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Background
To the best of our knowledge, after an extensive review of the literature, this is the first case report of apical hypertrophic cardiomyopathy (AHCM) presenting as atrioventricular nodal re-entrant tachycardia (AVNRT). 1-3 It is important to recognise this type of arrhythmia given that catheter ablation of the arrhythmia has a good long-term outcome. AHCM is a rare type of hypertrophic cardiomyopathy (HCM) in western countries.
Case presentation
A 63-year-old African-American man with no known medical history presented with persistent palpitations while having sexual intercourse. Emergency medical service was called and documented a supraventricular rhythm ( figure 1 ). He was given three doses of adenosine which did not halt the arrhythmia necessitating synchronised cardioversion. Postcardioversion his ECG showed deep T waves in aVL, I and V4 to V6 suggestive of AHCM ( figure 2 ). An echocardiogram confirmed the presence of apical type of HCM ( figure 3 ). The patient denies any history of syncope or history of palpitations. He does not have any family history of sudden cardiac death or heart disease. The patient had a coronary angiogram performed which did not show any coronary artery disease. An electrophysiological (EP) study was carried out to identify and isolate the arrhythmia. During the EP study, arrhythmia induction showed that the VA time (which reflects the RP interval in a surface ECG) was 50 ms. A VA time <70 has a 99% positive predictive value for a diagnosis of AVNRT. Ventricular entrainment showed a VAVA response which is typical of an AVNRT. AVNRT ablation was subsequently mapped and ablated. There was no induced tachyarrhythmia induced following ablation suggesting successful ablation. The patient improved and was discharged with referral to genetics to evaluate the familial nature of the disease.
Investigations
ECG
Echocardiography
EP study
Differential diagnosis
Supraventricular tachycardia with aberrancy
Idiopathic fascicular ventricular tachycardia
Treatment
AVNRT ablation.
Outcome and follow-up
The patient had successful ablation of AVNRT. He has had no recurrence of the arrhythmia. He was referred to genetics for further evaluation and management.
Discussion
AHCM was described by Sakamoto and Yamaguchi et al 4 as a form of non-obstructive HCM characterised in an ECG by giant negative T waves (>10 mm) associated with a high QRS voltage (R wave >26 mm in...