Cardiac function assessed by attenuation-corrected radionuclide pressure-volume indices.

Area of Science:

• Cardiology
• Nuclear Medicine
• Biomedical Engineering

Background:

• Assessing left ventricular (LV) function is critical in diagnosing and managing cardiovascular diseases.
• Traditional methods like ejection fraction have limitations in sensitivity for detecting subtle abnormalities.
• Radionuclide ventriculography offers a nongeometric approach to volume assessment, but accuracy can be affected by attenuation artifacts.

Purpose of the Study:

• To evaluate the diagnostic utility of the ratio of left ventricular (LV) peak systolic pressure to end systolic volume (P/V ratio) in patients with coronary artery disease (CAD).
• To compare the sensitivity of the P/V ratio with ejection fraction for detecting abnormal LV function and predicting CAD.
• To assess the value of the slope of the end systolic pressure-volume line under varying loading conditions for CAD prediction.

Main Methods:

• Attenuation-corrected radionuclide ventriculography was used to measure LV volumes.
• Arm-cuff peak systolic pressures were obtained at rest.
• The P/V ratio was calculated at rest, and the slope of the end systolic pressure-volume line was determined under rest, isometric handgrip, and post-nitroglycerin conditions.

Main Results:

• The resting P/V ratio was more sensitive than ejection fraction for identifying abnormal LV function and predicting CAD in 43 patients.
• The slope of the end systolic pressure-volume line showed similar sensitivity to the resting P/V ratio but aided in identifying patients with CAD.
• The study highlights the importance of accurate, nongeometric LV end-systolic volume measurements, improved by attenuation correction.

Conclusions:

• Attenuation-corrected radionuclide P/V ratio measurements offer improved sensitivity for detecting LV dysfunction and CAD compared to ejection fraction.
• The end systolic pressure-volume line slope provides complementary information for CAD identification.
• Accurate, nongeometric LV volume assessment is essential for advancing pressure-volume loop analysis in clinical cardiology.