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[Electrocardiographic left ventricular hypertrophy without echocardiographic abnormalities evaluated by myocardial
1Department of Cardiology, Sumitomo Hospital, Osaka.
Insights
Myocardial perfusion and fatty acid imaging reveal abnormalities in patients with electrocardiographic left ventricular hypertrophy but normal echocardiograms. These imaging techniques help identify a pathological process similar to hypertrophic cardiomyopathy in some patients.
Area of Science:
- Cardiology
- Nuclear Medicine
- Pathophysiology
Background:
- Electrocardiographic (ECG) left ventricular hypertrophy (LVH) with ST-T changes can occur without echocardiographic abnormalities.
- The underlying pathophysiologic processes in these patients are not fully understood.
- Investigating these subtle cardiac changes is crucial for accurate diagnosis and management.
Purpose of the Study:
- To investigate the pathophysiologic process in patients with ECG-LVH and ST-T changes but normal echocardiograms.
- To evaluate the utility of myocardial perfusion imaging and fatty acid metabolic imaging in identifying cardiac abnormalities in this patient group.
Main Methods:
- Exercise stress 99mTc-methoxy-isobutyl isonitrile (MIBI) perfusion imaging and rest 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP) metabolic imaging were performed in 59 patients.
- Patients included those with ECG-LVH, with or without hypertension and echocardiographic hypertrophy.
- Coronary angiography and left ventricular myocardial biopsy were performed in a subset of patients.
Main Results:
- Transient perfusion abnormalities and apical defects on 123I-BMIPP imaging were more frequent in normotensive patients compared to hypertensive patients (32% vs 17% for perfusion, 62% vs 30% for BMIPP).
- 123I-BMIPP imaging revealed defects that were larger than perfusion abnormalities.
- Myocardial biopsy specimens showed myocardial disarray with hypertrophy, without coronary stenoses.
Conclusions:
- Many normotensive patients with ECG-LVH exhibit a pathological process resembling hypertrophic cardiomyopathy.
- Myocardial perfusion and 123I-BMIPP imaging are valuable tools for identifying these subtle cardiac abnormalities.
- These imaging modalities aid in differentiating patients with underlying pathology despite normal echocardiograms.
Abstract:
The pathophysiologic process in patients with electrocardiographic left ventricular hypertrophy with ST, T changes but without echocardiographic abnormalities was investigated by myocardial perfusion imaging and fatty acid metabolic imaging. Exercise stress 99mTc-methoxy-isobutyl isonitrile (MIBI) imaging and rest 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP) imaging were performed in 59 patients with electrocardiographic hypertrophy including 29 without apparent cause including hypertension and echocardiographic hypertrophy, and 30 with essential hypertension. Coronary angiography was performed in 6 patients without hypertension and 4 with hypertension and biopsy specimens were obtained from the left ventricular apex from 6 patients without hypertension. Myocardial perfusion and 123I-BMIPP images were classified into 3 types: normal, increased accumulation of the isotope at the left ventricular apex (high uptake) and defect. Transient perfusion abnormality and apical defect observed by 123I-BMIPP imaging were more frequent in patients without hypertension than in patients with hypertension (32% vs 17%, p = 0.04671 in perfusion; 62% vs 30%, p = 0.0236 in 123I-BMIPP). Eighteen normotensive patients with apical defect by 123I-BMIPP imaging included 3 of 10 patients with normal perfusion at exercise, 6 of 10 patients with high uptake and 9 of 9 patients with perfusion defect. The defect size revealed by 123I-BMIPP imaging was greater than that of the perfusion abnormality. Coronary stenoses were not observed and myocardial specimens showed myocardial disarray with hypertrophy. Moreover, 9 patients with hypertension and apical defects by 123I-BMIPP showed 3 different types of perfusion. Many patients without hypertension show a pathologic process similar to hypertrophic cardiomyopathy. Perfusion and 123I-BMIPP imaging are useful for the identification of these patients.