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[Progression to the dilated phase of hypertrophic cardiomyopathy in children]
M Yoshibayashi1, Y Ono, T Kohata
1Department of Pediatrics, Kyoto University School of Medicine.
Insights
Progression to dilated cardiomyopathy is common in children with hypertrophic cardiomyopathy (HCM). Thallium myocardial imaging (TMI) can detect perfusion defects, signaling early progression before echocardiographic changes appear.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Diagnostic Imaging
Background:
- Hypertrophic cardiomyopathy (HCM) is a primary cardiac condition affecting children.
- Progression to a dilated phase in pediatric HCM can significantly alter prognosis.
- Early identification of disease progression is crucial for timely intervention.
Purpose of the Study:
- To investigate the progression of hypertrophic cardiomyopathy to the dilated phase in pediatric patients.
- To evaluate the utility of thallium myocardial imaging (TMI) in detecting early signs of progression.
- To correlate imaging findings with myocardial biopsy results.
Main Methods:
- Longitudinal follow-up of 23 children with HCM (aged 2 months to 15 years) for over four years.
- Utilized echocardiography to measure left ventricular end-diastolic dimension (LVDd) and fractional shortening (FS).
- Assessed myocardial perfusion defects (PD) using thallium myocardial imaging (TMI); cardiac catheterization and endomyocardial biopsy performed in 18 patients.
Main Results:
- Two patients progressed to the dilated phase, exhibiting increased LVDd and decreased FS.
- Extensive perfusion defects (PD) on TMI preceded echocardiographic changes by 15 and 31 months in these patients.
- Endomyocardial biopsies revealed interstitial fibrosis, hypertrophy, and myocardial cell disarray in patients with PD.
Conclusions:
- Progression to the dilated phase is a significant event in pediatric hypertrophic cardiomyopathy.
- Thallium myocardial imaging (TMI) demonstrates value as an early detection tool for HCM progression.
- Histopathological findings support TMI's ability to identify underlying myocardial changes.
Abstract:
Twenty-three children with hypertrophic cardiomyopathy (HCM) (aged 2 months to 15 years) were followed up for more than four years using thallium myocardial imaging (TMI) and echocardiography. With echocardiography, the left ventricular end-diastolic dimension (LVDd) and fractional shortening (FS) were measured. Perfusion defect (PD) was assessed using TMI. Cardiac catheterization and right ventricular endomyocardial biopsy were performed in 18 patients within one week before or after their TMI. During the follow-up period, two patients showed a marked increase in LVDd and a marked decrease in FS at ages 13 and 16 years, respectively. These two patients were judged to have progressed to the dilated phase. In these two patients, extensive PD was detected in the left ventricular wall on TMI, 15 and 31 months prior to the appearance of the echocardiographic changes, respectively. Right ventricular endomyocardial biopsy at the time of extensive PD revealed marked interstitial fibrosis along with hypertrophy and disarray of myocardial cells. In conclusion, progression to the dilated phase is not a rare event in children with HCM and TMI appears to be a useful tool for early detection of the progression.