Frequency Analysis of Atrial Fibrillation From the Surface Electrocardiogram

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy are sufficiently predictable by clinical and echocardiographic parameters. Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface electrocardiogram (ECG) using digital signal processing (filtering, subtraction of averaged QRST complexes, and power spectral analysis) and shows large inter-individual variability. This measurement correlates well with intraatrial cycle length, a parameter which appears to have primary importance in AF domestication and response to therapy. AF with a low fibrillatory rate is more likely to terminate spontaneously, and responds better to antiarrhythmic drugs or cardioversion while high rate AF is more often persistent and refractory to therapy. In conclusion, frequency analysis of AF seems to be useful for non-invasive assessment of electrical remodeling in AF and may subsequently be helpful for guiding AF therapy

Evaluation of a new k-means approach for exploratory clustering of items

Evaluation of a new k-means approach for exploratory clustering of item

Frequency Analysis of Atrial Fibrillation From the Surface Electrocardiogram

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. Neither the natural history of AF nor its response to therapy are sufficiently predictable by clinical and echocardiographic parameters. Atrial fibrillatory frequency (or rate) can reliably be assessed from the surface electrocardiogram (ECG) using digital signal processing (filtering, subtraction of averaged QRST complexes, and power spectral analysis) and shows large inter-individual variability. This measurement correlates well with intraatrial cycle length, a parameter which appears to have primary importance in AF domestication and response to therapy. AF with a low fibrillatory rate is more likely to terminate spontaneously, and responds better to antiarrhythmic drugs or cardioversion while high rate AF is more often persistent and refractory to therapy. In conclusion, frequency analysis of AF seems to be useful for non-invasive assessment of electrical remodeling in AF and may subsequently be helpful for guiding AF therapy

First Case of Automatic His Potential Detection With a Novel Ultra High-density Electroanatomical Mapping System for AV Nodal Ablation

AbstractA 74-year old was considered for atrioventricular (AV) nodal ablation in view of atrial fibrillation (AF) with poorly controlled ventricular rate despite being on amiodarone. Targeted AV nodal ablation was successfully performed after identifying the target site for ablation by reviewing an ultra high-density map of the His region produced by automatic electrogram annotation

Heme Oxygenase-1 Induction and Organic Nitrate Therapy: Beneficial Effects on Endothelial Dysfunction, Nitrate Tolerance, and Vascular Oxidative Stress

Organic nitrates are a group of very effective anti-ischemic drugs. They are used for the treatment of patients with stable angina, acute myocardial infarction, and chronic congestive heart failure. A major therapeutic limitation inherent to organic nitrates is the development of tolerance, which occurs during chronic treatment with these agents, and this phenomenon is largely based on induction of oxidative stress with subsequent endothelial dysfunction. We therefore speculated that induction of heme oxygenase-1 (HO-1) could be an efficient strategy to overcome nitrate tolerance and the associated side effects. Indeed, we found that hemin cotreatment prevented the development of nitrate tolerance and vascular oxidative stress in response to chronic nitroglycerin therapy. Vice versa, pentaerithrityl tetranitrate (PETN), a nitrate that was previously reported to be devoid of adverse side effects, displayed tolerance and oxidative stress when the HO-1 pathway was blocked pharmacologically or genetically by using HO-1+/– mice. Recently, we identified activation of Nrf2 and HuR as a principle mechanism of HO-1 induction by PETN. With the present paper, we present and discuss our recent and previous findings on the role of HO-1 for the prevention of nitroglycerin-induced nitrate tolerance and for the beneficial effects of PETN therapy

Feasibility and Reliability of SmartWatch to Obtain 3-Lead Electrocardiogram Recordings

Some of the recently released smartwatch products feature a single-lead electrocardiogram (ECG) recording capability. The reliability of obtaining 3-lead ECG with smartwatches is yet to be confirmed in a large study. This study aimed to assess the feasibility and reliability of smartwatch to obtain 3-lead ECG recordings, the classical Einthoven ECG leads I-III compared to standard ECG. To record lead I, the watch was worn on the left wrist and the right index finger was placed on the digital crown for 30 s. For lead II, the watch was placed on the lower abdomen and the right index finger was placed on the digital crown for 30 s. For lead III, the same process was repeated with the left index finger. Spearman correlation and Bland-Altman tests were used for data analysis. A total of 300 smartwatch ECG tracings were successfully obtained. ECG waves’ characteristics of all three leads obtained from the smartwatch had a similar duration, amplitude, and polarity compared to standard ECG. The results of this study suggested that the examined smartwatch (Apple Watch Series 4) could obtain 3-lead ECG tracings, including Einthoven leads I, II, and III by placing the smartwatch on the described positions

Subject-Specific Calculation of Left Atrial Appendage Blood-Borne Particle Residence Time Distribution in Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia that leads to thrombus formation, mostly in the left atrial appendage (LAA). The current standard of stratifying stroke risk, based on the CHA2DS2-VASc score, does not consider LAA morphology, and the clinically accepted LAA morphology-based classification is highly subjective. The aim of this study was to determine whether LAA blood-borne particle residence time distribution and the proposed quantitative index of LAA 3D geometry can add independent information to the CHA2DS2-VASc score. Data were collected from 16 AF subjects. Subject-specific measurements included left atrial (LA) and LAA 3D geometry obtained by cardiac computed tomography, cardiac output, and heart rate.We quantified 3D LAA appearance in terms of a novel LAA appearance complexity index (LAA-ACI). We employed computational fluid dynamics analysis and a systems-based approach to quantify residence time distribution and associated calculated variable (LAA mean residence time, tm) in each subject. The LAA-ACI captured the subject-specific LAA 3D geometry in terms of a single number. LAA tm varied significantly within a given LAA morphology as defined by the current subjectivemethod and it was not simply a reflection of LAA geometry/appearance. In addition, LAA-ACI and LAA tm varied significantly for a given CHA2DS2-VASc score, indicating that these two indices of stasis are not simply a reflection of the subjects’ clinical status. We conclude that LAA-ACI and LAA tm add independent information to the CHA2DS2-VASc score about stasis risk and thereby can potentially enhance its ability to stratify stroke risk in AF patients

Rate of acquired pulmonary vein stenosis after ablation of atrial fibrillation referred to electroanatomical mapping systems: Does it matter?

Background: Thermal injury during radiofrequency ablation (RFA) of atrial fibrillation (AF) can lead to pulmonary vein stenosis (PVS). It is currently unclear if routine screening for PVS by imaging (echocardiography, computed tomography) is clinically meaningful and if there is a correlation between PVS and the electroanatomical mapping system (EAMS) used for the ablation procedure. It was therefore investigated in the current single center experience. Methods: All patients from January 2004 to December 2016 with the diagnosis of PVS after interventional ablation of AF by radiofrequency were retrospectively analyzed. From 2004 to 2007, transesophageal echocardiography was routinely performed as screening for RFA-acquired PVS (group A). Since 2008, diagnostics were only initiated in cases of clinical symptoms suggestive for PVS (group B). Results: The overall PVS rate after interventional RFA for AF of the documented institution is 0.72% (70/9754). The incidence was not influenced by screening: group A had a 0.74% PVS rate and group B a 0.72% rate (NS). Referred to as the EAMS, there were significant differences: 20/4229 (0.5%) using CARTO®, 48/4510 (1.1%) using EnSite®, 1/853 (0.1%) using MediGuide®, and 1/162 (0.6%) using Rhythmia®. Since 2009, no significant difference between technologies was found. Conclusions: The present analysis of 9754 procedures revealed 70 cases of PVS. The incidence of PVSis not related to screening but to the application of different EAMS. Possible explanations are technological backgrounds (magnetic vs. electrical), learning curves, operator experience, and work-flow differences. Furthermore, incorporation of new technologies seems to be associated with higher incidences of PVS before workflows are optimized

Twitter for professional use in electrophysiology: practical guide for #EPeeps.

Abstract Social media (SoMe) becomes more and more popular in the cardiological community. Among them, Twitter is an emerging and dynamic medium to connect, communicate and educate academic and clinical cardiologists. However, in contrast to traditional scientific communications, the content provided through SoMe is not peer-reviewed and may not necessarily always represent scientific evidence or may even be used to unjustifiably promote therapies for commercial purposes. For the unintended, this means of communication might be appear difficult to handle. This article aims to provide a practical guide on how to use Twitter efficiently for professional use to keep yourself up-to-date about new techniques, the latest study results and news presented at national or international conferences. Additionally, important limitations will be discussed