Left ventricular systolic pressure-volume area correlates with oxygen consumption

Area of Science:

• Cardiovascular Physiology
• Cardiac Metabolism

Background:

• Left ventricular oxygen consumption (MVO2) is crucial for cardiac function.
• Accurate measurement of MVO2 is essential for understanding cardiac energetics.

Purpose of the Study:

• To investigate the correlation between left ventricular oxygen consumption per beat (MVO2) and the pressure-volume (P-V) area.
• To determine if P-V area can serve as an index for ventricular oxygen consumption.

Main Methods:

• Utilized 13 excised, cross-circulated canine hearts.
• Manipulated ventricular pressure and volume loads using a volume servo pump to alter P-V area.
• Measured MVO2 under varying load conditions during both isovolumic and ejecting contractions.

Main Results:

• A significant linear correlation was observed between MVO2 and P-V area (correlation coefficient = 0.92 +/- 0.016).
• Linear regression analysis provided a formula: MVO2 = alpha[P-V area] + b, with specific coefficients for slope and basal oxygen consumption.
• The P-V area explained a substantial portion of the variation in MVO2.

Conclusions:

• The pressure-volume (P-V) area is a strong and reliable index of left ventricular oxygen consumption per beat.
• This finding has implications for assessing cardiac energetics and function non-invasively.
• The established linear relationship provides a quantitative method for estimating MVO2 based on P-V loops.