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Hypertrophic apical cardiomyopathy: a subtype of hypertrophic cardiomyopathy
Insights
This study reports hypertrophic apical cardiomyopathy outside Japan, a distinct form of hypertrophic cardiomyopathy. Investigations reveal unique ECG and echocardiographic findings, differing from obstructive types.
Area of Science:
- Cardiology
- Internal Medicine
Background:
- Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease.
- Apical hypertrophic cardiomyopathy (AHC) is a rare variant, predominantly reported in Japan.
Observation:
- This is the first reported case of AHC outside of Japan.
- Clinical investigations included electrocardiography (ECG), vectorcardiography, echocardiography, and hemodynamic/angiographic studies.
Findings:
- ECG showed giant negative T waves, prominent R waves, absent septal Q waves, and normal frontal plane QRS axis.
- Vectorcardiography revealed specific QRS and T loop orientations.
- Echocardiography demonstrated marked septal and posterior wall thickening toward the apex.
- Left ventriculography showed a characteristic spade-like configuration.
- Hemodynamic studies revealed no significant intraventricular pressure gradient.
Implications:
- AHC represents a distinct subset of HCM, differing from obstructive HCM and left-ventricular cavity obliteration.
- The absence of a significant pressure gradient may have therapeutic implications.
- This case expands the known geographical distribution of AHC.
Abstract:
This is the first report of hypertrophic apical cardiomyopathy outside of Japan. Electrocardiographic, vectorcardiographic, echocardiographic, hemodynamic and angiographic investigations support the view that this entity is a subset of hypertrophic cardiomyopathy that differs from hypertrophic obstructive cardiomyopathy and left-ventricular cavity obliteration. The ECG recorded giant negative T waves associated with prominent R waves in the precordial leads and septal Q waves were absent, with a normal mean QRS axis in the frontal plane. The vectorcardiogram showed a QRS loop oriented to the left anteriorly and inferiorly, while the T loop was characteristically discordant, elongated and situated in the right posterior quadrant. An M-mode ECG scan along the left-ventricular long axis revealed a marked increase in both septal and posterior wall thickness and excursions toward the apex. A characteristic spadelike configuration was observed in the left ventriculogram at end-diastole. Pressure studies at rest and after ventricular ectopic beats and isoproterenol provocation revealed no significant peak systolic pressure gradient within the left ventricle. This may have certain therapeutic implications.