Apical hypertrophic cardiomyopathy (AHCM) is a condition that primarily involves the apex of the left ventricle. Two of its main characteristics are a non-obstructive physiology and apical hypertrophy of the left ventricle with giant negative T waves. AHCM is uncommon, and its prevalence is notably affected by ethnicity. The diagnosis is challenging to make and requires multimodal imaging techniques.^1,6 Here we describe two cases of AHCM with cerebrovascular disease as the presenting condition: Patient 1 had atrial fibrillation (AF), while Patient 2 showed evidence of aortic plaques as the possible embolic source. Nonetheless, Patient 2 also presented an akinetic apex. Hence, it was impossible to rule out the previous migration of an apical thrombus as the cause of the ischemic stroke. The main clinical lesson learned from our cases is that stroke in patients with AHCM is a multifactorial complication potentially caused by AF, aortic plaques, and intracavitary thrombus. Therefore, although AHCM is uncommon, it should be considered when determining the cause of cerebrovascular embolic events.

AHCM, also known as Yamaguchi syndrome, is an uncommon disease that was first described by Sakamoto et al. in 1976.² It accounts for 3% and 13–25% of hypertrophic cardiomyopathy cases in the United States and Japan, respectively.³

Clinically, AHCM has a nonspecific manifestation with no pathognomonic complaints. Accordingly, its diagnosis is often delayed by around 4.7 years.⁴ However, some common clinical findings at presentation include atypical chest pain, dyspnea, exercise intolerance, palpitations, AF, and syncope or presyncope.¹ Patients may also have hypertension (30%) and family members with hypertrophic cardiomyopathy or a history of sudden cardiac death (26%).^1,8 Additionally, around 30% of patients with AHCM will present one or more morbid events such as AF, myocardial infarction, congestive heart failure, transient ischemic attack, stroke, ventricular tachycardia, and ventricular fibrillation.⁴

The reported prevalence of AF in AHCM is 12–31%.^4,5 Furthermore, cerebral embolic events were found to affect 6.7–18.8% of the patients, with left atrium size (hazard ratio, 1.2) and AF (hazard ratio, 5.5) as the main risk factors.^4,5 Both of our patients presented a cerebrovascular condition as a complication of AHCM, but only Patient 1 had evidence of AF, whereas Patient 2 presented with aortic plaques. However, Patient 2 also had an akinetic apex on TEE evaluation, which could represent a potential embolic source. This leads us to remark that, in patients with a history of stroke, hypertrophic cardiomyopathy (as well as other structural pathologies), along with AF and arterial plaques, should be considered potential sources of embolic events.

For the diagnosis of AHCM, a multimodality imaging approach is often used. This commonly starts with an ECG and includes echocardiography and cardiovascular magnetic resonance (CMR). In our case, the key signs that led us to the diagnosis of AHCM were the giant negative T waves and the left-ventricular apical hypertrophy with the classical “ace of spades” shape observed on the echocardiogram (Figure 2). However, it is important to remember that giant negative T waves are not specific to AHCM since a considerable number of conditions such as Wellens’ syndrome, cocaine ischemia, non-Q wave myocardial infarction, myocarditis, Takotsubo cardiomyopathy, massive pulmonary embolism, and subarachnoid hemorrhage could also cause them.⁶

In the diagnosis of AHCM made via echocardiography, the apex should be measured below the insertion of the papillary muscle, and it must be thicker than 15 mm (with a basal-to-apex wall thickness ratio of 1.3 or greater).^1,6 It is also important to measure the gradient between the apex and the left ventricular cavity since it increases the risk for thromboembolism, ventricular arrhythmias, and perfusion abnormalities.¹ Moreover, the global ejection fraction is commonly preserved, but signs of diastolic dysfunction are often observed, as seen in both of our cases.

TEE is helpful for detecting intracavitary thrombus and guiding cardiac surgery.¹ Unfortunately, false-negative results are possible in an echocardiography examination. Hence, CMR may be used. Relevant clinical findings of AHCM with CMR include the left-ventricular “ace of spades” silhouette and apical wall width greater than 15 mm, with a basal-to-apex wall thickness ratio exceeding 1.5.¹

Valuable treatment options are available for patients with AHCM. In cases with a preserved ejection fraction, β-blockers or calcium channel blockers are recommended in maximal tolerated doses.^1,6 Patients with AHCM often present diastolic dysfunction and thus benefit from diastole prolongation.¹ Furthermore, surgical treatments such as apical myectomy are available.¹ Finally, there is no strong consensus about the prognosis of AHCM since it is considered a relatively benign disease, but a few cases are complicated by atypical angina, heart failure with a preserved ejection fraction, AF, apical aneurysm, thrombus, and cardioembolic stroke.⁶ Table 2 presents the most important guidelines released by the American and European Cardiology Societies.

As previously discussed, AHCM is a relatively uncommon disease that is occasionally complicated by stroke. Both cases presented here demonstrated cerebrovascular embolic events as the leading manifestation of AHCM. It is interesting to note that one patient presented with AF, while the other had aortic plaques and an akinetic LV apex. We believe that these conditions are associated with AHCM with the cause of stroke. In contrast, Patient 1 had both AF and hyperthyroidism, a known cause of AF.¹⁰ Thus, it is uncertain whether AF resulted from the hyperthyroidism or from the relationship between AHCM and diastolic dysfunction, leading to increased LV filling pressure, dilation of the left atrium, and an increased risk of AF.² Finally, as stated in the guidelines, since the echocardiography findings were conclusive of AHCM, we decided not to order a CMR scan. Figure 4 illustrates the mechanism of cerebrovascular embolic events as well as the diagnostic methods we used.