Cardiac vignette: Isolated case of right ventricular non-compaction

Abstract

A 33-year-old female experienced a witnessed cardiac arrest in the emergency department. No significant prior medical history. Initial presenting complaint of progressive dyspnoea with ECG findings of sinus tachycardia. Subsequent development of sinus bradycardia on monitoring followed by cardiac arrest requiring cardiopulmonary resuscitation. Urgent bedside transthoracic echocardiography upon successful resuscitation showed severely dilated and dysfunctional right ventricle (RV). Emergent thrombolysis performed with subsequent CTPA showing evidence of extensive filling defects involving the right pulmonary arterial vasculature consistent with acute pulmonary embolism. Formal transthoracic and transoesophageal echocardiography (Images 1 and 2, respectively) were performed showing significant RV dilatation and prominent trabeculations within the RV apex, in keeping with RV non-compaction (RVNC). Cardiac MRI was subsequently performed (Image 3 and 4), confirming diagnosis of RV non-compaction with RV dilatation as well as prominent left ventricular trabeculations. No significant intra-cardiac luminal thrombus was seen. Patient underwent RV endomyocardial biopsy which revealed mild interstitial fibrosis along with significant fat infiltration (30-40% of the biopsy specimen was infiltrated and replaced by fat). No significant myocyte hypertrophy or myofibre disarray was noted. No significant inflammation, granulomas, iron deposits and amyloid deposits were seen. The clinical case illustrates the difficulty faced in diagnosis of RVNC. Along with RV dilatation (found in pulmonary embolism), histopathological findings point to the diagnosis of RV dysplasia. Imaging findings however raise the likelihood of RVNC. Though well described in literature, the histological features of RVNC is yet to be clearly elucidated and hence radiological and clinical correlation is suggested for accurate diagnosis.