bluuebunny/crossref_metadata_2025_split huggingface dataset:
P1887Development and validation of a novel premature ventricular contraction detector in an insertable cardiac monitor
Authors: Rajagopal G , Sarkar S , Reiland J , Koehler J , Lustgarten D L 
Published: October 2019

Abstract

Background
High premature ventricular contraction (PVC) burden may increase the risk of cardiac arrhythmias, PVC-induced cardiomyopathy and heart failure.

Purpose
We developed and validated an algorithm for continuous long-term monitoring of PVC burden in implantable loop recorders or insertable cardiac monitors (ICM).

Methods
The PVC algorithm uses long-short-long RR interval sequence and similarity and differences in r-wave morphology for three consecutive beats to detect the occurrence of a single PVC beat. Various threshold combinations were used for long-short-long RR interval sequence and degree of difference and similarity of R-wave morphology to be able to detect various types of PVCs including monomorphic, polymorphic, bigeminal, trigeminal, and interpolated PVCs. For example, a high degree of difference in R-wave morphology only required the short interval to be less than the longer interval by a smaller amount. The algorithm was designed with the intention to achieve minimum over reporting of PVC burden, i.e. maximum specificity. The algorithm was developed and validated using ECG strips stored in an ICM from real world patients. Gross, patient average and generalized estimating equation (GEE) estimates for sensitivity, specificity, positive and negative predictive value are reported.

Results
The PVC detection algorithm was developed using 87 2-minute ECG strips recorded by an ICM containing 2129 single PVC beats and 12,402 non-PVC beats to obtain a gross sensitivity and specificity of 75.9% and 98.8%. The validation data cohort consisted of 787 ICM recorded ECG strips 7–10 minutes in duration from 134 patients, providing over 460,000 beats of which 439,106 (94%) were normal beats, 8398 (2%) single PVC beats and 16,634 (4%) noisy beats. Couplets and triplets were excluded. Table 1 shows the performance results of the PVC detection algorithm in this validation set.
Performance of PVC detector Gross Patient average GEE (95% CI) Sensitivity 75.2% 69.9% 72.5% (65.8–78.3) Specificity 99.6% 99.4% 99.4% (99.2–99.6) Positive Predictive Value (PPV) 75.9% 40.6% 40.6% (33.6–48.0) Negative Predictive Value (NPV) 99.5% 99.6% 99.6% (99.3–99.7)

Conclusions
The PVC detection algorithm was able to achieve a high specificity, which ensures that 99.6% of the normal events are not incorrectly identified as PVCs, while detecting 75% of PVCs on a continuous long-term basis in insertable cardiac monitors. The accuracy of PVC burden estimates during continuous monitoring using this algorithm needs further validation using Holter studies.

Acknowledgement/Funding
Medtronic Plc
P1890Pioglitazone inhibits diabetes-induced atrial mitochondrial oxidative stress and improves mitochondrial biogenesis, dynamics and function through the PGC-1 signaling pathway
Authors: Liu T , Zhang Z , Zhang X , Meng L , Gong M , Li J , Qiu J , Suo Y , Liang X , Wang X , Jiang N , Tse G , Li G , Zhao Y 
Published: October 2019

Abstract

Background
Oxidative stress contributes to adverse atrial remodeling in diabetes mellitus. This can be prevented by the PPAR-γ agonist pioglitazone through its anti-oxidant and anti-inflammatory effects.

Purpose
In this study, the molecular mechanisms underlying these effects were investigated.

Methods
Rabbits were randomly divided into control (C), diabetic (DM), and pioglitazone-treated DM (Pio) groups. Echocardiographic, hemodynamic, electrophysiological, intracellular Ca2+ properties were measured. Serum PPAR-γ levels, serum and tissue oxidative stress and inflammatory markers, mitochondrial morphology, reactive oxygen species (ROS) production rate, respiratory function, and mitochondrial membrane potential (MMP) levels were measured. Protein expression of pro-fibrotic marker transforming growth factor β1 (TGF-β1), and the mitochondrial proteins (PGC-1α, fission and fusion-related proteins) were measured.

Results
Compared with controls, the DM group demonstrated larger left atrial diameter and fibrosis area associated with a higher incidence of inducible AF. Lower serum PPAR-γ level was associated with lower PGC-1α, higher NF-κB and higher TGF-β1 expression. Mn-SOD protein was not different but lower mitochondrial fission- and fusion-related proteins were detected. Mitochondrial swelling, higher mitochondrial ROS, lower respiratory control rate, lower MMP and higher intracellular Ca2+ transients were observed. In the Pio group, reversal of structural remodeling and lower inducible AF incidence were associated with higher PPAR-γ and PGC-1α. NF-κB and TGF-β1 were lower and biogenesis, fission and fusion-related protein were higher. Mitochondrial structure and function, and intracellular Ca2+ transients were improved. In HL-1 cell line, transfected with PGC-1α siRNA blunted the effect of pioglitazone on Mn-SOD protein expression and MMP collapse in H2O2-treated cells.

Conclusion
Diabetes mellitus induces adverse atrial structural and electrophysiological remodeling, abnormal Ca2+ handling and mitochondrial damage and dysfunction. Pioglitazone prevented these abnormalities through the PPAR-γ/PGC-1α pathway.

Acknowledgement/Funding
National Natural Science Foundation of China (No 81570298, 81270245, 30900618 to T.L.)
P1891CD8+CD28null T lymphocytes are associated with the development of atrial fibrillation after elective cardiac surgery
Authors: Kazem N , Sulzgruber P , Thaler B , Koller L , Pilz A , Fleck T , Laufer G , Steinlechner B , Wojta J , Niessner A 
Published: October 2019

Abstract

Background
Post-operative atrial fibrillation (POAF) is assumed as a complex and multifactorial interaction of different pathogenic factors. Data suggests an inflammatory process as a main trigger of this specific type of atrial fibrillation. CD8+ T lymphocytes that lack the surface protein CD28 were found to be crucially involved in chronic inflammatory processes within the cardiovascular system. Of utmost interest, these so called CD8+CD28null T cells are known to present with auto-aggressive behavior and deleterious cytotoxic effects on human tissue. Therefore, the impact of cellular immunity on the development of POAF was sought to assess.

Methods
To elucidate the impact of cellular immunity on the development of POAF, we prospectively enrolled 129 patients undergoing elective cardiac valve and/or coronary-artery-bypass-graft surgery. Fluorescein-activated cell sorting (FACS) was performed to investigate lymphocyte subsets. Patients were stratified in two subgroups according to patients developing POAF (n=60) and individuals free of POAF (n=69). Binary logistic regression analysis was performed to assess the impact of cellular immunity on the development of POAF.

Results
Comparing patients developing POAF to individuals free of POAF the fraction of CD8+ lymphocytes was significantly higher in individuals developing POAF (30.5% [POAF] vs. 25.7% [non-POAF]; p=0.021) Interestingly, the fraction of CD8+CD28nullT-lymphocytes was significantly higher in the POAF sub-group (66.7% [POAF] vs. 61.6% [non-POAF]; p=0.043). Binary logistic regression further proved that the fraction of CD8+CD28null T cells was a strong prognosticator for the development of POAF with a crude odds ratio per one standard deviation of 3.45 (95% CI 1.11–10.70; p=0.032). The prognostic potential remained stable after adjustment for potential confounders (age, male gender and type of surgery) within the multivariate model with an adjusted odds ratio per one standard deviation of 3.21 (95% CI 1.01–10.18; p=0.048).

Conclusion
We found that cytotoxic CD8+CD28null T lymphocytes proved to be a strong and independent predictor for the development of POAF after elective cardiac surgery. Our results potentially indicate an auto-immune impact of this preexisting, highly cytotoxic T cell subset in the pathogenesis of POAF.

Acknowledgement/Funding
Verein zur Förderung der Forschung – Atherosclerosis Thrombosis and Vascular Biology (Vienna, Austria)
P1892Asymmetric and symmetric dimethylarginine in atrial fibrillation progression and recurrence
Authors: Buettner P , Schwedhelm E , Hindricks G , Boeger R H , Thiele H , Kornej J 
Published: October 2019

Abstract

Background
Asymmetric and symmetric dimethylarginine (ADMA and SDMA) are post-translationally modified amino-acids that inhibit nitric oxide (NO) production and have been associated with cardiovascular events and death. Recently, an association of ADMA with atrial fibrillation (AF) incidence and prevalence has been described. In this study we analyzed the association of ADMA and SDMA with the progression and recurrence of AF.

Methods
In total, 254 patients (64±11 years, 67% males, BMI 29±8 kg/m2, 53% paroxysmal AF, 27% low voltage areas (LVA)) undergoing first AF ablation were included into analyses. LVA were determined using high-density maps and defined as <0.5 mV. AF progression was defined as paroxysmal AF (PAF) with/without LVA and continuous AF (CAF) with/without LVA. AF recurrences were defined as any atrial arrhythmia occurring after ablation 3 to 18 months. Blood plasma samples were collected before catheter ablation and at follow-up. ADMA and SDMA were measured in plasma samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Results
While no differences were detected for ADMA, the SDMA plasma concentrations were significantly higher in AF patients with CAF and LVA (n=50, median 0.587 μmol/L; inter quartile range (IQR) 0.514–0.689 μmol/L, p=0.029) compared to PAF without LVA (n=90, 0.532; IQR 0.467–0.640 μmol/L), PAF with LVA (n=12, 0.494; IQR 0.444–0.615 μmol/L) and CAF without LVA (n=86, 0.537; IQR 0.465–0.633) μmol/L. There were 28 patients with available follow-up data and 18 patients (64%) had sinus rhythm. These patients had significantly lower SDMA plasma concentrations (0.458; IQR 0.405–0.517 vs. 0.507; IQR 0.449–0.604 μmol/L; p<0.001) at follow-up, while baseline SDMA levels were similar compared with patients with AF recurrence (p=0.944). Furthermore, patients without recurrence had significantly lower ADMA plasma concentrations (0.466; IQR 0.422–0.520 vs. 0.545; IQR 0.456–0.608 μmol/L, p<0.03) at follow-up, while baseline ADMA levels were similar independent on rhythm outcome (p=0.759).

Conclusion
Increased SDMA levels correlated with AF progression phenotypes characterized by persistent AF and the presence of LVA. In patients without arrhythmia recurrences ADMA and SDMA levels decreased.
P1912Incidence of silent cerebral thromboembolism in catheter ablation for atrial fibrillation under the use of DOAC: Comparison of cryoballoon versus radiofrequency ablation system
Authors: Aso A , Nakamura T , Fukuyama Y , Fukuda S , Sibao K , Araki M , Meno K , Yakebe D , Omura S , Mori T , Takenaka K , Murasato Y 
Published: October 2019

Abstract

Background
Silent cerebral thromboembolism (CE) in catheter ablation for atrial fibrillation (AF) is not rare. Prior our study has reported lower incidence of silent CE in AF radiofrequency (RF) ablation using irrigated-tip catheter than conventional 4 or 8mm-tip catheter. In addition, the incidence of silent CE in AF ablation under direct oral anticoagulant (DOAC) was equivalent to continuous therapeutic warfarin. Recently pulmonary vein isolation (PVI) using cryoballoon (CB) has emerged as an alternative technique to RF ablation because some studies suggested that the efficacy for PVI by CB was equivalent to RF. However, incidence of silent CE in CB ablation under the use of DOAC is unknown.

Objective
We aimed to evaluate the incidence new silent CE in AF ablation using CB system compared with irrigated RF system under the use of DOAC.

Methods
322 consecutive patients with paroxysmal or persistent AF (155 using CB system, 167 using RF system) who underwent the first AF ablation were taking DOAC more than one month prior to the procedure. Throughout AF ablation procedure, heparin was administered to maintain activated clotting time (ACT) between 300 and 400 seconds. Head MRI was performed in all patients within 24 hours after the procedure.

Results
In 14 (9.0%) patients using CB and in 20 (12.0%) patients using RF, head MRI showed new embolic lesions without neurological symptom (P=0.469). Although the amount of heparin during the procedure in group CB was significantly less than in group RF (16134±3125 U vs. 18689±5222 U; P<0.0001), amount of heparin per hour in group CB was more than in group RF (8335±1955 U/h vs. 6143±1918 U/h; P<0.0001) because procedure time in group CB was shorter than in group RF (121.3±34.1 min vs. 189.5±47.4 min; P<0.0001). Mean ACT in both groups was maintained high level (3367±25.3 sec. vs. 338.6±23.5 sec.; P=0.479). In univariate analysis, minimum ACT during procedure, as before puncture of interatrial septum, were significantly correlated with the incidence of silent CE (P=0.027).

Conclusions
The incidence of silent CE in AF ablation using CB system was lower than RF system, although it was not a significant difference between different ablation techniques for AF. In AF ablation, the use of CB may be preferred rather than RF as ablation system in regard to risk reduction of thromboembolic complications.
P1913Implantable Loop Recorder Detected Pattern of Atrial Fibrillation Recurrence Following Cryoballoon Pulmonary Vein Isolation in Patients with Persistent Atrial Fibrillation
Authors: Musat D , Milstein N , Shaw R , Bhatt A , Preminger M , Sichrovsky T , Pistilli C , Mittal S 
Published: October 2019

Abstract

Background
Cryoballoon (CB) pulmonary vein isolation (PVI) is increasingly being used in patients (pts) with persistent atrial fibrillation (AF). However, there are limited data about the pattern of atrial fibrillation (AF) recurrence in these pts.

Objective
To assess, using an implantable loop recorder (ILR), the patterns of AF recurrence following CB PVI in pts with persistent atrial fibrillation.

Methods
We enrolled consecutive pts with persistent AF ablation undergoing their first CB ablation. Other cavotricuspid isthmus ablation when indicated, no other ablation was performed. A Reveal LINQ ILR (Medtronic) was implanted <3 months following ablation; all pts had a minimum of 1-year follow-up. The recurrence of any atrial arrhythmia was determined and adjudicated; 4 distinct AF patterns were characterized (Figure).

Results
We studied 64 pts (66±9 years; 50 [78%] male; CHA2DS2-VASc 2.6±1.9) with persistent AF; 52 (81%) pts were on an antiarrhythmic drug (AAD) peri-ablation. During 803±361 days of follow-up, 33 (52%) pts had their 1st AF recurrence 91–365 days post-ablation and another 17 (27%) pts had their 1st AF recurrence >365 days post-ablation. No AF was seen in 14 (31%) pts. Most pts (33 of 50, 66%) with AF recurrence presented with 1 of 3 distinct patterns of paroxysmal AF (Figure), which ranged from 22 min to 124 hours. In 2/3 of these pts, all AF recurrences lasted <24 hours. Only 17 (34%) pts recurred with persistent AF.

Conclusion
Following single CB PVI, most pts with persistent AF remained free of persistent AF during long-term follow-up. Most pts with recurrent AF have 1 of 3 distinct patterns with episodes commonly last <24 hours. These data suggest that CB PVI ablation may halt AF progression in pts initially presenting with persistent AF.
P1914Relationship between myocardial injury, inflammation and early, late recurrence after pulmonary vein isolation may be different between radiofrequency catheter ablation and cryoballoon ablation
Authors: Yano M , Nishino M , Nakamura H , Matsuhiro Y , Yasumura K , Yasumoto K , Tanaka A , Nakamura D , Matsunaga-Lee Y , Yamato M , Egami Y , Shutta R , Tanouchi J 
Published: October 2019

Abstract

Background
High sensitive cardiac troponin I (hs-TnI), subunit of cardiac troponin complex, is a sensitive and specific marker of myocardium injury as troponin T. Several studies showed hs-TnI was associated with worse cardiovascular outcomes but relationship between serum hs-TnI level in patients with atrial fibrillation (AF) after pulmonary vein isolation (PVI) and AF recurrence remains unclear.

Methods
We enrolled 444 consecutive AF patients who underwent PVI from May 2017 to September 2018. We investigated the difference of relationship between serum hs-TnI, inflammation markers at 48 hours after PVI and early or late recurrence of AF (ERAF, <3 months and LRAF, during 1 year after PVI in patients with AF) between radiofrequency ablation (RFA) group and cryoballoon ablation (CBA) group.

Results
RFA and CBA were performed in 328 and 116 patients, respectively. There were no significant differences in patient characteristics between RFA group and CBA group. Serum hs-TnI in RFA group was significantly lower than in CBA group (1.93 ng/ml±3.28 vs 5.08 ng/ml±4.29, p<0.001), while hs-CRP was significantly higher in RFA group than CB group (1.97±2.38 mg/dl vs 1.10±0.84 mg/dl, p<0.001). The incidence of ERAF was similar between the two groups (RFA group: 26.8% and CBA group: 21.6%, p=0.262). There was no significant difference of hs-TnI and hs-CRP between patients with ERAF and without ERAF (table). In 213 patients who were followed during 1 year (PVIs were performed from May 2017 to January 2018, RFA 149 and CBA 64 patients), there was no significant association between hs-TnI, hs-CRP and incidence of LRAF (table).
TnI and CRP between RFA and CBA RFA (n=328) CBA (n=116) P value hs-TnI 1.93±3.28 5.08±4.29 <0.001 hs-CRP 1.97±2.38 1.10±0.84 <0.001 3 months follow-up RFA (n=328) CBA (n=116) ERAF (+) ERAF (−) P value ERAF (+) ERAF (−) P value hs-TnI 1.68±1.90 2.02±3.66 0.410 5.03±3.17 5.10±4.56 0.943 hs-CRP 2.23±2.65 1.88±2.27 0.238 1.01±0.84 1.13±0.85 0.524 1 year follow-up RFA (n=149) CBA (n=64) LRAF (+) LRAF (−) P value LRAF (+) LRAF(−) P value hs-TnI 1.61±1.77 1.87±2.69 0.570 4.71±2.14 5.60±5.69 0.664 hs-CRP 2.18±2.24 1.92±2.24 0.550 1.12±0.64 1.12±0.98 0.991

Conclusion
CBA may cause more myocardial injury than RFA, on the contrary RFA may cause more inflammation than CBA. These markers did not affect ERAF and LRAF after PVI.
P1922Ablation index-guided ablation versus second-generation cryoballoon for first pulmonary vein isolation in atrial fibrillation
Authors: Felix-Oliveira A , Carmo J , Carmo P , Cavaco D , Fontes A , Rodrigues G , Matos D , Moscoso Costa F , Bello Morgado F , Adragao P , Carvalho S 
Published: October 2019

Abstract

Background
In a recent trial, cryoballoon (CB) ablation was non-inferior to radiofrequency ablation regarding effectiveness in atrial fibrillation (AF). Ablation index (AI) provides a more accurate estimation of ablation quality using three variables: power delivered with time, contact force and catheter stability. The additional benefit of AI-guided ablation versus CB ablation is unknown.

Objective
To compare AI-guided ablation and CB ablation for first pulmonary vein isolation (PVI) in patients with AF.

Methods
We assessed 141 patients (62±12 years old, 76 men and 126 paroxysmal AF) with drug refractory symptomatic AF submitted to AI-guided PVI or second-generation CB catheter. Endpoint was AF/AT/AFL recurrence after a 3-month blanking period with a minimum follow-up of 6 months. Cox regression was used to assess the relationship between type of ablation and AF recurrence.

Results
Fifty-seven patients underwent AI-guided PVI and 84 patients underwent CB ablation. The baseline characteristics are described in table 1. Procedure duration was significantly higher in AI group (150 vs 111 min, P<0.001) although requiring significant less fluoroscopy time (5 min vs 20 min; P<0.001). There was a transient phrenic nerve palsy in CB group and a cardiac tamponade in AI group. During a mean follow-up of 10±3 months there were 23 recurrences (27%) in CB group vs 7 recurrences (12%) in AI group (log rank 0.042) (Fig B). When adjusted for CHA2DS2-VASc score, left atrium diameter (mm) and type of AF (Cox regression), there was lower arrhythmia recurrence in AI group (HR 0.42; 95% CI 0.18–0.99; p=0.047).
Table 1. Baseline characteristics

Conclusion
In this analysis, AI-guided ablation was associated with lower arrhythmia recurrence when compared with CB ablation. This hypothesis should be further evaluated in a prospective randomized trial.
P1925Machine learning versus classic electrocardiographic criteria for left ventricular hypertrophy in a young pre-participation cohort: results from the SAFE protocol study
Authors: Sng G , Lim D Y Z , Sia C H , Lee J S W , Shen X Y , Lee E C Y , Dalakoti M , Wang K J , Kwan C K W , Chow W E , Tan R S , Lam C S P , Chua T , Yeo T J , Chong D T T 
Published: October 2019

Abstract

Background/Introduction
Classic electrocardiographic (ECG) criteria for left ventricular hypertrophy (LVH) have been well studied in Western populations, particularly in hypertensive patients. However, their utility in Asian populations is not well studied, and their applicability to young pre-participation cohorts is unclear. We sought to evaluate the performance of classical criteria against that of machine learning models.

Aims
We sought to evaluate the performance of classical criteria against the performance of novel machine learning models in the identification of LVH.

Methodology
Between November 2009 and December 2014, pre-participation screening ECG and subsequent echocardiographic data was collected from 13,954 males aged 16 to 22, who reported for medical screening prior to military conscription.
Final diagnosis of LVH was made on echocardiography, with LVH defined as a left ventricular mass index >115g/m2. The continuous and binary forms of classical criteria were compared against machine learning models using receiver-operating characteristics (ROC) curve analysis. An 80:20 split was used to divide the data into training and test sets for the machine learning models, and three fold cross validation was used in training the models. We also compared the important variables identified by machine learning models with the input variables of classical criteria.

Results
Prevalence of echocardiographic LVH in this population was 0.91% (127 cases). Classical ECG criteria had poor performance in predicting LVH, with the best predictions achieved by the continuous Sokolow-Lyon (AUC = 0.63, 95% CI = 0.58–0.68) and the continuous Modified Cornell (AUC = 0.63, 95% CI = 0.58–0.68). Machine learning methods achieved superior performance – Random Forest (AUC = 0.74, 95% CI = 0.66–0.82), Gradient Boosting Machines (AUC = 0.70, 95% CI = 0.61–0.79), GLMNet (AUC = 0.78, 95% CI = 0.70–0.86). Novel and less recognized ECG parameters identified by the machine learning models as being predictive of LVH included mean QT interval, mean QRS interval, R in V4, and R in I.
ROC curves of models studies

Conclusion
The prevalence of LVH in our population is lower than that previously reported in other similar populations. Classical ECG criteria perform poorly in this context. Machine learning methods show superior predictive performance and demonstrate non-traditional predictors of LVH from ECG data. Further research is required to improve the predictive ability of machine learning models, and to understand the underlying pathology of the novel ECG predictors identified.