Computer-Aided Clinical Decision Support Systems for Atrial Fibrillation

Clinical decision support systems (clinical DSSs) are widely used today for various clinical applications such as diagnosis, treatment, and recovery. Clinical DSS aims to enhance the end‐to‐end therapy management for the doctors, and also helps to provide improved experience for patients during each phase of the therapy. The goal of this chapter is to provide an insight into the clinical DSS associated with the highly prevalent heart rhythm disorder, atrial fibrillation (AF). The use of clinical DSS in AF management is ubiquitous, starting from detection of AF through sophisticated electrophysiology treatment procedures, all the way to monitoring the patient\u27s health during follow‐ups. Most of the software associated with AF DSS are developed based on signal processing, image processing, and artificial intelligence techniques. The chapter begins with a brief description of DSS in general and then introduces DSS that are used for various clinical applications. The chapter continues with a background on AF and some relevant mechanisms. Finally, a couple of clinical DSS used today in regard with AF are discussed, along with some proposed methods for potential implementation of clinical DSS for detection of AF, prediction of an AF treatment outcome, and localization of AF targets during a treatment procedure

Safety and efficacy of cardioversion of acute atrial fibrillation – the Fincv (Finnish cardioversion) study

Background: The inherent risk of thromboembolism after cardioversion of atrial fibrillation with a duration of more than 48 hours is well established. However, the potential increased risk of these complications after cardioversion of recent-onset episodes of atrial fibrillation has been more controversial. Thus, the aim of this dissertation was to evaluate the safety and efficacy of cardioversion of acute (< 48 hours) atrial fibrillation. Methods: The FinCV study is a multicenter (n=3) retrospective study of 3143 patients who underwent 7660 cardioversions for acute atrial fibrillation. Of those procedures, 5362 were performed without, and 2298 with, anticoagulation protection. Results: The success rate of electrical cardioversions was 94.2%. After successful procedures, atrial fibrillation recurred in 17.3% of cases within 30 days. The rate of thromboembolic events (mainly ischemic strokes) was 0.7% in non-anticoagulated patients after successful cardioversion of acute atrial fibrillation. Significant independent predictors of these complications were old age, female sex, heart failure and diabetes, along with a cardioversion delay of 12 hours or longer. The risk of thromboembolism was as high as 9.8% in patients with both heart failure and diabetes. The incidence of thromboembolic complications also increased significantly from 0.4% in nonanticoagulated patients with CHA2DS2VASc score of ≤ 1 to 2.3% in those with a score of ≥ 5. Overall, the incidence of thromboembolism was significantly lower after cardioversions performed during anticoagulation (0.1% vs. 0.7%). Altogether, 0.9% of electrical cardioversions resulted in bradyarrhythmia, and 44.4% of those patients underwent pacemaker implantation later. Conclusions: The cardioversion of acute atrial fibrillation does not increase the risk of thromboembolism in anticoagulated patients. However, this risk is unacceptably high in non-anticoagulated patients with conventional risk factors for stroke. High CHA2DS2VASc score and a delay to cardioversion of 12 hours or longer are significant predictors of thromboembolism. Overall, electrical cardioversion is an effective procedure and immediate arrhythmic complications are rare after these procedures.Akuutin eteisvärinän kardioversion turvallisuus ja teho – Fincv-tutkimus Tausta: Yli 2 vuorokautta kestäneen eteisvärinän kardioversioon liittyvä kohonnut aivohalvauksen riski on hyvin tiedossa. Sen sijaan, akuutin eteisvärinän kääntöön liittyvä aivohalvauksen riski on aikaisemmin ollut kiistanalaisempi. Tästä syystä väitöskirjatutkimuksen tarkoituksena oli selvittää akuutin (kesto alle 48 tuntia) eteisvärinän rytminsiirron turvallisuus ja teho. Menetelmät: FinCV-tutkimuksen aineisto on kerätty retrospektiivisesti kolmesta tutkimuskeskuksesta. Se sisältää tiedot 3143 potilaalle tehdystä 7660:stä akuutin eteisvärinän kardioversiosta. Näistä 2298 tehtiin antikoagulaatiohoidon aikana ja 5362 ilman vastaavaa hoitoa. Tulokset: Sähköisistä kardioversioista 94,2 % onnistui, mutta 17,3 %:lla potilaista eteisvärinä uusiutui 30 päivän seurannassa. Antikoaguloimattomilla potilailla 0,7 % onnistuneista kardioversioista johti tromboemboliseen komplikaatioon (pääosa aivoinfarkteja). Näiden komplikaatioiden itsenäisiä riskitekijöitä olivat korkea ikä, naissukupuoli, diabetes ja sydämen vajaatoiminta, yhdessä akuutin eteisvärinän käännön viivästymiseen yli 12 tuntiin kohtauksen alusta. Kardioversioon liittyvä tromboembolian riski oli erityisen suuri samanaikaisesti diabetesta ja sydämen vajaatoimintaa sairastavilla potilailla – 9,8 prosenttia. Tromboembolisten komplikaatioiden ilmaantuvuus antikoaguloimattomilla potilailla oli 2,3 prosenttia CHA2DS2VAScriskipisteiden ollessa yli neljä, kun taas potilailla, joilla riskipisteitä oli vähemmän kuin kaksi, riski oli ainoastaan 0,4 prosenttia. Antikoaguloiduilla potilailla tromboembolisten komplikaation esiintyvyys kardioversion jälkeen oli selvästi vähäisempää verrattuna antikoaguloimattomiin potilaisiin (0,1 % vs. 0,7 %). Sähköisistä kardioversioista 0,9 % johti välittömästi käännön jälkeen ilmenevään bradyarytmiaan ja 44,4 %:lle näistä potilaista asennettiin myöhemmin tahdistin. Päätelmät: Akuutin eteisvärinän rytminsiirtoon liittyy huomattava tromboembolisten komplikaatioiden vaara tietyillä potilasryhmillä. Korkea CHA2DS2VASc -pistemäärä ja rytminsiirron viivästyminen yli 12 tuntiin oireiden alusta lisäävät selvästi tätä riskiä. Antikoagulaatiohoidon aikana tehty kardioversio ei näyttäisi kuitenkaan lisäävän tromboembolian vaaraa. Sähköinen kardioversio on tehokas toimenpide ja käännön yhteydessä ilmenevät arytmiset komplikaatiot ovat harvinaisia ja hyvänlaatuisia

Does atrial fibrillation affect plasma endothelin level?

Background: Atrial fibrillation (AF) may result in endocardial endothelium dysfunction. The main objective of the study was to evaluate the plasma concentration of endothelin-1 (ET-1) during persistent AF and after sinus rhythm recovery following direct-current cardioversion and to assess the predictive value of ET-1 in AF patients. Methods: The study group consisted of 43 patients with persistent AF and normal left ventricle systolic function who had undergone successful cardioversion. Blood samples were collected twice: 24 hours before and 24 hours after cardioversion. All patients were also examined in terms of sinus rhythm maintenance on the 30th day after cardioversion. Results: There were no differences in ET-1 plasma concentration between the persistent AF group and the control group (2.6 &#177; 2.9 fmol/mL vs 2.3 &#177; 4.5 fmol/mL, NS). Plasma ET-1 levels did not change within 24 hours after successful cardioversion (2.5 &#177; 2.8 fmol/mL vs 2.6 &#177; 2.9 fmol/mL, NS). There was no correlation between the baseline plasma levels of ET-1 in patients with persistent AF and sinus rhythm maintenance 30 days after cardioversion. Conclusions: Persistent AF does not affect plasma ET-1 concentration in patients with normal left ventricle systolic function and with no symptoms of heart failure. There are no significant changes in plasma ET-1 level during the 24 hours after cardioversion. (Cardiol J 2010; 17, 5: 471-476

Role of Echocardiography in Atrial Fibrillation

Atrial fibrillation (AF) is most common arrhythmia and its prevalence appears to be increasing as the population ages. Echocardiography can play a key role in risk stratification and management of patients with AF. Transthoracic echocardiography allows rapid and comprehensive assessment of cardiac anatomical structure and function. Pulmonary vein flow monitoring using echocardiography has the potential to an increasing role in the evaluation of cardiac function and AF ablation procedures. Transesophageal echocardiography also provides accurate information about the presence of a thrombus in the atria and thromboembolic risk. The novel technique of intracardiac echocardiography has emerged as a popular and useful tool in the everyday practice of interventional electrophysiology. Other imaging modalities, such as computed tomography and magnetic resonance imaging have complementary roles in risk stratification and assessment of patients with AF. Echocardiography continues to be the foundation of clinical evaluation and management of AF

Interventional techniques in the management of persistent atrial fibrillation

Atrial fibrillation (AF) is a common cardiac rhythm problem experienced by patients and comprises an increasing demand on healthcare systems. AF is characterised by advanced neurohormonal remodelling in the atria resulting in dilation and variable degree of atrial fibrosis that can be measured by imaging techniques with difficulty in developing methods of identifying and quantifying left atrial (LA) fibrosis. LA fibrosis can be estimated by measuring LA scar using non-invasive imaging methods such as strain imaging in advanced echocardiography and in cardiac magnetic resonance (CMR) imaging. Achieving rhythm control strategy utilising catheter ablation (CA) has shown to be advantageous in improving quality of life (QOL) in patients with paroxysmal AF. The most effective method in management of AF has remained elusive in non-paroxysmal AF. Thoracoscopic surgical ablation (TSA) has been developed over the last decade by experienced surgeons with some promising early results but has not been investigated in long-standing persistent AF (LSPAF). I have attempted to answer some of the relevant questions that have remained in management of LSPAF by conducting a multicentre randomised control trial comparing efficacy between CA and TSA (CASA-AF RCT) and improvements in quality of life indices. In a sub-study, I measured LA volumes using echocardiography and CMR to determine reverse remodelling and LA function using tissue Doppler imaging and strain imaging to predict AF recurrence. In a CMR sub-study, a novel automatic LA segmentation algorithm was used to quantify LA fibrosis before and after ablation. I was able to quantify the response of the autonomic nervous system to targeted ganglionic plexi (GP) ablation as part of TSA compared to CA by measuring heart rate variability. I am hopeful that the knowledge gained from this thesis will help with an appropriate selection that will improve the management of patients with LSPAF.Open Acces

The atrial fibrillation burden during the blanking period is predictive of time to recurrence after catheter ablation

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Objective: This study aimed to assess whether atrial fibrillation (AF) occurrence or its corresponding daily mean burden (in minutes/day) during the mid to late blanking period after pulmonary vein isolation (PVI), predicts AF recurrence. Methods: Analysis of consecutive first PVI ablation patients undergoing prolonged electrocardiogram (ECG) monitoring during the second and third months after PVI. The clinical variables, total AF burden, and their relationship with time to recurrence were studied. Results: 477 patients with a mean age of 56.9 (SD = 12.3) years (63.7 % male; 71.7 % paroxysmal AF), from which 317 (66.5 %) had an external event recorder between 30 and 90 days after ablation. Median follow-up of 16.0 (P 25:12.0: P 75:33.0) months, 177 (37 %) patients had an AF recurrence, with 106 (22.2 %) having the first episode after 12 months of follow-up. In the group of patients with an event recorder, 80 (25.2 %) had AF documented during the blanking period. Multivariable analysis showed that AF during the blanking period was associated with a 4-fold higher risk of recurrence (HR: 3.98; 95 %CI: 2.95-5.37), and, compared to patients in sinus rhythm, those with an AF burden ≥ 23 min/day had an approximately 7-fold higher risk of recurrence (HR estimate: 6.79; 95 %CI: 4.56-10.10). Conclusions: The probability of experiencing AF recurrence can be predicted by atrial tachyarrhythmia episodes during the second and third months after PVI. Atrial arrhythmias burden > 23 min/day has a high predictive ability for recurrence.info:eu-repo/semantics/publishedVersio

Cardiac fibrosis in patients with atrial fibrillation: Mechanisms and clinical implications

atrial fibrillation, heart failure, cardiac fibrosisAtrial fibrillation (AF) is associated with structural, electrical and contractile remodeling of the atria. Development and progression of atrial fibrosis is the hallmark of structural remodeling in AF and is considered to be substrate for AF perpetuation. In contrast, experimental and clinical data on impact of ventricular fibrotic processes in pathogenesis of AF and its complications are controversial. Ventricular fibrosis appears to contribute to abnormalities in cardiac relaxation and contractility, and development of heart failure, a common finding in AF. Given the frequent coexistence of AF and heart failure and the fact that both conditions affect patient prognosis better understanding of mutual impact of fibrosis in AF and heart failure is of particular interest. In this review article, we provide an overview on the general mechanisms of cardiac fibrosis in AF, differences between fibrotic processes in atria and ventricles, and the clinical and prognostic significance of cardiac fibrosis in AF

Catheter Ablation for Atrial Fibrillation: Predicting Recurrence

Background Catheter ablation has emerged as treatment for atrial fibrillation (AF). Health care-related variables have not been explored as predictors of first ablation outcome. Determining factors associated with arrhythmia recurrence may help select patients likely to benefit. The objective was to identify variables associated with recurrence following AF ablation. Methods Retrospective cohort design of 314 AF patients who had undergone first ablation. Follow-up visits occurred at 3, 6 and 12 months. Variables and the outcome of recurrence were modeled with Cox proportional hazards analysis. Results/Conclusions After mean follow-up of 239+/-125 days, 110/314 patients (35.0%) experienced recurrence. Adjusted Cox proportional hazards models demonstrated cardiomyopathy [HR (95% CI) = 1.97 (1.13-3.41)] was associated with arrhythmia recurrence. Conversely, height per cm increase [HR (95% CI) = 0.96 (0.94-0.99)], and targeted ablation outside the pulmonary veins [HR (95% CI) = 0.531 (0.29-0.98)] were associated with hazard reduction. Wait time was not associated with recurrence