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Relation between regional contractile dynamics and myocardial lesions in patients with hypertrophic cardiomyopathy
S Usuki1, Y Yokota, H Fukuzaki
1First Department of Internal Medicine, Kobe University School of Medicine, Japan.
Insights
Hypertrophic cardiomyopathy (HCM) patients show reduced regional left ventricular (LV) function due to both LV hypertrophy and myocardial lesions. Echocardiography may help identify these lesions in HCM.
Area of Science:
- Cardiology
- Pathology
- Medical Imaging
Background:
- Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular (LV) hypertrophy.
- The impact of myocardial lesions on regional LV contractile dynamics in HCM requires further investigation.
Purpose of the Study:
- To investigate how wall hypertrophy and myocardial lesions influence regional LV contractile dynamics in HCM patients.
- To compare these dynamics with secondary concentric hypertrophic heart disease (SHH) and normal controls.
Main Methods:
- Echocardiography was used to measure LV wall thickness and regional systolic wall thickening (%NRWT) in HCM, SHH, and control groups.
- Autopsy specimens were analyzed for pathological wall thickness (P.T.), myocyte diameter (MD), fibrosis (%F), and disarray (%D).
Main Results:
- HCM patients exhibited significantly reduced %NRWT in the ventricular septum (VS) compared to SHH patients.
- HCM patients had greater MD, %F, and %D in the LV wall than SHH patients.
- %NRWT correlated inversely with end-diastolic thickness (E.Td), %F, and %D in HCM patients.
Conclusions:
- Both LV hypertrophy and myocardial lesions (fibrosis and disarray) contribute to abnormal regional LV contractile dynamics in HCM.
- Echocardiographic assessment of regional contractile dynamics may aid in identifying myocardial lesions associated with HCM.
Abstract:
To investigate the influence of wall hypertrophy and myocardial lesions on the regional contractile dynamics of the left ventricle (LV) in patients of hypertrophic cardiomyopathy (HCM), we obtained the thicknesses of the ventricular septum (VS) and posterior wall at end-diastole and systole (E.Td, E.Ts) from echocardiograms made before death for 11 patients of HCM and 6 patients of secondary concentric hypertrophic heart disease (SHH), and the percent regional systolic wall thickening normalized by that of 15 normal controls (%NRWT). We then compared the %NRWT with the pathological wall thickness (P.T.), myocyte diameter (MD), and percent areas of fibrosis (%F) and disarray (%D) in specimens of the corresponding portion from each autopsied heart. The %NRWT in the VS of HCM patients was significantly less than that in SHH patients. All of the MD, %F and %D in the LV wall of HCM patients were significantly greater than those in SHH patients. The %NRWT in the LV wall of HCM patients and SHH patients correlated inversely with the E.Td (r = -0.53, p less than 0.02 and r = -0.70, p less than 0.02, respectively), but not with the E.Ts or P.T. The %NRWT in the LV wall of HCM patients had an inverse correlation with the %F (r V -0.59, p less than 0.005). Furthermore, that in the VS had an inverse relationship with the %D (r = -0.63, p less than 0.05). Thus, it is suggested that not only LV hypertrophy, but also LV myocardial lesions affect the abnormality of the regional LV contractile dynamics in HCM patients. In addition, observation of the regional contractile dynamics by echocardiography may be useful for speculating on myocardial lesions associated with this disease.