Increased variance of P wave duration on the electrocardiogram distinguishes patients with idiopathic paroxysmal atrial fibrillation

Study of P wave dispersion in patients with paroxysmal atrial fibrillation and its role in prediction of atrial fibrillation recurrence

BACKGROUND

It has been known that increased P wave duration and P wave dispersion reflect prolongation of intra-atrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. The objective of this study was assessment of P wave dispersion value in cases with paroxysmal atrial fibrillation and its role in predicting recurrence.

RESULTS

Forty-eight patients with documented paroxysmal AF were subjected to clinical evaluation, electrocardiogram and routine Doppler echocardiogram. We found that a statistically significant association was detected between P wave dispersion and older age, diabetic and hypertensive cases with positive correlation also detected with left atrial dimension (LAD), left ventricle size and diastolic dysfunction grade. Mean corrected P wave dispersion and corrected QT interval were higher among cases using sotalol, ca channel blockers, among cases using nitrates and among cases with Morris index > 0.04. Higher mean value of corrected QT was associated with biphasic P v1 shape. Old age, female sex, P wave dispersion and QT wave dispersion are statistically significant predictors of PAF recurrence.

CONCLUSION

P wave dispersion in patients with paroxysmal atrial fibrillation was strongly correlated to older age, diabetic and hypertensive patients and also with left atrial dimension (LAD), left ventricle size and diastolic dysfunction grade. Also, mean corrected P wave dispersion can predict atrial fibrillation recurrence in patients with Morris index > 0.04, old age, female sex, and QT wave dispersion.

CatBoost-based improved detection of P-wave changes in sinus rhythm and tachycardia conditions: a lead selection study

Examining P-wave morphological changes in Electrocardiogram (ECG) is essential for characterizing atrial arrhythmias. However, standard 12-lead ECGsuffer from diagnostic redundancy due to low signal-to-noise ratio of P-waves. To address this issue, various optimal leads have been proposed for improved atrial activity recording, but the right selection among these leads is crucial for enhancing diagnostic efficacy. This study proposes an automated lead selection technique using the CatBoost machine learning (ML) model to improve the detection of P-wave changes among optimal bipolar leads under different heart rates. ECGs were obtained from healthy participants with a mean age of 25 ± 3.81 years (34% women), including 114 in sinus rhythm (SR) and 38 in sinus tachycardia (ST). The recordings were made using a newly designed atrial lead system (ALS), standard limb lead (SLL), modified limb lead (MLL), modified Lewis lead (LLM) and P-lead. P-wave features and Atrioventricular (AV) ratio were extracted for statistical analysis and ML classification. The optimum ML model was chosen to identify the best-performing optimal lead, which was selected based on the SLL metrics among different ML classifiers. CatBoost was found to outperform the other ML models in SLL-II with the highest accuracy and sensitivity of 0.82 and 0.90, respectively. The CatBoost model, amid other optimal leads, gave the best results for AL-I and AL-II (0.86 and 0.83 in accuracy and 0.91 and 0.93 in sensitivity). The developed CatBoost model selected AL-I and AL-II as the top two best-performing optimal leads for the enhanced acquisition of P-wave changes, which may be useful for diagnosing atrial arrhythmias.

Exploiting exercise electrocardiography to improve early diagnosis of atrial fibrillation with deep learning neural networks

Atrial fibrillation (AF) is the most common type of sustained arrhythmia. It results from abnormal irregularities in the electrical performance of the atria, and may cause heart thrombosis, stroke, arterial disease, thromboembolism, and heart failure. Prior to the onset of atrial fibrillation, most people experience atrial cardiomyopathy which, if effectively managed, can be prevented from progressing to atrial fibrillation. Electrocardiogram (ECG) can show changes in the heartbeats, and is a common and painless tool to detect heart problems. P-waves in exercise ECGs change more drastically than those in regular ECG, and are more effective in the detection of atrial myocardial diseases. In this paper, we propose a deep learning system to help clinicians to early detect if a patient has atrial enlargement or fibrillation. Firstly, a Convolutional Recurrent Neural Network is employed to locate the P-waves in the patient's exercise ECGs taken in the exercise ECG test process. Relevant parameters are then calculated from the located P-waves. Then a Parallel Bi-directional Long Short-Term Memory Network is applied to analyze the obtained parameters and make a diagnosis for the patient. With our proposed deep learning system, the changes of P-waves collected in different phases in the exercise ECG test can be analyzed simultaneously to get more stable and accurate results. The system can take data of different length as input, and is also applicable to any number of ECG collections. We conduct various experiments to show the effectiveness of our proposed system. We also show that the more ECG data collected in the exercise phase are involved, the more effective our system is in diagnosis of the diseases.

Clinical value of the combined use of P-wave dispersion and troponin values to predict atrial fibrillation recurrence in patients with paroxysmal atrial fibrillation

INTRODUCTION

P-wave dispersion (PWD) and cardiac troponin levels are independently associated with the recurrence of atrial fibrillation (AF) in patients with paroxysmal AF (PAF). We investigated the clinical usefulness of combining PWD and cardiac troponin I to predict AF recurrence in patients presenting to the emergency department with PAF.

METHODS

This study included 65 patients with PAF who were divided into three groups according to baseline troponin I and PWD values (group 1, troponin I<0.11 ng/dl and PWD<44.5 ms; group II, troponin I<0.11 ng/dl and PWD≥44.5 ms, or troponin I≥0.11 ng/dl and PWD<44.5 ms; group III, troponin I≥0.11 ng/dl and PWD≥44.5 ms).

RESULTS

The AF recurrence rate was significantly higher in group III than in groups I and II. Multivariate analysis revealed that the troponin I and PWD values in group III (odds ratio: 7.236, 95% confidence interval: 1.879-27.861, p=0.004) were independent predictors of AF recurrence.

CONCLUSIONS

The combined use of PWD and basal troponin I levels is a better predictor of AF recurrence than either value alone.

Novel Predictor for New-Onset Atrial High-Rate Episode in Patients With a Dual-Chamber Pacemaker

Background: The incidence of new-onset atrial high-rate episode (AHRE) is higher among patients with cardiac implantable electronic devices (CIEDs) than in the general population. We sought to elucidate the clinical factors associated with AHRE in CIED patients, including P-wave dispersion (PWD) in sinus rhythm.

Methods and Results: In all, 101 patients with CIEDs newly implanted between 2010 and 2014 were included in the study. PWD was measured at the time of device implantation via a body-surface electrocardiogram. AHRE was defined as any episode of sustained atrial tachyarrhythmia (>170 beats/min) recorded in the device’s memory. Patients were divided into an AHRE (n=34) and non-AHRE (n=67) group based on the presence or absence of AHRE within 1 year of device implantation and compared. Mean (±SD) patient age was 75±11 years. A greater incidence of sick sinus syndrome (P=0.05) and longer PWD (62.6±13.1 vs. 38.2±13.9 ms; P<0.0001) were apparent in the AHRE than non-AHRE group. Multivariate analysis revealed that PWD was an independent predictor of new-onset AHRE (odds ratio 1.11; 95% confidence interval 1.06–1.17; P<0.0001). In logistic regression analysis, receiver-operating characteristic curve analysis (area under the curve 0.90; P<0.001) suggested the best cut-off value for PWD was 48 mm (sensitivity 73.8%, specificity 77.9%).

Conclusions: PWD is a simple but feasible predictor of new-onset AHRE in patients with CIEDs.

A Classification and Prediction Hybrid Model Construction with the IQPSO-SVM Algorithm for Atrial Fibrillation Arrhythmia

Atrial fibrillation (AF) is the most common cardiovascular disease (CVD), and most existing algorithms are usually designed for the diagnosis (i.e., feature classification) or prediction of AF. Artificial intelligence (AI) algorithms integrate the diagnosis of AF electrocardiogram (ECG) and predict the possibility that AF will occur in the future. In this paper, we utilized the MIT-BIH AF Database (AFDB), which is composed of data from normal people and patients with AF and onset characteristics, and the AFPDB database (i.e., PAF Prediction Challenge Database), which consists of data from patients with Paroxysmal AF (PAF; the records contain the ECG preceding an episode of PAF), and subjects who do not have documented AF. We extracted the respective characteristics of the databases and used them in modeling diagnosis and prediction. In the aspect of model construction, we regarded diagnosis and prediction as two classification problems, adopted the traditional support vector machine (SVM) algorithm, and combined them. The improved quantum particle swarm optimization support vector machine (IQPSO-SVM) algorithm was used to speed the training time. During the verification process, the clinical FZU-FPH database created by Fuzhou University and Fujian Provincial Hospital was used for hybrid model testing. The data were obtained from the Holter monitor of the hospital and encrypted. We proposed an algorithm for transforming the PDF ECG waveform images of hospital examination reports into digital data. For the diagnosis model and prediction model trained using the training set of the AFDB and AFPDB databases, the sensitivity, specificity, and accuracy measures were 99.2% and 99.2%, 99.2% and 93.3%, and 91.7% and 92.5% for the test set of the AFDB and AFPDB databases, respectively. Moreover, the sensitivity, specificity, and accuracy were 94.2%, 79.7%, and 87.0%, respectively, when tested using the FZU-FPH database with 138 samples of the ECG composed of two labels. The composite classification and prediction model using a new water-fall ensemble method had a total accuracy of approximately 91% for the test set of the FZU-FPH database with 80 samples with 120 segments of ECG with three labels.

Clinical value of the combined use of P-wave dispersion and troponin values to predict atrial fibrillation recurrence in patients with paroxysmal atrial fibrillation

INTRODUCTION

P-wave dispersion (PWD) and cardiac troponin levels are independently associated with the recurrence of atrial fibrillation (AF) in patients with paroxysmal AF (PAF). We investigated the clinical usefulness of combining PWD and cardiac troponin I to predict AF recurrence in patients presenting to the emergency department with PAF.

METHODS

This study included 65 patients with PAF who were divided into three groups according to baseline troponin I and PWD values (group 1, troponin I<0.11 ng/dl and PWD<44.5 ms; group II, troponin I<0.11 ng/dl and PWD≥44.5 ms, or troponin I≥0.11 ng/dl and PWD<44.5 ms; group III, troponin I≥0.11 ng/dl and PWD≥44.5 ms).

RESULTS

The AF recurrence rate was significantly higher in group III than in groups I and II. Multivariate analysis revealed that the troponin I and PWD values in group III (odds ratio: 7.236, 95% confidence interval: 1.879-27.861, p=0.004) were independent predictors of AF recurrence.

CONCLUSIONS

The combined use of PWD and basal troponin I levels is a better predictor of AF recurrence than either value alone.

Assessing Atrial Fibrillation Substrates by P Wave Analysis: A Comprehensive Review

Atrial fibrillation (AF) is the most common cardiac arrhythmia. Pharmacologic and non-pharmacologic rhythm control strategies impact on AF-related symptoms, while leaving largely unaffected the risk of stroke. Moreover, up to 20% of AF patients are asymptomatic during paroxysmal relapses of arrhythmia, thus underlying the need for early markers to identify at-risk patients and prevent cerebrovascular accidents. Indeed, non-invasive assessment of pre-clinical substrate changes that predispose to AF could provide early identification of at-risk patients and allow for tailored care paths. ECG-derived P wave analysis is a simple-to-use and inexpensive tool that has been successfully employed to detect AF-associated structural and functional atrial changes. Beyond standard electrocardiographic techniques, high resolution signal averaged electrocardiography (SAECG), by recording microvolt amplitude atrial signals, allows more accurate analysis of the P wave and possibly AF risk stratification. This review focuses on the evidence that support P wave analysis to assess AF substrates, predict arrhythmia relapses and guide rhythm-control interventions.

A Deep Learning Method to Detect Atrial Fibrillation Based on Continuous Wavelet Transform

Atrial fibrillation (AF) is one of the most common arrhythmias. The automatic AF detection is of great clinical significance but at the same time it remains a big problem to researchers. In this study, a novel deep learning method to detect AF was proposed. For a 10 s length single lead electrocardiogram (ECG) signal, the continuous wavelet transform (CWT) was used to obtain the wavelet coefficient matrix, and then a convolutional neural network (CNN) with a specific architecture was trained to discriminate the rhythm of the signal. The ECG data in multiple databases were divided into 4 classes according to the rhythm annotation: normal sinus rhythm (NSR), atrial fibrillation (AF), other types of arrhythmia except AF (OTHER), and noise signal (NOISE). The method was evaluated using three different wavelet bases. The experiment showed promising results when using a Morlet wavelet, with an overall accuracy of 97.56%, an average sensitivity of 97.56%, an average specificity of 99.19%. Besides, the area under curve (AUC) value is 0.9983, which showed that the proposed method was effective for detecting AF.

ECG analysis in patients with acute coronary syndrome undergoing invasive management: rationale and design of the electrocardiography sub-study of the MATRIX trial

BACKGROUND

The twelve‑lead electrocardiogram (ECG) has become an essential tool for the diagnosis, risk stratification, and management of patients with acute coronary syndromes (ACS). However, several areas of residual controversies or gaps in evidence exist. Among them, P-wave abnormalities identifying atrial ischemia/infarction are largely neglected in clinical practice, and their diagnostic and prognostic implications remain elusive; the value of ECG to identify the culprit lesion has been investigated, but validated criteria indicating the presence of coronary occlusion in patients without ST-elevation are lacking; finally, which criteria among the multiple proposed, better define pathological Q-waves or success of revascularisation deserve further investigations.

METHODS

The Minimizing Adverse hemorrhagic events via TRansradial access site and systemic Implementation of AngioX (MATRIX) trial was designed to test the impact of bleeding avoidance strategies on ischemic and bleeding outcomes across the whole spectrum of patients with ACS receiving invasive management. The ECG-MATRIX is a pre-specified sub-study of the MATRIX programme which aims at analyzing the clinical value of ECG metrics in 4516 ACS patients (with and without ST-segment elevation in 2212 and 2304 cases, respectively) with matched pre and post-treatment ECGs.

CONCLUSIONS

This study represents a unique opportunity to further investigate the role of ECGs in the diagnosis and risk stratification of ACS patients with or without ST-segment deviation, as well as to assess whether the radial approach and bivalirudin may affect post-treatment ECG metrics and patterns in a large contemporary ACS population.

Silent atrial fibrillation is associated with P-wave duration index in patients with cardiac resynchronisation therapy

Introduction

Atrial fibrillation (AF) attacks can be silent, symptomatic, or emerge with its complications in pacemaker-implanted patient groups. P-wave duration index (PWDI), a novel parameter, is calculated by dividing the P-wave duration (PWD) by the PR interval. This study aimed to investigate the relation between PWDI and silent AF development in cardiac resynchronisation therapy defibrillator (CRT-D)-applied patients.

Material and methods

The study population consisted of 181 CRT-D device-implanted patients. Atrial fibrillation attacks that last at least 30 s with no symptoms were accepted as silent AF.

Results

Patients were separated into two groups: ”with silent AF” and ”without silent AF“. The without silent AF group comprised 121 patients (mean age: 62.9 ±8.7 years, 62% male). The with silent AF group included 60 patients (mean age: 67.9 ±9.7 years, 60% male). The silent AF group had significantly higher mean age (p = 0.001). PR duration was significantly higher in the without silent AF group (p = 0.001). Patients with first-degree IAB and PWDI values were significantly higher in the with silent AF group (p-values were 0.001 and < 0.001, respectively). Age (OR = 1.073, 95% CI: 1.028–1.119, p = 0.001) and PWDI (OR = 1.053, 95% CI: 1.028–1.078, p < 0.001) were detected as independent predictors for silent AF in the binomial logistic regression analysis. In the ROC analysis, a PWDI cut-off value of 0.67 determined silent AF with 81.7% sensitivity and 51.4% specificity (AUC = 0.701, p < 0.001).

Conclusions

P-wave duration index was significantly associated with silent AF in patients with CRT-D.

Association of vitamin D deficiency with electrocardiographic markers of left atrial abnormalities

OBJECTIVE

Electrocardiographic markers of left atrial (LA) abnormalities are linked to increased risk of cardiovascular disease (CVD). We examined the relationship of vitamin D deficiency with prolonged P wave duration and PR interval as markers of LA abnormalities.

METHODS

This analysis included 5,894 participants (58.12 ± 12.9 years; 54.7% women; 49.8% non-Hispanic Whites) without clinical CVD from NHANES III. A multivariable logistic regression model was used to examine the association of vitamin D categories (<20 ng/ml, 20-29 ng/ml and >30 ng/ml (reference) with prolonged P wave duration (≥120 ms) and PR interval (≥200 ms).

RESULTS

There was an incremental increase in the prevalence of prolonged P wave duration and PR interval across vitamin D categories with the highest prevalence in study participants with vitamin D levels <20 ng/ml, followed by 20-29 ng/ml and then >30 ng/ml (trend p-value < 0.0001). Vitamin D deficiency (<20 ng/ml) was associated with prolonged P wave duration (OR [95% CI]: 1.22 [1.03-1.45], p = 0.02) and prolonged PR interval (OR [95% CI]: 1.48 [1.12-1.97], p = 0.006) in multivariable logistic regression models adjusted for demographics, CVD risk factors, and other potential confounders. These associations were consistent across subgroups stratified by age, sex, and race.

CONCLUSIONS

Vitamin D deficiency is associated with an increased risk of LA abnormalities. This association elucidates an alternate pathway through which vitamin D deficiency may increase CVD risk. Whether vitamin D supplementation would improve LA abnormalities requires further investigation.

Coronary Artery Dominance May Predict Future Risk of Atrial Fibrillation

Background

Ischemia of the atria and conductive system of the heart results in greater atrial electrophysiological changes and propensity for atrial fibrillation. P wave duration and dispersion have been proposed to be useful for the prediction of paroxysmal atrial fibrillation (PAF). This study aimed to investigate the effect of coronary artery dominance on P wave duration and dispersion.

Methods

The study population included 194 patients with left dominant circulation (LDC) and 200 age- and gender-matched controls with right dominant circulation (RDC) and without coronary artery disease based on invasive coronary angiography findings. P wave dispersion (PWD) was defined as the difference between the maximum and minimum P wave duration. Arrhythmias were identified by 24-hour Holter electrocardiogram at 3 years of follow-up.

Results

PWD was significantly prolonged in the patients with LDC compared to the controls with RDC (p = 0.001). There were positive correlations between PWD and age (r: 0.502, p = 0.009), left ventricular mass (LVM) (r: 0.614, p = 0.001), LVM index (r: 0.727, p < 0.001) and left atrium (LA) diameter (r: 0.558, p = 0.003) in the LDC group. Multivariate logistic regression analysis showed that age, LVM index, LA diameter and LDC were independent predictors of prolonged PWD. At 3 years of follow-up, 7 (3.9%) patients with LDC and 1 (0.5%) patient with RDC had PAF in Holter electrocardiogram (p < 0.001).

Conclusions

LDC could lead to an increased risk of atrial fibrillation through prolonged PWD. We recommend following up these patients to assess the development of atrial fibrillation.

Electrocardiogram (ECG) for the Prediction of Incident Atrial Fibrillation: An Overview

Electrocardiograms (ECGs) have been employed to medically evaluate participants in population-based studies, and ECG-derived predictors have been reported for incident atrial fibrillation (AF). Here, we reviewed the status of ECG in predicting new-onset AF. We surveyed population-based studies and revealed ECG variables to be risk factors for incident AF. When available, the predictive values of each ECG risk marker were calculated. Both the atrium-related and ventricle-related ECG variables were risk factors for incident AF, with significant hazard risks (HRs) even after multivariate adjustments. The risk factors included P-wave indices (maximum P-wave duration, its dispersion or variation and P-wave morphology) and premature atrial contractions (PACs) or runs. In addition, left ventricular hypertrophy (LVH), ST-T abnormalities, intraventricular conduction delay, QTc interval and premature ventricular contractions (PVCs) or runs were a risk of incident AF. An HR of greater than 2.0 was observed in the upper 5th percentile of the P-wave durations, P-wave durations greater than 130 ms, P-wave morpholyg, PACs (PVCs) or runs, LVH, QTc and left anterior fascicular blocks. The sensitivity , specificity and the positive and negative predictive values were 3.6-53.8%, 61.7-97.9%, 2.9-61.7% and 77.4-97.7%, respectively. ECG variables are risk factors for incident AF. The correlation between the ECG-derived AF predictors, especially P-wave indices, and underlying diseases and the effects of the reversal of the ECG-derived predictors on incident AF by treatment of comorbidities require further study.

Association of P wave duration index with atrial fibrillation recurrence after cryoballoon catheter ablation

AIM

We aimed to investigate the relationship between the recurrence of AF and P wave duration index (PWDI) in patients with nonvalvular PAF.

METHODS

We included 114 patients who underwent cryoballoon catheter ablation with the diagnosis of paroxysmal atrial fibrillation (PAF) (55 male, 59 female; mean age 55.5±10,9years). PWDI was calculated by dividing the Pwd by the PR interval in DII lead of 12‑lead ECG. Patients had regular follow-up visits with 12-lead ECG, medical history and clinical evaluation. 24h Holter ECG monitoring had been recorded at least 12months after ablation.

RESULTS

AF recurrence was detected in 24 patients after 1year. Patients were divided into two groups according to the AF recurrence. All parameters were compared between the two groups. Age, DM, HT frequency, ACEI-ARB use, CHA2DS2VASc and HAS-BLED score, HsCRP, LA diameter, LA volume, LA volume index, Pwd and PWDI were related to AF recurrence. In binary logistic regression analysis, PWDI (OR=1.143, p=0.001) and HT (OR=0.194, p=0.020) were found to be independent parameters for predicting AF recurrence. Every 0,01 unit increase in PWDI was found to be associated with 14.3% increase in the risk of AF recurrence. The cut-off value of PWDI obtained by ROC curve analysis was 59,9 for prediction of AF recurrence (sensitivity: 75.0%, specificity: 69.0%). The area under the curve (AUC) was 0.760 (p<0.001).

CONCLUSION

Increased PWDI may help to identify those patients in whom electrical remodeling has already occurred and who will get less benefit from cryoablation.

Utility of P-Wave Dispersion in the Prediction of Atrial Fibrillation

Prevention is important in the case of the most common sustained arrhythmia-atrial fibrillation, with the intention of obtaining both medical and economic benefits. Electrocardiographic parameters have been tested as predictors of atrial fibrillation in different settings, and indices of P-wave have been assiduously studied.Increased P-wave dispersion has been described in different illnesses and correlated with several echocardiographic and clinical parameters. Several studies have demonstrated the relationship between P-wave dispersion with the first episode or paroxysmal atrial fibrillation, as well as with the recurrence of atrial fibrillation after conversion to sinus rhythm. Despite of some critics, the current evidencesentitleus to continue studying P-wave dispersion and use it for identifying patients with risk for atrial fibrillation.

Screening strategies for atrial fibrillation: a systematic review and cost-effectiveness analysis

Background

Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of thromboembolic events. Anticoagulation therapy to prevent AF-related stroke has been shown to be cost-effective. A national screening programme for AF may prevent AF-related events, but would involve a substantial investment of NHS resources.

Objectives

To conduct a systematic review of the diagnostic test accuracy (DTA) of screening tests for AF, update a systematic review of comparative studies evaluating screening strategies for AF, develop an economic model to compare the cost-effectiveness of different screening strategies and review observational studies of AF screening to provide inputs to the model.

Design

Systematic review, meta-analysis and cost-effectiveness analysis.

Setting

Primary care.

Participants

Adults.

Intervention

Screening strategies, defined by screening test, age at initial and final screens, screening interval and format of screening {systematic opportunistic screening [individuals offered screening if they consult with their general practitioner (GP)] or systematic population screening (when all eligible individuals are invited to screening)}.

Main outcome measures

Sensitivity, specificity and diagnostic odds ratios; the odds ratio of detecting new AF cases compared with no screening; and the mean incremental net benefit compared with no screening.

Review methods

Two reviewers screened the search results, extracted data and assessed the risk of bias. A DTA meta-analysis was perfomed, and a decision tree and Markov model was used to evaluate the cost-effectiveness of the screening strategies.

Results

Diagnostic test accuracy depended on the screening test and how it was interpreted. In general, the screening tests identified in our review had high sensitivity (> 0.9). Systematic population and systematic opportunistic screening strategies were found to be similarly effective, with an estimated 170 individuals needed to be screened to detect one additional AF case compared with no screening. Systematic opportunistic screening was more likely to be cost-effective than systematic population screening, as long as the uptake of opportunistic screening observed in randomised controlled trials translates to practice. Modified blood pressure monitors, photoplethysmography or nurse pulse palpation were more likely to be cost-effective than other screening tests. A screening strategy with an initial screening age of 65 years and repeated screens every 5 years until age 80 years was likely to be cost-effective, provided that compliance with treatment does not decline with increasing age.

Conclusions

A national screening programme for AF is likely to represent a cost-effective use of resources. Systematic opportunistic screening is more likely to be cost-effective than systematic population screening. Nurse pulse palpation or modified blood pressure monitors would be appropriate screening tests, with confirmation by diagnostic 12-lead electrocardiography interpreted by a trained GP, with referral to a specialist in the case of an unclear diagnosis. Implementation strategies to operationalise uptake of systematic opportunistic screening in primary care should accompany any screening recommendations.

Limitations

Many inputs for the economic model relied on a single trial [the Screening for Atrial Fibrillation in the Elderly (SAFE) study] and DTA results were based on a few studies at high risk of bias/of low applicability.

Future work

Comparative studies measuring long-term outcomes of screening strategies and DTA studies for new, emerging technologies and to replicate the results for photoplethysmography and GP interpretation of 12-lead electrocardiography in a screening population.

Study registration

This study is registered as PROSPERO CRD42014013739.

Funding

The National Institute for Health Research Health Technology Assessment programme.

QT dispersion and P wave dispersion in patients with fibromyalgia

OBJECTIVE

Fibromyalgia (FM) is a chronic disease characterized by widespread pain. Somatic complaints associated with the cardiovascular system, such as chest pain and palpitations, are frequently seen in FM patients. P and QT dispersions are simple and inexpensive measurements reflecting the regional heterogeneity of atrial and ventricular repolarization, respectively. QT dispersion can cause serious ventricular arrhythmias. The aim of the present study was to evaluate QT dispersion and P wave dispersion in patients with FM.

MATERIAL AND METHODS

The study involved 48 FM patients who fulfilled the established criteria and 32 healthy controls (HC). A standard 12-lead electrocardiogram was performed on all participants. QT dispersion was defined as the difference between the longest and the shortest QT intervals. Similarly, the differences between the shortest and longest P waves were defined as P wave dispersion.

RESULTS

The QT dispersion and corrected QT dispersion were shorter in the FM group compared with the HC group (p<0.001 for both). In terms of the P wave dispersion value, there was no significant difference between the FM and HC groups (p=0.088).

CONCLUSION

Longer QT and P wave dispersions are not problems in patients with FM. Therefore, it may be concluded that fibromyalgia does not include an increased risk of atrial and/or ventricular arrhythmias.

P-wave indices as predictors of atrial fibrillation recurrence after pulmonary vein isolation in normal left atrial size

AIMS

Prolonged P-wave duration and dispersion are universally accepted noninvasive markers for atrial electrical remodeling. Our aim was to analyze P-wave indices as predictors of atrial fibrillation recurrence after pulmonary vein isolation in patients with normal left atrial size.

METHODS

From January 2008 to December 2011, 426 patients with drug-resistant symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation as an index procedure by conventional radiofrequency or cryoballoon ablation in our center. Patients with left atrial dilatation, poor-quality electrocardiograms, atrial pacemaker stimulation, and those undergoing repeat procedures were excluded. A total of 201 patients were analyzed during a mean follow-up of 22 ± 16 months.

RESULTS

Patients with prolonged P-wave duration had higher rates of atrial fibrillation recurrences compared with those without prolonged P-wave duration (49 vs. 14%; P < 0.001). Atrial fibrillation recurrence was significantly associated with prolonged P-wave duration (129 ± 13 vs. 119 ± 11 ms; P < 0.001) and P-wave dispersion (54 ± 12 vs. 42 ± 10 ms; P < 0.001) compared with those who remained in sinus rhythm. P-wave duration and dispersion were independently associated with atrial fibrillation recurrence (hazard ratio 1.045, 95% confidence interval 1.027-1.063, P < 0.001; and hazard ratio 1.049, 95% confidence interval 1.022-1.078, P < 0.001, respectively), after adjusting for left atrial size and age.

CONCLUSION

Prolonged P-wave duration and dispersion were found to be independently associated with higher recurrence rates of atrial fibrillation after pulmonary vein isolation in patients with normal left atrial dimension. Therefore, a prolongation of P-wave indices may help to identify those patients in whom electrical remodeling has already occurred and a more extensive ablation may be indicated.

Effect of Intensive Blood Pressure Lowering on Incident Atrial Fibrillation and P-Wave Indices in the ACCORD Blood Pressure Trial

BACKGROUND

There are no proven strategies to prevent atrial fibrillation (AF) in patients with type 2 diabetes (T2DM). We compared standard blood pressure (BP) lowering vs. intensive BP lowering in reducing incidence of AF or P-wave indices (PWI-ECG markers of left atrial abnormality that are considered intermediate phenotypes of AF) in patients with T2DM.

METHODS

We analyzed data from the ACCORD BP trial-a randomized controlled nonblinded trial (2001-2009) which randomized patients with T2DM and systolic BP (SBP) 130-180mm Hg on ≤3 antihypertensive medications aged 40-79 years with cardiovascular disease (CVD) or aged 55-79 years with subclinical CVD or ≥2 CVD risk factors to standard BP lowering (SBP <140mm Hg) vs. intensive BP lowering (SBP <120mm Hg). The primary outcome was a composite of incident AF and PWI.

RESULTS

Data from 3,087 participants (mean age, 62.2 years; women, 48.2%; non-White, 39.2%) were analyzed. During a mean follow-up of 4.4 years, the primary outcome occurred in 1,063 participants (incidence rate, 84.5 per 1,000 person-years in the standard-therapy group vs. 73.9 per 1,000 person-years in the intensive-therapy group). The adjusted hazard ratios (95% confidence intervals) of intensive-therapy group for the primary outcome and for incident PWI alone were 0.87 (0.77-0.98), P = 0.02 and 0.87 (0.76-0.98), P = 0.02, respectively. The effect of intensive therapy on the incidence of AF alone did not reach statistical significance.

CONCLUSIONS

In patients with T2DM, intensive BP lowering reduces the incidence of the composite outcome of AF and PWI, suggesting a potential benefit from stringent BP control in patients with T2DM. clinical trials registration Trial Number NCT00000620.

QTC Dispersion and P-Wave Dispersion during Migraine Attacks

The aim of this study was to investigate increase of QTc dispersion and P-wave dispersion during migraine attacks. Fifty-five patients (16–65 years of age, 49 women, six men) with migraine were included in our study. Heart rate, QTc interval, maximum and minimum QTc interval, QTc dispersion, maximum and minimum P-wave duration and P-wave dispersion were measured from 12-lead ECG recording during migraine attacks and pain-free periods. ECGs were transferred to a personal computer via a scanner and then used for magnification of x400 by Adobe Photoshop software. Maximum QTc interval (454 ± 24 ms vs. 429 ± 23 ms, P < 0.001), QTc interval (443 ± 26 ms vs. 408 ± 22 ms, P <0.001) and QTc dispersion (63 ± 18 ms vs. 43 ± 14 ms, P <0.001) were found significantly higher during migraine attacks compared with pain-free periods. Maximum P-wave duration (107 ± 11 ms vs. 100 ± 11 ms, P <0.001) and P-wave dispersion (45 ± 13 ms vs. 35 ± 13 ms, P <0.001) were found higher during migraine attacks than pain-free periods. We concluded that migraine attacks are associated with increased QTc and P-wave dispersion compared with pain-free periods.

Hemodiafiltration and hemodialysis differently affect P wave duration and dispersion on the surface electrocardiogram

AIM

The incidence of atrial fibrillation is increased during hemodialysis (HD); however, the effects of hemodiafiltration (HDF) on atrial arrhythmias have not been evaluated. The prolongation of the P wave and P dispersion (Pd) can predict atrial arrhythmias.

METHODS

Data from 30 patients receiving HDF over a period of 3 months were collected; the same group of patients was then evaluated during treatment with conventional HD for at least another 3 months. Electrolyte values were obtained, and surface electrocardiograms (ECG), echocardiography, and Holter ECGs were performed.

RESULTS

The duration of the P wave and Pd increased significantly during HD. The left atrial diameter decreased significantly only during HDF. During HDF, the left atrial cross diameter measured at the beginning of the session was positively correlated with the incidence of supraventricular premature beats (p = 0.011, r = 0.4556). The decrease in left atrial diameter during HDF was negatively correlated with the incidence of supraventricular premature beats (p = 0.016, r = -0.43). During HDF, the changes in sodium and Pd were significantly positively correlated (p < 0.05, r = 0.478). During HD, the changes in ionized calcium levels and Pd were positively correlated (p < 0.05, r = 0.377).

CONCLUSION

Our results suggest that HDF has a more beneficial effect on P wave duration and Pd than HD. The alterations in the ECG markers may be the result of the simultaneous occurrence of certain electrolyte imbalances and renal replacement methods.

Advanced Interatrial Block Predicts New Onset Atrial Fibrillation in Patients with Severe Heart Failure and Cardiac Resynchronization Therapy

BACKGROUND

Advanced interatrial block (aIAB) on the surface electrocardiogram (ECG), defined as a P-wave duration ≥120 milliseconds with biphasic (±) morphology in inferior leads, is frequently associated with atrial fibrillation (AF). The aim of this study was to determine whether preoperative aIAB could predict new-onset AF in patients with severe congestive heart failure (CHF) requiring cardiac resynchronization therapy (CRT).

METHODS

Retrospective analysis of consecutive patients with CHF and no prior history of AF undergoing CRT for standard indications. A baseline 12-lead ECG was obtained prior to device implantation and analyzed for the presence of aIAB. ECGs were scanned at 300 DPI and maximized 8×. Semiautomatic calipers were used to determine P-wave onset and offset. The primary outcome was the occurrence of AF identified through analyses of intracardiac electrograms on routine device follow-up.

RESULTS

Ninety-seven patients were included (74.2% male, left atrial diameter 45.5 ± 7.8 mm, 63% ischemic). Mean P-wave duration was 138.5 ± 18.5 milliseconds and 37 patients (38%) presented aIAB at baseline. Over a mean follow-up of 32 ± 18 months, AF was detected in 29 patients (30%) and the incidence was greater in patients with aIAB compared to those without it (62% vs 28%; P < 0.003). aIAB remained a significant predictor of AF occurrence after multivariate analysis (OR 4.1; 95% CI, 1.6-10.7; P < 0.003).

CONCLUSION

The presence of aIAB is an independent predictor of new-onset AF in patients with severe CHF undergoing CRT.

P-wave duration in lead aVR and the risk of atrial fibrillation in hypertension

BACKGROUND

Hypertension entails atrial remodeling that affect P-wave (PW) duration on electrocardiogram (ECG). PW indices (e.g., variance, dispersion, and terminal force) are associated with a higher risk for atrial fibrillation (AF), but their calculation requires multiple measurements of PW duration, limiting their use in clinical practice. We evaluated whether PW duration in specific ECG leads may identify patients with increased susceptibility to AF in a population of hypertensive patients.

METHODS

In a case-control study, AF and control subjects were matched for age, sex, and left atrial (LA) dimensions. PW duration was measured from digitally stored ECGs. Logistic regression was used to assess the association of PW duration and indices with AF.

RESULTS

We enrolled 44 hypertensive AF patients (16 paroxysmal and 28 persistent) and 44 hypertensive controls. AF and control subjects were matched for sex (males, n = 27), age (67 ± 8 years), LA diameter (40 ± 5 mm), and were comparable for left ventricular mass (45 ± 11 g/m(2.7) vs 48 ± 12 g/m(2.7) , P = 0.19), ejection fraction (58 ± 7% in both groups), and prevalence of mild valvular heart disease (7% vs 5%; P = 0.64). PW duration in lead aVR was significantly higher in AF patients as compared with controls (115 ± 18 ms vs 101 ± 14 ms; P < 0.0001) and was the best independent predictor of AF in multivariable logistic regression (PW ≥ 100 ms: RR = 3.7; 95% CI: 1.3-10.3; P = 0.02).

CONCLUSIONS

Simple measurement of PW duration in lead aVR allows effective identification of AF patients in a population of hypertensives. Confirmation of this finding in a larger population would provide a simple and effective risk marker of AF in hypertensive patients.

Limited Ablation for Persistent Atrial Fibrillation Using Preprocedure Reverse Remodelling

Pulmonary vein isolation (PVI) has been demonstrated to be a highly effective treatment option for patients with paroxysmal atrial fibrillation (AF), but less effective for patients with persistent AF. The lower efficacy of PVI alone has been attributed to adverse atrial electrical and structural remodelling in the setting of AF. Strategies to improve efficacy of catheter ablation for persistent AF alter these pathophysiological characteristics of atrial tissue remodelling. Here we will review the physiology of atrial electrical remodelling observed during AF and evidence that it is reversible. Further, we will explore its uses to reduce the amount of atrial tissue that needs to be ablated to successfully treat patients with persistent AF.

Effect of birth asphyxia on p wave dispersion

OBJECTIVES

To evaluate the cardiac conduction system using P wave dispersion on electrocardiogram and its relationship with the short term mortality and development of arrhythmia in asphyxiated neonates.

METHODS

Thirty term babies with evidence of asphyxia and without any congenital abnormalities were consecutively evaluated as cases. They were compared with thirty healthy term babies without asphyxia. Twelve-lead surface electrocardiography was obtained from all the patients and the controls, and P wave dispersion was calculated according to its definition as the difference between P maximum duration and P minimum duration in 12-lead electrocardiogram.

RESULTS

A statically significant difference of P wave dispersion was observed between the patients and the control group (0.027 ± 0.011 mm/s and 0.016 ± 0.006 mm/s, respectively; P value = 0.0001). The P wave dispersion had a statistically significant correlation with the grade of asphyxia (P = 0.004, r = 0.62), the P wave dispersion had no statistically significant correlation with Apgar scores, short term arrhythmia, and troponin I level in asphyxiated neonates (P < 0.05).

CONCLUSIONS

The P wave dispersion increased in asphyxiated neonates and correlated with grade of asphyxia; however, the increased P wave dispersion was not correlated with the short term mortality, arrhythmia and troponin I level of the asphyxiated neonates.

Effects of lying position on P-wave dispersion in patients with heart failure

OBJECTIVE

It was the aim of this study to investigate the effects of the right lateral decubitus, left lateral decubitus and supine lying position on P-wave dispersion (PWD) in patients with heart failure (HF).

SUBJECTS AND METHODS

Seventeen patients with HF whose ejection fraction was <35% were included in the study. Right lateral decubitus, left lateral decubitus and supine electrocardiogram (ECG) recordings were obtained. The recordings for each of the three positions were taken after the patients had maintained each position for 30 min to ensure a stabilized hemodynamic position. For the baseline recording, in supine position, there was no 30-min waiting period before the ECG.

RESULTS

After the right lateral decubitus position, there was a statistically significant reduction in the longest P-wave duration (100.0 ± 14.5 and 84.7 ± 16.2 ms; p = 0.001) and a significant decrease in PWD (41.7 ± 8.0 and 24.1 ± 7.1 ms; p < 0.0001). After the left lateral decubitus position, there was no significant change between the baseline PWD values (41.7 ± 8.0 and 40.2 ± 9.7 ms; p = 0.606). After the supine position, there was no significant change between the baseline PWD values (41.7 ± 8.0 and 39.7 ± 9.4 ms; p = 0.427).

CONCLUSION

Our study revealed that patients' PWDs and maximum P-wave durations were lower in the right lateral decubitus lying position than in other positions. The clinical implication of this study needs to be further explored.

Short-term repeatability of electrocardiographic P wave indices and PR interval

BACKGROUND

P wave indices and PR interval from 12-lead electrocardiograms (ECGs) are predictors of cardiovascular morbidity and mortality, but their repeatability has not been examined.

OBJECTIVES

Determine the short-term repeatability of P wave indices (P axis, maximum P area and duration, P dispersion and P terminal force in V1) and PR interval.

METHODS

Participants (n=63) underwent two standard ECGs at each of two visits, two weeks apart. We calculated the intra-class correlation coefficient (ICC), weighted kappa, and minimal detectable change and difference.

RESULTS

ICCs were 0.93 for PR interval, 0.78 for P axis, 0.77 for maximum P area, and 0.58 for maximum P duration. Within- and between-visit Kappa were 0.30 and 0.11 for P dispersion, and 0.68 and 0.46 for P terminal force.

CONCLUSION

Repeatability of PR duration was excellent, that of P wave axis and maximum area was fair, and maximum P wave duration and terminal force was poor. Repeatability of P wave dispersion was fair within visit, yet poor between visits. These results illustrate potential biases when measurement error of some P wave indices is ignored in clinical and epidemiologic studies.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Increased incidence of interatrial block in younger adults with cryptogenic stroke and patent foramen ovale

Background

Stroke is often unexplained in younger adults, although it is often associated with a patent foramen ovale (PFO). The reason for the association is not fully explained, and mechanisms other than paradoxical embolism may be involved. Young stroke patients with PFO have more atrial vulnerability than those without PFO. It is plausible that stretching of the interatrial septum may disrupt the interatrial conduction pathways causing interatrial block (IAB). IAB is associated with atrial fibrillation, dysfunctional left atria and stroke.

Methods

Electrocardiogram (ECG) characteristics of prospectively recruited young patients (≤55 years of age) with unexplained stroke (TOAST and A-S-C-O) were compared with control data. All stroke cases underwent bubble contrast transthoracic and transoesophageal echography. IAB was defined as a P-wave duration of ≥110 ms. ECG data were converted to electronic format and analysed in a blind manner.

Results

Fifty-five patients and 23 datasets were analysed. Patients with unexplained stroke had longer P-wave duration (p = 0.013) and a greater prevalence of IAB (p = 0.02) than healthy controls. Case status was an independent predictor of P-wave duration in a significant multivariate model. There was a significant increase in the proportion of cases with a PFO with IAB compared with cases without PFO and with controls (p = 0.005).

Conclusions

Young patients with unexplained stroke, particularly those with PFO, exhibit abnormal atrial electrical characteristics suggesting atrial arrhythmia or atrial dysfunction as a possible mechanism of stroke.

Fine particulate air pollution is associated with higher vulnerability to atrial fibrillation--the APACR study

The acute effects and the time course of fine particulate pollution (PM₂.₅) on atrial fibrillation/flutter (AF) predictors, including P-wave duration, PR interval duration, and P-wave complexity, were investigated in a community-dwelling sample of 106 nonsmokers. Individual-level 24-h beat-to-beat electrocardiogram (ECG) data were visually examined. After identifying and removing artifacts and arrhythmic beats, the 30-min averages of the AF predictors were calculated. A personal PM₂.₅ monitor was used to measure individual-level, real-time PM₂.₅ exposures during the same 24-h period, and corresponding 30-min average PM₂.₅ concentration were calculated. Under a linear mixed-effects modeling framework, distributed lag models were used to estimate regression coefficients (βs) associating PM₂.₅ with AF predictors. Most of the adverse effects on AF predictors occurred within 1.5-2 h after PM₂.₅ exposure. The multivariable adjusted βs per 10-μg/m³ rise in PM₂.₅ at lag 1 and lag 2 were significantly associated with P-wave complexity. PM₂.₅ exposure was also significantly associated with prolonged PR duration at lag 3 and lag 4. Higher PM₂.₅ was found to be associated with increases in P-wave complexity and PR duration. Maximal effects were observed within 2 h. These findings suggest that PM₂.₅ adversely affects AF predictors; thus, PM₂.₅ may be indicative of greater susceptibility to AF.

Pulmonary vein isolation alone in patients with persistent atrial fibrillation: an ablation strategy facilitated by antiarrhythmic drug induced reverse remodeling

INTRODUCTION

Pulmonary vein isolation (PVI) alone has been thought to be insufficient in patients with persistent atrial fibrillation (PersAF). We hypothesized that preablation treatment of PersAF with a potent antiarrhythmic drug (AAD) would facilitate reverse atrial remodeling and result in high procedural efficacy after PVI alone.

METHODS AND RESULTS

Seventy-one consecutive patients (59.4 ± 9.8 years) with PersAF and prior AAD failure were treated with oral dofetilide (768 ± 291 mcg/day) for a median of 85 days pre-PVI. P-wave duration (Pdur) on ECG was used to assess reverse atrial remodeling. Thirty-five patients with paroxysmal (P) AF not treated with an AAD served as controls. All patients underwent PVI alone; dofetilide was discontinued 1-3 mos postablation. In the PersAF patients, the Pdur decreased from 136.3 ± 21.7 ms (assessed postcardioversion on dofetilide) to 118.6 ± 20.4 ms (assessed immediately prior to PVI) (P < 0.001). In contrast, no change in Pdur (122.6 ± 11.5 ms vs. 121.3 ± 13.7 ms, P = NS) was observed in PAF patients. The 6 and 12 mos AAD-free response to ablation was 76% and 70%, respectively, in PersAF patients, similar to the 80% and 75%, response in PAF patients (P = NS). A decline in Pdur in response to dofetilide was the only predictor of long-term clinical response to PVI in patients with PersAF.

CONCLUSIONS

Pre-treatment with AAD resulted in a decrease in Pdur suggesting reverse atrial electrical remodeling in PersAF patients. This may explain the excellent clinical outcomes using PVI alone, and may suggest an alternative ablation strategy for PersAF.

P-wave indices, distribution and quality control assessment (from the Framingham Heart Study)

BACKGROUND

P-wave indices of maximum P-wave duration and P-wave dispersion have been examined in a broad array of cardiovascular and noncardiovascular disease states. The P-wave indices literature has been highly heterogeneous in measurement methodologies, described quality control metrics, and distribution of values. We therefore sought to determine the reproducibility of P-wave indices in a community-based cohort.

METHODS

P-wave indices were measured in sequential subjects enrolled in the Framingham Heart Study. Electrocardiograms were obtained at the 11th biennial visit of the Original Cohort (n = 250) and the initial visit of the Offspring Cohort (n = 252). We determined the mean P-wave durations, interlead correlations, and P-wave indices. We then chose 20 ECGs, 10 from each cohort, and assessed intrarater and interrater variability.

RESULTS

The maximum P-wave duration ranged from 71 to 162 ms with mean of 112 + or - 12 ms. The minimum P-wave duration ranged from 35 to 103 ms with mean of 65 + or - 10 ms. P-wave dispersion ranged from 12 to 82 ms. The mean P-wave dispersion was 48 + or - 12 ms (40-56). The intrarater intraclass correlation coefficient (ICC) was r = 0.80 for maximum P-wave duration and r = 0.82 for P-wave dispersion. The interrater ICC was 0.56 for maximum P-wave duration and 0.70 for P-wave dispersion.

CONCLUSIONS

We demonstrated excellent intrarater reproducibility and fair interrater reproducibility for calculating P-wave indices. Reproducibility is frequently lacking in studies of P-wave indices, but is an essential component for the field's growth and epidemiologic contribution.

Ethnic distribution of ECG predictors of atrial fibrillation and its impact on understanding the ethnic distribution of ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

The paradox of the reported low prevalence of atrial fibrillation (AF) in blacks compared with whites despite higher stroke rates in the former could be related to limitations in the current methods used to diagnose AF in population-based studies. Hence, this study aimed to use the ethnic distribution of ECG predictors of AF as measures of AF propensity in different ethnic groups.

METHODS

The distribution of baseline measures of P-wave terminal force, P-wave duration, P-wave area, and PR duration (referred to as AF predictors) were compared by ethnicity in 15 429 participants (27% black) from the Atherosclerosis Risk in Communities (ARIC) study by unpaired t test, chi(2), and logistic-regression analysis, as appropriate. Cox proportional-hazards analysis was used to separately examine the association of AF predictors with incident AF and ischemic stroke.

RESULTS

Whereas AF was significantly less common in blacks compared with whites (0.24% vs 0.95%, P<0.0001), similar to what has been reported in previous studies, blacks had significantly higher and more abnormal values of AF predictors (P<0.0001 for all comparisons). Black ethnicity was significantly associated with abnormal AF predictors compared with whites; odds ratios for different AF predictors ranged from 2.1 to 3.1. AF predictors were significantly and independently associated with AF and ischemic stroke with no significant interaction between ethnicity and AF predictors, findings that further justify using AF predictors as an earlier indicator of future risk of AF and stroke.

CONCLUSIONS

There is a disconnect between the ethnic distribution of AF predictors and the ethnic distribution of AF, probably because the former, unlike the latter, do not suffer from low sensitivity. These results raise the possibility that blacks might actually have a higher prevalence of AF that might have been missed by previous studies owing to limited methodology, a difference that could partially explain the greater stroke risk in blacks.

Update on cardiac arrhythmias in the ICU

PURPOSE OF REVIEW

To explore recent findings on the treatment and outcome of cardiac arrhythmias and how they affect ICU activities.

RECENT FINDINGS

The rate vs. rhythm control debate for the treatment of chronic atrial fibrillation continues. It is still unclear whether the postcardiac surgery inflammatory response contributes to the development of atrial fibrillation. In noncardiothoracic surgery/trauma patients hospitalized in an ICU, new-onset supraventricular arrhythmias are associated with markedly elevated mortality when compared with patients with a prior history of such arrhythmias and patients who do not develop arrhythmias. The onset of new supraventricular arrhythmias in such patients appears to be a manifestation of multiple system organ failure as it is closely associated with sepsis. Cardioversion of supraventricular arrhythmias with biphasic waveforms is being studied to determine whether it is more effective than cardioversion with monophasic waveforms.

SUMMARY

Supraventricular arrhythmias, especially atrial fibrillation, occur frequently in ICU patients. Intensivists not only treat atrial fibrillation itself but also its complications and the complications of the therapies used to prevent these complications. In ICU patients, ventricular arrhythmias have ominous implications because they usually portend either a major cardiac or a systemic dysfunction or both.