Apical Hypertrophic Cardiomyopathy

Apical hypertrophic cardiomyopathy is a subtype of hypertrophic cardiomyopathy that predominantly involves the apex of the left ventricle. It is a common form of hypertrophic cardiomyopathy in Asian countries, but relatively rare in Western populations.

While apical hypertrophic cardiomyopathy has a low rate of cardiovascular mortality, severe clinical manifestations have been reported (e.g., arrhythmias and myocardial infarction with segmental aneurysm formation).

Because the diagnostic accuracy of echocardiography for apical hypertrophic cardiomyopathy is limited without using contrast or 3-dimensional echocardiography, MRI has an important role in diagnosis.

The diagnostic criteria for apical hypertrophic cardiomyopathy:

• Absolute apical wall thickness > 15 mm, OR
• A ratio of apical to basal left ventricular wall thicknesses of 1.3–1.5

A characteristic spade-like shape of the left ventricular cavity can be seen at end diastole on vertical long-axis views and on ventriculography. This configuration is caused by localized apical hypertrophy.

Other findings on MRI include apical aneurysms and delayed enhancement in the hypertrophic or nonhypertrophic segments.

The vertical long-axis image above shows circumferential increased wall thickness in the apical portion of the left ventricle, measuring up to 16 mm. This results in a spade-like appearance of the left ventricular cavity. Delayed enhancement at the cardiac apex is compatible with myocardial fibrosis.

References

• Chun EJ, Choi SI, Jin KN, Kwag HJ, Kim YJ, Choi BW, Lee W, Park JH. Hypertrophic cardiomyopathy: assessment with MR imaging and multidetector CT. Radiographics. 2010 Sep;30(5):1309-28.
• Fattori R, Biagini E, Lorenzini M, Buttazzi K, Lovato L, Rapezzi C. Significance of magnetic resonance imaging in apical hypertrophic cardiomyopathy. Am J Cardiol. 2010 Jun 1;105(11):1592-6.