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Distribution of left ventricular hypertrophy in hypertrophic cardiomyopathy: a two-dimensional echocardiographic
Insights
Two-dimensional echocardiography reveals diverse patterns of left ventricular hypertrophy in hypertrophic cardiomyopathy, including symmetric, asymmetric septal, and distal ventricular types. M-mode echocardiography limitations may bias previous understanding of this condition.
Area of Science:
- Cardiology
- Medical Imaging
- Echocardiography
Background:
- Hypertrophic cardiomyopathy is characterized by left ventricular hypertrophy.
- Previous assessments may have been limited by diagnostic techniques.
Purpose of the Study:
- To assess the distribution of left ventricular hypertrophy in hypertrophic cardiomyopathy using M-mode and two-dimensional echocardiography.
- To identify limitations of M-mode echocardiography in diagnosing hypertrophic cardiomyopathy patterns.
Main Methods:
- Echocardiography (M-mode and 2D) was performed on 89 patients.
- Myocardial thickness was measured in multiple left ventricular regions.
- Hypertrophy patterns were classified as symmetric, asymmetric septal, or distal ventricular.
Main Results:
- All patients exhibited hypertrophy in at least one region.
- Asymmetric septal hypertrophy was most common (55%), followed by symmetric (31%) and distal ventricular (14%).
- M-mode echocardiography failed to diagnose 11 of 12 patients with distal ventricular hypertrophy, highlighting its limitations.
Conclusions:
- Two-dimensional echocardiography reveals a broader spectrum of left ventricular hypertrophy patterns in hypertrophic cardiomyopathy than previously recognized.
- M-mode echocardiography's limitations may have historically biased the understanding of hypertrophic cardiomyopathy, overemphasizing asymmetric septal hypertrophy.
Abstract:
The distribution of left ventricular hypertrophy was assessed by M-mode and two-dimensional echocardiography in 89 patients with hypertrophic cardiomyopathy. Myocardial thickness was measured in the septum and the free and posterior wall in both the proximal and distal left ventricle. All patients had at least one myocardial region that was hypertrophied. The predominant pattern of hypertrophy was defined as symmetric (31%), asymmetric septal (55%) and distal ventricular (14%). The spectrum of wall thickness measurements between patients with symmetric hypertrophy was wide (1.5 to 4.5 cm) and was not related to age. In patients with asymmetric septal hypertrophy, the distribution of hypertrophy conformed to previously described patterns; hypertrophy was localized to the anterior septum (14%) or the anterior and posterior septum (35%) or involved both the septum and the left ventricular free wall (51%). The patients with distal ventricular hypertrophy had marked papillary muscle thickening, and only 1 of 12 patients could be correctly diagnosed using M-mode echocardiography. The proportion of patients with symmetric and distal ventricular hypertrophy was greater than that reported when patients are selected on the basis of M-mode diagnostic criteria. This reflects the limitations of the M-mode technique in the assessment of left ventricular hypertrophy and suggests that the recognition and understanding of hypertrophic cardiomyopathy have been biased by patients with asymmetric septal hypertrophy who previously were most readily identified.