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Radionuclide assessment of nitroglycerin influence on abnormal left ventricular segmental contraction in patients
Insights
Noninvasive cardiac blood pool imaging effectively distinguishes reversible from irreversible ventricular contraction abnormalities in coronary heart disease patients. This technique accurately detects myocardial ischemia using technetium-99m imaging and nitroglycerin response.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Chronic coronary heart disease (CHD) can cause abnormal ventricular segmental contraction.
- Differentiating reversible from irreversible contraction is crucial for patient management.
- Noninvasive imaging techniques are valuable for assessing cardiac function.
Purpose of the Study:
- To evaluate the utility of noninvasive gated cardiac blood pool imaging using technetium-99m autologous erythrocytes.
- To differentiate reversible versus irreversible abnormal ventricular segmental contraction in CHD patients.
- To assess regional wall and pump responses to sublingual nitroglycerin.
Main Methods:
- Utilized noninvasive gated cardiac blood pool imaging with technetium-99m autologous erythrocytes.
- Administered sublingual nitroglycerin to assess regional wall and pump responses.
- Analyzed end-systolic volumes, end-diastolic volumes, and ejection fractions.
- Correlated imaging findings with the presence or absence of ECG-documented infarctions.
Main Results:
- Patients without ECG infarctions showed significantly greater decreases in end-systolic volumes and greater increases in ejection fractions post-nitroglycerin compared to those with infarctions.
- No significant difference was observed in the percent reduction of end-diastolic volumes between the two groups.
- Improvement in regional dyssynergy following nitroglycerin was related to the absence of prior infarction on ECG.
Conclusions:
- Noninvasive scintigraphy accurately detects reversible localized dyssynergy due to myocardial ischemia in CHD.
- The response to nitroglycerin, assessed by cardiac blood pool imaging, can differentiate reversible from irreversible ventricular dysfunction.
- Absence of prior infarction is associated with a better response to nitroglycerin, indicating less irreversible damage.
Abstract:
Noninvasive gated cardiac blood pool imaging with technetium-99m autologous erythrocytes was employed to differentiate reversible verus irreversible abnormal ventricular segmental contraction by regional wall and pump responses to sublingual nitroglycerin in 25 patients with chronic coronary heart disease. In 12 patients without ECG infarctions compared to 13 with infarctions, radioisotopic images demonstrated significantly greater percent decreases in end-systolic volumes (33.8 +/- 6.7 SEM vs 187 +/- 4.4; P less than 0.05) without differences in percent reductions in end-diastolicvolumes (13.7 +/- 3.9 vs 11.6 +/- 6.1; NS) and thereby significantly greater percent increases in ejection fractions (9.3 +/- 1.6 vs 4.1 +/- 2.0; P less than 0.05). In the 22 patients with regional dyssynergy, improvement in disordered pattern and extent of localized dyssynergy following antianginal action of nitroglycerin was related to ECG absence of prior infarction. These obsevations demonstrate the clinical accuracy of atraumatic scintigraphy in the detection of reversible localized dyssynergy due to myocardial ischemia in coronary heart disease.