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Scintigraphic assessment of patients with electrocardiographic left ventricular hypertrophy with ST-T changes without
Michihiro Narita1, Tadashi Kurihara
1Department of Cardiology, Sumimoto Hospital, Osaka, Japan. michihiro-narita@sumishobilkan.co.jp
Insights
Electrocardiographic left ventricular hypertrophy (ECG-LVH) with unexplained causes often shows apical sympathetic nerve abnormalities. These findings, detected by I-123 MIBG imaging, may precede metabolic and perfusion changes.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Cardiovascular Imaging
Background:
- Electrocardiographic left ventricular hypertrophy with ST-T changes (ECG-LVH) can be challenging to diagnose.
- Routine examinations may not fully elucidate the underlying pathology in some ECG-LVH patients.
Purpose of the Study:
- To investigate the pathologic processes in patients with ECG-LVH using advanced scintigraphic techniques.
- To clarify the role of sympathetic nerve function and metabolism in unexplained ECG-LVH.
Main Methods:
- Utilized myocardial I-123 MIBG imaging, I-123 BMIPP imaging, and stress perfusion imaging in 29 patients with ECG-LVH.
- Assessed visual abnormalities and calculated I-123 MIBG washout. Echocardiography was used for LV assessment.
- Included myocardial biopsy in nine patients for histopathological correlation.
Main Results:
- Apical abnormalities were detected in 76% (I-123 MIBG), 52% (I-123 BMIPP), and 17% (perfusion imaging).
- I-123 MIBG defects preceded I-123 BMIPP and perfusion abnormalities over time.
- High apical I-123 MIBG washout and myocardial disarray were observed in the apical regions.
Conclusions:
- Sympathetic nerve abnormalities at the cardiac apex are common in ECG-LVH without apparent cause.
- These findings resemble those in hypertrophic cardiomyopathy and may indicate early stages of cardiac pathology.
- Apical sympathetic dysfunction can precede alterations in fatty acid metabolism and myocardial perfusion.
Purpose:
Some patients who show electrocardiographic left ventricular hypertrophy with ST-T changes (ECG-LVH) are difficult to evaluate using routine examinations. To clarify the pathologic process in these patients, the authors performed several scintigraphic examinations.
Materials And Methods:
Twenty-nine patients with ECG-LVH, without apparent cause, such as left ventricular (LV) systolic overloading or increased LV mass, were examined by myocardial I-123 MIBG imaging, I-123 BMIPP imaging, and exercise-induced stress perfusion imaging. In addition to the visual assessment of each image, we calculated global and regional myocardial washout of I-123 MIBG (%washout). The LV was assessed using conventional echocardiography.
Results:
Visually observed abnormalities were located exclusively at the LV apex with all imaging methods and were detected in 76%, 52%, and 17% of patients by I-123 MIBG, I-123 BMIPP, and perfusion imaging, respectively. A follow-up study revealed that the apical defects of I-123 MIBG were subsequently followed by defects of I-123 BMIPP and then perfusion abnormalities. In patients with an apical defect revealed by I-123 MIBG imaging, apical %washout was high. In nine patients who underwent myocardial biopsy, myocardial disarray was observed at the apical regions.
Conclusions:
In many patients with ECG-LVH without apparent cause, sympathetic abnormalities are observed at the apex, similar to pathologic changes in hypertrophic cardiomyopathy. These abnormalities may lead to changes in fatty acid metabolism and perfusion.