Genetic variants, pathophysiological pathways, and oral anticoagulation in patients with hypertrophic cardiomyopathy and atrial fibrillation

Identification of a novel likely pathogenic TPM1 variant linked to hypertrophic cardiomyopathy in a family with sudden cardiac death

AIMS

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic cardiac disorder characterized by unexplained left ventricular hypertrophy. It can cause a wide spectrum of clinical manifestations, ranging from asymptomatic to heart failure and sudden cardiac death (SCD). Approximately half of HCM cases are caused by variants in sarcomeric proteins, including α-tropomyosin (TPM1). In this study, we aimed to characterize the clinical and molecular phenotype of HCM in an Iranian pedigree with SCD.

METHODS AND RESULTS

The proband and available family members underwent comprehensive clinical evaluations, including echocardiography, cardiac magnetic resonance (CMR) imaging and electrocardiography (ECG). Whole-exome sequencing (WES) was performed in all available family members to identify the causal variant, which was validated, and segregation analysis was conducted via Sanger sequencing. WES identified a novel missense variant, c.761A>G:p.D254G (NM_001018005.2), in the TPM1 gene, in the proband, his father and one of his sisters. Bioinformatic analysis predicted it to be likely pathogenic. Clinical features in affected individuals were consistent with HCM.

CONCLUSIONS

The identification of a novel TPM1 variant in a family with HCM and SCD underscores the critical role of genetic screening in at-risk families. Early detection of pathogenic variants can facilitate timely intervention and management, potentially reducing the risk of SCD in individuals with HCM.

Pathophysiology of Atrial Fibrillation and Approach to Therapy in Subjects Less than 60 Years Old

Atrial fibrillation (AF) is an arrhythmia that affects the left atrium, cardiac function, and the patients' survival rate. Due to empowered diagnostics, it has become increasingly recognized among young individuals as well, in whom it is influenced by a complex interplay of autoimmune, inflammatory, and electrophysiological mechanisms. Deepening our understanding of these mechanisms could contribute to improving AF management and treatment. Inflammation is a complexly regulated process, with interactions among various immune cell types, signaling molecules, and complement components. Addressing circulating antibodies and designing specific autoantibodies are promising therapeutic options. In cardiomyopathies or channelopathies, the first manifestation could be paroxysmal AF; persistent forms tend not to respond to antiarrhythmic drugs in these conditions. Further research, both in vitro and in vivo, on the use of genomic biotechnology could lead to new therapeutic approaches. Additional triggers that can be encountered in AF patients below 60 years of age are systemic hypertension, overweight, diabetes, and alcohol abuse. The aims of this review are to briefly report evidence from basic science and results of clinical studies that might explain the juvenile burden of the most encountered sustained supraventricular tachyarrhythmias in the general population.

Managing Stroke Prevention in Hypertrophic Obstructive Cardiomyopathy (HOCM) Patients Without Confirmed Persistent Atrial Fibrillation: A Dilemma of Anticoagulation

Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic cardiovascular disorder characterized by the thickening of the heart muscle, particularly the left ventricle. It is a leading cause of sudden cardiac death in young individuals. HOCM is associated with various complications, including arrhythmias and an increased risk of stroke. Patients with HOCM are at an increased risk of stroke due to the development of atrial fibrillation (AFib), a common arrhythmia observed in HOCM. AFib can result in the formation of blood clots in the atria, which may subsequently embolize the brain, causing a stroke. However, not all HOCM patients develop persistent AFib, leading to uncertainty regarding the appropriate management of stroke prevention in these cases. This case study aims to explore the management of recurrent cerebrovascular events (CVA) in a patient with HOCM who does not have confirmed persistent AFib. The argument revolves around whether anticoagulation should be offered for secondary stroke prevention in HOCM patients without a confirmed diagnosis of persistent AFib.