P Wave Dispersion: A Valuable Electrocardiographic Marker for the Prediction of Paroxysmal Lone Atrial Fibrillation

Assessment of P Wave Indices in Healthy Standardbred Horses

P wave indices are used as non-invasive electrocardiographic markers of atrial remodelling in humans. Few studies have investigated their use in animals. The aim of this study was to measure P wave duration and P wave dispersion (Pd) in healthy standardbred horses and investigate variables that might influence these measurements. A 12-lead electrocardiogram was recorded at rest and P wave indices were calculated in 53 horses. A general linear model was used to investigate the main effects: age, bodyweight, sex, resting heart rate, presence of a murmur, exercise status and the number of years raced. There were significant associations with exercise status for both the maximum P wave duration and Pd, with both values being increased in strenuously exercising versus non-active horses. Furthermore, a significant moderate positive correlation was identified between the duration of exercise (number of years raced) and both Pmax and Pd. No other significant associations were identified. These findings are similar to those reported in elite human athletes versus sedentary individuals. The increases in these P wave indices most likely occur due to prolongation and heterogeneity in atrial conduction time, which are associated with structural and electrical remodelling, and may explain the increased risk of atrial fibrillation in athletic horses.

Electrocardiographic and Echocardiographic Predictors of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy

Background

Patients with hypertrophic cardiomyopathy (HCM) have an increased prevalence of atrial fibrillation (AF) compared to the general population, and left atrium (LA) remodeling is strongly correlated with the risk of AF. This prospective, monocentric study aimed to assess the role of LA electrocardiographic and echocardiographic (structural and functional) parameters in predicting the risk for incident AF in patients with HCM.

Methods and Results

The study population consisted of 126 HCM patients in sinus rhythm (52.6 ± 16.2 years, 54 men), 118 of them without documented AF. During a median follow-up of 56 (7–124) months, 39 (30.9%) developed a new episode of AF. Multivariable analysis showed that LA booster pump function (assessed by ASr, HR = 4.24, CI = 1.84–9.75, and p = 0.038) and electrical dispersion (assessed by P wave dispersion – Pd, HR = 1.044, CI = 1.029–1.058, and p = 0.001), and not structural parameters (LA diameter, LA volume) were independent predictors of incident AF. Seventy-two patients had a LA diameter < 45 mm, and 16 of them (22.2%) had an AF episode during follow-up. In this subgroup, only Pd emerged as an independent predictor for incident AF (HR = 1.105, CI = 1.059–1.154, and p = 0.002), with good accuracy (AUC = 0.89).

Conclusion

Left atrium booster pump function (ASr) and electrical dispersion (Pd) are related to the risk of incident AF in HCM patients. These parameters can provide further stratification of the risk for AF in this setting, including in patients considered at lower risk for AF based on the conventional assessment of LA size.

Effect of chronic toluene exposure on heart rhythm parameters

BACKGROUND

Toluene is used extensively in various industrial processes, and an increasing number of workers are getting exposed to its vapor. Cardiac abnormalities that have been reported in association with toluene exposure (in toxic doses) are atrioventricular conduction abnormalities, sinus bradycardia, ventricular tachycardia, recurrent myocardial infarction, dilated cardiomyopathy, and coronary vasospasm.

HYPOTHESIS

We aimed to investigate the effects of chronic toluene exposure on cardiac rhythm.

METHODS

In this study, 40 workers in the polishing industry with more than 3 months of exposure to a mixture of organic solvents including toluene and 38 control subjects working in other fields who were matched by age, sex, smoking, habits, and living accommodation were investigated. Twelve-lead surface electrocardiogram and 24-hour Holter recordings were performed to determine QRS duration, PR duration (P and R wave interval on electrocardiograms), P wave dispersion, corrected QT dispersion, and heart rate variability parameters.

RESULTS

The maximum heart rate was significantly lower in the toluene-exposed group compared to the control group (130.5 ± 15.1 vs 138.6 ± 16.0, P = 0.02). Corrected low frequency (cLF) and cLF/corrected high frequency (cHF) were also significantly lower in toluene-exposed group (43.6 ± 7.2 vs 50.7 ± 10.5, P = 0.01 and 1.4 ± 0.4 vs 2.2 ± 1.0, P < 0.01, respectively). Mean cHF, root-mean-square successive difference, and standard deviation of all five-minute NN interval means values were significantly higher in the toluene-exposed group (32.8 ± 8.1 vs 25.4 ± 8.2, P ≤ 0.01; 74.0 ± 46.1 vs 60.3 ± 59.4, P = 0.02; and 149.5 ± 77.0 vs 108.9 ± 43.2, P = 0.01, respectively).

CONCLUSIONS

This study implies that chronic toluene exposure disturbs cardiac autonomy, particularly by suppressing sympathetic activity, and parasympathetic suppression also occurs with increased exposure duration. We also demonstrated that chronic toluene exposure was not associated with major cardiac arrhythmias and rhythm conduction system disorders.

The evaluation of a new marker of transmyocardial repolarization parameters in ischemic stroke patients; T peak-T end (T p-e), T p-e/QTc

The cardiovascular manifestations of acute ischemic stroke have been well known. Several electrocardiography (ECG) abnormalities have been reported in patients following acute stroke, including QT interval prolongation, ST segment deviation and T-wave changes. This study aimed to investigate the changes in transmyocardial repolarization parameters, in ischemic stroke patients. The study is a prospective, blind, and controlled clinical study. The patients without cardiac disease who received ischemic stroke diagnoses were included in the study. ECG was received from the patients in the first hour and 72 h. The P, QT, T _p-e, T _p-e dispersion, and the T _p-e/QT ratio were calculated. Moreover, fifty-five stroke patients and 35 control subjects were included to the study. All dispersion values and T _p-e/QT_c ratio in patients group were higher than those of control group (p < 0.05 for all values). When evaluated between ECGs' on first and third days, it was found that decreasing on all dispersion values and T _p-e/QT_c ratio in ECGs on third day than ECGs on first day (p < 0.05 for all values). QT, QT_c, and T _p-e dispersions values in patients who have insular lobe involvement were higher than those of patients who do not have insular lobe involvement (p < 0.001 for all values). In this study, we showed that acute stroke increases that P _d, QT_d, QT_cd and new repolarization markers T _p-e and T _p-e/QT_c, during first 24 and 72 h in acute stroke patients without cardiovascular disease compared with the control group. The physicians should be aware about ventricular dysrhythmias in patients with ischemic stroke and these patients closely observed with cardiac monitoring, especially within first 24 h, and especially patients with insular lobe involvement.

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.

The role of the atrial electromechanical delay in predicting atrial fibrillation in beta-thalassemia major patients

BACKGROUND

Paroxysmal atrial tachyarrhythmias frequently occur in beta-thalassemia major (β-TM) patients. The aim of the current study was to evaluate the atrial electromechanical delay (AEMD) in a large β-TM population with normal cardiac function and its relationship to atrial fibrillation (AF) onset.

METHODS

Eighty β-TM patients (44 men, 36 women), with a mean age of 36.2 ± 11.1 years, and 80 healthy subjects used as controls, matched for age and gender, were studied for the occurrence of AF during a 5-year follow-up, through 30-day external loop recorder (ELR) monitoring performed every 6 months. Intra-AEMD and inter-AEMD of both atria were measured through tissue Doppler echocardiography. P-wave dispersion (PD) was carefully measured using 12-lead electrocardiogram (ECG).

RESULTS

Compared to the healthy control group, the β-TM patients showed a statistically significant increase in inter-AEMD, intra-left AEMD, maximum P-wave duration, and PD. Dividing the β-TM group into two subgroups (patients with or without AF), the inter-AEMD, intra-left AEMD, maximum P-wave duration, and PD were significantly higher in the subgroup with AF compared to the subgroup without AF. There were significant good correlations of intra-left AEMD and inter-AEMD with PD. A cut-off value of 40.1 ms for intra-left AEMD had a sensitivity of 76.2% and a specificity of 97.5% in identifying β-TM patients with AF risk. A cut-off value of 44.8 ms for inter-AEMD had a sensitivity of 81.2% and a specificity of 98.7% in identifying this category of patients.

CONCLUSIONS

Our results showed that the echocardiographic atrial electromechanical delay indices (intra-left and inter-AEMD) and the PD were significantly increased in β-TM subjects with normal cardiac function. PD and AEMD represent non-invasive, inexpensive, useful, and simple parameters to assess the AF risk in β-TM patients.

Impact of Continuous Positive Airway Pressure Therapy on Atrial Electromechanical Delay in Obesity-Hypoventilation Syndrome Patients

BACKGROUND

Obesity-hypoventilation syndrome (OHS) is defined as daytime hypercapnia and hypoxemia in obese patients with sleep-disordered breathing. We evaluated the electrocardiographic P-wave duration and dispersion (PD) and echocardiographic noninvasive indicators of atrial conduction heterogeneity in OHS patients and the impact of CPAP on atrial conduction and atrial fibrillation incidence.

METHODS AND RESULTS

We enrolled 50 OHS patients and 50 sex- and age-matched obese subjects as control. Study population underwent cardiologic evaluation and polysomnography before enrollment, at 1- and 6-month follow-ups after CPAP therapy. The OHS group showed a significant increase in inter-atrial (35.2 ± 8 milliseconds vs. 20.1 ± 2.7 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 16.5 ± 2 milliseconds, P < 0.0001), and intra-right atrial electromechanical delays (AEMD)(24.8 ± 10 milliseconds vs. 15 ± 2.6 milliseconds, P < 0.0001) as well as in Pmax (130 ± 7.4 milliseconds vs. 97 ± 7.2 milliseconds, P = 0.002) and PD (56.5 ± 8.5 milliseconds vs. 31 ± 7.2 milliseconds, P = 0.002) compared to the control group. Significant improvement was noted after 6 months of CPAP therapy in inter-atrial (35.2 ± 8 milliseconds vs. 24.5 ± 6.3 milliseconds, P < 0.0001), intra-left (30.5 ± 7.2 milliseconds vs. 20.6 ± 5 milliseconds, P = 0.003), and intra-right AEMD (24.8 ± 10 milliseconds vs. 17 ± 7.5 milliseconds, P < 0.0001), as well as in Pmax (130 ± 7.4 milliseconds vs. 95 ± 10 milliseconds, P < 0.0001) and in PD (56.5 ± 8.5 milliseconds vs. 32.5 ± 6 milliseconds, P < 0.0001) in the OHS group. External loop recorder monitoring detected paroxysmal AF in 19 OHS patients (38%) with significant reduction in paroxysmal AF episodes (12 ± 6 vs. 47 ± 12, P < 0.0001) after 6-month CPAP therapy.

CONCLUSION

Our findings showed a significant increase of electrocardiographic and echocardiographic indexes of atrial conduction heterogeneity in OHS patients. The CPAP therapy, having a positive impact on atrial conduction time, seems to reduce AF incidence in OHS patients.

Atrial Septal Aneurysms and Supraventricular Arrhythmias: The Role of Atrial Electromechanical Delay

BACKGROUND

Paroxysmal supraventricular arrhythmias (SVAs) frequently occur in patients with atrial septal aneurysm (ASA). The aim of the current study was to evaluate the electrocardiographic (P-wave duration and dispersion) and echocardiographic (atrial electromechanical delay, AEMD) noninvasive indicators of atrial conduction heterogeneity in healthy ASA subjects without interatrial shunt and to assess the AEMD role in predicting the SVAs onset in this population.

MATERIALS AND METHODS

One hundered ASA patients (41 males, mean age of 32.5 ± 8 years) and 100 healthy subjects used as controls, matched for age and gender, were studied for the occurrence of SVAs during a 4-year follow-up, through 30-day external loop recorder (ELR) monitoring performed every 3 months. ASAs were diagnosed by transthoracic echocardiography based on the criteria of a minimal aneurismal base of ≥15 mm and an excursion of ≥10 mm. Intra-AEMD and inter-AEMD of both atria were measured through tissue Doppler echocardiography. P-wave dispersion (PD) was carefully measured using 12-lead electrocardiogram (ECG).

RESULTS

Compared to the healthy control group, the ASA group showed a statistically significant increase in inter-AEMD, intra-left AEMD, maximum P-wave duration, and PD. Dividing the ASA group into 2 subgroups (patients with or without SVAs), the inter-AEMD, intra-left AEMD, P max, and PD were significantly higher in the subgroup with SVAs compared to the subgroup without SVAs. There were significant good correlations of intra-left AEMD and inter-AEMD with PD. A cutoff value of 40.1 msec for intra-left AEMD had a sensitivity of 82% and a specificity of 83% in identifying ASA patients at risk for SVA.

CONCLUSION

Our results showed that the echocardiographic AEMD indices (intra-left and inter-AEMD) and the PD were significantly increased in healthy ASA subjects without interatrial shunt. PD and AEMD represent noninvasive, inexpensive, useful, and simple parameters to assess the SVAs' risk in ASA patients.

Atrial Fibrillation and Beta Thalassemia Major: The Predictive Role of the 12-lead Electrocardiogram Analysis

BACKGROUND

Paroxysmal atrial tachyarrhythmias frequently occur in beta-thalassemia major (β-TM) patients.The aim of our study was to investigate the role of maximum P-wave duration (P max) and dispersion (PD), calculated trough a new manually performed measurement with the use of computer software from all 12-ECG-leads,as predictors of atrial-fibrillation (AF) in β-TM patients with conserved systolic or diastolic cardiac function during a twelve-months follow-up.

MATERIALS AND METHODS

50 β-TM-patients (age38.4±10.1; 38M) and 50-healthy subjects used as controls, matched for age and gender, were studied for the occurrence of atrial arrhythmias during a 1-year follow-up, through ECG-Holter-monitoring performed every three months. The β-TM-patients were divided into two groups according to number and complexity of premature-supraventricular-complexes at the Holter-Monitoring (Group1: <30/h and no repetitive forms, n:35; Group2: >30/h or couplets, or run of supraventricular tachycardia and AF, n:15).

RESULTS

Compared to the healthy control-group, β-TM patients presented increased P-max (107.5± 21.2 vs 92.1±11ms, P=0.03) and PD-values (41.2±13 vs 25.1±5 ms,P=0.03). In the β-TM population, the Group2 showed a statistically significant increase in PD (42.8±8.6 vs 33.2±6.5ms, P<0.001) and P-max (118.1±8.7 vs 103.1±7.5ms, P<0.001) compared to the Group1. Seven β-TM patients who showed paroxysmal AF during this study had significantly increased P-max and PD than the other patients of the Group2. Moreover, P-max (OR:2.01; CI:1.12-3.59; P=0.01) and PD (OR=2.06;CI:1.17-3.64;P=0.01) demonstrated a statistically significant association with the occurrence of paroxysmal AF,P min was not associated with AF-risk (OR=0.99; CI:0.25-3.40; P=0.9) in β-TM-patients. A cut-off value of 111ms for P-max had a sensitivity of 80% and a specificity of 87%, a cut-off value of 35.5ms for PD had a sensitivity of 90% and a specificity of 85% in identifying β-TM patients at risk for AF.

CONCLUSION

Our results indicate that P-max and PD are useful electrocardiographic markers for identifying the β-TM-high-risk patients for AF onset, even when the cardiac function is conserved.

P-wave dispersion in children with acute rheumatic fever

As a new and simple electrocardiographic marker, P-wave dispersion is reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. The current study aimed to investigate P-wave dispersion in children with acute rheumatic fever. The study population consisted of 47 children with acute rheumatic fever (29 patients with carditis and 18 patients without carditis) and 31 healthy control subjects. Maximum and minimum P-wave durations were measured from the 12-lead surface electrocardiogram. The P-wave dispersion was calculated as the difference between maximum and minimum P-wave durations. The maximum P-wave duration and the P-wave dispersion of the patients with and without carditis were significantly greater than those of the control subjects. The P-wave dispersion of the patients with carditis was significantly greater than that of the patients without carditis. In conclusion, the P-wave dispersion was higher in the children with acute rheumatic fever than in the healthy control subjects.

Early electrocardiographic evaluation of atrial fibrillation risk in beta-thalassemia major patients

Although previous studies have documented a variety of electrocardiogram abnormalities in beta-thalassemia major (β-TM), little is known about P-wave dispersion (PD), an independent risk factor for development of atrial fibrillation. The aim of our study was to evaluate PD in β-TM patients with conserved systolic and diastolic functions. The study involved 40 β-TM patients (age 37.5 ± 10.2; 33 M) and 40 healthy subjects used as controls, matched for age and gender. PD was carefully measured using a 12-lead electrocardiogram. Cardiac iron levels were measured by cardiac magnetic resonance T2 star (CMR T2*) imaging. Comparing to the healthy control group, β-TM group presented increased values of the PD (40.1 ± 12.9 vs. 24 ± 7 ms; P < 0.004) and decreased CMR T2* imaging (29 ± 15 vs. 55 ± 13 ms; P = 0.03). We found a significant correlation between PD and CMR T2* values. Our study showed a significant increase of PD in β-TM patients with conserved systolic and diastolic cardiac functions. Our results indicate that PD is correlated to myocardial iron deposit, as assessed by CMR T2* imaging.

Acute sleep deprivation is associated with increased electrocardiographic P-wave dispersion in healthy young men and women

BACKGROUND

Sleep deprivation (SD) is associated with worse cardiovascular outcome including mortality. Prolonged P-wave duration and P-wave dispersion (Pd) are known to represent inhomogeneous conduction of sinus impulses and are known to be electrophysiologic predictors of atrial fibrillation. Pd in normal subjects has been reported to be influenced by the autonomic tone. Because autonomic tone is affected by sleep and sleep duration, we evaluated the effect of acute SD on P-wave duration and Pd in healthy young adults and whether the effect was gender selective.

METHODS

We obtained electrocardiograms of 37 healthy young volunteers (age: 28.45 +/- 7.97; 11 women) after a night of regular sleep and repeated after a night with sleep debt. We measured minimum and maximum P-wave durations (Pmin, Pmax) and Pd in milliseconds.

RESULTS

Average sleep time of the subjects were 7.7 +/- 0.8 hours during regular sleep and 1.7 +/- 1.6 hours during a night of sleep debt (P < 0.001). Subjects had significantly lower values of Pmin in milliseconds after a night of sleep debt when compared to regular sleep (65.13 +/- 8.03 vs 74.86 +/- 10.95; P < 0.001), whereas they had significantly higher values of Pmax and Pd (102.16 +/- 9.46 vs 95.13 +/- 11.21; P < 0.001 and 37.02 +/- 8.11 vs 20.27 +/- 11.42; P < 0.001, respectively). In Pearson's correlation analysis Pmin was positively and Pmax and Pd were negatively correlated with sleep time (P < 0.001, r = 0.465; P = 0.003, r =-0.336 and P < 0.001, r =-0.698 respectively). Effect of SD on P-wave duration and Pd was similar for both men and women.

CONCLUSIONS

In conclusion, prolongation of Pmax and Pd in acute SD suggests that acute SD might contribute to development and/or recurrence of atrial fibrillation.

Coronary Collateral Circulation: Any Effect on P-Wave Dispersion?

Coronary collateral circulation determines the severity of ischemic myocardial damage. Increased P-wave dispersion is an independent predictor for atrial fibrillation. Consistent evidence is little about the relation between coronary collateral circulation and arrhythmia risk. In this article, the effect of coronary collateral circulation on P-wave dispersion was evaluated. Collateral grade and P-wave dispersion were ascertained in 100 patients with ≥85% diameter stenoses in left anterior descending or right coronary arteries. Left ventricular function score was also determined in all patients. Coronary collateral circulation was absent in 32 patients, whereas 68 patients had coronary collateral circulation. Patients with collateral grade ≥1 had greater left ventricular function score than did patients with collateral grade 0 ( P = .048). However, there was no significant difference between P-wave dispersion of patients with and without coronary collateral circulation ( P = .45). The presence of coronary collateral circulation failed to exert a beneficial decreasing effect on P-wave dispersion.

Assessment of P-wave duration and dispersion in patients with isolated coronary artery ectasia

INTRODUCTION

Coronary artery ectasia (CAE) is defined as localized or diffuse dilatation of the epicardial coronary arteries. We sought to determine whether isolated CAE may alter P-wave duration and dispersion (PD).

METHODS

The study population consisted of 26 patients (mean age: 61.6+/-11.0 years) with isolated CAE (group 1) and sex- and age-matched 26 control subjects (group 2). Both groups underwent a standard 12-lead surface electrocardiogram recorded at 50 mm/s. Maximal (P(max)) and minimal P-wave durations (P(min)) are measured. PD was defined as the difference between P(max) and P(min).

RESULTS

In group 1, P(max) (114.2+/-10.4 ms vs 104.8+/-10.6 ms, p<0.002) and PD (34.0+/-12.7 ms vs 24+/-10.6, p<0.004) were significantly higher than those of group 2. Moreover a significant correlation was found between P(max) and PD with ectatic segment number (r=0.625, r=0.626, respectively; p=<0.001); and P(max) and PD with ectatic vessel number (r=0.698, r=0.704 respectively; p=<0.0001).

CONCLUSION

Isolated CAE and the degree of the ectasia were found to be associated with prolonged P(max) and PD.

The increase in P-wave dispersion is associated with the duration of disease in patients with Behçet's disease

AIM

P-wave dispersion (PD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. Behçet's disease (BD) is a chronic multi-system disease presenting with recurrent oral and genital ulceration, and relapsing uveitis. Left ventricular diastolic dysfunction, ventricular arrhythmia and sudden cardiac death have been documented in Behçet's disease. The aim of this study was to evaluate myocardial involvement noninvasively in patients with BD by measuring PD.

METHODS

Study population included 29 patients with BD (group I), (16 males, mean age: 60.4+/-10.1 years), and 45 normal (group II), (23 males, mean age: 61.2+/-12.0 years). The maximum and minimum P-wave duration (Pmax and Pmin) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed.

RESULTS

There was no statistically significant difference between two groups in respect to age, gender, hypertension, diabetes mellitus, hyperlipidemia and cigarette smoking (p>0.05). Pmax and PD of patients with BD were found to be significantly higher than those of control subjects (116.2+/-14.0 ms vs. 102.0+/-16.5 and 49.3+/-12.7 ms vs. 29.3+/-8.5 ms, respectively p<0.0001). Moreover, we found a significant positive correlation between PD with BD duration (r=0.78, p<0.0001).

CONCLUSION

Pmax and PD are found to be greater in patients with BD than in controls and are related with the duration of the disease.

Severe obesity and P-wave dispersion: the effect of surgically induced weight loss

BACKGROUND

Recent data have shown that obesity is an important potential risk factor for atrial fibrillation (AF). The mechanism of development of AF in obesity patients is still unclear and may be related to atrial refractoriness heterogeneity. The aim of our study was to determine the influence of bariatric surgery with a consequent substantial weight loss on P-wave dispersion in morbidly obese population.

METHODS

We enrolled in this study 40 severe obese patients, and 40 age-matched non-obese healthy subjects were also recruited as controls. All subjects underwent conventional 12-lead electrocardiography for the analysis of P-wave dispersion. All subjects underwent bariatric surgery and were resubmitted to electrocardiography, biochemical, and anthropometric examination within 12 months after intervention.

RESULTS

Severe obese patients had greater values in P-wave duration and dispersion than the normal weight controls. Bariatric surgery reduced significantly P-wave dispersion. There was a significant correlation between decrease of atrial refractoriness heterogeneity and bariatric-surgery-induced weight loss.

CONCLUSIONS

In severe obese patients, surgically induced weight loss reduction is associated with significant decreased in P-wave dispersion. The reduction of the atrial refractoriness heterogeneity may be of clinical significance by reducing the risk of atrial fibrillation in morbidly obese subjects.

The effect of VVI pacing on P-wave dispersion in patients with dual-chamber pacemakers

The incidence of atrial fibrillation is higher in patients with VVI pacing mode than DDD pacing mode, but the likely mechanism is not clearly understood. We aimed to evaluate whether short-term VVI pacing increases inhomogeneous atrial conduction by using P-wave dispersion. Forty-seven patients (32 men, 15 women, mean age 54 +/- 13 years) with DDD pacemakers were enrolled in this study. Twelve-lead surface ECGs were obtained in all patients during VDD pacing after an observation period of 1 week. The mode was then changed to VVI and 12 lead surface ECGs were obtained after another 1-week observation period. P-wave durations were calculated in all 12 leads in both VDD and VVI pacing modes. The difference between the maximum and the minimum P-wave duration was defined as the P-wave dispersion (PWD = P(max) - P(min)). P-wave maximum duration (P(max)) calculated in VVI pacing mode was significantly longer than in VDD pacing mode (128 +/- 19 vs 113 +/- 16 ms, P < 0.001). There was no significant difference in the P-wave minimum durations (80 +/- 13 ms vs 79 +/- 12 ms, P = 0.7) between VVI pacing and VDD pacing. The P-wave dispersion value was higher in the VVI pacing mode than in the VDD pacing mode (48 +/- 8 ms vs 34 +/- 7 ms, P < 0.001). Short-term VVI pacing induces prolongation of P(max) and results in increased P-wave dispersion, which might be responsible for the development of atrial fibrillation more frequently in these patients than in those with the VDD pacing mode.

P-wave dispersion: a novel predictor of paroxysmal atrial fibrillation

BACKGROUND

The prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with paroxysmal atrial fibrillation (AF). Previous studies have demonstrated that individuals with a clinical history of paroxysmal AF show a significantly increased P-wave duration in 12-lead surface electrocardiograms (ECG) and signal-averaged ECG recordings.

METHODS

The inhomogeneous and discontinuous atrial conduction in patients with paroxysmal AF has recently been studied with a new ECG index, P-wave dispersion. P-wave dispersion is defined as the difference between the longest and the shortest P-wave duration recorded from multiple different surface ECG leads. Up to now the most extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for AF in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease and in patients undergoing coronary artery bypass surgery. P-wave dispersion has proven to be a sensitive and specific ECG predictor of AF in the various clinical settings. However, no electrophysiologic study has proven up to now the suspected relationship between the dispersion in the atrial conduction times and P-wave dispersion. The methodology used for the calculation of P-wave dispersion is not standardized and more efforts to improve the reliability and reproducibility of P-wave dispersion measurements are needed.

CONCLUSIONS

P-wave dispersion constitutes a recent contribution to the field of noninvasive electrocardiology and seems to be quite promising in the field of AF prediction.

P-wave duration and dispersion in patients with coronary slow flow and its relationship with Thrombolysis in Myocardial Infarction frame count

AIM

P-wave dispersion (PD), and duration has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. The aim of this study was to investigate the PD in patients with coronary slow flow (CSF) phenomenon.

METHODS

Study population included 48 patients with angiographically proven normal coronary arteries and slow coronary flow in all 3 coronary vessels (group I, 36 men; mean age, 54 +/- 9 years) and 32 subjects with angiographically proven normal coronary arteries without associated slow coronary flow (group II, 24 men, mean age, 53 +/- 10 years). Coronary flow rates of all patients and control subjects were documented by Thrombolysis In Myocardial Infarction (TIMI) frame count. All patients in group I had TIMI frame counts greater than 2 SD above those of control subjects (group II). The mean TIMI frame count for each patient and control subject was calculated by adding the TIMI frame counts for each major epicardial coronary artery and then dividing the obtained value into 3. The maximum and minimum P-wave duration (P(max) and P(min)) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed.

RESULTS

There was no statistically significant difference between the 2 groups with respect to age, sex, hypertension, diabetes mellitus, hyperlipidemia, and cigarette smoking (P > .05). P-wave dispersion and P(max) of patients with CSF were found to be significantly higher than those of control subjects (39.4 +/- 17 vs 21.2 +/- 10 milliseconds and 121.6 +/- 17.1 vs 104.3 +/- 10.4 milliseconds, respectively; P < .0001). Moreover, we found a significant positive correlation between both P(max) and PD with mean TIMI frame count (r = 0.836 and r = 0.806, respectively; P < .0001).

CONCLUSIONS

P-wave dispersion and P-wave duration both were found to be greater in patients with CSF than in controls.

Effect of weight loss on P wave dispersion in obese subjects

OBJECTIVE

The aim of this study was to investigate effect of loss weight on P wave dispersion in obese subjects.

RESEARCH METHODS AND PROCEDURES

After a 12-week weight loss program (diet and medical therapy), a total of 30 (24 women and six men) obese subjects who had lost at least 10% of their original weight were included in the present study. All subjects underwent a routine standard 12-lead surface electrocardiogram. Electrocardiograms were transferred to a personal computer by a scanner and then magnified 400 times by Adobe Photoshop software (Adobe Systems, Mountain View, CA). P wave dispersion, which is also defined as the difference between the maximum P wave duration and the minimum P wave duration, was also calculated.

RESULTS

After a 12-week weight loss program, BMI (p < 0.001), maximum P wave duration (p < 0.001), and P wave dispersion (p < 0.001) significantly decreased. The mean percentage of weight loss was 13% (10% to 20.3%). The decrease in the level of P wave dispersion (21 +/- 10 and 7 +/- 12 ms, p < 0.002) was more prominent in Group II (>or=12% loss of their original weight) than Group I (<12% loss of their original weight) after the weight loss program. A statistically significant correlation between decrease in the level of P wave dispersion and percentage of weight loss was found (r = 0.624, p < 0.001).

DISCUSSION

Substantial weight loss in obese subjects is associated with a decrease of P wave duration and dispersion. Therefore, these observations suggest that substantial weight loss is associated with improvement in atrial repolarization abnormalities in obese subjects.

Anxiety and P Wave Dispersion in a Healthy Young Population

BACKGROUND

P wave dispersion (P(d)), defined as the difference between the maximum (P(max)) and the minimum P wave duration (P(min)), and P(max) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time. P(d) in normal subjects has been reported to be influenced by the autonomic tone, which induces changes in atrial size and the velocity of impulse propagation. However, the association between P(d) and anxiety has not been studied in normal subjects.

METHODS AND RESULTS

P(max), P(min) and P(d) were measured in 726 physically and mentally healthy young male volunteers, aged 21.23 +/- 1.25 years (range 20-26). The Spielberger State-Trait Anxiety Inventory (STAI) was scored concomitantly. Blinded intra- and interobserver reproducibility of the P wave duration and P(d) measurement were evaluated, and comparison revealed a Pearson correlation coefficient of 0.87 and 0.89 for the P wave duration, and 0.93 and 0.90 for P(d), respectively (p < 0.001). P(max) and P(d) were significantly correlated with the state anxiety (STAI-1) subscale (r = 0.662, p < 0.001, and r = 0.540, p < 0.001, respectively) and the trait anxiety (STAI-2) subscale (r = 0.583, p < 0.001, and r = 0.479, p < 0.001, respectively). P(min) did not show any significant correlation with anxiety. Across 3 variables included in a multiple linear regression analysis, STAI-1 and STAI-2 were the significant independent determinants of P(max) and P(d). Beta coefficients indicated that the contribution of STAI-1 to P(max) (66.3 and 33.7%) and P(d) (65 and 35%) was much greater than that of STAI-2.

CONCLUSIONS

STAI-1 and STAI-2 are associated with an increase in P(max) and P(d). The association of P(d) resulted from an augmentation of P(max). This is the first study to show the relation between P(max), P(d) and anxiety.

Effects of long-term beta-blocker therapy on P-wave duration and dispersion in patients with rheumatic mitral stenosis

BACKGROUND

P-wave dispersion (PWD), has been defined as the difference between maximum and minimum P-wave duration. Prolonged P-wave duration and increased PWD have been reported to be related with increased risk for atrial fibrillation (AF). AF is the most common sustained arrhythmia encountered in patients with rheumatic mitral stenosis (MS). Beta-blockers are the mainstay of therapy in patients with rheumatic MS to control ventricular rate both during sinus rhythm and AF. In the present study, we aimed to evaluate the effect of long-term beta-blocker therapy on P-wave duration and PWD in patients with rheumatic MS.

METHOD

Study population includes 46 patients (group I, 8 men, 38 women, mean age = 34+/-8 years) with newly diagnosed moderate-to-severe rheumatic MS who have not taken any medication before and prescribed oral beta-blocker therapy and 46 healthy control subjects without any cardiovascular disease (group II, 8 men, 38 women, mean age = 35+/-7 years). Mitral valve area, maximum and mean diastolic mitral gradients, left atrial diameter, and systolic pulmonary artery pressure were evaluated by transthoracic echocardiography before initiation of beta blocker therapy and repeated at the end of the first month. Baseline maximum and minimum P-wave duration and PWD were determined on 12-lead electrocardiogram recorded for each patient and control subject and repeated at the end of the first month after initiation of beta-blocker therapy in patient group.

RESULTS

Maximum P-wave duration and PWD were found to be significantly higher in patients with MS than those in control subjects (Maximum P-wave duration: 128+/-7 ms vs. 104+/-4 ms and PWD: 52+/-6 ms vs. 27+/-3 ms, p < 0.001 for both). Both groups had comparable minimum P-wave duration (75+/-4 ms vs. 76+/-4 ms, p = 0.093). Maximum P-wave duration and PWD were found to be significantly decreased by long-term beta blocker therapy (Maximum P-wave duration; 128+/-7 ms vs. 122+/-6 ms, p < 0.001, PWD; 52+/-6 ms vs. 47+/-5 ms, p < 0.001). However, there was no significant difference between the values of minimum P wave duration measured before and at the end of the first month of beta-blocker therapy (75+/-4 ms vs. 75+/-3 ms, p = 0.678). Statistically significant decrease were detected on maximum and mean mitral gradient and systolic pulmonary artery pressure and resting heart rate at the end of the first month of beta-blocker therapy. However, only the change in resting heart rate was found to be significantly correlated with the decrease in maximum P-wave duration and PWD (Maximum P-wave duration: r = 0.327, p = 0.026, PWD: r = 0.378, p = 0.01).

CONCLUSION

We have shown for the first time that long-term beta-blocker therapy causes a significant decrease in maximum P-wave duration and PWD in patients with rheumatic MS.

P-wave duration and P-wave dispersion in patients with dilated cardiomyopathy

BACKGROUND

P-wave dispersion (PWD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. In the present study, we aimed to investigate PWD in patients with dilated cardiomyopathy.

METHOD

The study population consisted of 72 patients with dilated cardiomyopathy and 72 healthy control subjects. Left atrial diameter, left ventricular end-diastolic and end-systolic diameters and left ventricular ejection fraction of all patients and control subjects were measured by means of transthoracic echocardiography. Maximum P-wave duration (Pmaximum) and minimum P-wave duration (Pminimum) were measured from the 12-lead surface electrocardiogram. PWD was calculated as the difference between Pmaximum and Pminimum.

RESULTS

Pmaximum and PWD of patients with dilated cardiomyopathy were significantly higher than those of control subjects (Pmaximum: 126+/-12 ms vs. 116+/-10 ms, PWD: 47+/-6 ms vs. 38+/-7 ms, respectively, P<0.001 for all). However, there was no statistically significant difference between patient group and control group regarding Pminimum (79+/-7 ms vs. 78+/-6 ms, respectively, P=0.27). Left atrial diameter was significantly higher in patients with dilated cardiomyopathy compared to control subjects (4.51+/-0.62 cm vs. 3.60+/-0.43 cm, respectively, P<0.001). Left ventricular ejection fraction was found to be significantly lower in patients with dilated cardiomyopathy compared to control subjects (33+/-5% vs. 63+/-7%, respectively, P<0.001).

CONCLUSION

PWD was found to be significantly higher in patients with dilated cardiomyopathy than in healthy control subjects.

Increased P wave dispersion and maximum P wave duration after hemodialysis

BACKGROUND

Atrial fibrillation is a frequent arrhythmia in patients undergoing hemodialysis. The consequences of hemodialysis on P wave durations and P wave dispersion have not been fully understood. The objective of this study was to study the effect of dialysis on P wave maximum (Pmax), P wave minimum (Pmin), and P wave dispersion (Pd).

METHODS

We studied Pmax, Pmin, and Pd in 32 patients (17 men and 15 women, mean age 54 +/- 18 years) with chronic renal failure undergoing hemodialysis. The difference between maximum and minimum P wave duration was calculated and defined as P wave dispersion (Pd= Pmax- Pmin).

RESULTS

There was a significant increase in Pmax at the end of dialysis compared to the beginning (98 +/- 13 ms vs. 125 +/- 12 ms, P < 0.001). Pmin did not show any significant change (71 +/- 11 ms vs. 73 +/- 10 ms, P = 0.42). Pd was significantly increased at the end of dialysis (27 +/- 9 ms vs. 52 +/- 11 ms, P < 0.001). There was a negative correlation between serum potassium, magnesium, phosphate, blood urea nitrogen, and creatinin at the end of dialysis and Pmax and Pd, respectively (P < 0.05). A weak positive correlation was found between serum calcium, bicarbonate at the end of dialysis and Pmax and Pd (P < 0.05).

CONCLUSION

Hemodialysis ends with significant increase in P wave maximum duration and P wave dispersion, which might be responsible for the increased occurrence of atrial fibrillation in these groups of patients.

Sinus and Paced P Wave Duration and Dispersion as Predictors of Atrial Fibrillation After Pacemaker Implantation in Patients with Isolated Sick Sinus Syndrome

The aim of this study was to prospectively evaluate the sinus and the paced P wave duration and dispersion as predictors of AF after pacemaker implantation in patients with isolated sick sinus syndrome (SSS). The study included 109 (69 women, mean age 72 +/- 11 years) patients with SSS, 59 with bradycardia-tachycardia syndrome (BTS). A 12-lead ECG was recorded before pacemaker implantation and during high right atrial and septal right atrial pacing at 70 and 100 beats/min. The ECGs were scanned into a computer and analyzed on screen. The patients were treated with AAIR (n = 52) or DDDR pacing. The P wave duration was measured in each lead and mean P wave duration and P wave dispersion were calculated for each ECG. AF during follow-up was defined as: AF in an ECG at or between follow-up visits; an atrial high rate episode with a rate of > or =220 beats/min for > or =5 minutes, atrial sensing with a rate of > or =170 beats/min in > or =5% of total counted beats, mode-switching in >/=5% of total time recorded, or a mode switching episode of > or =5 minutes recorded by the pacemaker telemetry. The ECG parameters were correlated to AF during follow-up. Mean follow-up was 1.5 +/- 0.9 years. None of the ECG parameters differed between patients with AF and patients without AF during follow-up, nor was there any difference between groups after correction for BTS and age. BTS was the strongest predictor of AF during follow-up (P < 0.001). P wave duration and dispersion measured before and during pacemaker implantation were not predictive of AF after pacemaker implantation in patients with isolated SSS.

P wave amplitude and duration may predict immediate recurrence of atrial fibrillation after internal cardioversion

BACKGROUND

Although internal cardioversion (IC) for atrial fibrillation (AF) is effective at restoring sinus rhythm, immediate recurrence (IR) of AF after IC is a major and largely unpredictable clinical problem. The purpose of the study was to determine the role of P wave duration and amplitude in prediction of IR of AF after IC. Forty-five consecutive patients undergoing IC for chronic AF were evaluated.

MATERIAL AND METHODS

After successful IC, 1-minute ECG recording was obtained in all patients. P wave duration and amplitude in Lead II and V1 were measured using computer. Forty patients (88%) had successful IC. Thirteen patients experienced IR of AF within 1 minute of restoring sinus rhythm.

RESULTS AND CONCLUSION

As a result, the incidence of IR of AF after IC was higher in the patients with shorter P wave amplitude (for lead II P<0.01, for V1 P<0.01) and larger P wave duration (for lead II P<0.01, for V1 P<0.05).

Duration of the P wave and P wave dispersion in subclinical hyperthyroidism

OBJECTIVE

To determine whether the values for P wave dispersion (Pdis) and adjusted Pdis, which are simple noninvasive electrocardiographic markers to detect paroxysmal atrial fibrillation, differ in patients with endogenous subclinical hyperthyroidism in comparison with those in healthy control subjects.

METHODS

We measured the maximal P wave duration and the difference between the maximal and the minimal P wave duration (Pdis) from the 12-lead surface electrocardiogram of 36 patients with endogenous subclinical hyperthyroidism and of 22 age- and sex-matched healthy control subjects. Adjusted Pdis (Pdis/square root of the number of measured electrocardiographic leads) was also calculated from each electrocardiogram.

RESULTS

The minimal P wave duration was significantly shorter in patients with subclinical hyperthyroidism than in healthy control subjects (P<0.001). Pdis and adjusted Pdis were also significantly higher in the patient group than in the control subjects (P<0.05). By univariate analysis, only thyrotropin levels were found to be associated with adjusted Pdis (r = -0.28; P = 0.03).

CONCLUSION

Pdis and adjusted Pdis differed in patients with endogenous subclinical hyperthyroidism in comparison with those values in healthy control subjects. Thus, these simple electrocardiographic markers may be useful for identifying patients with endogenous subclinical hyperthyroidism who are at risk for paroxysmal atrial fibrillation.

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

We hypothesized that the variance of P wave duration (P variance) in the 12-lead ECG could reflect the spatial dispersion of P wave duration due to inhomogeneous and delayed propagation of sinus impulses in the atria, and moreover could present better reproducibility than maximum P wave duration and P wave dispersion that have already been used for the prediction of idiopathic paroxysmal AF. We also tested a semiautomated PC-based method to improve the accuracy and reproducibility of P wave measurements. A 12-lead ECG was obtained from 60 patients with idiopathic paroxysmal AF and from 50 healthy controls. All ECGs were analyzed manually using magnifying lens and calipers, while 20 randomly selected ones were scanned and analyzed on screen using common commercial software. P maximum, P dispersion, and P variance were all significantly higher in patients with paroxysmal AF than in controls. A P maximum value of 110 ms, a P dispersion value of 40 ms, and a P variance value of 120 ms2 separated patients from controls with a sensitivity of 88%, 83%, and 80%, respectively and a specificity of 75%, 85%, and 74%, respectively. The reproducibility of P variance was higher compared to P dispersion and P maximum. Finally, the PC-based method significantly increased accuracy and reproducibility of P wave measurements. Thus, the variance of P wave duration could be a useful ECG marker for the prediction of paroxysmal idiopathic AF and the use of PC-based methods may enhance the accurate measuring of P wave duration on the ECG.

Clinical and electrocardiographic predictors of recurrent atrial fibrillation

Patients with frequent episodes of paroxysmal atrial fibrillation (AF) are prone to develop permanent AF and have an increased thromboembolic risk. We have previously shown that P wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P wave duration, and maximum P wave duration (P maximum) can distinguish patients with paroxysmal lone AF. The ability of those ECG markers and of other clinical and ECG variables to detect patients at risk for recurrent AF was tested in 88 patients, aged 64 +/- 12 years. All patients had a history of symptomatic episodes of AF during the last 2 years and had not previously received any antiarrhythmic prophylaxis. P maximum and P dispersion were calculated from a 12-lead surface ECG recorded in all patients during sinus rhythm. A computerized ECG system was used and P maximum and P dispersion were calculated on screen from the averaged complexes of all 12 leads. Age (P = 0.01), history of organic heart disease (P = 0.03), P maximum (P < 0.001), minimum P wave duration (P = 0.05), and P dispersion (P < 0.001) were found to be significant univariate predictors of recurrent AF, whereas only P maximum (P < 0.001) and age (P = 0.037) remained significant independent predictors of frequent AF paroxysms in the multivariate analysis. It is concluded that advanced age and prolonged P wave duration may be used as predictors of frequently relapsing AF. Therefore, simple AF predictors exist that could possibly distinguish the patients in whom prophylaxis with antiarrhythmic medicines should be instituted.

Effects of ischemia on P wave dispersion and maximum P wave duration during spontaneous anginal episodes

P wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P wave duration, and maximum P wave duration (P maximum) are electrocardiographic (ECG) markers that have been used to evaluate the discontinuous propagation of sinus impulses and the prolongation of atrial conduction time, respectively. To study the effects of myocardial ischemia on P dispersion and P maximum, 95 patients with coronary artery disease (CAD) and typical angina pectoris and 15 controls with angina like symptoms underwent 12-lead surface ECG during and after the relief of pain. During pain and during the asymptomatic period, P maximum and P dispersion were calculated from the averaged complexes of all 12 leads. P dispersion increased significantly during spontaneous angina (45+/-17 ms) compared to the asymptomatic period (40+/-15 ms), P < 0.001 only in the patient group. Both P maximum and P dispersion showed higher values during angina in those patients who developed diffuse ischemia, as estimated with ST segment changes in multiple ECG leads. P dispersion showed higher values during the anginal episode in patients with left ventricular dysfunction, independently of the presence of a previous myocardial infarction. Atrial conduction abnormalities, as estimated with P maximum and particularly P dispersion, are significantly influenced by myocardial ischemia in patients with CAD and spontaneous angina.

Comparison of different methods for manual P wave duration measurement in 12-lead electrocardiograms

To determine whether different methods for the manual measurement of P wave duration are mutually consistent, we evaluated the intraobserver and interobserver errors of P wave measurements obtained in three different ways: (1) by cursor on a high resolution computer screen (on screen), (2) by calipers and a magnifying glass (on paper), and (3) by a high resolution digitizing board (on board). The agreement between the methods was assessed in 30 normal subjects and 30 patients with a history of atrial fibrillation. The maximum P wave duration (P maximum), the minimum P wave duration (P minimum), mean P wave duration (P mean), P wave dispersion (P dispersion = P maximum - P minimum), and the standard deviation of the P wave duration in all measured leads (P SD) were calculated from a 12-lead electrocardiogram in each subject. Only P maximum, P mean, and P dispersion were significantly higher in patients than in controls with all three methods. Intraobserver and interobserver relative errors were significantly different among the three methods; the lowest errors were associated with the on-screen measurement. The agreement between the three different methods was acceptable for P maximum, P mean, and P SD and rather poor for P minimum and P dispersion in both groups. The differences of the measurement by different methods did not consistently differ between the two groups. Hence, the on-screen measurements are consistent with other manual methods and provide more stable results. Manual measurement of ECG patterns should be preferably performed with digital ECG recordings displayed on a high resolution computer screen.

Detection of hypertensive patients at risk for paroxysmal atrial fibrillation during sinus rhythm by computer-assisted P wave analysis

OBJECTIVE AND METHODS

To determine whether hypertensive patients at risk for paroxysmal atrial fibrillation (AF) could be detected while in sinus rhythm, a computer-based 12-lead surface electrocardiogram was recorded in 50 hypertensive patients with history of paroxysmal AF (group A) and in 60 hypertensive patients without history of AF (group B). The maximum P-wave duration (P(maximum)), the minimum P-wave duration (P(minimum)), P-wave dispersion (Pdispersion = Pmaximum Pminimum), adjusted P-wave dispersion (APdispersion = Pdispersion/square root of the number of measurable leads), mean P-wave duration (mean P) and the standard deviation of the P-wave duration in all measured leads (SDP) were calculated.

RESULTS

Pdispersion, APdispersion and SDP were significantly higher in group A than in group B (Pdispersion, 52 +/- 19 versus 41 +/- 15 ms, P< 0.001; APdispersion, 15.2 +/- 5.5 versus 11.9 +/- 4.6 ms, P< 0.001; SDP, 16 +/- 5 versus 13 +/- 5 ms, P < 0.001). P(minimum), mean P and left ventricle ejection fraction (LVEF) were significantly lower in group A than in group B (Pminimum, 79 +/- 18 versus 91 +/- 13 ms, P < 0.001; mean P, 108 +/- 18 versus 116 +/- 13 ms, P= 0.005; LVEF, 64 +/- 5 versus 69 +/- 8%, P< 0.001). Pminimum, Pdispersion, mean P, SDP, APdispersion and LVEF were found to be significant univariate predictors of paroxysmal AF, whereas only Pminimum (P< 0.001) remained a significant independent predictor of paroxysmal AF in the multivariate analysis.

CONCLUSION

Hypertensive patients at risk for paroxysmal AF could be detected while in sinus rhythm by computer-assisted electrocardiographic P-wave analysis.