Palpitations are best defined as an intermittent “thumping,” “pounding,” or “fluttering” sensation in the chest. It is a common symptom that is seen in primary care, emergency rooms and specialty clinics. There is a wide differential diagnosis for this including endocrine eg. thyrotoxicosis, psychatric eg. anxiety and cardiovascular eg. atrial fibrillation causes. In fact, most patients with palpitations do not have serious arrhythmias or underlying structural heart disease.
A 66 year-old man developed palpitations in the morning which he initially ignored. When the palpitations persisted for 4 hours, he presented to the emergency room. He had no present or prior history of chest pain, palpitations, shortness of breath or syncope. He had a past history of type 2 diabetes mellitus for 3 years on Januvia and hypertension for 4 years on hydrochlorothiazide. Family history was non-contributory.On exam, he was normotensive (136/83 mm Hg) and tachycardic (168 beats/min). Cardiac, respiratory, thyroid and abdominal exams were normal. Electrocardiography revealed a wide complex tachycardia with a left bundle branch block pattern. In view of this, he was started on intravenous amiodarone and transferred to us for further care.He converted to sinus rhythm with left bundle branch block at a heart rate of around 80 beats/min. Overnight, his troponin T levels trended upwards from 0.13 - 0.20 - 0.24 (normal < 0.01) ng/mL. Therefore he was started on intravenous heparin and sent for a coronary angiogram the next day which revealed an 80% mid-right coronary artery lesion to which a stent was delivered. He also had an echocardiogram that revealed an ejection fraction of 20% with evidence of left ventricular non-compaction.Therefore, he was sent for an electrophysiological study that revealed an atrio-ventricular nodal reentrant tachycardia which was ablated successfully. An implantable cardioverter-defibrillator was then placed for primary prophylaxis of sudden death, he was started on Warfarin for thromboembolism prophylaxis and heart failure medications and dismissed subsequently. On follow up at six months, he remains asymptomatic and active.
Isolated left ventricular non-compaction (LVNC) syndrome is a rare genetic primary cardiomyopathy thought to arise from intra-uterine arrest of normal myocardial compaction. It is defined by the presence of prominent trabeculations, communication between the ventricular cavity and the ventricular wall through trabeculations, presence of a two layer wall structure and end-systolic ratio of non-compacted to compacted (NC/C) myocardium of > 2:1 in the absence of coexisting concomitant congenital cardiac anomalies. The exact prevalence of this condition is unclear. LVNC has been associated with heart failure, cardioembolic events and ventricular tachyarrhythmias. Our patient had a wide complex tachycardia which sparked concern for ventricular tachycardia but this was actually an atrio-ventricular nodal reentrant tachycardia. To the best of the author’s knowledge, this is the only case in reported literature of LVNC presenting as palpitations and supraventricular tachycardia.
Isolated left ventricular non-compaction syndrome is a rare primary cardiomyopathy which may present in a variety of clinical scenarios. Echocardiography plays a pivotal role in the diagnosis. Management of the condition should focus on standard heart failure therapy, thromboembolism prophylaxis and family screening.
Gautam Kumar, No Financial Disclosure Information; No Product/Research Disclosure Information