Association of Epicardial Adipose Tissue Thickness with Left Atrial Size and Atrial Fibrillation

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with detrimental consequences. Epicardial fat is consistently associated with the presence, severity, and recurrence of AF. Aim: The aim of the work was to investigate the association of epicardial adipose tissue thickness with left atrial size in patients with atrial fibrillation. Patients and Methods: This study was conducted on 25 atrial fibrillation (AF) patients and 25 subjects with normal sinus rhythm as a control group matched in body weight. All patients underwent transthoracic echocardiogram. EAT (epicardial adipose tissue) thickness was measured on the right ventricular free wall of the two- dimensional parasternal long-axis view at end systole. Results: The results showed that there was a significant difference between the two groups in waist circumference, EAT (epicardial adipose tissue) thickness, left atrium diameter, LA volume. Receiver operating characteristics (ROC) analysis showed that an EAT thickness of > 0.30 cm maximizes the sensitivity and specificity to predict the development of AF. Conclusion: Increases epicardial adipose tissue is associated with the occurrence of atrial fibrillation.

Artificial Intelligence-Driven Algorithm for Drug Effect Prediction on Atrial Fibrillation: An in silico Population of Models Approach

Background: Antiarrhythmic drugs are the first-line treatment for atrial fibrillation (AF), but their effect is highly dependent on the characteristics of the patient. Moreover, anatomical variability, and specifically atrial size, have also a strong influence on AF recurrence.Objective: We performed a proof-of-concept study using artificial intelligence (AI) that enabled us to identify proarrhythmic profiles based on pattern identification from in silico simulations.Methods: A population of models consisting of 127 electrophysiological profiles with a variation of nine electrophysiological variables (GNa, INaK, GK1, GCaL, GKur, IKCa, [Na]ext, and [K]ext and diffusion) was simulated using the Koivumaki atrial model on square planes corresponding to a normal (16 cm2) and dilated (22.5 cm2) atrium. The simple pore channel equation was used for drug implementation including three drugs (isoproterenol, flecainide, and verapamil). We analyzed the effect of every ionic channel combination to evaluate arrhythmia induction. A Random Forest algorithm was trained using the population of models and AF inducibility as input and output, respectively. The algorithm was trained with 80% of the data (N = 832) and 20% of the data was used for testing with a k-fold cross-validation (k = 5).Results: We found two electrophysiological patterns derived from the AI algorithm that was associated with proarrhythmic behavior in most of the profiles, where GK1 was identified as the most important current for classifying the proarrhythmicity of a given profile. Additionally, we found different effects of the drugs depending on the electrophysiological profile and a higher tendency of the dilated tissue to fibrillate (Small tissue: 80 profiles vs Dilated tissue: 87 profiles).Conclusion: Artificial intelligence algorithms appear as a novel tool for electrophysiological pattern identification and analysis of the effect of antiarrhythmic drugs on a heterogeneous population of patients with AF.

Recurrence of atrial fibrillation after pulmonary vein isolation in dependence of arterial stiffness

Background Arterial stiffness (AS) has emerged as a strong predictor of cardiovascular (CV) diseases. Although increased AS has been described as a predictor of atrial fibrillation (AF), its role as a risk marker for AF recurrence has not yet been elucidated. Methods Patients with AF who underwent pulmonary vein isolation (PVI) were included in this study. Presence of AS was evaluated by measuring aortic distensibility (AD) of the descending aorta by transoesophageal echocardiography. Results In total, 151 patients (mean ± standard deviation (SD) age 71.9 ± 9.8 years) were enrolled and followed for a median duration of 21 months (interquartile range 15.0–31.0). During follow-up, AF recurred in 94 (62.3%) patients. AF recurrence was seen more frequently in patients with permanent AF (27% vs 46%, p = 0.03) and in those who had undergone prior PVI (9% vs 23%, p = 0.02). AD was significantly reduced in patients with AF recurrence (mean ± SD 2.6 ± 2.3 vs 1.5 ± 0.7 × 10−3 mm Hg−1, p < 0.0001), as well as left atrial volume index (LAVI) (mean ± SD 29 ± 12 vs 44 ± 15 ml/m2, p < 0.0001). Multivariable analysis revealed LAVI (odds ratio (OR) 2.9, 95% confidence interval (CI) 1.2–3.4) and AS (OR 3.6, 95% CI 2.8–4.1) as independent risk factors of AF recurrence. Conclusion Increased AS and left atrial size were independent predictors of AF recurrence after PVI. AD as surrogate marker of AS seemed to reflect the overall CV risk. In addition, AD was significantly correlated with left atrial size, which suggests that increased AS leads to atrial remodelling and thus to AF recurrence. Trial registration German registry for clinical studies (DRKS), DRKS00019007.

Abstract 16831: Provoked PFO Shunt And Posterior Circulation Stroke: An Underrecognized Association

Case Presentation: A 50 year old man presented with nausea and weakness. MRI brain showed a small acute infarct in the right pons. CT angiography of the head and neck was unremarkable. No thrombus, vegetation, or inter-atrial communication was seen on transthoracic echocardiogram: LVEF was 55-60% with normal left atrial size. No history of atrial fibrillation, hypertension, diabetes or drug abuse was reported; lower extremity duplex was negative for deep venous thrombosis. TSH was normal. Transesophageal echocardiography showed an aneurysmal atrial septum: agitated saline injection did not demonstrate an inter-atrial communication (figure 1). Repeat saline injection during the same procedure with Valsalva maneuver demonstrated a moderate-sized, provoked right-to-left, patent foramen ovale (PFO) shunt (figure 2). Discussion: Physiologically decreased sympathetic innervation spares posterior cerebral circulation from Valsalva-induced vasoconstriction. The disproportionate increase in posterior cerebral blood flow when venous return/cardiac output increases in the immediate post-strain period explains the association of provoked PFO shunt and paradoxical embolism to posterior circulation. Although the association has been described in literature, it remains underappreciated. Recognition of the association expedited secondary prevention of stroke in this non-elderly patient by circumventing the need to exclude atrial fibrillation on ambulatory rhythm monitoring (3-6 months) before referral for PFO closure.