What question did this study set out to answer?

Determine whether subepicardial wall thickening is preserved relative to subendocardial thickening during exercise-induced myocardial ischemia.

November 1, 1988CirculationOpen Access

Subendocardial and subepicardial wall thickening during ischemia in exercising dogs.

Q: What does this research mean for the field?

During ischemia in exercising dogs, outer ventricular wall thickening is depressed disproportionately to reductions in outer wall blood flow and is not preserved relative to inner wall thickening. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

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Why the study?

Does exercise with coronary stenosis alter subepicardial versus subendocardial wall thickening in dogs?

Key Points

Determine whether subepicardial wall thickening is preserved relative to subendocardial thickening during exercise-induced myocardial ischemia.
Instrumented 10 dogs with circumflex artery flow probes, hydraulic occluders, and ultrasonic microcrystals to measure transmural and outer ventricular wall thickness.
Assessed systolic wall thickening and regional myocardial blood flow during treadmill exercise under control conditions and during coronary stenosis adjusted to maintain resting circumflex flow.
During exercise with stenosis, systolic thickening fell to 17.7 ± 28.5% of control in the outer wall and 40.1 ± 32.3% of control in the inner wall, with no significant difference between layers.
Normalized inner wall blood flow during ischemic exercise (25.0 ± 16.0%) was significantly less than outer wall flow (48.5 ± 20.9%).
Inner wall thickening correlated strongly with inner wall blood flow (r = 0.84), whereas outer wall function correlated weakly with outer wall blood flow (r = 0.62, p = 0.04).

Structured PICO

Does exercise with coronary stenosis alter subepicardial versus subendocardial wall thickening in dogs?

Population

10 dogs chronically instrumented with circumflex artery flow probes, hydraulic occluders, and pairs of ultrasonic microcrystals

Intervention

Treadmill exercise with a coronary stenosis that reduced circumflex artery flow to resting control levels

Comparator

Control treadmill exercise without stenosis

Outcome

Subendocardial (inner) and subepicardial (outer) systolic wall thickeningsurrogate

During ischemia in exercising dogs, outer wall thickening is depressed out of proportion to reductions in outer wall blood flow and is not preserved relative to inner wall thickening.

Discussion

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Implication

Challenges subepicardial preservation hypothesis during ischemic exercise; leaves open translation to human coronary disease.

Cite This Study

Homans et al. (1988) studied this question.

synapsesocial.com/papers/6a154b5779ff98d0de4e6588 https://doi.org/10.1161/01.cir.78.5.1267

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Subendocardial and subepicardial wall thickening during ischemia in exercising dogs.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Subendocardial and subepicardial wall thickening during ischemia in exercising dogs.

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

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