This is a case of a 30 year-old female presented in acute heart failure secondary to left ventricular noncompaction cardiomyopathy (LVNC) found to have a novel sodium channel mutation. Patient with no significant medical history presented with shortness of breath and dyspnea, chest radiograph consistent with bilateral large pleural effusions, cardiomegaly, and pulmonary vascular congestion. Her electrocardiograms consistent with sinus tachycardia, otherwise no acute changes were noted and echocardiogram demonstrated ejection fraction (EF) 20% and grade II diastolic dysfunction. Her nuclear stress test did not reveal any ischemic cause subsequent cardiac magnetic resonance imaging (MRI) demonstrated (EF) of 23% and non-compacted to compacted myocardium ratio of 2.4, which is consistent with LVNC. Cardiac profile demonstrated negative troponin levels and Pro B type natriuretic peptide of 2262. She was adequately diuresed, with significant improvement of her symptoms, although she developed non-sustained arrhythmias which necessitated implantation of a defibrillator. With an unclear cause of her LVNC, an extensive work was conducted including a dilated cardiomyopathy genetic panel which revealed an abnormal cardiac sodium channel alpha-subunit gene (SCN5A) variant C2102C>T(P710L). As part of LVNC work up all first-degree relatives were screened, interestingly patient’s daughter was found to have apical trabeculations suggestive of LVNC as well. At 2 month follow, she remained asymptomatic after initiation of goal directed heart failure medications.
Discussion:
LVNC is a rare, predominantly genetic condition with an adult prevalence of 0.014%. Although its pathogenesis is debated, a proposed mechanism includes the arrest of endomyocardial morphogenesis during the embryological development. This leads to its characteristic pattern of prominent trabeculae, thin compacted myocardium layer, and deep intertrabecular recesses. Clinically, LVNC can result in heart failure, malignant arrhythmias and thromboembolic events. SCN5A is a gene, which encodes integral membrane protein primarily found in the cardiac muscle and is involved in the myocardial action potential. Mutation in skeletal muscles leads to myotonia similarly cardiac involvement can be expect LVNC. Familial penetrance up to 40%. A study conducted on Japanese population revealed that SCN5A gene has been associated with LVNC with certain variants causing a severe form of LVNC.
Conclusions:
To our knowledge, this is a first known association between C2102C>T(P710L) variant and LVNC. This finding proposes that in patients with LVNC, genetic studies should be recommended especially since many healthy and disease free patients can falsely meet the LVNC criteria on imaging. Recognizing the exact variant causing the LVNC can predict patient’s risk for developing malignant arrhythmias and accelerate the path to early intervention. As LVNC becomes increasingly recognized etiology of cardiac disease, genetic work up will be extremely useful in better understanding factors of this disease, allowing for better prognosis and appropriate counseling on affected families.