ECG Never Lies: A Case of Apical Hypertrophic Cardiomyopathy

Abstract

Apical hypertrophic cardiomyopathy (ApHCM) is a less common variant of hypertrophic cardiomyopathy, characterized by predominant thickening of the left ventricular apex. We describe a 64-year-old man presenting with dyspnea and T-wave inversions in the lateral precordial leads. Although initial echocardiography was reported as normal, further imaging revealed an “ace of spades” configuration on ventriculography and an anechoic apical area on off-axis views. Contrast echocardiography confirmed apical wall thickening with systolic obliteration. Cardiac magnetic resonance imaging showed patchy late gadolinium enhancement, and Holter monitoring excluded sustained arrhythmias. This case highlights the role of multimodality imaging in ApHCM.

INTRODUCTION

Apical hypertrophic cardiomyopathy (ApHCM) is a morphological subtype of hypertrophic cardiomyopathy (HCM) characterized by unexplained left ventricular hypertrophy predominantly affecting the apex. ApHCM accounts for up to 25% of HCM cases in Asian populations, and between 1% and 10% in non-Asian population.[1,2] Diagnosis is typically suggested by electrocardiographic findings, including tall R waves and giant T-wave inversions in the precordial leads. Transthoracic echocardiography is the primary imaging modality for initial evaluation and may reveal an “ace of spades” configuration at end-diastole, along with systolic apical obliteration of the left ventricle. However, when the phenotypic expression is not clearly evident, the diagnosis may be challenging, and multimodality imaging becomes essential. In such cases, contrast-enhanced echocardiography and cardiac magnetic resonance (CMR) play a crucial role.[2]

CASE REPORT

A 64-year-old man presented to the emergency department with dyspnea. He had been referred by his general practitioner for suspected myocardial ischemia, based on an electrocardiogram (ECG) showing inverted T waves in the lateral precordial leads [Figure 1a]. On the same day, he also underwent an outpatient transthoracic echocardiogram, which was interpreted as normal. Laboratory tests revealed normal levels of hs-troponin and a slight increase in B-type natriuretic peptide (BNP). His medical history included paroxysmal atrial fibrillation, previously treated with catheter ablation 3 years earlier, and arterial hypertension. The patient was admitted to the cardiology ward for further evaluation. He underwent coronary angiography, which showed noncritical stenosis of the left anterior descending and circumflex arteries. Ventriculography was also performed, showing an “ace of spades” configuration of the left ventricle at end diastole [Figure 1b]. Transthoracic echocardiography using the standard apical four-chamber view at the fifth intercostal space did not initially reveal any overt abnormalities of the left ventricular apex [Figure 1c]. Given the suspicion of ApHCM, off-axis apical views were acquired along the mid-axillary line, revealing an anechoic area of 12 mm at the apex, consistent with either an apical aneurysm or focal apical hypertrophy [Figure 1d]. The study was completed with contrast-enhanced echocardiography using SonoVue^® (Bracco Diagnostics), which demonstrated increased apical wall thickness (12 mm) with systolic obliteration, confirming the diagnosis of ApHCM [Figure 1e]. To further assess arrhythmic risk, CMR imaging was performed and revealed a small area of patchy late gadolinium enhancement at the left ventricular apex [Figure 1f]. Finally, a 24-h ambulatory ECG monitoring showed no evidence of sustained ventricular arrhythmias. The patient was enrolled in a clinical follow-up program, and family screening was recommended.

Figure 1.

Multimodality evaluation: (a) electrocardiogram. (b) Ventriculography. (c) Transthoracic echocardiography, standard apical four-chambers view. (d) Transthoracic echocardiography, off-axis apical view. (e) Contrast-enhanced echocardiography. (f) Cardiac magnetic resonance

DISCUSSION

This case highlights the importance of multimodality imaging in the diagnosis of cardiomyopathies, particularly ApHCM. In the authors’ opinion, the first step in a multimodality imaging approach should always be a careful interpretation of the ECG. In this case, without the clinical suspicion raised by the ECG and the use of off-axis apical echocardiographic views, a routine echocardiogram was misinterpreted as normal. Contrast-enhanced echocardiography is also essential when ApHCM is suspected, as it enables differentiation between apical hypertrophy and apical aneurysm, the latter being present in approximately 13%–15% of ApHCM cases.[2] CMR may detect early ApHCM phenotypes more effectively than echocardiography. According to Pons-Lladó et al., echocardiography failed to detect ApHCM in 40% of cases that were later diagnosed by CMR.[3] Our findings support that, in ApHCM, an absolute apical wall thickness <15 mm is not always necessary for diagnosis. In fact, greater diagnostic and prognostic value may lie in the absence of apical tapering and in “relative” apical hypertrophy, even when the wall thickness does not reach 15 mm.[1] As with classic HCM, ApHCM is predominantly caused by autosomal dominant mutations in sarcomeric protein genes.[4] Therefore, early identification enables appropriate treatment and follow-up, not only for the proband but also for affected family members.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.