Pulsed Field or Conventional Thermal Ablation for Paroxysmal Atrial Fibrillation

BACKGROUND

Catheter-based pulmonary vein isolation is an effective treatment for paroxysmal atrial fibrillation. Pulsed field ablation, which delivers microsecond high-voltage electrical fields, may limit damage to tissues outside the myocardium. The efficacy and safety of pulsed field ablation as compared with conventional thermal ablation are not known.

METHODS

In this randomized, single-blind, noninferiority trial, we assigned patients with drug-refractory paroxysmal atrial fibrillation in a 1:1 ratio to undergo pulsed field ablation or conventional radiofrequency or cryoballoon ablation. The primary efficacy end point was freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation. The primary safety end point included acute and chronic device- and procedure-related serious adverse events.

RESULTS

A total of 305 patients were assigned to undergo pulsed field ablation, and 302 were assigned to undergo thermal ablation. At 1 year, the primary efficacy end point was met (i.e., no events occurred) in 204 patients (estimated probability, 73.3%) who underwent pulsed field ablation and 194 patients (estimated probability, 71.3%) who underwent thermal ablation (between-group difference, 2.0 percentage points; 95% Bayesian credible interval, -5.2 to 9.2; posterior probability of noninferiority, >0.999). Primary safety end-point events occurred in 6 patients (estimated incidence, 2.1%) who underwent pulsed field ablation and 4 patients (estimated incidence, 1.5%) who underwent thermal ablation (between-group difference, 0.6 percentage points; 95% Bayesian credible interval, -1.5 to 2.8; posterior probability of noninferiority, >0.999).

CONCLUSIONS

Among patients with paroxysmal atrial fibrillation receiving a catheter-based therapy, pulsed field ablation was noninferior to conventional thermal ablation with respect to freedom from a composite of initial procedural failure, documented atrial tachyarrhythmia after a 3-month blanking period, antiarrhythmic drug use, cardioversion, or repeat ablation and with respect to device- and procedure-related serious adverse events at 1 year. (Funded by Farapulse-Boston Scientific; ADVENT ClinicalTrials.gov number, NCT04612244.).

Expert-enhanced machine learning for cardiac arrhythmia classification

We propose a new method for the classification task of distinguishing atrial fibrillation (AFib) from regular atrial tachycardias including atrial flutter (AFlu) based on a surface electrocardiogram (ECG). Recently, many approaches for an automatic classification of cardiac arrhythmia were proposed and to our knowledge none of them can distinguish between these two. We discuss reasons why deep learning may not yield satisfactory results for this task. We generate new and clinically interpretable features using mathematical optimization for subsequent use within a machine learning (ML) model. These features are generated from the same input data by solving an additional regression problem with complicated combinatorial substructures. The resultant can be seen as a novel machine learning model that incorporates expert knowledge on the pathophysiology of atrial flutter. Our approach achieves an unprecedented accuracy of 82.84% and an area under the receiver operating characteristic (ROC) curve of 0.9, which classifies as "excellent" according to the classification indicator of diagnostic tests. One additional advantage of our approach is the inherent interpretability of the classification results. Our features give insight into a possibly occurring multilevel atrioventricular blocking mechanism, which may improve treatment decisions beyond the classification itself. Our research ideally complements existing textbook cardiac arrhythmia classification methods, which cannot provide a classification for the important case of AFib↔AFlu. The main contribution is the successful use of a novel mathematical model for multilevel atrioventricular block and optimization-driven inverse simulation to enhance machine learning for classification of the arguably most difficult cases in cardiac arrhythmia. A tailored Branch-and-Bound algorithm was implemented for the domain knowledge part, while standard algorithms such as Adam could be used for training.

Formula to estimate left atrial volume using antero-posterior diameter in patients with catheter ablation of atrial fibrillation

In patients undergoing atrial fibrillation (AF) ablation, an enlarged left atrium (LA) is a predictor of procedural failure as well as AF recurrence on long term. The most used method to assess LA size is echocardiography-measured diameter, but the most accurate remains computed tomography (CT).The aim of our study was to determine whether there is an association between left atrial diameters measured in echocardiography and the left atrial volume determined by CT in patients who underwent AF ablation.The study included 93 patients, of whom 60 (64.5%) were men and 64 (68.8%) had paroxysmal AF, who underwent AF catheter ablation between January 2018 and June 2019. Left atrial diameters in echocardiography were measured from the long axis parasternal view and the LA volume in CT was measured on reconstructed three-dimensional images.The LA in echocardiography had an antero-posterior (AP) diameter of 45.0 ± 6 mm (median 45; Inter Quartile Range [IQR] 41-49, range 25-73 mm), longitudinal diameter of 67.5 ± 9.4 (median 66; IQR 56-88, range 52-100 mm), and transversal diameter of 42 ± 8.9 mm (IQR 30-59, range 23-64.5 mm). The volume in CT was 123 ± 29.4 mL (median 118; IQR 103-160; range 86-194 mL). We found a significant correlation (r = 0.702; P < .05) between the AP diameter and the LA volume. The formula according to which the AP diameter of the LA can predict the volume was: LA volume = AP diam3 + 45 mL.There is a clear association between the left atrial AP diameter measured on echocardiography and the volume measured on CT. The AP diameter might be sufficient to determine the increase in the volume of the atrium and predict cardiovascular outcomes.

Subtype of atrial fibrillation and the outcome of transcatheter aortic valve replacement: The FinnValve Study

Whether the subtype of atrial fibrillation affects outcomes after transcatheter aortic valve replacement for aortic stenosis is unclear. The nationwide FinnValve registry included 2130 patients who underwent primary after transcatheter aortic valve replacement for aortic stenosis during 2008-2017. Altogether, 281 (13.2%) patients had pre-existing paroxysmal atrial fibrillation, 651 (30.6%) had pre-existing non-paroxysmal atrial fibrillation and 160 (7.5%) were diagnosed with new-onset atrial fibrillation during the index hospitalization. The median follow-up was 2.4 (interquartile range: 1.6-3.8) years. Paroxysmal atrial fibrillation did not affect 30-day or overall mortality (p-values >0.05). Non-paroxysmal atrial fibrillation demonstrated an increased risk of overall mortality (hazard ratio: 1.61, 95% confidence interval: 1.35-1.92; p<0.001), but not 30-day mortality (p = 0.084). New-onset atrial fibrillation demonstrated significantly increased 30-day mortality (hazard ratio: 2.76, 95% confidence interval: 1.25-6.09; p = 0.010) and overall mortality (hazard ratio: 1.68, 95% confidence interval: 1.29-2.19; p<0.001). The incidence of early or late stroke did not differ between atrial fibrillation subtypes (p-values >0.05). In conclusion, non-paroxysmal atrial fibrillation and new-onset atrial fibrillation are associated with increased mortality after transcatheter aortic valve replacement for aortic stenosis, whereas paroxysmal atrial fibrillation has no effect on mortality. These findings suggest that non-paroxysmal atrial fibrillation rather than paroxysmal atrial fibrillation may be associated with structural cardiac damage which is of prognostic significance in patients with aortic stenosis undergoing transcatheter aortic valve replacement.

Analysis of Relevant Features from Photoplethysmographic Signals for Atrial Fibrillation Classification

Atrial Fibrillation (AF) is the most common cardiac arrhythmia found in clinical practice. It affects an estimated 33.5 million people, representing approximately 0.5% of the world's population. Electrocardiogram (ECG) is the main diagnostic criterion for AF. Recently, photoplethysmography (PPG) has emerged as a simple and portable alternative for AF detection. However, it is not completely clear which are the most important features of the PPG signal to perform this process. The objective of this paper is to determine which are the most relevant features for PPG signal analysis in the detection of AF. This study is divided into two stages: (a) a systematic review carried out following the Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies (PRISMA-DTA) statement in six databases, in order to identify the features of the PPG signal reported in the literature for the detection of AF, and (b) an experimental evaluation of them, using machine learning, in order to determine which have the greatest influence on the process of detecting AF. Forty-four features were found when analyzing the signal in the time, frequency, or time-frequency domains. From those 44 features, 27 were implemented, and through machine learning, it was found that only 11 are relevant in the detection process. An algorithm was developed for the detection of AF based on these 11 features, which obtained an optimal performance in terms of sensitivity (98.43%), specificity (99.52%), and accuracy (98.97%).

A retrospective cohort study of oral anticoagulant treatment in patients with acute coronary syndrome and atrial fibrillation

OBJECTIVE

To examine the real-world patterns of oral anticoagulant (OAC) therapy in patients with acute coronary syndrome (ACS) and atrial fibrillation (AF) in Southern China undergoing percutaneous coronary intervention (PCI) and determine the clinical characteristics associated with OAC prescription.

DESIGN

A retrospective cohort study.

SETTING

This study was conducted in the Shunde Hospital, Southern Medical University and the second hospital of Zhaoqing, China, from January 2013 to 31 December 2018.

PARTICIPANTS

Patients were aged ≥18 years, hospitalised for ACS and received PCI treatment.

OUTCOME MEASURES

AF was diagnosed based on an ECG recording or a Holter monitor. Prescription of OACs and antiplatelets were determined from the discharge medication list.

RESULTS

A total of 3612 patients with ACS were included: 286 (7.9%) were diagnosed with AF, including 45 (1.2%) with paroxysmal AF, 227 (6.3%) with persistent/permanent AF and 14 (0.4%) with unclassified AF. Although 95.5% of patients with AF were at high risk (CHA₂DS₂-VASc score ≥2) of stroke, only 21.7% of them were discharged on OACs (10.5% received warfarin and 11.2% received non-vitamin K antagonist OACs). Patients with pre-admission use of OAC, a HAS-BLED score <3, with persistent/permanent AF were more likely to receive OAC treatment at discharge.

CONCLUSION

We found that approximately 8% of patients who underwent PCI during ACS hospitalisation also demonstrated AF. Anticoagulant therapy was greatly underused. Patients with paroxysmal AF and an increased risk of bleeding were less likely to receive anticoagulant treatment. Further efforts should be made to increase the adherence to guideline recommendations for OACs.

Cardiovascular Disease Update: Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. The prevalence increases with age, especially in the seventh and eighth decades of life. AF also is associated with multiple risk factors and conditions that are managed commonly in family medicine settings, such as hypertension and diabetes. Rhythm control and rate control are primarily equivalent for mortality rate, but patients treated for rhythm control have more hospitalizations; however, rhythm control may be a viable option for select patients. Beta blockers and nondihydropyridine calcium channel blockers can be used to achieve rate control. Pharmacotherapy or electrical cardioversion can be used to achieve rhythm control, and antiarrhythmic drugs are used to maintain sinus rhythm. Catheter ablation is an option for symptomatic patients whose AF is refractory to standard treatment. The CHA2DS2-VASc score should be used to predict the risk of stroke for patients with AF. Patients with nonvalvular AF and a history of stroke or transient ischemic attack or CHA2DS2-VASc scores of 2 or greater should be treated with warfarin or novel oral anticoagulants. Patients with valvular AF should be treated with warfarin.

Use of self-gated radial cardiovascular magnetic resonance to detect and classify arrhythmias (atrial fibrillation and premature ventricular contraction)

BACKGROUND

Arrhythmia can significantly alter the image quality of cardiovascular magnetic resonance (CMR); automatic detection and sorting of the most frequent types of arrhythmias during the CMR acquisition could potentially improve image quality. New CMR techniques, such as non-Cartesian CMR, can allow self-gating: from cardiac motion-related signal changes, we can detect cardiac cycles without an electrocardiogram. We can further use this data to obtain a surrogate for RR intervals (valley intervals: VV). Our purpose was to evaluate the feasibility of an automated method for classification of non-arrhythmic (NA) (regular cycles) and arrhythmic patients (A) (irregular cycles), and for sorting of common arrhythmia patterns between atrial fibrillation (AF) and premature ventricular contraction (PVC), using the cardiac motion-related signal obtained during self-gated free-breathing radial cardiac cine CMR with compressed sensing reconstruction (XD-GRASP).

METHODS

One hundred eleven patients underwent cardiac XD-GRASP CMR between October 2015 and February 2016; 33 were included for retrospective analysis with the proposed method (6 AF, 8 PVC, 19 NA; by recent ECG). We analyzed the VV, using pooled statistics (histograms) and sequential analysis (Poincaré plots), including the median (medVV), the weighted mean (meanVV), the total number of VV values (VVval), and the total range (VVTR) and half range (VVHR) of the cumulative frequency distribution of VV, including the median to half range (medVV/VVHR) and the half range to total range (VVHR/VVTR) ratios. We designed a simple algorithm for using the VV results to differentiate A from NA, and AF from PVC.

RESULTS

Between NA and A, meanVV, VVval, VVTR, VVHR, medVV/VVHR and VVHR/VVTR ratios were significantly different (p values = 0.00014, 0.0027, 0.000028, 5×10-9, 0.002, respectively). Between AF and PVC, meanVV, VVval and medVV/VVHR ratio were significantly different (p values = 0.018, 0.007, 0.044, respectively). Using our algorithm, sensitivity, specificity, and accuracy were 93 %, 95 % and 94 % to discriminate between NA and A, and 83 %, 71 %, and 77 % to discriminate between AF and PVC, respectively; areas under the ROC curve were 0.93 and 0.89.

CONCLUSIONS

Our study shows we can reliably detect arrhythmias and differentiate AF from PVC, using self-gated cardiac cine XD-GRASP CMR.

Pharmacotherapy of Atrial Fibrillation

Atrial fibrillation is the most common sustained arrhythmia of clinical significance. Its prevalence rises with age. It is a significant cause of thromboembolic phenomena. We describe briefly the etiology and classification of atrial fibrillation, the risk factors for thromboembolism and stroke associated with it, the indications for hospitalization, and the therapeutic goal. We discuss in depth the management strategies for such patients and compare the impact of rate versus rhythm control in reducing morbidity and mortality attributed to arrhythmia, in light of past and present trials. A brief overview of the drugs used in the management of atrial fibrillation, their pharmacology and dosage, their effects and use in rhythm versus rate control with important side effects are also included. Finally, the prevention and treatment of thromboembolism in patients with atrial fibrillation, an important aspect of therapy, is revisited in light of recent advances.

Classification of persistent and long-standing persistent atrial fibrillation by means of surface electrocardiograms

Atrial fibrillation, which is the most common cardiac arrhythmia, is typically classified into four clinical subtypes: paroxysmal, persistent, long-standing persistent and permanent. The ability to distinguish between them is of crucial significance in choosing the most suitable therapy for each patient. Nevertheless, classification is currently established once the natural history of the arrhythmia has been disclosed as it is not possible to make an early differentiation. This paper presents a novel method to discriminate persistent and long-standing atrial fibrillation patients by means of a time-frequency analysis of the surface electrocardiogram. Classification results provide approximately 75% accuracy when evaluating ECGs of consecutive unselected patients from a tertiary center and higher than 80% when patients are not under antiarrhythmic treatment or do not have structural heart disease (76% sensitivity and 88% specificity). Moreover, to our knowledge, this is the first study that discriminates between persistent and long-standing persistent subtypes in a heterogeneous population sample and without discontinuing antiarrhythmic therapy to patients. Thus, it can help clinicians to address the most suitable therapeutic approach for each patient.

Dietary Fat Intake Is Differentially Associated with Risk of Paroxysmal Compared with Sustained Atrial Fibrillation in Women

BACKGROUND

Dietary fats have effects on biological pathways that may influence the development and maintenance of atrial fibrillation (AF). However, associations between n-3 (ω-3) polyunsaturated fatty acids and AF are inconsistent, and data on other dietary fats and AF risk are sparse.

OBJECTIVES

We examined the association between dietary fatty acid (FA) subclasses and risk of incident AF and explored whether these associations differed for sustained and paroxysmal AF.

METHODS

We conducted a prospective cohort study in 33,665 women ≥45 y old without cardiovascular disease (CVD) and AF at baseline in 1993. Fat intake was estimated from food frequency questionnaires at baseline and in 2004. Incident AF was confirmed by medical records through October 2013. AF patterns were classified according to the most sustained form of AF within 2 y of diagnosis. Cox proportional hazards models with the use of a competing risk model approach estimated the RR.

RESULTS

Over 19.2 y, 1441 cases of incident AF (929 paroxysmal and 467 persistent/chronic) were confirmed. Intakes of total fat and FA subclasses were not associated with risk of AF. Saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were differentially associated with AF patterns. The RR for a 5% increment of energy from SFAs was 1.47 (95% CI: 1.04, 2.09) for persistent/chronic and 0.85 (95% CI: 0.66, 1.08) for paroxysmal AF (P-difference = 0.01). For MUFAs, the RR for a 5% increment was 0.67 (95% CI: 0.46, 0.98) for persistent/chronic and 1.03 (95% CI: 0.78, 1.34) for paroxysmal AF, although the difference between patterns was not significant (P-difference = 0.07).

CONCLUSIONS

Dietary fat was not associated with risk of incident AF in women without established CVD or AF. High SFA and low MUFA intakes were associated with greater risk of persistent or chronic, but not paroxysmal, AF. Improving dietary fat quality may play a role in the prevention of sustained forms of AF. The Women's Health Study was registered at clinicaltrials.gov as NCT00000479.

Application of higher order spectra for accurate delineation of atrial arrhythmia

The electrocardiogram (ECG) is being commonly used as a diagnostic tool to distinguish different types of atrial tachyarrhythmias. The inherent complexity and mechanistic and clinical inter-relationships often brings about diagnostic difficulties to treating physicians and primary health care professionals creating frequent misdiagnoses and cross classifications using visual criteria. The current paper presents a methodology for ECG based pattern analysis for detection of atrial flutter, atrial fibrillation and normal sinus rhythm beats. ECG is an inherently non-linear and non-stationary signal; its variation may contain indicators of current disease, or warnings about impending cardiac diseases. Routinely used time domain and frequency domain methods will not be able to capture the hidden information present in the ECG beats. In the present study, we have used non-linear features of higher order spectra (HOS) to differentiate the normal, atrial fibrillation and atrial flutter ECG beats. The bispectrum features were subjected to independent component analysis (ICA) for data reduction. The ICA coefficients were subsequently subjected to K-nearest-neighbor (KNN), classification and regression tree (CART) and neural network (NN) classifiers to evaluate the best automated classifier. We have obtained an average accuracy of 97.65%, sensitivity and specificity of 98.75% and 99.53% respectively using ten-fold cross validation. Overall, the results show that application of higher order spectra statistics is useful for the classification of atrial tachyarrhythmias with reasonably high accuracies. Further validation of the proposed technique will yield acceptable results for clinical implementation.

Optimization of novel spectral estimator for fractionated electrogram analysis is helpful to discern atrial fibrillation type

INTRODUCTION

Paroxysmal versus persistent atrial fibrillation (AF) can be distinguished based on differences in the spectral parameters of fractionated atrial electrograms. Maximization of these differences would improve characterization of the arrhythmogenic substrate. A novel spectral estimator (NSE) has been shown previously to provide greater distinction in AF spectral parameters as compared with the Fourier transform estimator. Herein, it is described how the differences in NSE spectral parameters can be further improved.

METHOD

In 10 persistent and 9 paroxysmal AF patients undergoing electrophysiologic study, fractionated electrograms were acquired from the distal bipolar ablation electrode. A total of 204 electrograms were recorded from the pulmonary vein (PV) antra and from the anterior and posterior left atrial free wall. The following spectral parameters were measured: the dominant frequency (DF), which reflects local activation rate, the DF amplitude (DA), and the mean spectral profile (MP), which represents background electrical activity. To optimize differences in parameters between paroxysmal versus persistent AF patients, the NSE was varied by selectively removing subharmonics, using a threshold. The threshold was altered in steps to determine the optimal subharmonics removal.

RESULTS

At the optimal threshold level, mean differences in persistent versus paroxysmal AF spectral parameters were: ΔDA=+0.371 mV, ΔDF=+0.737 Hz, and ΔMP=-0.096 mV. When subharmonics were not removed, the differences were substantially less: ΔDA=+0.301 mV, ΔDF=+0.699 Hz, and ΔMP=-0.063 mV.

CONCLUSIONS

NSE optimization produces greater spectral parameter difference between persistent versus paroxysmal AF data. Quantifying spectral parameter differences can be assistive in characterizing the arrhythmogenic substrate.

[Atrial fibrillation: recent progress]

Atrial fibrillation is the most common cardiac arrhythmia. Pharmacological treatment plays still an important role in the management of this disease. However, pulmonary vein isolation techniques are more and more important due to the high rate of recurrences and many side effects associated with antiarrhythmic drugs. This article is focused on the main changes that are important for the general practitioner in his daily clinical practice.

[Perioperative management of atrial fibrillation]

Atrial fibrillation is a frequent complication in the perioperative period. When it appears there is an increased risk of perioperative morbidity due to stroke, thromboembolism, cardiac arrest, myocardial infarction, anticoagulation haemorrhage, and hospital readmissions. The current article focuses on the recommendations for the management of perioperative atrial fibrillation based on the latest Clinical Practice Guidelines on atrial fibrillation by the European Society of Cardiology and the Spanish Society of Cardiology. This article pays special attention to the preoperative management, as well as to the acute perioperative episode. For this reason, the latest recommendations for the control of cardiac frequency, antiarrhythmic treatment and anticoagulation are included.

Neural network and wavelet average framing percentage energy for atrial fibrillation classification

ECG signals are an important source of information in the diagnosis of atrial conduction pathology. Nevertheless, diagnosis by visual inspection is a difficult task. This work introduces a novel wavelet feature extraction method for atrial fibrillation derived from the average framing percentage energy (AFE) of terminal wavelet packet transform (WPT) sub signals. Probabilistic neural network (PNN) is used for classification. The presented method is shown to be a potentially effective discriminator in an automated diagnostic process. The ECG signals taken from the MIT-BIH database are used to classify different arrhythmias together with normal ECG. Several published methods were investigated for comparison. The best recognition rate selection was obtained for AFE. The classification performance achieved accuracy 97.92%. It was also suggested to analyze the presented system in an additive white Gaussian noise (AWGN) environment; 55.14% for 0dB and 92.53% for 5dB. It was concluded that the proposed approach of automating classification is worth pursuing with larger samples to validate and extend the present study.

[The altered endothelial function in patients with arterial hypertension and different forms of atrial fibrillation]

The role of endothelial function in the development of cardiovascular diseases has recently attracted attention of many researchers due to increasingly more data suggesting the relationship between endothelial dysfunction (ED) and disturbed cardiac rhythms including atrial fibrillation (AF). ED is known to precede lesions in target organs related to arterial hypertension (AH) which makes the study of endothelial function as an early marker of vascular lesions in AH and AF a topical issue.

AIM

To study changes of endothelial function in patients with AH and AF.

MATERIALS AND METHODS

Group 1 included 84 patients with AH (inclusion criteria: essential AH and confirmed paroxysm of AF), group 2 contained 20 patients with AH and permanent AF, control group was comprised of 30 AH patients without AF. The vasomotor function of endothelium was evaluated from reactive hyperemia determined by the ultrasonic method, blood samples for biochemical analysis and determination of Willebrand factor (WF) were taken during fasting.

RESULTS

Patients of group 2 showed significant changes of endothelium-dependent vasodilation of the brachial artery. Its diameter within 60 sec after decompression increased by 5.8 +/- 0.9% and 12.3 +/- 1.2% in groups 1 and 3 respectively (p < 0.05). In group 2, collagen-binding activity of WF increased significantly to 1500 +/-140 U/100 ml compared with 1060 +/- 120 and 840 +/- 110 in groups 2 and 3 (p < 0.05).

CONCLUSION

Patients with AH and persistent AF had altered endothelial function in the form of significant decrease of endothelium-dependent vasodilation of the brachial artery and increase of collagen-binding activity of WF.

Preventing stroke in patients with atrial fibrillation

Adults with atrial fibrillation are at an increased risk for stroke. New oral antithrombotic agents are now available to help prevent stroke and other thromboembolic events. This article provides an update on factors to consider when determining various treatment options for these high-risk patients in hopes of improving outcomes.

Atrial fibrillation: an anesthesiologist's perspective

Atrial fibrillation (AF) is not only the most common arrhythmia in the global population but also the most frequent one encountered in the operating room. For an anesthesiologist, it is crucial to have the ability to maintain hemodynamics and prevent complications of patients who present AF perioperatively. Here we provide a brief review in the novel concept of the classification, pathophysiology, and management of AF to provide a practical approach for physicians coming across this arrhythmia during the perioperative period.

Insights into atrial fibrillation

Atrial fibrillation is the most common clinically relevant heart rhythm disorder and is associated with increased morbidity and mortality. Most important risk factors for atrial fibrillation are high age, arterial hypertension, diabetes mellitus, heart failure and rheumatic heart disease. Chronic atrial fibrillation is classified as paroxysmal, persistent, long-standing persistent and permanent atrial fibrillation. Spontaneous conversion to sinus rhythm is observed in paroxysmal atrial fibrillation, whereas in persistent atrial fibrillation, pharmacological or electrical cardioversion is required in order to restore sinus rhythm. In permanent atrial fibrillation, the arrythmia is accepted by patient and physician and cardioversion is not attempted. Rate control only is thus applied in permanent atrial fibrillation, whereas in paroxysmal and persistent atrial fibrillation, addition rhythm control with anti-arrhythmic drugs and/or ablation is attempted if symptoms persist and age and co-morbidities do not pose contra-indications. Besides rhythm management, oral anticoagulation is the mainstay of therapy for most patients with atrial fibrillation. Risk scores such as the CHA2DS2-VASc score help to identify patients with a high risk of stroke and need for oral anticoagulation. The underuse of vitamin K antagonists in clinical practise is partly due to considerable disadvantages: an increased bleeding risk, a narrow therapeutic window and multiple drug interactions prompting frequent laboratory controls to assess an individual dosage. New oral anticoagulants targeting thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban and edoxaban) may replace warfarin in many patients with atrial fibrillation due to convincing data both on efficacy and safety as well as convenience. However, challenges remain with respect to lack of specific antidotes and high costs.

Catheter ablation of atrial fibrillation in patients with hypertrophic cardiomyopathy: atrial fibrillation type determines the success rate

BACKGROUND

Atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is generally associated with deterioration of the clinical status, functional capacity, and quality of life. It is also an independent risk factor for stroke and death. Studies evaluating the effectiveness of AF ablation in this cohort are relatively scant, have included relatively few patients, and their results are somewhat conflicting. Thus, the aim of this study was to assess the safety and efficacy of catheter ablation of AF in patients with HCM.

METHODS

Thirty patients (10 females; mean age 48.7 ± 11 years) with drug-refractory paroxysmal (n = 14), persistent (n = 7), or long-persistent (> 1 year; n = 9) AF were prospectively recruited into the study. Eleven patients were in New York Heart Association (NYHA) class I, 13 patients were in NYHA class II, and 6 patients were in NYHA class III. Mean atrial volume was 180 ± 47 mL, interventricular septum thickness was 20.5 ± 6.3 mm, and left atrial area was 29.8 ± 6.2 cm2. Ablation protocol was adjusted to the clinical and electrophysiological status of the patients. Pulmonary vein isolation and bidirectional cavo-tricuspid isthmus block were performed in all patients. In addition, left atrial linear lesions were created and complex fragmented atrial potentials were ablated in patients with persistent and long-persistent AF, as well as during repeated procedures.

RESULTS

At 12 months, stable sinus rhythm (SR) was present in 16 (53%) patients, significantly more frequently in patients with paroxysmal AF (71% in SR) compared to those with persistent (57.1% in SR) or long-persistent (22% in SR) AF. A significant reduction of AF burden was observed in 85.7% of patients with paroxysmal AF, 71.4% of patients with persistent AF, and 55.5% of patients with long-persistent AF. Single procedure success rate was 33% (10 patients), and repeat ablation procedures were performed in 13 patients. No periprocedural complications occurred. Thromboembolic events were noted in 2 patients with arrhythmia recurrence during the follow-up, including stroke in 1 patient and peripheral embolism in the other patient. In both these patients, heart failure worsening was observed during these events, and anticoagulation was inadequate in one of them. Five of 16 patients in whom stable SR was observed during the follow-up were off antiarrhythmic drug therapy at final evaluation. In the other 6 patients, antiarrhythmic drug therapy was continued due to ventricular arrhythmias. Successfully treated patients more often had paroxysmal AF (successful ablation: paroxysmal AF in 10 of 16 patients; unsuccessful ablation: paroxysmal AF in 4 of 14 patients; p = 0.009) and were younger (45 ± 11.5 years vs. 52.6 ± 9.2 years; p = 0.046). In addition, a trend toward a reduced need for cardioversion at the end of the procedure was also observed in these patients (3 patients in the successful ablation group vs. 8 patients in the unsuccessful ablation group; p = 0.056). In multivariate regression analysis, paroxysmal AF was the only independent predictor of a successful outcome.

CONCLUSIONS

Catheter ablation of AF in patients with HCM is an effective and safe therapeutic option, particularly in patients with paroxysmal AF. Effectiveness of ablation is significantly smaller in patients with persistent AF and even more so in those with long-persistent AF. Repeated procedures were often necessary. Continued antiarrhythmic drug therapy is often required due to a significant degree of atrial remodelling.

[Pathophysiology and clinical manifestations of atrial fibrillation]

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia among elderly people. The condition is frequently associated with structural heart disease, although a substantial number of patients have no underlying disease. Stretch in the pulmonary vein is considered to play the most important role in its pathogenesis, particularly in patients with hypertension and heart failure. The autonomic nervous system is known to contribute to its initiation. Based on its duration, AF can be classified into paroxysmal, persistent, and permanent, but its progression from the former to the latter is common over years. Palpitations are most frequently complained in paroxysmal AF, whereas absence of symptoms is not unusual in permanent AF. But regardless of types or symptoms of AF, AF is notorious for potentially causing stroke and heart failure, which increase morbidity and mortality.

Vitamin D deficiency is unrelated to type of atrial fibrillation and its complications

INTRODUCTION

Vitamin D plays an important role in a broad range of organ functions, including the cardiovascular system. Only one study has tested the association between vitamin D deficiency and arrhythmia and it found no association. The aim of the present study was to evaluate the association between vitamin D deficiency and the type of atrial fibrillation (AF) and complications to AF.

MATERIAL AND METHODS

In total, 258 patients were consecutively included from March 2009 to February 2011. All in- and out-patients in the Department of Cardiology at Hvidovre Hospital were invited to participate, provided they had electrocardiographically documented AF. Patients with dementia or terminal illness were excluded. 25 hydroxyvitamin D (25 OHD) was measured with a chemiluminescence assay (Liaison from DiaSorin, Stillwater, Minnesota, USA).

RESULTS

No association between vitamin D level and type of AF was found. Furthermore, no association between vitamin D deficiency and ischaemic heart disease, stroke or acute myocardial infarction was found. Vitamin D deficiency was significantly associated with low age (p = 0.02) and gender with a higher proportion of females having the optimal level of 25 OHD (p = 0.0005).

CONCLUSION

Other studies have found a beneficial effect of vitamin D on cardiovascular diseases, but we found no association between vitamin D deficiency and the type of AF or complications to AF. Further investigation is necessary to determine whether vitamin D supplementation improves cardiovascular outcomes in patients with AF.

FUNDING

The study has received financial support from several private and one public fund.

TRIAL REGISTRATION

The study was approved by the National Ethics Committee (Project-ID: H-C-2009-014).

Surgical treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia, resulting in significant morbidity and mortality, and enormous socio-economic consequences. Though many surgical procedures exist for the treatment ofAF, the Cox-Maze IV procedure developed at Washington University has shown excellent long-term results in diverse patient populations. Furthermore, advances in preoperative diagnostic technology currently under investigation at our institution may allow for further refinement and individualization of the surgical treatment ofAF in the future.

Atrial fibrillation: diagnosis and treatment

Atrial fibrillation is the most common cardiac arrhythmia. It impairs cardiac function and increases the risk of stroke. The incidence of atrial fibrillation increases with age. Key treatment issues include deciding when to restore normal sinus rhythm, when to control rate only, and how to prevent thromboembolism. Rate control is the preferred management option in most patients. Rhythm control is an option for patients in whom rate control cannot be achieved or who have persistent symptoms despite rate control. The current recommendation for strict rate control is a resting heart rate of less than 80 beats per minute. However, one study has shown that more lenient rate control of less than 110 beats per minute while at rest was not inferior to strict rate control in preventing cardiac death, heart failure, stroke, and life-threatening arrhythmias. Anticoagulation therapy is needed with rate control and rhythm control to prevent stroke. Warfarin is superior to aspirin and clopidogrel in preventing stroke despite its narrow therapeutic range and increased risk of bleeding. Tools that predict the risk of stroke (e.g., CHADS2) and the risk of bleeding (e.g., Outpatient Bleeding Risk Index) are helpful in making decisions about anticoagulation therapy. Surgical options for atrial fibrillation include disruption of abnormal conduction pathways in the atria, and obliteration of the left atrial appendage. Catheter ablation is an option for restoring normal sinus rhythm in patients with paroxysmal atrial fibrillation and normal left atrial size. Referral to a cardiologist is warranted in patients who have complex cardiac disease; who are symptomatic on or unable to tolerate pharmacologic rate control; or who may be candidates for ablation or surgical interventions.

Noninvasive organization analysis along consecutive episodes of paroxysmal atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. Although its mechanisms are incompletely understood, electrophysiological and structural remodeling of the atria seem to play an important role in the arrhythmia transition from paroxysmal to persistent. However, the time course of the atrial remodeling along onward episodes of non-induced paroxysmal AF has not been investigated yet. In this work, a non-invasive method, based on the regularity estimation of AF through sample entropy (SampEn), has been used to assess the organization evolution along onward episodes of paroxysmal AF. Given that AF organization has been associated to the number of existing wavelets wandering throughout the atrial tissue, SampEn could be considered as a concomitant estimator of atrial remodeling. The achieved results, in close agreement with previous findings obtained from invasive recordings, showed a progressive disorganization increase along onward episodes of AF for 63% of the analyzed patients and a stable AF organization degree in the remaining 37%. Additionally, a positive correlation between episode duration and SampEn was also noticed (R = 0.541, p < 0.01). As a consequence, it could be considered that atrial electrophysiological dynamics that occur along onward paroxysmal AF episodes are reflected and can be quantified from ECG recordings through non-invasive organization estimation.

[Long-term result of the maze procedure for atrial fibrillation]

Long-term result of the maze operation is unknown. Anticoagulation therapy is controversial even after success of the maze operation. Between 1997 and 2008, 213 patients underwent the maze procedure. Atrial fibrillation (Af) was chronic in 151 patients and paroxysmal in 62. Concomitant mitral valve procedure were performed in 72%. Early mortality was 1.9%. By dismissal electrocardiography 157 patients (74%) wes free from Af. At the last follow-up (mean 38 +/- 30 months), late Af recurrence had occurred in 16 patients. Af recurrence had occurred within 1-year in 15 patients. Risk factors for late Af recurrence was left atrial dimension of 50 mm or greater (P<0.001). There was no difference in 5-year freedom from Af between the Cox maze procedure versions. Anticoagulation for patients with large left atrium is mandatory for 1-year after surgery.

Cardiac arrhythmia classification using wavelets and Hidden Markov Models - a comparative approach

This paper reports a comparative study of feature extraction methods regarding cardiac arrhythmia classification, using state of the art Hidden Markov Models. The types of beat being selected are normal (N), premature ventricular contraction (V) which is often precursor of ventricular arrhythmia, two of the most common class of supra-ventricular arrhythmia (S), named atrial fibrillation (AF), atrial flutter (AFL), and normal rhythm (N). The considered feature extraction methods are the standard linear segmentation and wavelet based feature extraction. The followed approach regarding wavelets was to observe simultaneously the signal at different scales, which means with different level of focus. Experimental results are obtained in real data from MIT-BIH Arrhythmia Database and show that wavelet transform outperforms the conventional standard linear segmentation.

Atrial flutter versus atrial fibrillation in a general population: differences in comorbidities associated with their respective onset

OBJECTIVE

Determine and compare the prevalence of known risk factors for cardiovascular disease among unselected individuals presenting with their first ever episode of atrial flutter (AFL) and atrial fibrillation (AF).

STUDY DESIGN AND SETTING

We evaluated 11 pre-selected clinical variables including age, sex, smoking history and other potential cardiac risk factors. Using the resources of the Marshfield Epidemiologic Study Area, a population-based database, all newly diagnosed cases of either AFL or AF in the region during a 4-year period were identified.

RESULTS

Among the 472 incident cases, 76 (16.1%) had AFL and 396 (83.9%) had AF. Compared to those with AF, subjects with AFL were more likely to have had a history of chronic obstructive pulmonary disease (25% vs. 12%, P = 0.006), heart failure (28% vs. 17%, P = 0.05), and smoking (49% vs. 37%, P = 0.06). Hypertension, on the other hand, was more common among individuals with AF (63% vs. 47%, P = 0.01).

CONCLUSION

This study represents the first report to evaluate potential differences in the conditions associated with the development of AFL versus AF. Research into the mechanisms of atrial arrhythmogenesis may lead to improved preventive and therapeutic interventions.

[Dynamic of the changes of the paced QT dispersion after ventricular pacemaker implantation (WIR) and radiofrequency atrioventricular junction ablation in drug refractory atrial fibrillation]

INTRODUCTION

Transcutaneous RF catheter ablation of the atrioventricular junction (AVJ) in pts with ventricular pacemaker (VVIR) implantated is an accepted treatment for drug-intolerant or drug refractory atrial fibrillation. The ventricular arrhythmias and sudden cardiac death may be associated with increased of QT dispersion (QTD), mainly in pts with reduced LV function (low ejection fraction - EF) after AVJ ablation. The present study evaluates the dynamic of the changes of QTD in response to a sudden pacing rate drop from 80/min to 40/min in follow up 1 day, 3, 6 and 9 months after ablation (1d, 3m, 6m, 9m).

MATERIAL AND METHODS

The 12-lead ECGs were recorded on 22 pts (mean age 72.6+/-5.4 yrs) (10 with low EF (<50%) - group A, 12 with normal EF (> or =50%) - group B) on the 1 day, 3, 6 and 9 months following AVJ ablation during a sudden drop in ventricular pacing rate from 80 to 40 beats/min. The maximum QT interval (QTM), minimum QT interval (QTm), and QTD were measured on the last 5 beats prior to the rate drop (QTM-80, QTm-80, QTD-80) and on the first 5 beats after the rate drop (QTM-40, QTm-40, QTD-40). These QT parameters were compared. The echocardiographical studies were performed on the 1d, 3m, 6m and 9m following AVJ ablation.

RESULTS

In response to a sudden paced heart rates drop from 80 to 40 beats/min, the DeltaQTM (QTM-40 - QTM-80) increased during follow-up in both groups, while the DeltaQTm (QTm-40-QTm-80) increased in group B(23.3+/-25.7 in 1d, 27,5+/-20.1ms in 9m; p< 0.001), but not in group A (1+/-16.6 in 1d, 5+/-25.1ms in 9m). Consequently, the AQTD (QTD-40 - QTD-80) increased significantly in group A at 6 months (29+/-31.1ms; p<0.05) but not in group B (9.2+/-17.3msl. The negative correlation between QTD-40, QTD-80 and EF was observed in group A.

CONCLUSIONS

Following AVJ ablation, QTD increased during a sudden rate drop in pts with reduced LV function, but not in pts with EF > or = 50%. The significant correlation between QTD and paced rate was found in pts with LV dysfunction. The increased QTD in response to a sudden heart rate drop in pts with low EF was due to a failure of the expected prolongation of the QTm.

Circulating levels of collagen type I degradation marker depend on the type of atrial fibrillation

AIMS

To investigate the hypothesis that circulating levels of collagen type I degradation or synthesis markers are associated with the presence and pattern of atrial fibrillation (AF).

METHODS AND RESULTS

We assessed the serum concentrations of amino-terminal propeptide of procollagen type I (PINP) and of carboxy-terminal telopeptide of collagen type I (CITP), indexes of collagen type I synthesis and degradation, respectively, in 98 paroxysmal AF (PAF) patients (65 +/- 14 years, 62 men), in 80 persistent AF (PsAF) patients (73 +/- 8 years, 32 men), in 114 permanent AF (PmAF) patients (73 +/- 10 years, 54 men), and in 180 patients in sinus rhythm (SR) (66 +/- 13 years, 88 men) who represented a control group. Serum CITP levels were higher (P < 0.001) in AF patients [0.41 ng/mL, 95% confidence interval (CI) 0.38-0.44] when compared with SR patients (0.29 ng/mL, 95% CI 0.26-0.33) and were significantly different between the three AF pattern groups (P < 0.001). Patients with PAF (0.31 ng/mL, 95% CI 0.26-0.36) had lower CITP levels when compared with patients with PsAF (0.41 ng/mL, 95% CI 0.34-0.47) (P = 0.006), as well as with PmAF patients (0.49 ng/mL 95% CI, 0.43-0.56) (P < 0.001). Levels of CITP tended to be lower (P = 0.219) in PsAF patients when compared with sustained AF patients. No differences were found in PINP levels between AF and SR study groups (P = 0.637) as well as between the three AF pattern groups (P = 0.301).

CONCLUSION

In the clinical setting, circulating levels of collagen type I degradation marker are associated with both type and duration of AF. Further studies are needed to evaluate the clinical use of serum concentrations of CITP as a potential diagnostic, prognostic, and therapeutic target in patients with AF.

Surgical treatment of atrial fibrillation

Atrial fibrillation is a very common arrhythmia that carries a considerable risk of thromboembolic complications. Surgical treatment is an effective way to convert atrial fibrillation into sinus rhythm and significantly prevents thromboembolism postoperatively. In this review we describe recent advancements in the surgical options and detail our strategy for the surgical treatment of atrial fibrillation.

Evaluation and management of atrial fibrillation

Atrial fibrillation (AF) is the most common clinically encountered arrhythmia affecting 0.4% of the general population. Its prevalence increases with age, affecting more than 6% of people over 80 years of age. The annual risk of ischemic stroke in patients with lone AF is approximately 1.3%. This annual risk increases up to 10% -12% in patients with a prior stroke or transient ischemic attack. Randomized clinical trials (RCT) comparing adjusted-dose oral anticoagulation and placebo showed a risk reduction of 61% (95% CI 47% to 71%). The absolute risk reduction for stroke with oral anticoagulants is about 3% per year. Aspirin has been shown in meta-analyses to have on average a 20-25% relative risk reduction, and is inferior to oral anticoagulants. In high risk patients with AF warfarin is a class I ACC/AHA indication unless there is a contraindication for anticoagulation. Unfortunately, this therapy requires frequent monitoring with blood samples and the interaction with food and several medications makes its use difficult and sometimes unreliable. It requires strict patient compliance and its use is also linked to potentially serious bleeding complications. In clinical practice, less than 60% of patients who do not have contraindications to oral anticoagulation are actually receiving them. Additionally, of those that receive oral anticoagulation, less than 50% are consistently within therapeutic targets. As such, the "real world" efficacy of a strategy towards prescribing oral anticoagulants is likely significantly lower than that demonstrated in clinical trials. As such, the need to discover other methods of anticoagulation with oral bioavailability, predictable pharmacokinetics, and minimal interactions with diet and other pharmacological agents is imperative. Low molecular weight heparin has a more predictable bioavailability and a longer half-life, but its subcutaneous mode of administration and long-term risks, in particular, osteoporosis makes the chronic use of this medication non-feasible. Antiplatelet agents such as clopidogrel have proven efficacy and superiority compared to aspirin to prevent systemic vascular events in at-risk patient populations, but currently they do not play an important role in the prevention of AF related thromboembolic events. The ACTIVE study is a randomized trial comparing the combination of clopidogrel and aspirin therapy to oral anticoagulation with warfarin in patients with AF, and was unfortunately terminated prematurely by the data safety and monitoring board because of increased events in the antiplatelet arm. Direct thrombin inhibitors, such as ximelagatran, may be as effective as warfarin for stroke-risk reduction in patients with AF. No anticoagulation monitoring is needed and it has excellent bioavailability, with a twice-daily oral dose. Elevation of liver enzymes was an initial concern regarding the use of this new drug, which is not available for general use. Ongoing pharmacological research and future clinical trials may one day leave the "warfarin days" behind. Unfortunately, the new therapies that are being tested seem to be at least several years away from being available on a widespread basis. In this review, we discuss the underlying pathophysiology of AF and stroke. We also provide a comprehensive discussion regarding various available therapies to treat AF.

[Atrial fibrillation]

Atrial fibrillation is an arrhythmia characterized by no-coordinated atrial contraction that results in an inefficient atrial systole. The clinical classification of atrial fibrillation includes: ocassional, paroxysmal, persistent, and permanent. Multiple mechanisms have been described and accounts for a single ECG manifestation. Treatment should be individualized and has to considered several aspects including age, associated heart disease, and symptoms. Treatment strategies are: rhythm control, rate control, and thromboprophylaxis.

Electrophysiological Differences of the Spontaneous Onset of Paroxysmal and Persistent Atrial Fibrillation

BACKGROUND

Information about the spatiotemporal organization of atrial activity at the onset of atrial fibrillation (AF) is still limited.

METHODS

AF mapping was performed in 30 patients with AF (mean age 53 +/- 9 years, 26 males) by deploying a noncontact mapping balloon in the left atrium (LA). Twenty-four patients had paroxysmal AF and six patients had persistent AF. Three types of AF episodes were analyzed: nonsustained AF (lasting <or= 30 seconds), sustained AF (lasting > 30 seconds, with spontaneous conversion or requiring internal cardioversion and subsequent stable sinus rhythm), and persistent AF episodes (stable sinus rhythm lasting <or= 1 minute after cardioversion).

RESULTS

A total of 101 spontaneous AF onset episodes were analyzed. Analysis of AF onset showed that there was a progressive shortening of the initial cycle lengths from nonsustained episodes to sustained episodes and to persistent AF episodes. There was an earlier and more rapid reduction in the cycle lengths from persistent episodes to sustained episodes and to nonsustained episodes of AF (P < 0.05 for persistent vs sustained and for sustained vs nonsustained episodes). The development of multiwavelet activity and disorganization of conduction occurred earlier in persistent and sustained episodes than in nonsustained AF episodes. LA size was greater in patients with persistent AF episodes compared with patients with sustained or nonsustained AF episodes.

CONCLUSIONS

Electrophysiological events that develop at the onset of AF seem to be different in different types of AF. A more rapid degeneration into the fibrillatory activity was observed in persistent and sustained AF than in nonsustained AF episodes.

Prediction of Conversion from Paroxysmal to Permanent Atrial Fibrillation

BACKGROUND

Paroxysmal atrial fibrillation (PAF) transits to permanent atrial fibrillation (PEAF). The current study was to determine whether a P wave-triggered P wave signal averaged electrocardiogram (P-SAECG) and chemoreflexsensitivity (CHRS) are useful to predict a conversion to PEAF in patients with PAF.

METHODS

The filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) were measured by P-SAECG. The ratio between the difference of RR intervals in the ECG and venous pO2 before and after 5-minutes oxygen inhalation is measured (ms/mmHg) for the determination of CHRS.

RESULTS

A total of 180 patients with PAF were enrolled and followed for a mean of 22.5 months. PEAF occurred in 38 patients (21%) and these patients had a significantly larger left atrial size (43.2 +/- 4.9 vs. 41.0 +/- 5.4 mm, P = 0.021), a significantly longer FPD (158.8 +/- 18.2 vs. 136.7 +/- 16.6 ms, P < 0.0001), and a significantly lower CHRS (1.96 +/- 0.99 vs. 2.44 +/- 1.19 ms/mmHg, P = 0.024) than patients with PAF. Patients with PEAF tended to have a lower RMS 20 (2.38 +/- 0.65 vs. 2.75 +/- 1.18 microV, P = 0.067) than patients with PAF. The chi(2) test showed that the combination of FPD > or = 145 ms, RMS 20 < or = 3.0 microV, left atrial size > or = 41 mm, and CHRS < or = 2.0 ms/mmHg had the best predictive power for PEAF. Patients who fulfilled these criteria had a 12-fold increased risk for a conversion from PAF to PEAF.

CONCLUSIONS

Our results show that a P-SAECG, an analysis of CHRS, and left atrial enlargement are clinical predictors of a progression from PAF to PEAF.

Inflammatory markers according to types of atrial fibrillation

BACKGROUND

There is an increasing evidence linking inflammation to some cardiovascular conditions, such as coronary artery disease and hypertension. Similarly, there is emerging data to support the association between inflammation and atrial fibrillation (AF). We also investigated the role of systemic inflammation in different categories of AF.

METHODS

Eighty five consecutive patients with AF were enrolled in this study. AF was categorized as new onset, chronic (persistent and permanent) and lone. Age- and sex-matched 30 healthy people consisted of control group. Serum level of high sensitive C-reactive protein (hs-CRP) and interleukin-6 (IL-6) was measured.

RESULTS

Serum hs-CRP level was higher in overall AF patients than in controls (0.63+/-0.57 vs 0.23+/-0.1 mg/dL, p=0.001). Similarly, IL-6 level was also higher in all AF patients compared with controls (29+/-36 vs 11.6+/-9.7 pg/mL, p=0.008). In subgroup analysis, hs-CRP and IL-6 levels were significantly higher in both chronic (0.69+/-0.62 vs 0.23+/-0.1 mg/dL, p=0.001; 30+/-39 vs 11.6+/-9.7 pg/mL, p=0.001, respectively) and new onset AF patients (0.51+/-0.46 vs 0.23+/-0.1 mg/dL, p=0.003; 28.4+/-31 vs 11.6+/-9.7 pg/mL, p=0.009, respectively) compared with controls. These markers were not different in new onset and chronic AF subgroups. On the other hand, hs-CRP and IL-6 levels tended to be high in lone AF patients (p=0.06). The presence of AF was an independent factor for hs-CRP (OR=0.35, 95%CI=0.1-0.61, p=0.005) and IL-6 (OR=17, 95%CI=1-37, p=0.037).

CONCLUSIONS

Our results support that inflammation may have an important role in the AF pathogenesis.

Current strategies in the surgical treatment of atrial fibrillation: review of the literature and Onze Lieve Vrouw Clinic's strategy

Atrial fibrillation is the most common rhythm disturbance in clinical practice. It is a major source of stroke and morbidity. Although the Cox maze procedure effectively eliminates atrial fibrillation in most patients, the procedure has not found widespread application. As a consequence, new operations that use alternative sources of energy, such as radiofrequency, microwave, cryothermy, laser, and ultrasound have emerged to surgically create lesion sets to treat atrial fibrillation. This article reviews the fundamentals and current strategies in the surgical treatment of atrial fibrillation.