We present a case of apical hypertrophic cardiomyopathy (AHCM), also known as Yamaguchi syndrome, in a young female with no family history. She presented after recurrent syncopal events with cyanosis, palpitations and was found to have diffuse T-wave inversions and a pattern of left ventricular hypertrophy on ECG. Echocardiogram and cardiac magnetic resonance imaging (MRI) showed evidence of hypertrophic cardiomyopathy (HCM) localized to the apical wall segments along with late gadolinium enhancement (LGE), without left ventricular outflow tract (LVOT) obstruction. The patient required telemetry to monitor for malignant arrythmias. She required electrophysiology evaluation and genetic testing, which was significant for an autosomal dominant mutation localized to filamin C. The patient received a tilt table test and was positive for cardioinhibitory and vasodepressor response but did not have evidence of malignant arrhythmia. She received an implantable loop recorder (ILR) for long term monitoring and was stable for discharge with close out-patient follow up. The patient requires re-imaging with cardiac MRI due to risk of possible early progression of fibrosis and sudden cardiac death (SCD) with the identified genetic mutation. She was not able to tolerate beta blockers for medical therapy and is being monitored off medication. AHCM is a rare form of HCM characterized by left ventricular apical wall thickness measured to be greater than 15mm and may be identified by an “ace of spades” pattern of the left ventricular cavity during systole on echocardiogram and cardiac MRI. If associated with LGE, this can be a risk factor for SCD. It is also autosomal dominant in inheritance and can be associated with sarcomere protein mutations. The treatment of AHCM is similar to HCM, focusing on preserving left ventricular preload by slowing heart rate and contractility with beta blockers, calcium channel blockers, disopyramide. Patients that are refractory to medical therapy may benefit from surgical myomectomy or alcohol septal ablation. The long-term prognosis of AHCM has been studied to be favorable compared to other forms of HCM. This unique case offers insight into the diagnosis and treatment strategies of AHCM and offers a case to reappraise the potential challenges in identifying this condition without an established family history.

Cardiac biomarkers, Cardiomyopathies, Cardiovascular imaging, Pediatric cardiology