Sensitivity Analysis of Single Beat Left Ventricular Elastance Estimation by Chen Method

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Clinical Diagnostics

Background:

• Left ventricular end-systolic elastance (Ees) is a critical index of cardiac contractility.
• The single-beat (Ees(sb)) Chen method offers a non-invasive approach to estimate Ees using arm-cuff pressures and stroke volume (SV).
• Assessing the reliability of Ees(sb) is crucial for its accurate clinical application.

Purpose of the Study:

• To perform a sensitivity analysis of the Chen method's formula for Ees(sb).
• To evaluate the reliability and clinical applicability of the Ees(sb) estimation.
• To investigate the influence of various cardiovascular parameters on Ees(sb) using a mathematical model.

Main Methods:

• Sensitivity analysis of the Chen formula parameters under baseline conditions.
• Utilized a mathematical model of the cardiovascular system.
• Evaluated Ees(sb) sensitivity to end-diastolic LV elastance (Eed), Ees, arterial systemic resistance (Ras), and heart rate (HR).

Main Results:

• Ees(sb) demonstrated counterintuitive behavior, increasing with LV end-systolic volume and decreasing with SV, contrary to Ees definition.
• The Chen method often underestimated Ees when analyzed with a mathematical model.
• Ees(sb) was significantly influenced by Eed, HR, Ras, ejection time, and pre-ejection time.

Conclusions:

• The Ees(sb) estimation via the Chen method exhibits significant limitations and unreliability.
• Observed discrepancies with Ees definition highlight potential issues in clinical interpretation.
• The method's sensitivity to multiple cardiovascular parameters necessitates caution in its application.