What question did this study set out to answer?

This research aims to evaluate the validity of various indices of myocardial contractility under different physiological conditions.

November 1, 1973Cardiovascular Research

Problems in the use of indices of myocardial contractility

View Full Paper

Ask AI

Bookmark

This research aims to evaluate the validity of various indices of myocardial contractility under different physiological conditions.
Tested indices in isolated cat heart and anaesthetized dog models, controlling for left ventricular filling and ejection resistance.
Examined effects of increased load and heart size by constricting aorta and during ventricular distention.
Investigated LV dP/dt/P relationships and their extrapolation to determine Vmax.
None of the tested indices remained insensitve to increased load and heart size across all conditions.
Extrapolation of LV dP/dt/P to obtain Vmax proved complex, indicating time-dependent pressure dynamics.
Assumed linear relationships yielded challenging formulas for pressure as a function of time.

Structured PICO

Population

Isolated cat heart, open chest anaesthetized dog, closed chest anaesthetized dog with and without denervated heart, and conscious dog with and without denervated heart

Intervention

Increased load (constricting aorta between beats) and increased heart size (ventricular distention)

Outcome

Sensitivity of myocardial contractility indices (maximum acceleration of blood, LV dP/dt max, LV dP/dt max/P, (LV dP/dt/P) max, and X-Y plot of LV dP/dt/P against P) to increased load and heart sizesurrogate

Commonly used indices of myocardial contractility are sensitive to loading conditions and heart size, limiting their validity as load-independent measures of contractility.

Discussion

No takes yet. Share an insight, caveat, or question.

Implication

Contractility indices remain load- and size-sensitive in animal models; leaves open identification of valid load-independent measures for research and translation.

Cite This Study

Bos et al. (1973) studied this question.

synapsesocial.com/papers/6a21235c2c7e251d79c3ca8e https://doi.org/10.1093/cvr/7.6.834

View Full Paper

Ask AI

Bookmark

Implication

Contractility indices remain load- and size-sensitive in animal models; leaves open identification of valid load-independent measures for research and translation.

Problems in the use of indices of myocardial contractility

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Problems in the use of indices of myocardial contractility

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Keep reading

Keep reading