Inherited Structural Heart Diseases With Potential Atrial Fibrillation Occurrence

Long Non-coding RNA Involved in the Pathophysiology of Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is a prevalent and chronic cardiovascular disorder associated with various pathophysiological alterations, including atrial electrical and structural remodeling, disrupted calcium handling, autonomic nervous system dysfunction, aberrant energy metabolism, and immune dysregulation. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a significant role in the pathogenesis of AF.

OBJECTIVE

This discussion aims to elucidate the involvement of AF-related lncRNAs, with a specific focus on their role as miRNA sponges that modulate crucial signaling pathways, contributing to the progression of AF. We also address current limitations in AF-related lncRNA research and explore potential future directions in this field. Additionally, we summarize feasible strategies and promising delivery systems for targeting lncRNAs in AF therapy.

CONCLUSION

In conclusion, targeting AF-related lncRNAs holds substantial promise for future investigations and represents a potential therapeutic avenue for managing AF.

The Impact of Atrial Fibrillation on All Heart Chambers Remodeling and Function in Patients with Dilated Cardiomyopathy-A Two- and Three-Dimensional Echocardiography Study

Atrial fibrillation is frequently seen in patients with dilated cardiomyopathy (DCM), and its presence impacts the function of the heart, with clinical and prognostic consequences. In this prospective single-center study, we aimed to assess the impact of atrial fibrillation on cardiac structure and function, using comprehensive two- and three-dimensional echocardiography. We included 41 patients with DCM and persistent or permanent atrial fibrillation (38 male, age 58.8 ± 11 years), as well as 47 patients with DCM and in sinus rhythm (35 male, age 58 ± 12.5 years). Cardiac chambers and mitral and tricuspid valves' structure and function were assessed via standard two-dimensional, speckle-tracking, and three-dimensional echocardiography (3DE). Patients with DCM and atrial fibrillation had a more impaired left ventricular global longitudinal strain, higher 3DE left atrial volumes, and reduced function compared to patients in sinus rhythm in the presence of similar left ventricle volumes. Mitral annulus configuration was altered in atrial fibrillation DCM patients. Also, right heart volumes were larger, with more severe atrial and ventricular dysfunction, despite similar estimated pulmonary artery pressures and severity of tricuspid regurgitation. Using advanced echocardiography techniques, we demonstrated that atrial fibrillation induces significant remodeling in all heart chambers.

Anticoagulation with warfarin compared to novel oral anticoagulants for atrial fibrillation in adults with transthyretin cardiac amyloidosis: comparison of thromboembolic events and major bleeding

BACKGROUND

Atrial fibrillation (AF) is common in patients with transthyretin cardiac amyloidosis (ATTR-CA). The optimal strategy to prevent strokes in patients with ATTR-CA and AF is unknown.

OBJECTIVES

To compare outcomes in patients with ATTR-CA and AF treated with warfarin versus novel oral anticoagulants (NOACs).

METHODS

This study was a retrospective analysis of patients with ATTR-CA stratified by presence or absence of AF and anticoagulation therapy. The primary outcome included a time to event analysis for the combined outcomes of stroke, transient ischaemic attack (TIA), major bleed, or death.

RESULTS

Of 290 patients, 217 patients (74.8%) had AF. Of those with AF (n = 217), 78 (35.9%) patients received warfarin compared with 116 (53.5%) patients who received NOACs. There were 17 thrombotic events, all in those diagnosed with AF compared with none in the patients without AF (p = .01). Over a mean follow-up of 2.4 years (range 0.1-12) there was no difference in primary outcome between those with AF treated with warfarin compared with NOACs (p = .35).

CONCLUSION

Patient with ATTR-CA and AF are at increased risk for stroke compared to patients with ATTR-CA and without AF. Thrombotic events and major bleeds did not differ between those who received warfarin and NOACs.

Atrial fibrillation in patients with inherited cardiomyopathies

Atrial fibrillation (AF) often complicates the course of inherited cardiomyopathies and, in some cases, may be the presenting feature. Each inherited cardiomyopathy has its own peculiar pathogenetic characteristics that can contribute to the development and maintenance of AF. Atrial fibrillation may occur as a consequence of disease-specific defects, non-specific cardiac chamber changes secondary to the primary illness, or a combination thereof. The presence of AF can denote a turning point in the progression of the disease, promoting clinical deterioration and increasing morbidity and mortality. Furthermore, the management of AF can be particularly challenging in patients with inherited cardiomyopathies. In this article, we review the current information on the prevalence, pathophysiology, risk factors, and treatment of AF in three different inherited cardiomyopathies: hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy, familial dilated cardiomyopathy, and left ventricular non-compaction cardiomyopathy.

Direct Current Cardioversion of Atrial Arrhythmias in Adults With Cardiac Amyloidosis

BACKGROUND

Arrhythmias, conduction abnormalities, and intracardiac thrombus are common in patients with cardiac amyloidosis (CA). Outcomes of direct-current cardioversion (DCCV) for atrial arrhythmias in patients with CA are unknown.

OBJECTIVES

This study sought to examine DCCV procedural outcomes in patients with CA.

METHODS

Patients with CA scheduled for DCCV for atrial arrhythmias from January 2000 through December 2012 were identified and matched 2:1 with control patients by age, sex, type of atrial arrhythmia, and date of DCCV.

RESULTS

CA patients (n = 58, mean age 69 ± 9 years, 81% male) were included. CA patients had a significantly higher cardioversion cancellation rate (28% vs. 7%; p < 0.001) compared with control patients, mainly due to intracardiac thrombus identified on transesophageal echocardiogram (13 of 16 [81%] vs. 2 of 8 [25%]; p = 0.02); 4 of 13 of the CA patients (31%) with intracardiac thrombus on transesophageal echocardiogram received adequate anticoagulation ≥3 weeks and another 2 of 13 (15%) had arrhythmia duration <48 h. DCCV success rate (90% vs. 94%; p = 0.4) was not different. Procedural complications were more frequent in CA versus control patients (6 of 42 [14%] vs. 2 of 106 [2%]; p = 0.007); complications in CA included ventricular arrhythmias in 2 and severe bradyarrhythmias requiring pacemaker implantation in 2. The only complication in the control group was self-limited bradyarrhythmias.

CONCLUSIONS

Patients with CA undergoing DCCV had a significantly high cancellation rate mainly due to a high incidence of intracardiac thrombus even among patients who received adequate anticoagulation. Although the success rate of restoring sinus rhythm was high, tachyarrhythmias and bradyarrhythmias complicating DCCV were significantly more frequent in CA patients compared with control patients.

Left ventricular remodeling in hypertrophic cardiomyopathy patients with atrial fibrillation

Background

Atrial fibrillation (AF) is the most common complication in hypertrophic cardiomyopathy (HCM). The mechanisms of AF is associated with left atrial (LA) structural remodeling in HCM patients. However, the impact of left ventricular (LV) remodeling on the presence of AF in HCM patients has not been evaluated yet. We sought to investigate effect of LV remodeling on the presence of AF assessed by cardiovascular magnetic resonance (CMR) in HCM patients.

Methods

A total of 394 HCM patients were enrolled into this study, including HOCM patients (n = 293) and NOHCM patients (n = 101). Patients were divided into HCM with AF (50) and HCM without AF (n = 344). Data were collected from hospital records.

Results

LA diameter and LV remodeling index (LVRI) were significantly higher in HCM patients with AF than that of HCM patients without AF (46.6 ± 7.4 mm versus 39.9 ± 8.0 mm, p < 0.001, and 1.46 ± 0.6 versus 1.2 ± 0.4, p = 0.002, respectively). HCM patients with AF were older than HCM patients without AF (53.6 ± 11.7 years versus 47.7 ± 13.6 years, p = 0.002). Additionally, LVRI positively correlated to LA size (r = 0.12, p = 0.02). In a multivariable logistic regression analysis, when adjusting for age and LV end diastolic mass index, LVRI and LA size remained an independent determinant of AF in HCM patients (OR = 4.7, p = 0.001 and OR = 1.13, P < 0.001).

Conclusion

HCM patients with AF showed significantly more LA diameter, LVRI and age than HCM patients without AF. LVRI and LA size were strong independent predictor of AF in HCM, suggesting LV remodeling may contribute to the occurrence of AF in HCM patients.

Atrial Fibrillation Associated Genetic Variants and Left Atrial Histology: Evaluation for Molecular Sub-Phenotypes

INTRODUCTION

Genome wide association studies have identified several single nucleotide polymorphisms (SNPs) associated with atrial fibrillation (AF), but the mechanisms underlying these relationships have not yet been elucidated. Inflammation and fibrosis have been posited as important mechanisms responsible for AF. We sought to investigate the impact of SNP carrier status on inflammation and fibrosis in left atrial appendage tissue.

METHODS AND RESULTS

Carrier status of 10 AF-associated SNPs was evaluated on DNA extracted from left atrial appendage tissue in 176 individuals (120 with AF). The presence of inflammation was evaluated through visual quantification of leukocyte infiltration following hematoxylin and eosin staining, while fibrosis was quantified using picrosirius red with fast green staining. Unadjusted and adjusted linear and logistic regression models were utilized to evaluate for an association between SNP carrier status and inflammation and fibrosis. On adjusted logistic regression analysis, the rs7164883 SNP (intronic within HCN4) was associated with a reduced odds of inflammation (odds ratio: 0.42; 95% CI: 0.22-0.81, P = 0.01), and was not associated with fibrosis on adjusted linear regression analysis (β-coefficient: -0.31; 95% CI: -1.03-0.40, P = 0.40). None of the remaining SNPs exhibited significant associations with left atrial inflammation or fibrosis.

CONCLUSIONS

Among 10 AF-associated SNPs, a single genetic variant was associated with reduced left atrial inflammation, while no histologic differences were observed in the remaining 9. The known AF-associated SNPs do not appear to predispose to the development of pro-inflammatory or pro-fibrotic AF sub-phenotypes.

Catheter Ablation for Atrial Arrhythmias in Patients With Cardiac Amyloidosis

BACKGROUND

Cardiac amyloidosis (CA) is associated with increased atrial arrhythmias risk. The efficacy/safety of catheter-based ablation therapy in patients with CA has not been adequately assessed.

METHODS AND RESULTS

All diagnosed CA patients who underwent atrial arrhythmia ablation therapy from 1995 to 2015 were reviewed. Arrhythmia recurrence, NYHA symptoms, and mortality were recorded. A total of 26 patients with CA and atrial arrhythmias were included; there were 7 light-chain (AL), 17 wild-type transthyretin (ATTRwt), and 2 mutated transthyretin (ATTRm) amyloidosis patients in total. Of which 13 underwent atrial arrhythmia ablation (CA-A) and 13 underwent AV nodal ablation (CA-AVN). In the CA-A group, there were: 3 with atrial fibrillation (AF); 6 with atrial flutter (AFL); 2 with AF/AFL; and 2 with atrial tachycardia (AT). One-year and 3-year recurrence-free survival were 75% and 60%, respectively. NYHA symptom improvement 6 months postablation was observed in both CA-A and CA-AVN groups: 7/10 (70%) and 4/8 (50%), respectively. Eleven patients with CA died (8 in CA-AVN group vs. 3 in CA-A group).

CONCLUSIONS

Catheter-based ablation for patients with CA appears to provide important symptomatic relief. However, mortality from the underlying disease remains a significant issue for the amyloid light-chain subtype.