What question did this study set out to answer?

To determine whether ventricular end-diastolic volume alters myocardial oxygen consumption in mechanically unloaded contractions through length-dependent activation mechanisms.

May 1, 1989AJP Heart and Circulatory Physiology

Minor preload dependence of O2 consumption of unloaded contraction in dog heart

View Full Paper

Ask AI

Bookmark

Why the study?

Does end-diastolic volume affect myocardial oxygen consumption of mechanically unloaded contraction in the dog heart?

Population

Cross-circulated dog heart model

Comparison

Preloaded but maximally unloaded contractions… vs Isovolumic contraction at V0

Design

Preclinical

Authors

YYYoshio YasumuraHeart Failure / Cardiomyopathy TNTaneyoshi NozawaToranomon Hospital SFShiho FutakiJuntendo University Hospital

Discussion

Member takes

Implication

Animal data indicate unloaded VO2 is EDV-independent; leaves open relevance of length-dependent activation to human myocardial energetics.

Key Points

To determine whether ventricular end-diastolic volume alters myocardial oxygen consumption in mechanically unloaded contractions through length-dependent activation mechanisms.
Examined cross-circulated canine hearts contracting from varying end-diastolic volumes.
Abolished systolic pressure development and mechanical load by rapidly releasing ventricular volume at the onset of contraction, then measured resulting myocardial oxygen consumption.
Oxygen consumption during unloaded contractions from elevated end-diastolic volumes was only slightly greater than during isovolumic contractions at zero peak pressure volume.
The slight excess in oxygen consumption was attributable to residual systolic pressure-volume area rather than preload volume, indicating that length-dependent activation has a negligible effect on total energetic cost.

Structured PICO

Does end-diastolic volume affect myocardial oxygen consumption of mechanically unloaded contraction in the dog heart?

Population

Cross-circulated dog heart model

Intervention

Preloaded but maximally unloaded contractions from different end-diastolic volumes (EDVs) by quickly releasing ventricular volume

Comparator

Isovolumic contraction at V0 (volume at which peak isovolumic pressure was zero)

Outcome

Relation between myocardial oxygen consumption (VO2) and end-diastolic volume (EDV)surrogate

In a dog heart model, myocardial oxygen consumption during unloaded contraction is practically independent of end-diastolic volume, suggesting length-dependent activation of excitation-contraction coupling has negligible effect on VO2 in the whole heart.

Cite This Study

Yasumura et al. (1989) studied this question.

synapsesocial.com/papers/6a941d443c3b3bc8ec6d25da https://doi.org/10.1152/ajpheart.1989.256.5.h1289

View Full Paper

Ask AI

Bookmark

Implication

Animal data indicate unloaded VO2 is EDV-independent; leaves open relevance of length-dependent activation to human myocardial energetics.

Minor preload dependence of O2 consumption of unloaded contraction in dog heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Minor preload dependence of O2 consumption of unloaded contraction in dog heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider