Coexistence of apical hypertrophic cardiomyopathy and endomyocardial fibrosis with calcification: diagnosis using multimodality imaging.

A 48-year-old man from West Africa was evaluated for dyspnea. Echocardiography showed an echolucent mass at the left ventricular apex surrounded by a dense ridge of tissue, suggesting endomyocardial fibrosis (EMF). Doppler echocardiography showed restrictive hemodynamics and intramyocardial coronary blood flow at the hypertrophied apex, suggesting apical hypertrophic cardiomyopathy (ApHCM) with calcified thrombus. Cardiac magnetic resonance imaging showed a thickened myocardium with apical cavity obliteration and endomyocardial calcification, and gadolinium contrast demonstrated marked bright subendocardial and diffuse patchy intramyocardial hyperenhancement in the hypertrophied apical wall segment, confirming coexistence of EMF and ApHCM. Workup for known disorders of calcification was negative.

Introduction

Although isolated cases of endomyocardial fibrosis (EMF) and apical hypertrophic cardiomyopathy (ApHCM) have been frequently reported in the prior literature there is only one other case report of the coexistence of both entities in the same patient. We describe a patient with a rare coincident of ApHCM and EMF.

Case report

A 48‐year‐old man from West Africa with no family history of cardiac disease or sudden cardiac death was evaluated for chronic dyspnea. Initial electrocardiogram is shown (Figure 1). A transthoracic echocardiogram showed a thickened left ventricular (LV) apex (21 mm) with an echolucent mass at the LV apex surrounded by a dense ridge of tissue (Figure 2). Doppler echocardiography showed restrictive hemodynamics (Figure 3) and two‐dimensional speckle tracking myocardial longitudinal strain assessment showed reduced apical longitudinal strain (Figure 4 A). Given he was of West African descent, an initial diagnosis of endomyocardial fibrosis was entertained. However, because careful Doppler interrogation demonstrated intramyocardial coronary blood flow (Figure 4 B) at the hypertrophied apex, the possibility of ApHCM with a possible calcified apical thrombus also was considered. Cardiac magnetic resonance imaging (CMR) showed a thickened myocardium with apical cavity obliteration and endomyocardial calcification (Figure 5 A), and delayed imaging demonstrated two distinct patterns of hyperenhancement: one with marked bright “subendocardial” hyperenhancement and the other as diffuse patchy “intramyocardial” hyperenhancement in the hypertrophied apical wall segment (Figure 5 B). Computed tomography revealed marked calcification in the LV apex with apical hypertrophy and no coronary stenosis (Figure 6). Holter monitoring revealed several episodes of non‐sustained ventricular tachycardia (NSVT), and the patient had a hypotensive blood pressure response with runs of NSVT on treadmill testing. Gene testing for HCM was negative. The patient subsequently underwent a prophylactic defibrillator placement for primary prevention of sudden cardiac death. An extensive work‐up for known disorders of cardiac calcification, including hypercalcemia, myocarditis, myocardial infarction, prior radiation therapy or renal disease, was negative.

Figure 1

The electrocardiogram shows normal sinus rhythm with left ventricular hypertrophy and inverted T waves in the anterolateral leads.

Figure 2

The echocardiogram (A) without contrast and (B) with contrast shows calcium (white arrows) and a thick ridge of tissue surrounding the calcium (arrowheads). The red arrow points to the echo shadowing.

Figure 3

(A) The mitral inflow pattern shows a deceleration time of 144 ms. (B) Medial e' velocity is 2.5 cm/s.

Figure 4

(A) Color Doppler with a Nyquist limit of 12 cm/s shows the intramural coronary artery (arrow). (B) A bull's‐eye view of the left ventricular longitudinal strain shows decreased strain of the apex.

Figure 5

Cardiac magnetic resonance imaging (A) SSFP 4‐ch cine image and (B) late gadolinium enhancement images show calcification (green arrows). The red arrow points to the subendocardial fibrosis, and the arrowheads point to the area of patchy gadolinium enhancement.

Figure 6

Computed tomography of the heart (A) without contrast and (B) with contrast shows calcification in the endomyocardium of the left ventricular apex.

Discussion

Obliterative fibrosis and calcification of the LV is known to occur in EMF – a disease first described by Davies et al. in Uganda in 1947.1 The pathologic hallmark of EMF is scarring and fibrosis of the endocardium and inner third of the myocardium; five types of EMF, based on the different regions of the heart involved, have been described. Our patient was considered to have Type 1, with only apical involvement. Although biopsy is the mainstay of diagnosis, contemporary imaging modalities (e.g., CMR, computed tomography) with their high contrast and spatial resolution are very valuable for tissue characterization of the underlying fibrosis and calcification and preclude routine biopsies in suspected cases of EMF.2 ApHCM, on the other hand, is a phenotypic variant of HCM in which hypertrophy is localized to the LV apex with or without mid‐segment involvement (mixed morphologic subtype) and with or without the formation of an apical aneurysm. ApHCM patients with paradoxic jet flow gradients are prone to apical mural thrombus formation (which may calcify over time) with subsequent systemic thromboembolism. Myocardial fibrosis as evidenced by late gadolinium enhancement is commonly observed in ApHCM,3 and although endomyocardial calcification in ApHCM is reported, it is rare. The diffuse nature of intramyocardial fibrosis in ApHCM differentiates it from the dense subendocardial hyperenhancement in EMF. Initially, the differential diagnosis for the bright hyperenhancement was EMF vs trapped contrast. However, the absolute absence of blood flow established by color Doppler, contrast echocardiogram, and computed tomographic contrast in the left ventricular apical cavity between the calcium and apical hypertrophied muscle favored EMF as the diagnosis.

Careful multimodality imaging (computed tomography, CMR, and color Doppler) did not show any regional dysfunction, midcavitary obstruction, or paradoxic jet flow although reduced apical longitudinal strain with Grade III diastolic dysfunction were noted. Judicious evaluation by color Doppler with a low Nyquist limit clearly showed intramural coronary arteries in a hypertrophied apical segment, and the diagnosis of EMF was considered to be less likely until CMR clearly hinted at the presence of Type‐1 EMF. Since the etiopathogenesis of EMF remains elusive, it remains to be determined if ApHCM is a contributor or just an incidental finding. Moreover, as CMR techniques continue to mature, it is conceivable that more such synchronous cardiomyopathies may be able to be diagnosed in the future.

Conflicts of Interest

None declared.