What does this research mean for the field?

Adding a pressure-dependent source resistance to a time-varying elastance model accurately predicts isovolumic left ventricular pressure throughout systole, correcting the midsystolic underestimation seen in simple elastance models. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aimed to explore the relationship between left ventricular pressure and volume using time-varying elastance and source resistance.

July 1, 1987AJP Heart and Circulatory Physiology

Description of LV pressure-volume relations by time-varying elastance and source resistance

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Why the study?

Does adding a pressure-dependent source resistance to a time-varying elastance model improve the prediction of isovolumic left ventricular pressure in a canine model?

Population

Six dogs preinstrumented to measure left ventricular pressure, aortic flow, and LV volume from three…

Comparison

Time-varying elastance model with a… vs Simple time-varying elastance model without…

Design

Preclinical

Authors

WLWilliam C. LittleInterventional Cardiology GFG. L. FreemanThe University of Texas Health Science Center at San Antonio

Discussion

Member takes

Implication

Pressure-dependent resistance refines elastance-based LVP prediction in canines; extends E(t) framework but leaves open clinical translation.

Key Points

This study aimed to explore the relationship between left ventricular pressure and volume using time-varying elastance and source resistance.
Utilized six dogs pre-instrumented to measure left ventricular pressure and volume during normal ejecting and isovolumic beats.
Applied caval occlusions to vary left ventricular pressure and volume, enabling determination of time-varying elastance (E(t)).
Developed a model to predict left ventricular pressure by incorporating a pressure-dependent source resistance.
The simple E(t) model accurately predicted isovolumic left ventricular pressure during the first 70 ms of systole (r = 0.99), undershooting midsystolic pressure by 48 +/- 5 mmHg (P < 0.05).
Incorporation of pressure-dependent source resistance improved predictions throughout systole, maintaining accuracy (r = 0.99).
Pressure development to peak isovolumic pressure occurred 22 +/- 7 ms earlier than the model predicted.

Structured PICO

Does adding a pressure-dependent source resistance to a time-varying elastance model improve the prediction of isovolumic left ventricular pressure in a canine model?

Population

Six dogs preinstrumented to measure left ventricular pressure (LVP), aortic flow (Q), and LV volume (V) from three dimensions

Intervention

Time-varying elastance model with a pressure-dependent source resistance (K = 0.0015 s/ml)

Comparator

Simple time-varying elastance model without source resistance

Outcome

Accuracy of predicting isovolumic left ventricular pressure (LVP)surrogate

Incorporating a pressure-dependent source resistance into a time-varying elastance model significantly improves the prediction of left ventricular pressure during isovolumic contraction.

Cite This Study

Little et al. (1987) studied this question.

synapsesocial.com/papers/6a1d40dc28423f2ce504ebd8 https://doi.org/10.1152/ajpheart.1987.253.1.h83

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Implication

Pressure-dependent resistance refines elastance-based LVP prediction in canines; extends E(t) framework but leaves open clinical translation.

Description of LV pressure-volume relations by time-varying elastance and source resistance

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Description of LV pressure-volume relations by time-varying elastance and source resistance

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider