Utility of tissue characterization in apical hypertrophic cardiomyopathy diagnosis

Multimodality imaging in apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare morphologic variant of HCM in which the hypertrophy of myocardium is localized to the left ventricular apex. Symptoms of AHCM might vary from none to others mimic coronary artery disease including acute coronary syndrome, thus resulting in inappropriate hospitalization. Transthoracic echocardiography is the first-line imaging technique for the diagnosis of hypertrophic cardiomyopathies. However, when the hypertrophy of the myocardium is localized in the ventricular apex might results in missed diagnosis. Aim of this paper is to review the different imaging techniques used for the diagnosis of AHCM and their role in the detection and comprehension of this uncommon disease.

Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement

Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

Differences of left ventricular systolic deformation in hypertensive patients with and without apical hypertrophic cardiomyopathy

BACKGROUND

We tested the hypothesis that the apical myocardial mechanics differ from those of other ventricular segments in hypertensive patients with and without apical hypertrophic cardiomyopathy (ApHCM).

METHODS

We retrospectively studied hypertensive patients with and without ApHCM. Left ventricular longitudinal, circumferential, and radial strains were examined by two-dimensional speckle-tracking echocardiography at the basal, middle, and apical walls of the parasternal short-axis and apical 2-, 3- and 4-chamber views.

RESULTS

Fourteen consecutive patients with hypertension and ApHCM and 14 patients with hypertension without ApHCM were studied. Lower mitral annular peak systolic velocity and greater diastolic dysfunction were present in hypertensive patients with ApHCM than in hypertensive patients without ApHCM. Compared with hypertensive patients without ApHCM, hypertensive patients with ApHCM had significantly lower apical longitudinal (-13.9% vs -21.9%, p = 0.010) and radial strains (4.4% vs 11.5%, p = 0.017) without the base-to-apex gradient. The global longitudinal (-15.6% vs -18.8%, p = 0.027) and circumferential strains (-16.1% vs -19.2%, p = 0.019) were significantly lower in hypertensive patients with ApHCM than in hypertensive patients without ApHCM. Among systolic parameters, the global longitudinal strain was independently associated with hypertension with ApHCM (odds ratio, 1.457; 95% confidence interval, 1.002-2.119; p = 0.049).

CONCLUSIONS

Reduced apical longitudinal and radial strains without a base-to-apex gradient were present in hypertensive patients with ApHCM. The global longitudinal strain was independently associated with ApHCM in hypertensive patients.