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Radionuclide left ventricular function curve during atrial pacing in normal subjects and in patients with coronary
Insights
Radionuclide angiography during right atrial pacing effectively assesses left ventricular function. Abnormal pacing ventricular function curves in coronary artery disease patients indicate decreased contractile force during ischemia.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiovascular Physiology
Background:
- Left ventricular (LV) function is crucial for cardiac health.
- Assessing LV systolic function, especially during ischemia, remains a clinical challenge.
- The Frank-Starling relationship provides insights into cardiac performance.
Purpose of the Study:
- To evaluate left ventricular function using radionuclide angiography during right atrial pacing.
- To differentiate between normal and diseased ventricular function curves in coronary artery disease (CAD).
- To assess the utility of stroke volume (SV) to end-diastolic volume (EDV) relationship under controlled conditions.
Main Methods:
- Radionuclide angiography was performed in 7 normal subjects and 20 CAD patients.
- Right atrial pacing was employed to modulate cardiac loading.
- Left ventricular function curves plotting stroke volume against end-diastolic volume were generated.
Main Results:
- Normal subjects exhibited a linear pacing ventricular function curve through the origin.
- 18 of 20 CAD patients displayed abnormal pacing ventricular function curves.
- Three distinct abnormal curve shapes were observed, reflecting reduced contractility during ischemia.
Conclusions:
- Right atrial pacing combined with radionuclide angiography is a valuable method for assessing LV function.
- The SV-EDV relationship effectively evaluates systolic function, distinguishing it from compliance.
- Abnormal pacing ventricular function curves are sensitive indicators of impaired LV contractility in CAD.
Abstract:
We used radionuclide angiography during right atrial pacing to assess left ventricular function in 7 normal subjects and 20 patients with coronary artery disease. A left ventricular function curve relating stroke volume to end-diastolic volume was plotted for each patient. The normal pacing ventricular function curve was a straight line passing through the origin of axes. The pacing ventricular function curve was abnormal in 18 of the 20 patients with coronary artery disease, and three different shaped curves were obtained, reflecting decreased contractile force for the same end-diastolic volume during ischemia. Cardiac output and blood pressure do not change during atrial pacing, thus the Frank-Starling relationship is evaluated by this method during almost experimentally controlled conditions. Relating stroke volume to end-diastolic volume, and not end-diastolic pressure, distinguishes between overall left ventricular systolic function and left ventricular compliance.