January 1, 1975Japanese Heart JournalOpen Access

Left and Right Ventricular Volumes in A-V Block, and Their Changes Induced by the Infusion of Isoproterenol

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Why the study?

Does isoproterenol infusion improve cardiovascular dynamics and myocardial contractility in dogs with complete A-V block?

Population

11 mongrel dogs weighing 14.5 to 26.3 Kg with experimentally produced complete heart (A-V) block.

Comparison

Isoproterenol infusion during complete heart… vs Baseline control period in the same dogs.

Design

Preclinical

Authors

KMKikuo MachidaNational Defense Medical College Hospital

Discussion

Member takes

Implication

Supports direct inotropy in A-V block models; hypothesis-generating with no immediate clinical implications.

Structured PICO

Does isoproterenol infusion improve cardiovascular dynamics and myocardial contractility in dogs with complete A-V block?

Population

11 mongrel dogs weighing 14.5 to 26.3 Kg with experimentally produced complete heart (A-V) block.

Intervention

Isoproterenol infusion (8 µg/min intravenously) during complete heart block and right ventricular pacing.

Comparator

Baseline control period (before isoproterenol infusion) in the same dogs.

Outcome

Changes in cardiovascular dynamics including cardiac output, heart rate, stroke volume, ventricular residual fractions, and end-diastolic volume (EDV).surrogate

Isoproterenol augments myocardial contractility in complete A-V block primarily through direct inotropic action rather than via the Bowditch effect from increased heart rate.

Limitations

Force-velocity relationship is a crude means to analyze ventricular function based on the assumption that the left ventricle is a thin-walled sphere
MCSR provides the velocity of shortening of the myocardial fibers but not of the contractile elements

Cite This Study

Kikuo Machida (1975) studied this question.

synapsesocial.com/papers/6a2110fe570f73dd9ac3ac71 https://doi.org/10.1536/ihj.16.65

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Left and Right Ventricular Volumes in A-V Block, and Their Changes Induced by the Infusion of Isoproterenol

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

Left and Right Ventricular Volumes in A-V Block, and Their Changes Induced by the Infusion of Isoproterenol

Discussion

Member takes

Implication

Structured PICO

Limitations

Cite This Study

Also Consider

Also Consider