Advances in Arrhythmia and Electrophysiology |
From the Section of Cardiology (J.W.M., K.M.M., E.J.B.), Division of Medicine (M.A.W.), Division of Preventive Medicine (E.J.B.), Whitaker Cardiovascular Institute (E.J.B.), Boston University School of Medicine; Department of Epidemiology (E.J.B.), School of Public Health, Boston, Mass; the National Heart Lung and Blood Institutes Framingham Study (E.J.B.), Framingham, Mass; and Cardiovascular Research Center and Cardiac Arrhythmia Service (P.T.E.), Massachusetts General Hospital, Boston, Mass.
Correspondence to Emelia J. Benjamin, MD, ScM, Boston University School of Medicine and Public Health, The Framingham Heart Study, 73 Mount Wayte Ave, Framingham, MA 01702-5827. E-mail emelia{at}bu.edu
Key Words: P-wave indices epidemiology PR interval electrocardiography atrial fibrillation
| Introduction |
|---|
|
|
|---|
The P wave indices of maximum duration and dispersion have received increasing attention and have been examined in a broad range of clinical settings. The ECG, as a vectorcardiogram,1 quantifies the magnitude and direction of electric propagation and depolarization. Insults such as chronically elevated atrial pressure, ischemia, and metabolic stress lead to atrial remodeling marked by inflammation, fibrosis and poor cellular coupling. The electrophysiological result is slowed conduction with inhomogeneous recovery, defining a substrate for atrial fibrillation (AF).2
Investigators hypothesize that P wave prolongation is an intermediate step in the accumulation of insults ultimately leading to AF. Thus, initial studies sought to demonstrate significant differences between samples with a history of AF and healthy referents, arguing that prolonged P wave duration and dispersion predict recurrent AF. Further studies have used P wave indices to compare multiple samples with and without cardiac diseases. The most recent iteration of studies has extended use of P wave indices beyond cardiac pathology to distinguish a variety of disease entities and comparison groups; the wide array of disease samples studied is listed in Table 1. Given such broad clinical applications, automated reporting of the P wave duration in electrocardiographic measurement for screening purposes has been advocated.41
|
| Literature Search Methods |
|---|
|
|
|---|
| Measurement and Reproducibility of P Wave Indices |
|---|
|
|
|---|
We did not identify a report examining correlations of P wave indices measured in different electrocardiographic leads. Currently, P wave indices are calculated from the absolute difference between the shortest and longest P waves from the surface ECG. Use of adjacent leads with shared vectorial orientation may provide greater sensitivity for distinguishing the inhomogeneity of atrial activation. Future studies should analyze lead heterogeneity in findings, and report results highlighting the lead(s) from which they were derived.
The large majority of studies used the P wave of longest or shortest duration; few studies determined a mean value from multiple measurements.6,40 The largest studies (n=500 to 1353) to examine the relation of P wave duration and dispersion showed correlations ranging from 0.4242 to 0.66.43
P wave indices have been calculated by measurements on paper or digitized images. Manual measurement with calipers has entailed increasing the ECG rate to 50 mm/s and the voltage to 1 to 2 mV/cm,24,44 accompanied by use of magnification. There is potential for discrepancy in the 2 methods, and as reviewed below, the data consistently demonstrate that hand-held caliper measurements have less accuracy compared with digital measurements.44 The Figure demonstrates measurement of P wave indices in a normal ECG at 25 mm/s using a digital measurement technique. Reliability of P wave indices calculation requires accurate determination of the P wave on-set and off-set.
|
The literature has varied in reproducibility metrics reported. Studies have described mean interobserver percent error ranging from 2%26 to 14%.25 Coefficients of variation have ranged from 2%39 to 5%.24 Intraobserver reproducibility has been shown to be strong, with correlation coefficients ranging from r=0.7827 to r=0.97.45
| Distribution of P Wave Indices Reported in the Literature |
|---|
|
|
|---|
110 ms was 9.1% and
120 ms was 1.6%.49 A large, prospective cohort (n=8166) of patients after coronary artery bypass surgery had a median P wave duration of 112 ms (interquartile range 100 to 120 ms).48
|
110 ms has been estimated as high as 41%,50 and
120 ms as high as 47%51 in hospitalized samples prompting the description of this finding as "pandemic".52 A community-based sample of individuals
65 years identified 400 of 678 (59%) subjects as having a P wave duration
110 ms.53 The prevalence among men and women was similar (58.5% and 59.4%, respectively). Before coronary artery bypass surgery 56% of patients (868 of 1553 subjects) had a P wave duration >110 ms.32 Screening for P wave duration
120 ms increases the specificity of identifying prolonged P wave duration.47 In summary, studies suggest a large range for P wave indices in the community and ambulatory settings, with an increased prevalence of prolonged P wave indices with advancing age. To our knowledge, no large, community-based study has described the distribution of P wave indices in a reference sample without disease or risk factors, and then applied these values to define the range in a broad sample.
| Clinical Correlates Associated With P Wave Dispersion |
|---|
|
|
|---|
65 years) have been shown to have equivalent prevalence of P wave duration
110 ms.53 Similarly, ethnic/racial differences in P wave indices have been understudied.
Risk Factors
Cross-sectional studies have examined the relations between risk factors and P wave indices. Subjects with uncontrolled hypertension have been shown to have significantly prolonged P wave duration and dispersion.3 In an unadjusted cross-sectional case-control study subjects with diabetes (n=76) had significantly longer P wave indices than controls (n=40).10 Several studies have examined the relations of P wave indices to obesity and have shown individuals with obesity had significantly longer P wave indices compared with control groups.7,8 Body mass index was moderately correlated (r=0.50) with P wave dispersion,7 even in analyses adjusting for other clinical variables.8 Of interest, a decrease in P wave indices has been observed after weight loss.6 Similarly, bariatric surgery in a severely obese cohort was associated with a significant reduction in P wave indices over a 12-month period.9
Subclinical and Clinical Cardiac Disease
Cross-sectional studies have assessed diastolic function and P wave indices and associated diastolic dysfunction with prolonged P wave indices compared with referent cohorts.3,11 P wave indices and diastolic dysfunction may comprise markers of a common pathophysiologic process. P wave indices and diastolic dysfunction may influence each other in a bidirectional fashion, one may predispose to the other, or their association may be due to confounding resulting from a more complex pathophysiologic process. The associations identified by these studies raise multiple hypotheses which merit further elucidation.
Studies meeting inclusion criteria examining P wave indices and coronary syndromes ranged in size from 9536 to 147 individuals.37 P wave dispersion before and after coronary intervention decreased from 69.5 to 52.4 ms.38 These values are substantively longer than those reported by the other identified studies36,37 evaluating the association between P wave indices and ischemia.
P wave indices have been examined in structural and valvular disease. They were significantly longer in subjects with aortic stenosis compared with controls.18 A single-center, case control study identified a significant decrease in P wave indices at 1 month after mitral balloon valvuloplasty for mitral stenosis.19 Similarly, subjects with a secundum atrial septal defect have had longer maximum P wave duration and P wave dispersion compared with matched controls20; surgical repair of atrial septal defects has resulted in regression of P wave indices.21
Noncardiac Conditions
Studies have examined P wave indices in a variety of noncardiac conditions. The largest identified study (n=32) examining the effect of hemodialysis on P wave indices reported that maximum P wave duration and P wave dispersion increased significantly postdialysis.12 A study reported that individuals with hyperthyroidism (compared with euthyroid individuals) had greater baseline maximum P wave duration and P wave dispersion, and that hyperthyroidism suppressive therapy was associated with a decrease in indices.13 Other efforts have determined positive association between P wave indices and rheumatoid arthritis14 or scleroderma.15 A larger, single-center study compared P wave indices of 162, healthy pregnant women with 150 matched controls,16 and found the pregnant cohort had a decreased minimum P wave duration.
Summary of Clinical Correlates
P wave indices have been evaluated in multiple clinical contexts including cardiac and noncardiac disease states. Of particular interest are the relations between prolonged P wave indices and advancing age, hypertension, diabetes, and obesity, each of which has been identified as an independent risk factor for AF.54–56 Increased atrial pressures due to structural heart disease also clearly potentiate prolongation of P wave indices. These disease states may share common pathways of atrial inflammation and fibrosis57 that yield to atrial remodeling and inhomogeneity of conduction.
The investigations of P wave indices with clinical correlates, cardiovascular and noncardiac conditions have limitations. Most studies were small to moderate in sample size, involved referral cohorts, and consequently had limited power and generalizability. Furthermore, the cross-sectional studies generally did not assess for either confounding or effect modification between advancing age, and clinical correlates in relation to P wave indices. The long-term impact of treating most risk factors or disease states such as hypertension and diabetes has not been assessed systematically and merits elucidation. Multiple clinical correlates in the community have yet to be investigated.
| Electrocardiographic and Electrophysiological Correlates of P Wave Indices |
|---|
|
|
|---|
Limitations included small sample sizes, lack of adjustment for covariates, and cross-sectional design. However, these studies generate hypotheses about pathways involving aging, inflammation and other insults resulting in atrial fibrosis, and the accompanying increased atrial heterogeneity reflected in prolonged P wave indices. Such a nuanced phenotypic model is perhaps more descriptive of P wave prolongation than describing P wave prolongation as "interatrial block," and distinguishes electrophysiological atrial activity from atrial size; atrial fibrosis is not indicative of atrial enlargement.
The electrocardiographic correlates of P wave indices are incompletely described. Our search did not identify studies assessing the relations of P wave indices with PR interval or QRS duration. Heart rate (ie, RR interval) had a significant but modest association with P wave duration
110 ms in a large cohort of healthy young men (odds ratio 1.027 per bpm, 95% confidence interval 1.01 to 1.04)49 A clinical trial assessing the effect of exercise on P wave indices control subjects had a slight decrease in mean P wave duration (94.0 to 92.1 ms) and increase in mean dispersion (52.1 to 53.0) between rest and peak exercise.26
| Signal Average ECG |
|---|
|
|
|---|
| Genetic Variation and P Wave Indices |
|---|
|
|
|---|
| P Wave Indices and AF |
|---|
|
|
|---|
P Wave Indices and AF Recurrence
Subjects with recurrent AF have been shown to have significantly longer P wave indices and longer documented history of AF duration compared with individuals that maintained sinus rhythm. The largest cohort study included 64 subjects, and found the 28 with recurrence had significantly longer P wave indices.31
Association With Incident AF
Prolonged P wave indices have been associated with increased risk for incident AF. A retrospective cohort study followed 97 patients with essential hypertension for a mean duration of 25±3 months, identifying incident AF in 20%.4 Adjusting for age attenuated the odds ratio from 2.09 to 1.34 for prolonged P wave indices (maximum duration
130 ms and dispersion
40 ms) to predict AF. In a case-control study of 308 hospitalized subjects, the prevalence of P wave duration
110 ms was 52% in the cohort with AF, compared with 18% of the 308 subjects in a referent cohort.23 This study had a large age range (26 to 93 years) and calculated P wave duration from 3 leads. A nested case-control study from a population-based study found that 70% of 40 elderly subjects who developed AF after 10 years had baseline P wave durations >120 ms, compared with 41% of the 120 controls.28 P wave duration remained predictive of AF after adjustment for covariates of body mass index and hypertension. Finally, in a prospective cohort of patients presenting with myocardial infarctions, patients whose presentation was complicated by AF had longer P wave indices.37
P Wave Indices and Association With AF After Cardiothoracic Surgery
AF after cardiac surgery is associated with significant morbidity from prolonged hospitalization and an array of complications.68 Three retrospective studies examined P wave indices before cardiothoracic surgery to determine their relation to AF.32–34 The studies ranged in size from 12034 to 1553,32 and analyzed P wave duration as >100 or 110 ms. In multivariable analysis increased P wave duration was a significant predictor of AF.32,33 In a single center cohort analysis of 300 patients, mean P wave duration increased significantly after bypass surgery and predicted postoperative AF in multivariable analysis.33 Median P wave dispersion was similarly prolonged after thoracic surgery in a cohort which developed AF.35 In the cardiac surgery studies age,34 body surface area,33 prior AF or low cardiac output32 had a greater odds ratio for predicting postoperative AF than P wave duration.
Pacing Cohort
Studies have examined P wave indices and the development of AF in cohorts with pacemakers. P wave indices, paced or nonpaced, did not predict AF in 109 subjects with sick sinus syndrome.29 A large (n=660), prospective observational study followed a cohort paced for sinus bradycardia and found prolonged P wave indices were associated with AF hospitalization.29,30 Furthermore, subjects with longer P wave duration (
100 ms) had significantly longer paced P wave durations.
P Wave Indices, Other Dysrhythmias, and Incidence of AF
In unique small (n=72 and 78) studies of individuals referred for electrophysiological study of atrioventricular nodal re-entry tachycardia39 or accessory pathways41 subjects with a history of AF had significantly greater maximum P wave duration and P wave dispersion.
Summary of Relation of P Wave Indices to AF
Larger, more clinically robust studies with longer follow-up are necessary to determine the clinical relevance of P wave indices to incident AF. Limitations in the studies described earlier include lack of adjustment for covariates, short duration of follow-up, small to moderate sample sizes, and treatment of P wave duration as a binary trait rather than a continuous variable.
| Conclusion |
|---|
|
|
|---|
Despite the volume of studies, P wave indices reference ("normal") values have not been standardized. P wave duration cut-offs of 110 or 120 ms have been proposed, but the large prevalence of hospitalized patients found to meet these criteria suggests a low specificity and poor screening utility. No prospective, community-based study has developed reference values by identifying a reference population, articulating measurements of indices, and then applying those measurements to a broad sample with cardiovascular disease, risk factors, and the covariates identified here.
Measurement techniques have not been standardized. Investigators continue to use magnification and hand-held calipers, yet have reported measuring P wave duration to the hundredth of a millisecond with this technique. A single study compared measurement techniques and found improved quality control with digitized measurements.44 Quality control assessments have been limited. Most investigators used measurements surrounding the mean, potentially inflating reproducibility. Robust statistical measures for vigorous quality control are lacking. The deficits of standardized techniques and quality control severely limit the application of P wave indices.
Substantive questions remain concerning the correlations of calculated P wave indices and invasive electrophysiological studies. Agreement between these 2 methods will be essential to verify the validity of P wave indices. There has not been adequate comparison of SAECG and P wave indices. Finally, interlead heterogeneity has not been incorporated into the assessment of P wave indices.
Future Research Directions
Significant challenges remain with regard to our implementation of P wave indices as a relevant component of screening. Reference values from large, community-based studies will assist with standardizing indices for sex and height. Correlations with heart rate, PR interval, and QRS duration will assist with understanding the electrocardiographic significance and interrelation of electrocardiographic parameters.
To date, no direct study between P wave SAECG and P wave indices has been performed; such a comparison will be an important advance for the field. Comparing P wave indices and data from electroanatomical mapping will elucidate the correspondence between a noninvasive and invasive assessment of atrial electrophysiology. Such an undertaking has the potential to demonstrate further the utility of P wave indices for screening purposes.
Clinical correlation with cardiac and noncardiac disease states with attention to the influence of advancing age will provide further insights. For instance, cohort studies examining the associations of multiple cardiovascular risk factors and P wave indices will validate the findings of studies described in this review. Echocardiographic and MRI features also will assist with determining the impact of structural heart diseases on P wave indices. P wave indices may be heritable traits, and provide valuable endophenotypes to contribute to the research communitys understanding of the genetic basis of electrocardiographic and electrophysiological traits.
The utility of P wave indices as a clinically useful biomarker remains ambiguous. The chief question in establishing the relevance of a biomarker is whether such a measurement merely reflects pathophysiologic processes or provides unique, complementary insights to predict adverse outcomes. Large size, community-based cohort studies are necessary to achieve adequate power and adjustment for covariates. Such an effort will determine the utility of P wave indices to predict incident AF, heart failure, and overall mortality, and whether they provide additional data beyond already established clinical, echocardiographic and electrocardiographic covariates. P wave indices have potential to influence the treatment of AF. P wave indices may predict success with strategies such as elimination of triggers, ie, pulmonary vein isolation, or substrate modification by pharmacological intervention and risk factor management. Inexpensive and noninvasive, P wave indices may provide a cost effective screening mechanism. Further research is necessary to establish whether P wave indices will contribute independent information toward the ability predict the development of AF, adverse cardiovascular outcomes, and mortality.
| Acknowledgments |
|---|
Supported by NIH/NHLBI contract N01-HC-25195, HL076784, AG028321, and 6R01-NS 17950.
Disclosures
None.
| Footnotes |
|---|
Guest Editor for this article was Veronique L. Roger, MD, MPH.
| References |
|---|
|
|
|---|
2. Spach MS. Mounting evidence that fibrosis generates a major mechanism for atrial fibrillation. Circ Res. 2007; 101: 743–745.
3. Dagli N, Karaca I, Yavuzkir M, Balin M, Arslan N. Are maximum P wave duration and P wave dispersion a marker of target organ damage in the hypertensive population? Clin Res Cardiol. 2008; 97: 98–104.[CrossRef][Medline]
4. Ciaroni S, Cuenoud L, Bloch A. Clinical study to investigate the predictive parameters for the onset of atrial fibrillation in patients with essential. Am Heart J. 2000; 139: 814–819.[Medline]
5. Dilaveris PE, Gialafos EJ, Chrissos D, Andrikopoulos GK, Richter DJ, Lazaki E, Gialafos JE. Detection of hypertensive patients at risk for paroxysmal atrial fibrillation during sinus rhythm by computer-assisted P wave analysis. J Hypertens. 1999; 17: 1463–1470.[CrossRef][Medline]
6. Duru M, Seyfeli E, Kuvandik G, Kaya H, Yalcin F. Effect of weight loss on P wave dispersion in obese subjects. Obesity (Silver Spring). 2006; 14: 1378–1382.[CrossRef][Medline]
7. Kosar F, Aksoy Y, Ari F, Keskin L, Sahin I. P-wave duration and dispersion in obese subjects. Ann Noninvasive Electrocardiol. 2008; 13: 3–7.[Medline]
8. Seyfeli E, Duru M, Kuvandik G, Kaya H, Yalcin F. Effect of obesity on P-wave dispersion and QT dispersion in women. Int J Obes (Lond). 2006; 30: 957–961.[CrossRef][Medline]
9. Russo V, Ammendola E, De C, I, Docimo L, Santangelo L, Calabro R. Severe obesity and P-wave dispersion: the effect of surgically induced weight loss. Obes Surg. 2008; 18: 90–96.[CrossRef][Medline]
10. Yazici M, Ozdemir K, Altunkeser BB, Kayrak M, Duzenli MA, Vatankulu MA, Soylu A, Ulgen MS. The effect of diabetes mellitus on the P-wave dispersion. Circ J. 2007; 71: 880–883.[CrossRef][Medline]
11. Gunduz H, Binak E, Arinc H, Akdemir R, Ozhan H, Tamer A, Uyan C. The relationship between P wave dispersion and diastolic dysfunction. Tex Heart Inst J. 2005; 32: 163–167.[Medline]
12. Tezcan UK, Amasyali B, Can I, Aytemir K, Kose S, Yavuz I, Kursaklioglu H, Isik E, Demirtas E, Oto A. Increased P wave dispersion and maximum P wave duration after hemodialysis. Ann Noninvasive Electrocardiol. 2004; 9: 34–38.[CrossRef][Medline]
13. Katircibasi MT, Deniz F, Pamukcu B, Binici S, Atar I. Effects of short-term propylthiouracil treatment on P wave duration and P wave dispersion in patients with overt hypertyroidism. Exp Clin Endocrinol Diabetes. 2007; 115: 376–379.[CrossRef][Medline]
14. Guler H, Seyfeli E, Sahin G, Duru M, Akgul F, Saglam H, Yalcin F. P wave dispersion in patients with rheumatoid arthritis: its relation with clinical and echocardiographic parameters. Rheumatol Int. 2007; 27: 813–818.[CrossRef][Medline]
15. Can I, Onat AM, Aytemir K, Akdogan A, Ureten K, Kiraz S, Ertenli I, Ozer N, Tokgozoglu L, Oto A. Assessment of atrial conduction in patients with scleroderma by tissue Doppler echocardiography and P wave dispersion. Cardiology. 2007; 108: 317–321.[CrossRef][Medline]
16. Ozmen N, Cebeci BS, Yiginer O, Muhcu M, Kardesoglu E, Dincturk M. P-wave dispersion is increased in pregnancy due to shortening of minimum duration of P: does this have clinical significance? J Int Med Res. 2006; 34: 468–474.[Medline]
17. Can I, Aytemir K, Demir AU, Deniz A, Ciftci O, Tokgozoglu L, Oto A, Sahin A. P-wave duration and dispersion in patients with obstructive sleep apnea. Int J Cardiol. 2008 [Epub ahead of print].
18. Turhan H, Yetkin E, Atak R, Altinok T, Senen K, Ileri M, Sasmaz H, Cehreli S, Kutuk E. Increased P-wave duration and P-wave dispersion in patients with aortic stenosis. Ann Noninvasive Electrocardiol. 2003; 8: 18–21.[CrossRef][Medline]
19. Turhan H, Yetkin E, Senen K, Yilmaz MB, Ileri M, Atak R, Cehreli S, Kutuk E. Effects of percutaneous mitral balloon valvuloplasty on P-wave dispersion in patients with mitral stenosis. Am J Cardiol. 2002; 89: 607–609.[CrossRef][Medline]
20. Guray U, Guray Y, Yylmaz MB, Mecit B, Sasmaz H, Korknaz S, Kutuk E. Evaluation of P wave duration and P wave dispersion in adult patients with secundum atrial septal defect during normal sinus rhythm. Int J Cardiol. 2003; 91: 75–79.[CrossRef][Medline]
21. Guray U, Guray Y, Mecit B, Yilmaz MB, Sasmaz H, Korkmaz S. Maximum P wave duration and P wave dispersion in adult patients with secundum atrial septal defect: the impact of surgical repair. Ann Noninvasive Electrocardiol. 2004; 9: 136–141.[CrossRef][Medline]
22. Wong T, Davlouros PA, Li W, Millington-Sanders C, Francis DP, Gatzoulis MA. Mechano-electrical interaction late after Fontan operation: relation between P-wave duration and dispersion, right atrial size, and atrial arrhythmias. Circulation. 2004; 109: 2319–2325.
23. Agarwal YK, Aronow WS, Levy JA, Spodick DH. Association of interatrial block with development of atrial fibrillation. Am J Cardiol. 2003; 91: 882.[CrossRef][Medline]
24. Aytemir K, Ozer N, Atalar E, Sade E, Aksoyek S, Ovunc K, Oto A, Ozmen F, Kes S. P wave dispersion on 12-lead electrocardiography in patients with paroxysmal atrial fibrillation. Pacing Clin Electrophysiol. 2000; 23: 1109–1112.[CrossRef][Medline]
25. Andrikopoulos GK, Dilaveris PE, Richter DJ, Gialafos EJ, Synetos AG, Gialafos JE. Increased variance of P wave duration on the electrocardiogram distinguishes patients with idiopathic paroxysmal atrial fibrillation. Pacing Clin Electrophysiol. 2000; 23: 1127–1132.[CrossRef][Medline]
26. Yigit Z, Akdur H, Ersanli M, Okcun B, Guven O. The effect of exercise to P wave dispersion and its evaluation as a predictor of atrial fibrillation. Ann Noninvasive Electrocardiol. 2003; 8: 308–312.[CrossRef][Medline]
27. Dilaveris PE, Gialafos EJ, Sideris SK, Theopistou AM, Andrikopoulos GK, Kyriakidis M, Gialafos JE, Toutouzas PK. Simple electrocardiographic markers for the prediction of paroxysmal idiopathic atrial fibrillation. Am Heart J. 1998; 135: 733–738.[CrossRef][Medline]
28. De Bacquer D, Willekens J, De Backer G. Long-term prognostic value of P-wave characteristics for the development of atrial fibrillation in subjects aged 55 to 74 years at baseline. Am J Cardiol. 2007; 100: 850–854.[CrossRef][Medline]
29. Kristensen L, Nielsen JC, Mortensen PT, Christensen PD, Vesterlund T, Pedersen AK, Andersen HR. Sinus and paced P wave duration and dispersion as predictors of atrial fibrillation after pacemaker implantation in patients with isolated sick sinus syndrome. Pacing Clin Electrophysiol. 2004; 27: 606–614.[CrossRef][Medline]
30. Padeletti L, Santini M, Boriani G, Botto G, Ricci R, Spampinato A, Vergara G, Rahue WG, Capucci A, Gulizia M, Pieragnoli P, Grammatico A, Platonov P, Barold SS. Duration of P-wave is associated with atrial fibrillation hospitalizations in patients with atrial fibrillation and paced for bradycardia. Pacing Clin Electrophysiol. 2007; 30: 961–969.[CrossRef][Medline]
31. Dogan A, Avsar A, Ozturk M. P-wave dispersion for predicting maintenance of sinus rhythm after cardioversion of atrial fibrillation. Am J Cardiol. 2004; 93: 368–371.[CrossRef][Medline]
32. Amar D, Shi W, Hogue CW Jr, Zhang H, Passman RS, Thomas B, Bach PB, Damiano R, Thaler HT. Clinical prediction rule for atrial fibrillation after coronary artery bypass grafting. J Am Coll Cardiol. 2004; 44: 1248–1253.
33. Chandy J, Nakai T, Lee RJ, Bellows WH, Dzankic S, Leung JM Increases in P-wave dispersion predict postoperative atrial fibrillation after coronary artery bypass graft surgery. Anesth Analg. 2004; 98: 303–310,Table.
34. Chang CM, Lee SH, Lu MJ, Lin CH, Chao HH, Cheng JJ, Kuan P, Hung CR. The role of P wave in prediction of atrial fibrillation after coronary artery surgery. Int J Cardiol. 1999; 68: 303–308.[CrossRef][Medline]
35. Materazzo C, Piotti P, Mantovani C, Miceli R, Villani F. Atrial fibrillation after non-cardiac surgery: P-wave characteristics and Holter monitoring in risk assessment. Eur J Cardiothorac Surg. 2007; 31: 812–816.
36. Dilaveris PE, Andrikopoulos GK, Metaxas G, Richter DJ, Avgeropoulou CK, Androulakis AM, Gialafos EJ, Michaelides AP, Toutouzas PK, Gialafos JE. Effects of ischemia on P wave dispersion and maximum P wave duration during spontaneous anginal episodes. Pacing Clin Electrophysiol. 1999; 22: 1640–1647.[CrossRef][Medline]
37. Baykan M, Celik S, Erdol C, Durmus I, Orem C, Kucukosmanoglu M, Yilmaz R. Effects of P-wave dispersion on atrial fibrillation in patients with acute anterior wall myocardial infarction. Ann Noninvasive Electrocardiol. 2003; 8: 101–106.[CrossRef][Medline]
38. Celik T, Iyisoy A, Kursaklioglu H, Kilic S, Kose S, Amasyali B, Isik E. Effects of primary percutaneous coronary intervention on P wave dispersion. Ann Noninvasive Electrocardiol. 2005; 10: 342–347.[CrossRef][Medline]
39. Amasyali B, Kose S, Aytemir K, Kilic A, Turhan H, Celik T, Kursaklioglu H, Iyisoy A, Ozturk C, Isik E. P wave dispersion predicts recurrence of paroxysmal atrial fibrillation in patients with atrioventricular nodal reentrant tachycardia treated with radiofrequency catheter ablation. Ann Noninvasive Electrocardiol. 2006; 11: 263–270.[CrossRef][Medline]
40. Uhley H. It is time to include P-wave duration. Pacing Clin Electrophysiol. 2007; 30: 293–294.[CrossRef][Medline]
41. Aytemir K, Amasyali B, Kose S, Kilic A, Abali G, Oto A, Isik E. Maximum P-wave duration and P-wave dispersion predict recurrence of paroxysmal atrial fibrillation in patients with Wolff-Parkinson-White syndrome after successful radiofrequency catheter ablation. J Interv Card Electrophysiol. 2004; 11: 21–27.[CrossRef][Medline]
42. Ariyarajah V, Frisella ME, Spodick DH. Incremental prevalence of fractionated and inhomogeneous propagation of sinus impulses with increasing atrial depolarization abnormality among outpatients. Int J Cardiol. 2008; 127: 368–371.[CrossRef][Medline]
43. Gialafos EJ, Dilaveris PE, Synetos AG, Tsolakidis GF, Papaioannou TG, Andrikopoulos GK, Richter DJ, Triposkiadis F, Gialafos JE. P wave analysis indices in young healthy men: data from the digital electrocardiographic study in Hellenic Air Force Servicemen (DEHAS). Pacing Clin Electrophysiol. 2003; 26: 367–372.[CrossRef][Medline]
44. Dilaveris P, Batchvarov V, Gialafos J, Malik M. Comparison of different methods for manual P wave duration measurement in 12-lead electrocardiograms. Pacing Clin Electrophysiol. 1999; 22: 1532–1538.[CrossRef][Medline]
45. Boriani G, Diemberger I, Biffi M, Camanini C, Valzania C, Corazza I, Martignani C, Zannoli R, Branzi A. P wave dispersion and short-term vs. late atrial fibrillation recurrences after cardioversion. Int J Cardiol. 2005; 101: 355–361.[CrossRef][Medline]
46. Tukek T, Yildiz P, Akkaya V, Karan MA, Atilgan D, Yilmaz V, Korkut F. Factors associated with the development of atrial fibrillation in COPD patients: the role of P-wave dispersion. Ann Noninvasive Electrocardiol. 2002; 7: 222–227.[CrossRef][Medline]
47. Ariyarajah V, Frisella ME, Spodick DH. Reevaluation of the criterion for interatrial block. Am J Cardiol. 2006; 98: 936–937.[CrossRef][Medline]
48. Lauer MS, Martino D, Ishwaran H, Blackstone EH. Quantitative measures of electrocardiographic left ventricular mass, conduction, and repolarization, and long-term survival after coronary artery bypass grafting. Circulation. 2007; 116: 888–893.
49. Gialafos E, Psaltopoulou T, Papaioannou TG, Synetos A, Dilaveris P, Andrikopoulos G, Vlasis K, Gialafos J, Stefanadis C. Prevalence of interatrial block in young healthy men<35 years of age. Am J Cardiol. 2007; 100: 995–997.[CrossRef][Medline]
50. Jairath UC, Spodick DH. Exceptional prevalence of interatrial block in a general hospital population. Clin Cardiol. 2001; 24: 548–550.[CrossRef][Medline]
51. Asad N, Spodick DH. Prevalence of interatrial block in a general hospital population. Am J Cardiol. 2003; 91: 609–610.[CrossRef][Medline]
52. Ariyarajah V, Asad N, Tandar A, Spodick DH. Interatrial block: pandemic prevalence, significance, and diagnosis. Chest. 2005; 128: 970–975.
53. Ninios I, Pliakos C, Ninios V, Karvounis H, Louridas G. Prevalence of interatrial block in a general population of elderly people. Ann Noninvasive Electrocardiol. 2007; 12: 298–300.[CrossRef][Medline]
54. Kannel WB, Abbott RD, Savage DD, McNamara PM. Epidemiologic features of chronic atrial fibrillation: the Framingham study. N Engl J Med. 1982; 306: 1018–1022.[Abstract]
55. Wang TJ, Parise H, Levy D, D'Agostino RB Sr. Wolf PA, Vasan RS, Benjamin EJ. Obesity and the risk of new-onset atrial fibrillation. JAMA. 2004; 292: 2471–2477.
56. Benjamin EJ, Levy D, Vaziri SM, D'Agostino RB, Belanger AJ, Wolf PA. Independent risk factors for atrial fibrillation in a population-based cohort. The Framingham Heart Study. JAMA. 1994; 271: 840–844.
57. Everett TH, Olgin JE. Atrial fibrosis and the mechanisms of atrial fibrillation. Heart Rhythm. 2007; 4: S24–S27.[CrossRef][Medline]
58. Kistler PM, Sanders P, Fynn SP, Stevenson IH, Spence SJ, Vohra JK, Sparks PB, Kalman JM. Electrophysiologic and electroanatomic changes in the human atrium associated with age. J Am Coll Cardiol. 2004; 44: 109–116.
59. Xia Y, Hertervig E, Kongstad O, Ljungstrom E, Platonov P, Holm M, Olsson B, Yuan S. Deterioration of interatrial conduction in patients with paroxysmal atrial fibrillation: electroanatomic mapping of the right atrium and coronary sinus. Heart Rhythm. 2004; 1: 548–553.[CrossRef][Medline]
60. Date T, Yamane T, Inada K, Matsuo S, Kanzaki Y, Miyanaga S, Shibayama K, Miyazaki H, Sugimoto K, Taniguchi I, Mochizuki S. The effects of pulmonary vein isolation on the morphology of P waves: the contribution of pulmonary vein muscle excitation to the formation of P waves. Pacing Clin Electrophysiol. 2007; 30: 93–101.[Medline]
61. Budeus M, Hennersdorf M, Perings C, Wieneke H, Erbel R, Sack S. Prediction of the recurrence of atrial fibrillation after successful cardioversion with P wave signal-averaged ECG. Ann Noninvasive Electrocardiol. 2005; 10: 414–419.[CrossRef][Medline]
62. Aytemir K, Amasyali B, Abali G, Kose S, Kilic A, Onalan O, Tokgozoglu L, Kabakci G, Ozkutlu H, Nazli N, Isik E, Oto A. The signal-averaged P-wave duration is longer in hypertensive patients with history of paroxysmal atrial fibrillation as compared to those without. Int J Cardiol. 2005; 103: 37–40.[CrossRef][Medline]
63. Steinberg JS, Zelenkofske S, Wong SC, Gelernt M, Sciacca R, Menchavez E. Value of the P-wave signal-averaged ECG for predicting atrial fibrillation after cardiac surgery. Circulation. 1993; 88: 2618–2622.
64. Tamis JE, Steinberg JS Value of the signal-averaged P wave analysis in predicting atrial fibrillation after cardiac surgery. J Electrocardiol. 1998; 30 (suppl): 36–43.[CrossRef][Medline]
65. Budeus M, Felix O, Hennersdorf M, Wieneke H, Erbel R, Sack S. Prediction of conversion from paroxysmal to permanent atrial fibrillation. Pacing Clin Electrophysiol. 2007; 30: 243–252.[CrossRef][Medline]
66. Newton-Cheh C, Guo CY, Wang TJ, O'Donnell CJ, Levy D, Larson MG Genome-wide association study of electrocardiographic and heart rate variability traits: the Framingham Heart Study. BMC Med Genet. 2007; 8 (suppl 1): S7.[CrossRef][Medline]
67. Darbar D, Hardy A, Haines JL, Roden DM. Prolonged signal-averaged P-wave duration as an intermediate phenotype for familial atrial fibrillation. J Am Coll Cardiol. 2008; 51: 1083–1089.
68. Mathew JP, Fontes ML, Tudor IC, Ramsay J, Duke P, Mazer CD, Barash PG, Hsu PH, Mangano DT. A multicenter risk index for atrial fibrillation after cardiac surgery. JAMA. 2004; 291: 1720–1729.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Home | Subscriptions | Archives | Feedback | Authors | Help | Circulation Journals Home | AHA Journals Home | Search Copyright © 2009 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |