What question did this study set out to answer?

To determine whether metabolic inhibitors and hypoxia reproduce the linear relationship between intrinsic heart rate and ventricular contractility observed in human myocardial failure.

July 1, 1969Circulation Research

Effects of Hypoxia and Metabolic Inhibitors on the Intrinsic Heart Rate and Myocardial Contractility in Dogs

Q: What is the clinical evidence from this study?

Study design: Other. Population: acute heart failure produced by agents which impair myocardial energy synthesis. Intervention: Hypoxia (6% oxygen), sodium cyanide, parachloromercuribenzoate, or dinitrophenol. Primary outcome: Relationship between percent changes in contractile force and intrinsic rate (r=0.87).

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Key result

Hypoxia, cyanide, and parachloromercuribenzoate induced a linear relationship between percent changes in contractile force and intrinsic rate (r=0.87) in dogs after autonomic blockade.

Population

Anesthetized dogs after autonomic blockade by propranolol and atropine

Design

Preclinical

Authors

AJAnthony D. JoseJawaharlal Institute of Post Graduate Medical Education and Research FSFrank W. StittUniversity of Miami

Discussion

Member takes

Implication

No immediate implications for human acute HF management; extends mechanistic evidence for metabolic coupling of rate and force in canine models.

Key Points

To determine whether metabolic inhibitors and hypoxia reproduce the linear relationship between intrinsic heart rate and ventricular contractility observed in human myocardial failure.
Induced autonomic blockade in anesthetized dogs using propranolol and atropine.
Produced acute heart failure by ventilating with 6% oxygen or administering intravenous infusions of sodium cyanide, parachloromercuribenzoate, or dinitrophenol.
Hypoxia and sodium cyanide initially increased and then depressed both intrinsic rate and contraction, parachloromercuribenzoate depressed both, and dinitrophenol depressed only contraction.
Percent changes in contractile force and intrinsic rate correlated linearly under hypoxia, cyanide, and parachloromercuribenzoate (r=0.87; slopes of 3.2, 2.7, and 3.3, respectively).
Combined evaluation with pentobarbital and aminophylline yielded a single linear relationship between heart rate and contractility (r=0.89, slope 3.2).

Structured PICO

Population

Anesthetized dogs subjected to autonomic blockade and acute heart failure induced by metabolic inhibitors or hypoxia.

Intervention

Ventilation with 6% oxygen or intravenous infusion of sodium cyanide, parachloromercuribenzoate, or dinitrophenol

Outcome

Intrinsic heart rate and ventricular contractile forcesurrogate

Main Result

Effect estimate: r=0.87

In a canine model of acute heart failure, changes in intrinsic heart rate and myocardial contractility were linearly related during metabolic inhibition, suggesting a shared dependence on limited energy sources.

Cite This Study

Jose et al. (1969) studied acute heart failure produced by agents which impair myocardial energy synthesis. Hypoxia (6% oxygen), sodium cyanide, parachloromercuribenzoate, or dinitrophenol was evaluated on Relationship between percent changes in contractile force and intrinsic rate (r=0.87). Hypoxia, cyanide, and parachloromercuribenzoate induced a linear relationship between percent changes in contractile force and intrinsic rate (r=0.87) in dogs after autonomic blockade.

synapsesocial.com/papers/6a92d668a0a82415c1a299ff https://doi.org/10.1161/01.res.25.1.53

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Implication

No immediate implications for human acute HF management; extends mechanistic evidence for metabolic coupling of rate and force in canine models.

Effects of Hypoxia and Metabolic Inhibitors on the Intrinsic Heart Rate and Myocardial Contractility in Dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Effects of Hypoxia and Metabolic Inhibitors on the Intrinsic Heart Rate and Myocardial Contractility in Dogs

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider