Abstract 16685: Obstructive Fibrosis Related to Transverse Conduction Slowing in Chronic Atrial Fibrillation

Introduction: Patients with paroxysmal atrial fibrillation (AF) often transition between sinus rhythm and AF. For AF to initiate there must be both a trigger and a substrate that facilitates reentrant activity. This trigger is often caused by a premature atrial contraction or focal activations within the atrium. Hypothesis: We hypothesize long strands of continuous fibrosis act as a substrate that slows conduction, but only after a premature contraction. Methods: A high density electrode plaque was placed on 13 controls and 6 chronic AF goats (an average of 6 months of rapid pacing induced AF). Conduction slowing following a premature contraction was quantified. Atrial fibrosis was quantified into two groups, non-obstructive and obstructive fibrosis. Obstructive fibrosis was considered fibrosis that was at least the length of a myocyte (100 μm), thus potentially disrupting transverse cell to cell conduction. Non-obstructive fibrosis had a length less than 100 μm. Results: Conduction velocity of the AF goats was significantly slowed compared to the control goats in the transverse direction (0.40±0.03 m/s vs. 0.53±0.15 m/s, p<0.05) but not in the longitudinal direction (0.70±0.27 m/s vs. 0.76±0.18 m/s, p = N.S.) following a premature atrial contraction. The AF goats had more obstructive fibrosis than the controls (18±8 fibers/mm 2 vs. 9±3 fibers/mm 2 , p<0.05). The control group trended towards more non-obstructive, diffuse fibrosis than the AF animals (1109±309 fibers/mm 2 vs. 718±380 fibers/mm 2 , p = 0.07, N.S). Conclusions: Structural and electrophysiological remodeling in chronic AF leads conduction velocity slowing transverse to fiber orientation. Histology from goats with a history of chronic AF had more obstructive fibrosis, which may lead to the conduction slowing and alteration in conduction pathways to make the tissue more susceptible to AF. The amount of obstructive fibrosis may be more important to AF outcomes than the total density of fibrosis.

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Burden and Long Firing of Premature Atrial Contraction Early After Catheter Ablation Predict Late Recurrence of Atrial Fibrillation

Circulation Journal ◽

10.1253/circj.cj-19-0976 ◽

2020 ◽

Vol 84 (6) ◽

pp. 894-901 ◽

Cited By ~ 4

Author(s):

Hiroyuki Inoue ◽

Nobuaki Tanaka ◽

Koji Tanaka ◽

Yuichi Ninomiya ◽

Yuko Hirao ◽

...

Keyword(s):

Atrial Fibrillation ◽

Catheter Ablation ◽

Late Recurrence ◽

Atrial Contraction ◽

Premature Atrial Contraction

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Prevention of stroke in chronic andrecurrent atrial fibrillation

Australian Health Review ◽

10.1071/ah010061 ◽

2001 ◽

Vol 24 (3) ◽

pp. 61 ◽

Cited By ~ 4

Author(s):

Anne-Maree Kelly ◽

Debra Kerr ◽

Ruth Hew

Keyword(s):

Atrial Fibrillation ◽

High Risk ◽

American Heart ◽

Anticoagulation Therapy ◽

Heart Association ◽

Chronic Atrial Fibrillation ◽

Prior History ◽

Demographic Information ◽

Thromboembolic Stroke ◽

History Of

The objective was to determine the proportion of patients presenting to the Emergency Department (ED) in atrialfibrillation (AF) who are at high risk of thromboembolic stroke as defined by the American Heart Association andwho might benefit from anticoagulation therapy.We enrolled all patients identified as having AF between 28th June 1999 and 26th March 2000. Data collectedincluded demographic information, presenting complaint, discharge diagnosis, risk factors for thromboembolic stroke,contraindications to anticoagulation (as defined by the Stroke Prevention in AF Investigators), admission anddischarge medications, and cardiac rhythm on presentation and at discharge.193 patients were identified within the study period. Two patient histories were not available for review. 121 patientshad a prior history of AF. Of these, 65 patients were at high risk for thromboembolic stroke and had no contra-indicationto anticoagulation therapy. 43 (66%) were on Warfarin at presentation but 14 (22%) were on Aspirinand 8 (12%) were on neither.34% of patients with chronic atrial fibrillation presenting to the ED, at high risk of thromboembolic stroke andwithout contra-indication to anticoagulation, were not anticoagulated on presentation. ED attendance provides anopportunity for intervention for the prevention of stroke in this group.

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Prediction model for thyrotoxic atrial fibrillation: a retrospective study.

10.21203/rs.3.rs-428694/v1 ◽

2021 ◽

Author(s):

Daria Aleksandrovna Ponomartseva ◽

Ilia Vladislavovich Derevitskii ◽

Sergey Valerevich Kovalchuk ◽

Alina Yurevna Babenko

Keyword(s):

Machine Learning ◽

Atrial Fibrillation ◽

Heart Rate ◽

Retrospective Study ◽

Prediction Model ◽

Performance Metrics ◽

Premature Ventricular Contraction ◽

Ventricular Contraction ◽

Atrial Contraction ◽

Premature Atrial Contraction

Abstract Background: Thyrotoxic atrial fibrillation (TAF) is a recognized significant complication of hyperthyroidism. Early identification of the individuals predisposed to TAF would improve thyrotoxic patients’ management. However, to our knowledge, an instrument that establishes an individual risk of the condition is unavailable. Therefore, the aim of this study is to build a TAF prediction model and rank TAF predictors in order of importance. Methods: In this retrospective study, we have investigated 36 demographic and clinical features for 420 patients with overt hyperthyroidism, 30% of which had TAF. At first, the association of these features with TAF was evaluated by classical statistical methods. Then, we developed several TAF prediction models with eight different machine learning classifiers and compared them by performance metrics. The models included ten features that were selected based on their clinical effectuality and importance for model output. Finally, we ranked TAF predictors, elicited from the optimal final model, by the machine learning tehniques. Results: The best performance metrics prediction model was built with the extreme gradient boosting classifier. It had the reasonable accuracy of 84% and AUROC of 0.89 on the test set. The model confirmed such well-known TAF risk factors as age, sex, hyperthyroidism duration, heart rate and some concomitant cardiovascular diseases (arterial hypertension and conjestive heart rate). We also identified premature atrial contraction and premature ventricular contraction as new TAF predictors. The top five TAF predictors, elicited from the model, included (in order of importance) PAC, PVC, hyperthyroidism duration, heart rate during hyperthyroidism and age. Conclusions: We developed a machine learning model for TAF prediction. It seems to be the first available analytical tool for TAF risk assessment. In addition, we defined five most important TAF predictors, including premature atrial contraction and premature ventricular contraction as the new ones. These results have contributed to TAF prediction investigation and may serve as a basis for further research focused on TAF prediction improvement and facilitation of thyrotoxic patients’ management.

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Sciatic Nerve Conductivity is Impaired by Hamstring Strain Injuries

International Journal of Sports Medicine ◽

10.1055/s-0043-115735 ◽

2017 ◽

Vol 38 (11) ◽

pp. 803-808 ◽

Cited By ~ 7

Author(s):

Karina Kouzaki ◽

Koichi Nakazato ◽

Masuhiko Mizuno ◽

Tooru Yonechi ◽

Yusuke Higo ◽

...

Keyword(s):

Sciatic Nerve ◽

Conduction Velocity ◽

Nerve Conduction ◽

Nerve Conduction Velocity ◽

Control Group ◽

Injured Limb ◽

Hamstring Strain ◽

History Of

AbstractThe aim of this study was to assess sciatic nerve conductivity in athletes with a history of hamstring strain injuries. Twenty-seven athletes with a history of hamstring strain injuries were included in the injured group. The control group consisted of 16 uninjured participants. We measured the proximal and distal latencies and calculated the sciatic nerve conduction velocity to evaluate neuronal conductivity. The results were expressed as median values and interquartile ranges. Both proximal latency and distal latency of the injured limb in the injured group were significantly longer than those of the uninjured limb (p<0.05). The nerve conduction velocity of the injured limb in the injured group was significantly lower than that of the uninjured limb (p<0.05). There were no significant side-to-side differences in the control group. Sciatic nerve conductivity impairments may exist in athletes with a history of hamstring strain injuries.

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Abstract 18516: Regional Dysfunction of Left Atrial Appendage and its Association with Stroke in Atrial Fibrillation

Circulation ◽

10.1161/circ.130.suppl_2.18516 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Abdullah A Alissa ◽

Yuko Inoue ◽

Jochen Cammin ◽

Qiulin Tang ◽

Elliot Fishman ◽

...

Keyword(s):

Atrial Fibrillation ◽

Left Atrial ◽

Left Atrial Appendage ◽

Atrial Appendage ◽

Control Group ◽

Prior History ◽

Area Change ◽

Increased Risk ◽

History Of ◽

Regional Dysfunction

Background: Atrial Fibrillation (AF) is associated with an increased risk of cardioembolic stroke. Previous studies demonstrate that the Left atrial appendage (LAA) is the most common site of intracardiac thrombus, and the LAA morphology alone may determine the risk of stroke. We aimed to determine the association between LAA regional dysfunction using novel, noninvasive, image-based motion-estimation CT (iME) and prior history of stroke in patients with AF. Methods: Among the patients with history of AF referred for ablation who underwent pre-ablation CT with retrospective ECG gating, we identified 18 patients with a prior history of stroke or TIA, and 18 age- and gender-matched controls. The patients in AF at the time of CT were excluded. Four-dimensional motion vector field was estimated from reconstructed CT images using iME at every 5% RR interval. To assess myocardial deformation, area change ratio and area change rate were calculated over the endocardial surface of the LA and LAA. Univariate and multivariate comparisons were made by using binary logistic regression model. Results: A total of 36 patients (mean age 67.6 ± 8.1 years, 66.7% male, 16.7% persistent AF) were included in the study. Univariate analysis showed that the LA pre-atrial contraction area change ratio and LAA maximum area change ratio were significantly lower (P= 0.02 and 0.04, respectively) in the stroke/TIA group compared to the control group. These changes remained statistically significant in multivariate analysis (P=0.03 and 0.04, respectively) after adjusting for age, sex, body mass index, LV ejection fraction, type of AF, and CHADS score. Conclusions: LAA regional dysfunction is associated with stroke/TIA in patients with AF. LAA regional dysfunction detected by iME could represent a marker for stroke and a possible therapeutic target.

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Impact of Left Atrial Appendage Amputation on Left Atrial Morphology and Rhythm after Off-Pump CABG

The Thoracic and Cardiovascular Surgeon ◽

10.1055/s-0041-1735809 ◽

2021 ◽

Author(s):

Muhammed Gerçek ◽

Mina Ghabrial ◽

Lina Glaubitz ◽

Oliver Kuss ◽

Anas Aboud ◽

...

Keyword(s):

Atrial Fibrillation ◽

Left Atrial ◽

Left Atrial Appendage ◽

Artery Bypass ◽

Atrial Appendage ◽

Control Group ◽

Preoperative Risk ◽

Off Pump ◽

History Of ◽

Pump Cabg

Abstract Objectives Left atrial appendage (LAA) amputation concomitant to coronary artery bypass grafting (CABG) has become an increasingly performed technique in patients with atrial fibrillation (AF) or with sinus rhythm and a CHA2DS2-VASc score ≥2. However, LAA amputation has come under suspicion to cause postoperative atrial fibrillation (POAF) due to left atrial (LA) dilation. This study aims to assess this assumption in patients undergoing CABG in off-pump technique with and without amputation of the LAA. Methods Patients who underwent isolated CABG in off-pump technique without history of AF were retrospectively examined. Cohorts were divided according to the concomitant execution of LAA amputation. LA volume was measured by transthoracic echocardiography and rhythm was analyzed by electrocardiography, medication protocol, and visit documentation. Propensity score (PS) matching was performed based on 20 preoperative risk variables to correct for selection bias. Results A total of 1,522 patients were enrolled, with 1,267 in the control group and 255 in the LAA amputation group. Occurrence of POAF was compared in 243 PS-matched patient pairs. Neither the unmatched cohort (odds ratio [OR] 0.82; 95% confidence interval or CI [0.61; 1.11], p = 0.19) nor the PS-matched cohort (OR 0.94; 95% CI [0.62; 1.41], p = 0.75) showed significant differences in POAF occurrence. Subgroup analysis of sex, use of β-blockers, pulmonary disease, ejection fraction, and CHA2DS2-VASc-Score also showed no tendencies. LA volume did not change significantly (p = 0.18, 95% CI [−0.29; 1.51]). Conclusion Surgical amputation of the LAA concomitant to CABG did not lead to LA dilation and has no significant impact on the occurrence of POAF.

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Abstract 240: Assessing the Lack of Appropriate Anticoagulation in Patients With Atrial Fibrillation - Implications for Cardiology Registry-Based Care

Circulation Cardiovascular Quality and Outcomes ◽

10.1161/hcq.13.suppl_1.240 ◽

2020 ◽

Vol 13 (Suppl_1) ◽

Author(s):

Danielle Daly ◽

Jennifer Searl Como ◽

Jason H Wasfy

Keyword(s):

Atrial Fibrillation ◽

Atrial Flutter ◽

Administrative Data ◽

Persistent Atrial Fibrillation ◽

Chronic Atrial Fibrillation ◽

Administrative Claims ◽

Quality Problem ◽

History Of ◽

Problem Lists ◽

Lost To Follow Up

Intro: Anticoagulation is indicated for many patients with atrial fibrillation (AF) for prevention of cardioembolic stroke, although national proportions of eligible patients receiving anticoagulation remain suboptimal. Automated and semi-automated quality improvement techniques including registries and population health coordinators may help identify and increase eligible patients to receive anticoagulation. Methods: We queried our electronic health record to identify patients without anticoagulation but with atrial fibrillation (as identified as either paroxysmal atrial fibrillation, persistent atrial fibrillation, chronic atrial fibrillation, typical atrial flutter, atypical atrial flutter, or unspecified atrial flutter) either on the problem list or as billed administrative claims between September 2016 - September 2019 in MGH outpatient cardiology clinics. All patients were participating in MGH cardiology, with their primary care based either within MGH or outside of MGH. Then, we conducted detailed chart review to calculate thromboembolic risk with respective CHADS-VASC score and confirmed that the patient was not receiving anticoagulation. A typology was developed as charts were reviewed to categorize reasons for lacking anticoagulation. These categories were grouped into broader categories representing a (1) potential quality problem or (2) appropriate lack of anticoagulation. Results: Of 100 patients, 59 were deemed to have a potential quality problem and 41 were deemed to have appropriate lack of anticoagulation. Of the patients with a potential quality problem, 11 have a CHADS VASC score of 1, 18 have a CHADS VASC score of 2, 6 have a CHADS VASC score of 3, 10 have a CHADS VASC score of 4, and 8 have a CHADS of 5, and 6 have a CHADS VASC of 6 or above. Additionally, 3 patients have been lost to follow up, 12 patients had presented with current symptoms of AF within the last year, and 44 patients exhibited acute history of AF symptoms. 41 patients did not present concern for multiple reasons including: CHADS VASC=0, deceased, patients declined medication, followed by outside cardiologist, technology and medication discrepancies, inaccurate administrative data for AF, and prior major bleeding. Conclusions: We found that most un-anticoagulated AF patients identified by administrative claims and EHR problem lists are likely eligible for anticoagulation. Of those, most have a history of paroxysmal AF. As such, registry-based strategies based on queries of past AF may improve rates of anticoagulation in this population. Since automated queries still detect many patients with contraindications such as bleeding or inaccurate administrative data, manual review of administrative queries is likely to be important in quality efforts for AF.

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Atrial Fibrillation Detection from Wrist Photoplethysmography Signals Using Smartwatches

Scientific Reports ◽

10.1038/s41598-019-49092-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 11

Author(s):

Syed Khairul Bashar ◽

Dong Han ◽

Shirin Hajeb-Mohammadalipour ◽

Eric Ding ◽

Cody Whitcomb ◽

...

Keyword(s):

Atrial Fibrillation ◽

Detection Algorithm ◽

Motion Artifacts ◽

False Alarms ◽

Time Frequency ◽

Non Invasive ◽

Accelerometer Signal ◽

Atrial Contraction ◽

Premature Atrial Contraction ◽

Sensitivity Specificity

Abstract Detection of atrial fibrillation (AF) from a wrist watch photoplethysmogram (PPG) signal is important because the wrist watch form factor enables long term continuous monitoring of arrhythmia in an easy and non-invasive manner. We have developed a novel method not only to detect AF from a smart wrist watch PPG signal, but also to determine whether the recorded PPG signal is corrupted by motion artifacts or not. We detect motion and noise artifacts based on the accelerometer signal and variable frequency complex demodulation based time-frequency analysis of the PPG signal. After that, we use the root mean square of successive differences and sample entropy, calculated from the beat-to-beat intervals of the PPG signal, to distinguish AF from normal rhythm. We then use a premature atrial contraction detection algorithm to have more accurate AF identification and to reduce false alarms. Two separate datasets have been used in this study to test the efficacy of the proposed method, which shows a combined sensitivity, specificity and accuracy of 98.18%, 97.43% and 97.54% across the datasets.

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Time-course of recovery of atrial contraction after cardioversion of chronic atrial fibrillation

Heart and Vessels ◽

10.1007/bf01744390 ◽

1993 ◽

Vol 8 (2) ◽

pp. 98-106 ◽

Cited By ~ 7

Author(s):

Hiroshi Miwa ◽

Michio Arakawa ◽

Kensaku Kagawa ◽

Toshiyuki Noda ◽

Kazuhiko Nishigaki ◽

...

Keyword(s):

Atrial Fibrillation ◽

Time Course ◽

Chronic Atrial Fibrillation ◽

Atrial Contraction

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Chronic atrial fibrillation in patients with paroxysmal atrial fibrillation, atrioventricular node ablation and pacemakers

EP Europace ◽

10.1053/eupc.1998.0009 ◽

1999 ◽

Vol 1 (1) ◽

pp. 30-34 ◽

Cited By ~ 10

Author(s):

J. M. McComb ◽

G. M. Gribbin

Keyword(s):

Atrial Fibrillation ◽

Multivariate Analysis ◽

Pacemaker Implantation ◽

Atrioventricular Node ◽

Chronic Atrial Fibrillation ◽

Atrial Arrhythmias ◽

Av Node ◽

Surface Ecg ◽

History Of ◽

Atrial Rhythm

Abstract Aims This study examined the factors associated with the development of chronic (or permanent) atrial fibrillation (AF) in patients who had undergone atrioventricular (AV) node ablation with permanent pacing because of paroxysmal AF. Methods A retrospective review of case notes of all 65 consecutive patients identified as having had paroxysmal atrial arrhythmias, AV node ablation and permanent pacemaker implantation was performed. Atrial rhythm was established from all pacing records and from the surface ECG. Treatment with anti-arrhythmic drugs and with warfarin was recorded. A multivariate analysis was undertaken, using atrial rhythm on final ECG and chronic AF as outcome measures. Results During a mean follow-up of 30 months, 42% of patients with paroxysmal AF had developed chronic AF. Multivariate analysis showed that increasing age, history of electrical cardioversion and VVI pacing all contributed to the development of chronic AF. 25/62 patients were taking warfarin, and four had had strokes (2·5%/year). Conclusions The majority of patients with paroxysmal atrial arrhythmias treated with AV node ablation and pacing develop chronic AF eventually. Stroke remains a risk, particularly in those who develop chronic AF.

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