

Outcome

Severity of ischemic injury determined by mass spectrometric measurement of the increase in intramural carbon dioxide tension (delta PmCO2) in the ischemic zonesurrogate

Main Result

Absolute Event Rate: 76% vs 56%

p-value: p=<0.01

Inotropic stimulation with dobutamine does not significantly worsen acute myocardial ischemic injury in the nonfailing heart unless it simultaneously increases heart rate.

Cite This Study

Rude et al. (1982) studied Acute myocardial ischemic injury (n=22). Dobutamine vs. Control occlusion was evaluated on Increase in intramural carbon dioxide tension (delta PmCO2) in the ischemic zone (p=<0.01). Inotropic stimulation with dobutamine during coronary occlusion increased acute myocardial ischemic injury (delta PmCO2 76 vs 56 mm Hg, p<0.01) only when heart rate was simultaneously increased.

synapsesocial.com/papers/6a6eeb2afebe604dd7081463 https://doi.org/10.1161/01.cir.65.7.1321

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Effects of inotropic and chronotropic stimuli on acute myocardial ischemic injury. I. Studies with dobutamine in the anesthetized dog.

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Effects of inotropic and chronotropic stimuli on acute myocardial ischemic injury. I. Studies with dobutamine in the anesthetized dog.

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

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