Predictors of the voltage derived left atrial fibrosis in patients with long-standing persistent atrial fibrillation

Background: Left atrial (LA) arrhythmogenic substrate beyond the pulmonary veins (PV) seems to play a crucial role in the maintenance of atrial fibrillation (AF). The aim of this study was to evaluate the association of selected parameters with the presence and extent of voltage-defined LA fibrosis in patients with long-standing persistent AF (LSPAF) undergoing catheter ablation. Methods: One hundred and sixteen consecutive patients underwent high density-high resolution voltage mapping of the LA with a multielectrode catheter following PV isolation and restoration of sinus rhythm with cardioversion. A non-invasive dataset, such as clinical variables, two-and three-dimensional echocardiography determined LA size and function and fibrillatory-wave amplitude on a standard surface electrocardiogram were obtained during AF before ablation. Results: Low-voltage areas (LVA; 15 cm2 [IQR 8–31]) were detected in 56% of patients. Twenty nine percent of them presented mild, 43% moderate and 28% severe global LVA burden. In univariate analysis, age ≥ 57 years old, female sex, body surface area ≤ 1.76 m2, valvular heart disease, moderate mitral regurgitation, chronic coronary syndrome, hypothyroidism, CHA2DS2-VASc score ≥ 3 and ≥ 4 predicted the presence of LVA. In multivariate analysis only female sex, valvular heart disease and CHA2DS2-VASc ≥ 4 remained statistically significant. AF duration, LA size and function and fibrillatory-waves amplitude were neither associated with the prediction of the LVA, nor severe LVA burden. Conclusions: A LSPAF diagnosis does not indicate the presence of voltage defined fibrosis in many cases. Simple non-invasive screening of the LSPAF population could predict LVA prevalence

Predicting Silent Atrial Fibrillation in the Elderly: A Report from the NOMED-AF Cross-Sectional Study

Background: Silent atrial fibrillation (SAF) is common and is associated with poor outcomes. Aims: to study the risk factors for AF and SAF in the elderly (≥65 years) general population and to develop a risk stratification model for predicting SAF. Methods: Continuous ECG monitoring was performed for up to 30 days using a vest-based system in a cohort from NOMED-AF, a cross-sectional study based on a nationwide population sample. The independent risk factors for AF and SAF were determined using multiple logistic regression. ROC analysis was applied to validate the developed risk stratification score. Results: From the total cohort of 3014 subjects, AF was diagnosed in 680 individuals (mean age, 77.5 ± 7.9; 50.1% men) with AF, and, of these, 41% had SAF. Independent associations with an increased risk of AF were age, male gender, coronary heart disease, thyroid diseases, prior ischemic stroke or transient ischemic attack (ICS/TIA), diabetes, heart failure, chronic kidney disease (CKD), obesity, and NT-proBNP >125 ng/mL. The risk factors for SAF were age, male gender, ICS/TIA, diabetes, heart failure, CKD, and NT-proBNP >125 ng/mL. We developed a clinical risk scale (MR-DASH score) that achieved a good level of prediction in the derivation cohort (AUC 0.726) and the validation cohort (AUC 0.730). Conclusions: SAF is associated with various clinical risk factors in a population sample of individuals ≥65 years. Stratifying individuals from the general population according to their risk for SAF may be possible using the MR-DASH score, facilitating targeted screening programs of individuals with a high risk of SAF

Does a Vagal Response Indicate Cardiac Autonomic Modulation and Improve the Therapeutic Effect of Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation? Insights from Cryoballoon Ablation

Background: The incidence and influence of vagal response (VR) observed during cryoballoon-based pulmonary vein isolation (CBA-based PVI) on the cardiac autonomic nervous system (CANS) and ablation outcomes in paroxysmal atrial fibrillation (PAF) remain unknown. Methods: 296 patients were treated with a 28 mm second-generation cryoballoon (Medtronic). A total of 74 patients without structural heart disease and concomitant diseases were chosen for a detailed CANS assessment with a heart rate variability (HRV) analysis. All patients were screened over a 2-year post-ablation period. Results: VR was detected in 30% of patients and included sinus arrest (64%) or severe sinus bradycardia (46%). The presence of VR was not related to PV ostial dimension, patient clinical characteristics or intraprocedural ablation details. CANS modulation, manifesting as increased median HR and decreased HRV parameters with intact sympatho-vagal balance occurred independently of VR presence or absence and sustained for at least 12 months following ablation. VR was not related with more intensive CANS modulation and did not translate into better ablation outcomes when compared to the non-VR group (74% vs. 71% at 12 months and 69% vs. 65% at 24 months respectively). Conclusions: VR is frequent during CBA-based PVI for PAF and unrelated to any additional clinical benefit

Study of Light-Activated Regioregular Poly(3-Hexyltiophene) Photoconductive Polymer Sensing Properties in Nerve Agent Simulant (DMMP) Detection

In the present work, we report the use of regioregular poly(3-hexyltiophene) polymer (RR-P3HT) as a potential light-activated material for sensing the chemical nerve agent simulant dimethyl methylphosphonate (DMMP). The electrical response of thick films of RR-P3HT, deposited by spray-coating method onto a porous laminate substrate at room temperature, to DMMP vapours was investigated. The studied material was activated by light-emitting diodes that emitted light of different wavelengths. The sensing properties of RR-P3HT are considerably enhanced upon exposure to blue and yellow light. However, excitation by the low wavelength light (blue) caused degeneration of the material, resulting in lowered stability. In the case of the yellow light, degeneration was much slower and the limit of detection was 0.4 ppm. The studied material exhibited high selectivity, as it did not respond to 6 ppm of acetone and methanol vapours

Prevalence of atrial fibrillation in Polish population >=65 old. Report of cross-sectional NOMED-AF study

BackgroundAtrial fibrillation (AF) is the most common cardiac arrhythmia, characterized by an increased risk of thromboembolic complications that can be markedly reduced with anticoagulation. There is a paucity of studies assessing the total prevalence of AF in national populations.AimsTo assess the nationwide prevalence of AF in a population of adults ≥65 old and to determine the impact of duration of electrocardiogram (ECG) monitoring on the number of newly detected AF episodes.MethodsThe NOMED-AF study (ClinicalTrials.gov; NCT: 0324347) was a cross-sectional study performed on a nationally representative random sample of 3014 Polish citizens 65 years or older. Final estimates were adjusted to the national population. All participants underwent up to 30 days of continuous ECG monitoring. Total AF prevalence was diagnosed based on the patient's medical records or the presence of AF in ECG monitoring.ResultsThe prevalence of AF in the Polish population ≥65 years was estimated as 19.2% (95% confidence interval [CI], 17.9%-20.6%). This included 4.1% (95% CI, 3.5%-4.8%) newly diagnosed cases and 15.1% (95% CI, 13.9%-16.3%) previously diagnosed cases and consisted of 10.8% (95% CI, 9.8%-11.9%) paroxysmal AF and 8.4% (95% CI, 7.5%-9.4%) persistent/permanent AF. The incidence of all paroxysmal AF events as a function of ECG monitoring duration increased from 1.9% (95% CI, 1.4%-2.6%) at 24 hours to 6.2% (95% CI, 5.3%-7.2%) at 4 weeks.ConclusionsThe prevalence of AF in elderly adults is higher than estimated based on medical records only. Four weeks of monitoring compared to 24-hour ECG Holter allow detection of 7-fold more cases of previously undiagnosed paroxysmal AF