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[Mimicking of mitral stenosis by asymmetrical hypertrophic cardiomyopathy]
Insights
Hypertrophic cardiomyopathy can mimic mitral stenosis, causing confusion in diagnosis. This study highlights the importance of considering hypertrophic cardiomyopathy in differential diagnoses for mitral stenosis.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Cardiac Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) is a complex cardiac condition.
- HCM can present with symptoms that mimic other valvular heart diseases.
- Accurate diagnosis is crucial for appropriate patient management.
Purpose of the Study:
- To investigate the potential of hypertrophic cardiomyopathy to mimic mitral stenosis.
- To evaluate diagnostic findings in patients with HCM presenting with suspected mitral stenosis.
- To differentiate between true mitral stenosis and HCM-induced inflow obstruction.
Main Methods:
- Cardiac catheterization to measure pressure gradients between the atrium and left ventricle.
- Echocardiography and angiography for diagnosis confirmation and assessment.
- Analysis of pressure gradients under varying hemodynamic conditions (e.g., volume load).
Main Results:
- Five patients with hypertrophic cardiomyopathy showed pressure gradients mimicking mitral stenosis.
- Echocardiography revealed interventricular septal hypertrophy but normal mitral valve leaflets.
- One patient diagnosed with mitral stenosis via catheterization had normal mitral leaflets upon surgery.
Conclusions:
- Hypertrophic cardiomyopathy can present with findings that mimic mitral stenosis.
- Interventricular septal hypertrophy and reduced myocardial compliance may cause diastolic dysfunction and pressure gradients.
- Consider hypertrophic cardiomyopathy in the differential diagnosis of mitral stenosis, with echocardiography aiding evaluation.
Abstract:
Pressure gradients between atrium and left ventricle were measured in 5 of 17 patients with the diagnosis of hypertrophic cardiomyopathy. The diagnosis was confirmed by echocardiography and angiography. In 2 patients the hypertrophic cardiomyopathy was obstructive for the left ventricular outflow tract. Mitral stenosis was suspected in 3 out of the 5 patients who presented atrial fibrillation or frequent premature atrial beats and atrial overload phenomena of a third heart sound (which was misinterpreted as mitral opening snap) together with radiological enlargement of left atrium. Cardiac catheterization revealed middle pressure gradients between 7 and 14 mm Hg over mitral valve in 3 patients. In 2 patients significant early and middiastolic pressure gradients were recorded only after left ventricular angiography (volume load) was performed. Based on the data from cardiac catheterization, mitral stenosis was diagnosed in one patient, surgery revealed normal mitral leaflets. Echocardiography showed normally mobile mitral leaflets as well as signs of interventricular septal hypertrophy in all 5 patients. (In the patient who underwent surgery echocardiography was performed after the operation.) There were no echocardiographic signs of left ventricular inflow obstruction. The pathophysiologic mechanism of myocardial hypertrophy mimicking mitral stenosis is unknown. It may be suspected that third heart sound, diastolic murmur and the left ventricular inflow obstruction apparent from the pressure gradient are due to diminished myocardial compliance, direct mechanical effects of septal hypertrophy and decreased mobility of anterior mitral leaflet. Mimicking of mitral stenosis exists. Hypertrophic cardiomyopathy should therefore be considered in the differential diagnosis of mitral stenosis. Echocardiography may be helpful in evaluation.