Background: Interatrial block (IAB) is a conduction delay in Bachmann's bundle with a well-described association with structural heart disease, supraventricular arrhythmias, and cardiovascular events.
Case summary: We report the case of an asymptomatic 35-year-old man in whom the presence of IAB at electrocardiogram led to a comprehensive evaluation including speckle-tracking echocardiography, 24 h Holter monitoring, and genetic testing. Speckle-tracking echocardiography demonstrated a decrease in the longitudinal strain of interventricular septum, a typical feature of LMNA-related cardiomyopathy, and decreased indices of left atrial deformation. A diagnosis of cardiac laminopathy related to the frame shift variant c.1367 (p.Asn456Thrfs*24) of the LMNA gene was made. A dual-chamber implantable cardioverter defibrillator implantation was performed for the high risk of life-threatening ventricular tachyarrhythmias.
Discussion: This case demonstrates that IAB could be a rare presentation of a life-threatening laminopathy. Strain echocardiography is an essential tool to evaluate the deposition of fibrosis tissue in subclinical cardiomyopathies. Our report describes a novel variant of LMNA gene associated with a high risk of sudden cardiac death.
Keywords: Arrhythmic risk; Case report; ICD; Interatrial block; Laminopathy; Strain imaging.
© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.