Masry, H El

Background Connective tissue disorders (CTDs) such as Marfan syndrome, Loeys-Dietz syndrome, and Ehlers-Danlos syndromes are traditionally defined by vascular fragility and aortic complications. Increasing evidence, however, demonstrates that CTDs also predispose to atrial and ventricular arrhythmias, often independent of overt cardiomyopathy or severe valvular disease. Content This review integrates emerging data on the arrhythmogenic substrates of CTDs. Four mechanistic bridges are emphasized: (1) diffuse myocardial fibrosis driven by dysregulated TGF-β signaling, (2) structural valve and annular abnormalities, particularly mitral valve prolapse and mitral annular disjunction, (3) altered mechanotransduction linking extracellular matrix instability to cytoskeletal and nuclear signaling pathways, and (4) downstream ion-channel and gap-junction remodeling as secondary amplifiers. We outline the genetic architecture underlying these processes, focusing on established CTD-implicated genes in the TGF-β/SMAD pathway, valve and annulus regulators, cytoskeletal and myocyte-coupling proteins, and extracellular matrix components, while incorporating emerging CTD modifiers that expand the spectrum of arrhythmia susceptibility. Summary Recognition of CTDs as both vascular and electrical disorders reframes clinical management. Imaging markers such as mitral annular disjunction and diffuse fibrosis, together with targeted ambulatory rhythm monitoring and consideration of genetic context, may improve recognition of higher-risk phenotypes. Therapeutic strategies must balance arrhythmia control with procedural risk in fragile connective tissue substrates. Conclusions By unifying genetic, mechanistic, and clinical insights, this review provides an integrated framework for understanding arrhythmias in CTDs. It underscores the need for prospective registries and genotype-phenotype studies to refine surveillance and prevention strategies.

Abstract Background/Introduction Patients with transthyretin cardiac amyloidosis (ATTR-CA) and atrial fibrillation (AF) have increased risk for left atrial thrombi, necessitating anticoagulation therapy if bleeding risk is not prohibitive. Limited data is available comparing the use of direct oral anticoagulants (DOACs) to warfarin in this population. Purpose To evaluate and compare clinical efficacy and safety outcomes of DOACs versus warfarin in patients with ATTR-CA and AF. Methods We conducted a retrospective cohort study using the TriNetX Network, which includes data from over 140 million patients, between 2014 and 2022. Adults (aged ≥18 years) with ATTR-CA and AF were identified. These patients were further categorized into two groups: one cohort which utilized DOACs for oral anticoagulation and the other cohort on warfarin. 1:1 propensity score matching (PSM) was utilized to balance baseline characteristics between the two cohorts. The primary outcome was rate of stroke, with secondary outcomes including all-cause death, all-cause hospitalizations, and acute heart failure exacerbations. Safety outcomes included intracranial hemorrhage, gastrointestinal hemorrhage, and hematuria. Adjusted odds ratios (aORs) with 95% confidence intervals (CIs) were calculated. Results Among 8,214 adults with ATTR-CA and AF, 5,774 patients were on a DOAC while 2,440 patients were on warfarin. After PSM, 2,425 patients were included in each group. The use of DOACs for AF in patients with ATTR-CA was associated with a significantly lower risk of ischemic stroke compared to warfarin (5.7% versus 7.3%, aOR 0.771 [95% CI, 0.612-0.971]) by the end of the one year follow up. There were no differences in all-cause mortality (19.8% versus 21%, aOR 0.927 [95% CI, 0.806-1.066]), all-cause hospitalizations (19.2% versus 21.6%, aOR 0.863 [95% CI, 0.624-1.195]) or heart failure exacerbations (43.6% versus 46%, aOR 0.906 [95% CI, 0.809-1.015]). Safety outcomes favored DOACs over warfarin, with a lower risk of intracranial hemorrhage (4.5% versus 7.8%, aOR 0.565 [95% CI, 0.444-0.720]), and comparable rates of GI hemorrhage and hematuria. Conclusions DOACs may be safely used in ATTR-CA patients with AF, offering a lower risk of stroke compared to warfarin and a more favorable safety profile. These findings emphasize the potential advantages of DOACs in this population and underline the need for prospective studies to validate these results.