Photoplethysmography based atrial fibrillation detection: a review

Atrial fibrillation (AF) is a cardiac rhythm disorder associated with increased morbidity and mortality. It is the leading risk factor for cardioembolic stroke and its early detection is crucial in both primary and secondary stroke prevention. Continuous monitoring of cardiac rhythm is today possible thanks to consumer-grade wearable devices, enabling transformative diagnostic and patient management tools. Such monitoring is possible using low-cost easy-to-implement optical sensors that today equip the majority of wearables. These sensors record blood volume variations—a technology known as photoplethysmography (PPG)—from which the heart rate and other physiological parameters can be extracted to inform about user activity, fitness, sleep, and health. Recently, new wearable devices were introduced as being capable of AF detection, evidenced by large prospective trials in some cases. Such devices would allow for early screening of AF and initiation of therapy to prevent stroke. This review is a summary of a body of work on AF detection using PPG. A thorough account of the signal processing, machine learning, and deep learning approaches used in these studies is presented, followed by a discussion of their limitations and challenges towards clinical applications.

Atrial Fibrillation a Benign Condition? Quality of Life Approach

Introduction: Atrial fibrillation (AF) is the most frequent cardiac rhythm disorder, considered until recently benign. Due to its major complications (cardio-embolic episodes) patients need to be anticoagulated. Aim: To assess the quality of life (QOL) in patients with new oral anticoagulants (NOAC) versus those using classical anticoagulants (VKA). Methods: A total of 483 patients admitted consecutively in our clinic were evaluated during hospitalization and after discharge. Follow-up visits were conducted: at baseline, 6, 12, 18 and 24 months; the quality of life (QoL) was measured by a specific questionnaire (EQ-5D-3L), and the results were assessed. Patients were divided in two groups considering their anticoagulant use: NOAC or VKA. Baseline characteristics, clinical outcomes as well as QoL indices were compared between the two groups The current research has been conducted in accordance with the ethical prin ciples set out in the Helsinki Declaration and Good Clinical Practice Recommendations and was approved by our hospital Ethics Committee. Results: The mean age of our studied group (374 eligible patients) was 64.7 ± 8.2 years (p=0.220); 116 patients (31.01%) used NOAC. Patients with NOAC obtained better results in all domains: physical (57.0±8.9 vs. 51.1±12.5 vs. 42.0±6.2; p<0.001), social (62.6±19.8 vs. 52.5±20.0 vs. 45.7±16.0; p=0.019) and environmental (62.9±12.7 vs. 52.7±7.6 vs. 60.7±3.6; p =0.018). Compared to VKAs, NOACs were more commonly prescribed in patients with a history of stroke or with a higher thromboembolic risk (p<0.001). EQ-5D-3L total score: 75.6 ± 20.9; visual analogue scale: 63.1 ± 20.6. Conclusion(s): Satisfaction and QoL with oral anticoagulants were high, although they were both better with NOACs. A worse QoL was associated with comorbidities, polypragmasy, and previous treatment with VKA. Patients strongly expressed their desire to improve their QoL.

Testing of newly synthesized propafenone derivatives antiarrhythmic activity in aconitic model of cardiac arrhythmia in rats

By applying of aconitic test in in vivo experiments in rats under deep anesthesia, there was investigated the antiarrhythmic potential of newly synthetized fluorinated derivatives of propafenone. The animals were divided into four experimental groups. The first (aconitine group) was treated with aconitine at a dose of 60?g/kg, which led to pronounced cardiac rhythm disorder in a short period of time. The appearance of ventricular extrasystole (VES) was taken as a parameter for ascertainment of cardiac rhytm disorder. The remaining three animal groups were taken for testing the potential of propafenone and propafenone fluorinated derivatives to stop the arrhythmia, and which was induced by i.v. aconitine injection (60|jg/kg). Propafenone, as well as 5OF derivative, did not convert the disturbed cardiac rhythm (survival of animals was 0%). By applying 5PF derivative in a dose of 6 mg/kg, the animals survived with occasional establishment of sinus rhythm.

Finite Element Simulations of Left Atrial Filling Following Radiofrequency Ablation

Atrial fibrillation (AF) is a cardiac rhythm disorder characterized by rapid, erratic muscle contraction without concordant chamber motion. Given the rising prevalence of AF and failures of pharmaceutical therapies, clinicians have increasingly used radiofrequency (RF) ablation to electrically isolate the abnormal tissue [1]. A typical ablation procedure (PVI) electrically isolates the pulmonary veins (PV) by encircling them with lesions and has a 60% success rate [2]. More aggressive procedures have been proposed to increase the success rate, including wide-area circumferential ablation (WACA), which add more lesions without considering the functional impact of additional scarring [3]. The objective of this study was to develop a finite element model of a healthy left atrium, capable of simulating passive filling during ventricular systole, and explore the functional impact of ablation by simulating various scar patterns.

Oral anticoagulation use by patients with atrial fibrillation in Germany

SummaryAtrial fibrillation (AF) is the most common significant cardiac rhythm disorder. Oral anticoagulation (OAC) is recommended by guidelines in the presence of a moderate to high risk of stroke. Based on an analysis of claims-based data, the aim of this contribution is to quantify the stroke-risk dependent OAC utilisation profile of German AF patients as well as the possible causes and the associated clinical outcomes of OAC under-use. Our data set was derived from two large mandatory German medical insurance funds. Risk stratification of patients was based on the CHADS2-score and the CHA2DS2-VASc-score. Two different scenarios were constructed to deal with factors potentially disfavouring OAC use. Causes of OAC under-use and its clinical consequences were analysed using multivariate analysis. Observation year was 2008. A total of 183,448 AF patients met the inclusion criteria. This represents an AF prevalence of 2.21%. The average CHADS2-score was 2.8 (CHA2DS2-VASc-score: 4.3). On between 40.5 and 48.7% of the observed patient-days, there was no antithrombotic protection by OAC, other anticoagulants or aspirin. Older female patients with a high number of comorbidities had a higher risk of OAC under-use. Patients who had already experienced a thromboembolic event had a lower risk of OAC under-use. In the observation year, 3,367 patients experienced a stroke (incidence rate 1.8%). In our multi-level Poisson random effects estimate, OAC use decreases the stroke rate by almost 80% (IRR 0.236). In conclusion, OAC under-use is widespread in the German market. It is associated with severe clinical consequences.

Oral Anticoagulation In Patients with Atrial Fibrillation. Long-Term Follow-up

Abstract 4392 Atrial fibrillation (AF) is the most common cardiac rhythm disorder and an independent risk factor for stroke. It′s prevalence in AF pts without oral anticoagulation (OA) is 1 to 12%. OA is recommended in all valvular AF pts and in non valvular AF pts associated with other risk factors for stroke (CHADS2 score >1). Objective: to evaluate characteristics, evolution and incidence of thrombosis and bleeding in pts with AF under OA for at least 3 months. Methods: we retrospectively analyzed 850 pts between Jan 2003 and Jan 2010. Results: the mean follow-up was 25 months (range 3–169). The features of the entire group are listed in the table below: Minor bleeding was observed in 32.7% of the entire group (278/850) and major bleeding in 2.7% (23/850). Most of the major bleedings occurred at the gastrointestinal tract, and 53% of those pts presented INR <2 (8/15). Fatal bleeding (located at CNS) developed in 0.2% (2/850). Ten pts developed thrombosis during the follow-up period (1.17%); 50% of them with INR < 2. Conclusion: 45% of the pts were older than 74 years and most of them disclosed valvular AF. Minor bleeding was 15.4%/year, major bleeding: 1%/year, and thrombosis: 0.42%/year, according to the current literature. Disclosures: No relevant conflicts of interest to declare.

Oral Anticoagulation in Atrial Fibrillation. Comparison Between Patients Younger and Older Than 75 Years

Atrial fibrillation (AF) is the most common cardiac rhythm disorder. The prevalence is nearly 10 % in patients (pts) older than 75 years (yrs). Some authors are reluctant to give oral anticoagulant therapy for older pts based on their higher incidence of bleeding Objective : to compare characteristics, incidence of thrombosis and bleeding in 2 groups of pts with AF, under OA for at least 3 months. Methods: we retrospectively analyzed 184 pts below 75 yrs (Group A) and 133 pts with 75 yrs and older (Group B), between Jan 2002 and Aug 2007. Results: the mean follow-up was 514 pts/year for the A group and 382 pts/year for group B. The features of each group are listed in the table below: Group A Group B p Age (mean- range) 64,9 (33/74) 79,8 (75/91) Gender (M/F) 116/68 (1,7/1) 55/78 (0,7/1) Rheumatic AF 89/184 61/114 Non valvular AF 80/184 53/114 Previous thrombosis 21/184 (11.4%) 29/133 (21.8%) 0,01 Diabetes mellitus 28/184 (15.2%) 10/133 (7.5%) 0,05 Arterial Hypertension 78/184 (42.3 %) 53/133 (39.8%) Hyperthyroidism 29/184 (15.7%) 18/133 (13.5%) Left Mega Atrium 43/174 (24.7%) 32/110 (29%) Coronary Artery Disease 38/184 (20.6%) 31/133 (23.3%) Cardiomegaly 53/170 (31.1%) 41/122 (33.6%) Ejection Fraction ≤30% 26/175 (14,8%) 20/112 (17.8%) Creatinin ≥ 2 mg/dl 8/184 (4.3%) 8/133 (6.1%) Thromboses 4/184 (2.1%) 3/133 (2.2%) Bleeding minor 59/184 (32%} 49/133 (36.8%) major 5/184 (2.7%) 2/133 (1.5%) fatal 0 2/2 (100%) Controls with INR 2-3 61 % 60,5 % Conclusion: There was no difference in the incidence of major and minor bleeding/thrombotic complications between the groups. Group B disclosed a higher number of thromboses previous to OA therapy, and fewer pts with diabetes. In our experience, OA seemed to be equally safe and effective when we compared both populations. There was no difference in the incidence of major and minor bleeding/thrombotic complications between the groups.