Maximum P-wave Duration Research Articles

P‐Wave Indices, Distribution and Quality Control Assessment (from the Framingham Heart Study)

P-wave indices of maximum P-wave duration and P-wave dispersion have been examined in a broad array of cardiovascular and noncardiovascular disease states. The P-wave indices literature has been highly heterogeneous in measurement methodologies, described quality control metrics, and distribution of values. We therefore sought to determine the reproducibility of P-wave indices in a community-based cohort. P-wave indices were measured in sequential subjects enrolled in the Framingham Heart Study. Electrocardiograms were obtained at the 11th biennial visit of the Original Cohort (n = 250) and the initial visit of the Offspring Cohort (n = 252). We determined the mean P-wave durations, interlead correlations, and P-wave indices. We then chose 20 ECGs, 10 from each cohort, and assessed intrarater and interrater variability. The maximum P-wave duration ranged from 71 to 162 ms with mean of 112 + or - 12 ms. The minimum P-wave duration ranged from 35 to 103 ms with mean of 65 + or - 10 ms. P-wave dispersion ranged from 12 to 82 ms. The mean P-wave dispersion was 48 + or - 12 ms (40-56). The intrarater intraclass correlation coefficient (ICC) was r = 0.80 for maximum P-wave duration and r = 0.82 for P-wave dispersion. The interrater ICC was 0.56 for maximum P-wave duration and 0.70 for P-wave dispersion. We demonstrated excellent intrarater reproducibility and fair interrater reproducibility for calculating P-wave indices. Reproducibility is frequently lacking in studies of P-wave indices, but is an essential component for the field's growth and epidemiologic contribution.

P‐Wave Duration and Dispersion in Patients with Metabolic Syndrome

Metabolic syndrome (MS) has been reported to be associated with an increased risk of atrial fibrillation (AF). The aim of this study was to investigate P-wave dispersion (PWD) in patients with MS. The study population included 66 patients with MS (21 men, 45 women; mean age, 49.7 +/- 9.1 years) and 63 control subjects without MS (26 men, 37 women; mean age, 47.0 +/- 10.6 years). The diagnosis of MS was based on the National Cholesterol Education Program Adult Treatment Panel III criteria. A 12-lead electrocardiogram was recorded for each subject. The difference between maximum and minimum P-wave duration was calculated and defined as PWD. An echocardiographic examination was also performed for each subject. Maximum P-wave duration and PWD were found to be significantly higher in patients with MS compared with the control subjects (Maximum P-wave duration: 113.5 +/- 9.7 ms vs 101.0 +/- 8.1 ms, PWD: 37.8 +/- 7.6 vs 23.3 +/- 5.9, respectively, P < 0.001 for both). However, there was no statistically significant difference between two groups regarding minimum P-wave duration (75.6 +/- 6.9 ms vs 77.6 +/- 7.8 ms, respectively, P = 0.18). In addition, PWD was positively correlated with age, body mass index, waist circumference, systolic and diastolic blood pressure, triglyceride level, deceleration time, isovolumetric relaxation time and negatively correlated with high-density lipoprotein cholesterol level and early-to-late diastolic velocity ratio. We have shown that patients with MS have higher PWD, indicating increased risk for AF, compared to the control subjects without MS.

Assessment of Atrial Electromechanical Coupling Characteristics in Patients with Ankylosing Spondylitis

The aim of this study was to evaluate atrial conduction abnormalities obtained by Doppler tissue imaging (DTI) and electrocardiogram analysis in ankylosing spondylitis (AS) patients. A total of 40 patients with AS (22 males /18 females, 37.82 +/- 10.22 years), and 42 controls (22 males/20 females, 35.74 +/- 9.98 years) were included. Systolic and diastolic left ventricular (LV) functions were measured by using conventional echocardiography and DTI. Interatrial and intraatrial electromechanical coupling (PA) intervals were measured with DTI. P-wave dispersion (PD) was calculated from the 12-lead electrocardiogram. Atrial electromechanical coupling at the left lateral mitral annulus (PA lateral) was significantly delayed in AS patients (61.65 +/- 7.81 vs 53.69 +/- 6.75 ms, P < 0.0001). Interatrial (PA lateral - PA tricuspid), intraatrial electromechanical coupling intervals (PA septum - PA tricuspid), maximum P-wave (Pmax) duration, and PD were significantly longer in AS patients (23.50 +/- 7.08 vs 14.76 +/- 5.69 ms, P < 0.0001; 5.08 +/- 5.24 vs 2.12 +/- 2.09 ms, P = 0.001; 103.85 +/- 6.10 vs 97.52 +/- 6.79 ms, P < 0.0001; and 48.65 +/- 6.17 vs 40.98 +/- 5.37 ms, P < 0.0001, respectively). Reflecting LV diastolic function mitral A-wave and E/A, mitral E-wave deceleration time (DT), Am and Em/Am were significantly different between the groups (P < 0.05). We found a significant correlation between interatrial electromechanical coupling interval with PD (r = 0.536, P < 0.01). Interatrial electromechanical coupling interval was positively correlated with DT (r = 0.422, P < 0.01) and inversely correlated with E/A (r =-0.263, P < 0.05) and Em/Am (r =-0.263, P < 0.05). This study shows that atrial electromechanical coupling intervals and PD are delayed, and LV diastolic functions are impaired in AS patients.

Effects of slow coronary artery flow on P-wave dispersion and atrial electromechanical coupling

Aim Slow coronary flow (SCF) is characterized by angiographically normal coronary arteries with delayed opacification of the distal vasculature. The purpose of this study was to evaluate atrial electromechanical couplings and P-wave dispersion (Pd) reflecting intraatrial and interatrial conduction delays in SCF patients and the relationship between these parameters and Thrombolysis in Myocardial Infarction (TIMI) frame count. Methods Thirty-four patients with SCF and 40 controls were enrolled. From 12-lead surface electrocardiograms, Pd was calculated. Atrial electromechanical coupling (PA), intraatrial, and interatrial electromechanical delay were measured with tissue Doppler imaging. Results Maximum P-wave duration (Pmax) and Pd were higher in SCF patients than those of controls (109.2 ± 9.3 vs 92.3 ± 13.5 milliseconds; P < .0001 and 50.4 ± 9.4 vs 34.4 ± 8.9 milliseconds; P < .0001). Atrial electromechanical coupling at the left lateral mitral annulus (lateral PA), septal mitral annulus (septal PA), and right ventricular tricuspid annulus (RV PA) were significantly higher in SCF patients than controls (68.1 ± 8.1 vs 52.6 ± 7.3 milliseconds; P < .0001; 49.3 ± 9.8 vs 38.2 ± 5.3 milliseconds; P < .0001; 47.5 ± 9.0 vs 37.6 ± 4.6 milliseconds, P < .0001, respectively). Interatrial electromechanical delay (lateral PA − RV PA) was significantly longer in SCF patients (20.6 ± 9.1 vs 15.0 ± 6.0 milliseconds; P = .0002). A positive correlation was detected between circumflex coronary artery TIMI frame count and interatrial electromechanical delay ( r = 0.45; P < .01). Conclusions Prolongation of interatrial electromechanical delay, Pmax, and Pd suggest that SCF might contribute to development of adverse functional and electrophysiologic atrial characteristics in these patients.

Assessment of Atrial Conduction Time in Patients with Familial Mediterranean Fever

Increased inflammatory activity is known to be a pathophysiologic characteristic of atrial fibrillation. Familial Mediterranean fever (FMF) is a disease characterized by recurrent and sustained increased inflammatory activity. Atrial conduction abnormalities in these patients have not been investigated in terms of P-wave duration, P-wave dispersion (Pd), and atrial electromechanical delay measured by tissue Doppler echocardiography (TDE). We aimed to assess atrial conduction time in patients with FMF. A total of 33 patients with FMF (13 males/20 females, 28.4 +/- 12.5 years), and 33 controls (13 males/20 females, 28.5 +/- 12.1 years) were included. Atrial electromechanical coupling (PA) and intra- and interatrial electromechanical delay were measured with TDE. From the 12-lead electrocardiogram Pd was calculated. Atrial electromechanical coupling at the left lateral mitral annulus (PA lateral) was significantly higher in FMF patients (58.0 +/- 9.0 vs 51.0 +/- 5.8, P < 0.001). Interatrial (PA lateral-PA tricuspid) and intraatrial electromechanical delay (PA septum-PA tricuspid) were significantly longer in FMF patients (21.3 +/- 7.4 vs 12.9 +/- 4.6, P < 0.001 and 4.7 +/- 5.5 vs 2.1 +/- 1.7, P = 0.01, respectively). Also, Pd and maximum P-wave duration were significantly higher in FMF patients (42.8 +/- 7.9 vs 35.3 +/- 6.1, P < 0.001 and 98.6 +/- 9.0 vs 93.1 +/- 8.5, P = 0.01, respectively). A positive correlation was detected between interatrial electromechanical delay and Pd (r = 0.622, P < 0.001). Plasma level of C-reactive protein (CRP) correlated with interatrial electromechanical delay and Pd (r = 0.733, P < 0.001; and r = 0.427, P < 0.001, respectively). This study shows that atrial electromechanical delay and Pd are prolonged in FMF patients. Atrial electromechanical delay is closely associated with Pd and plasma level of CRP.

The Effects of Trimetazidine on P‐Wave Duration and Dispersion in Heart Failure Patients

P-wave duration and dispersion (PWD) have been shown to be noninvasive predictors for development of atrial fibrillation. Thus, it may be possible to attenuate atrial fibrillation risk through normalization of P-wave duration and dispersion. Trimetazidine, a metabolic modulator, has been reported to improve cardiac function in heart failure (HF) patients. Thirty-six HF patients being treated with angiotensin inhibitors, carvedilol, spironolactone, and furosemide were prescribed trimetazidine, 20 mg three times a day. Electrocardiographic and echocardiographic examinations were obtained before and 6 months after addition of trimetazidine in HF patients and 36 healthy control group patients having normal echocardiographic examination. Maximum P-wave duration (Pmax) (106.7 +/- 15.8 vs. 91.7 +/- 12.7 ms) and PWD (57.2 +/- 15.4 vs. 37.9 +/- 16.7 ms) were significantly longer in HF patients compared to the control group. There were significant correlations of Pmax and PWD with left atrial diameter (r = 0.508, P = < 0.001 and r = 0.315, P = 0.029), left ventricular ejection fraction (LVEF) (r = 0.401, p = 0.005 and r = 0.396, P = 0.005), deceleration time (r = 0.296, P = 0.032 and r = 0.312, P = 0.035), and isovolumetric relaxation time (r = 0.265, P = 0.038 and r = 0.322, P = 0.015). There were significant improvements in LVEF (32.7 +/- 6.5% to 37.2 +/- 5.5%, P = 0.036), left atrial diameter (41.5 +/- 6.7 to 40.3 +/- 6.1 mm, P < 0.001), and Pmax (106.7 +/- 15.8 to 102.2 +/- 11.5 ms, P = 0.006) and PWD (57.2 +/- 15.4 to 48.9 +/- 10.1 ms, P < 0.001) during follow-up. Trimetazidine added to optimal medical therapy in HF may improve Pmax and PWD in association with improved left ventricular function. Longer-term and larger studies are necessary to evaluate whether these findings may have clinical implications on prevention of atrial fibrillation.

Association of P-Wave Dispersion With Paroxysmal Atrial Fibrillation in Patients With Acute Anterior Wall ST Segment Elevation Myocardial Infarction

Background and Objectives: P-wave dispersion (PWD) is a well-known electrophysiologic parameter of atria which are prone to fibrillation. Although paroxysmal atrial fibrillation (PAF) following an acute myocardial infarction (AMI) is not uncommon, the relationship between PWD and PAF following AMI has not been determined. Subjects and Methods: We reviewed the electrocardiograms, recorded on admission and every day during hospitalization, of 144 patients with primary anterior AMIs and measured the P-wave duration. The left atrial diameter and left ventricular ejection fraction (LVEF) were evaluated by echocardiography. Results: PAF occurred in 20 patients. The maximum P-wave duration and PWD were found to be significantly higher in patients with PAF than those without PAF (120.1±8.6 vs. 109.2±12.2 ms, p<0.001; and 68.5±11.9 vs. 48.7±9.6 ms, p<0.001, respectively). The minimum P-wave duration was significantly lower in patients with PAF than in patients without PAF (51.6±13.3 vs. 60.4 ±11.7 ms, respectively, p=0.003). There was no significant difference in the left atrial diameter between patients with PAF and patients without PAF (37.3±4.4 vs. 36.8±5.1 mm, respectively p=0.652); however, the LVEF was significantly different in the patients who developed PAF compared to those who did not develop PAF (38.5± 11.4 vs. 45.1±8.7 %, respectively, p=0.003). Conclusion: The maximum P-wave duration and PWD were significant predictive factors of PAF in patients with anterior wall ST elevation AMI based on univariate analysis. On the basis of multivariate analysis, age was an independent predictive parameter for PAF as well. (Korean Circ J 2009;39:66-70)

The effect of rapid blood pressure control on P-wave dispersion in hypertensive urgency

A sharp increase in blood pressure, increase in atrial pressure and atrial strain, left ventricular diastolic dysfunction, and left ventricular hypertrophy (LVH) lead to heterogeneity and instability in atrial conduction. The resulting physiopathological situation may elevate maximum Pwave duration (P(max)) and P-wave dispersion (PWD) in electrocardiography. The objective of our study was to explore the effect of the sudden change in atrial hemodynamics on P(max) and PWD, which may indicate the risk of atrial fibrillation (AF) development in hypertensive urgency. The study included patients diagnosed as hypertensive urgency (systolic blood pressure > or =180 mmHg, diastolic blood pressure > or =110 mmHg). Nitroprusside was started at a dose of 0.2 microg/kg/min, and the ensuing dose was arranged according to blood pressure. Echocardiography and electrocardiography were used to noninvasively measure changes in diastolic function and PWD and P(max), respectively. The study enrolled 102 patients (mean age 57.9+/-11.6 years; 32 [31.4%] males, and 70 [68.6%] females). P(max) decreased from 99.9+/-11.1 msec (95% confidence intervals [CI] 97.7, 102) to 88.5+/-9.3 msec (95% CI 86.6, 90.3) (P<0.001), while PWD decreased from 60.1+/-7.4 msec (95% CI 58.7, 61.6) to 43.9+/-6.7 msec (95% CI 42.5, 45.2) (P<0.001). In addition, most patients had LVH and diastolic dysfunction. After nitroprusside treatment improvements in indicators of diastolic functions such as E/A ratio, deceleration time, and isovolumetric relaxation time were observed. The change observed in P(max) and PWD in hypertensive urgency may be associated with the rapid change in blood pressure and atrial strain, sympathetic nervous system activation, relative myocardial ischemia, and left ventricular diastolic dysfunction. Rapid regulation of blood pressure with nitroprusside brought about a marked decrease in P(max) and PWD in our patients. This improvement was interpreted as atrial conduction acquiring a stable and homogeneous character, which may reduce the risk of AF development in hypertensive urgency.

EFFECT OF ANAESTHETIC AGENTS ON P‐WAVE DISPERSION ON THE ELECTROCARDIOGRAM: COMPARISON OF PROPOFOL AND DESFLURANE

Anaesthetics influence cardiac electrical activity by various mechanisms; thus, they may have pro-arrhythmic or anti-arrhythmic actions. Increased P-wave dispersion is associated with a risk of paroxysmal atrial fibrillation. The aim of the present study was to analyse the impact of propofol and desflurane on changes in P wave dispersion, which may reflect the anti-arrhythmic effects of these drugs. Fifty patients undergoing scheduled surgery were included in the study. Patients were divided into two equal groups: a propofol group and a desflurane group. Patients in the propofol group were initially administered 2.5 mg/kg propofol, followed by infusion of 6 mg/kg per h propofol. Anaesthesia in the desflurane group was achieved using inhalation induction, with concentrations up to 8-12.5 vol%. When signs of adequate anaesthesia were observed, the concentration of desflurane was reduced to 6 vol%. An electrocardiogram (ECG) was obtained before induction and then again 1, 3 and 5 min after the initiation of propofol infusion or the induction of anaesthesia in the desflurane group; additional measurements were performed after tracheal intubation. P-wave dispersion was assessed by differences in maximal and minimal P-wave duration on a 12-lead ECG. P-wave dispersion did not change over time in the desflurane group. In the propofol group, there was a significant decrease in P-wave dispersion after 3 and 5 min of anaesthesia. Significant differences were observed between study groups after 1, 3 and 5 min of anaesthesia, and disappeared after tracheal intubation. Mean and maximal P-wave duration did not change in either group. In conclusion, propofol decreases P-wave dispersion and this seems to be connected with the anti-arrhythmic properties of the drug.

The effects of surgical repair on P-wave dispersion in children with secundum atrial septal defect

Atrial septal defect (ASD) is one of the most common congenital heart diseases in children. P-wave dispersion has been reported to be associated with non-homogeneous propagation of sinus impulses. The heterogeneity of atrial conduction time may predispose the atria to arrhythmias. The aim of this study was to determine the impact of surgical repair on P-wave indices in children with isolated secundum ASD. Children with isolated secundum ASD undergoing surgical repair (n=50; mean age, 7.0+/-3.0 years) and healthy controls (n=51; mean age, 7.6+/-2.7 years) were compared. Maximum P-wave duration (Pmax), shortest duration (Pmin) and P-wave dispersion (Pd) were measured using 12-lead surface electrocardiography. Mean Pmax was found to be significantly higher in children with ASD compared with controls (95.2+/-10.8 vs 84.1+/-9.2 msec; P<0.001), and Pd before surgery was significantly higher compared with controls (47.4+/-12.0 vs 38.8+/-9.7 msec; P<0.001). Both P-wave indices were significantly decreased within the first year after surgical closure - the values decreased to those comparable to healthy controls (Pmax, 86.2+/-9.7 msec; Pd, 39.8+/-10.7 msec; P>0.05). Surgical closure of ASD in children decreases Pmax and P-wave conduction time. We speculate that earlier closure of the defect may play an important role in avoiding permanent changes in the atrial myocardium and atrial fibrillation in adulthood.

Comparison of the effects of quinapril and irbesartan on P-wave dispersion in hypertensive patients

P-wave dispersion (PWD) has been shown to be a non-invasive electrocardiographic predictor for development of atrial fibrillation (AF). Thus, it may be possible to attenuate AF risk through improvement of PWD. In this study, we compared the effects of an angiotensin-converting enzyme (ACE) inhibitor, quinapril, and an angiotensin receptor blocker (ARB), irbesartan, on PWD. A total of 38 newly diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either irbesartan (150-300 mg) or quinapril (20-40 mg). P-wave durations and PWD were measured at baseline and after 6 and 12 months of treatment. Echocardiographic examinations were performed at baseline and after 12 months of treatment. Both drugs significantly reduced blood pressure to a similar degree (P<0.001). Deceleration time (both P<0.001) and isovolumetric relaxation time (both P=0.007) were also significantly reduced, whereas there was no significant change in the early diastolic flow/atrial contraction signal ratio. Both irbesartan and quinapril significantly decreased maximum P-wave duration (Pmax) (P<0.001 and P=0.002, respectively) and PWD (from 68.0+/-22.1 to 41.0+/-25.1 msec for irbesartan, and from 70.5+/-20.4 to 46.6+/-13.3 msec for quinapril; both P<0.001). Baseline and follow-up blood pressure, heart rate, echocardiographic findings, and P-wave values were not significantly different between the irbesartan and quinapril groups. No patient developed AF during follow-up. There was no significant correlation between PWD and blood pressure or diastolic function parameters. Antihypertensive treatment with either irbesartan or quinapril is associated with significant reductions in Pmax and PWD.

Usefulness of P-Wave Dispersion in Standard Twelve-Lead Electrocardiography to Predict Transition from Paroxysmal to Persistent Atrial Fibrillation

A prospective study was conducted to investigate the validity of the hypothesis that P-wave dispersion (Pd) may be a clinically useful predictor of progression from paroxysmal to persistent atrial fibrillation (AF). Two hundred four consecutive patients with a diagnosis of paroxysmal AF were studied. Standard 12-lead electrocardiography and echocardiography were performed on all patients at the time of entry into the study. Pd was measured as the difference between maximum and minimum P-wave duration in any of the 12 leads. Mean follow-up was 66 +/- 8 months. Group I included patients (n = 132) in whom paroxysmal AF did not progress to persistent AF, and group II included those (n = 72) who developed persistent AF. In group II, age, percentage of men, percentage of patients with diabetes mellitus, maximum P-wave duration, Pd, and left atrial dimension were significantly higher than in group I (p <0.05). Multivariate logistic regression analysis using these 6 factors identified age (odds ratio 2.18, 95% confidence interval 1.41 to 3.41, p <0.01) and Pd (odds ratio 1.91, 95% confidence interval 1.51 to 2.44, p <0.01) as independent predictors of a transition to persistent AF. Pd >or=40 ms predicted progression to persistent AF with sensitivity of 71%, specificity of 77%, positive predictive value of 63%, negative predictive value of 83%, and accuracy of 75%. In conclusion, Pd was a clinically useful predictor of progression from paroxysmal to persistent AF.

The Effect of Altitude on P‐Wave and QT Duration and Dispersion

Short-term and long-term exposure to high altitude has been reported to change the surface electrocardiogram. We aimed to compare P-wave and QT parameters between healthy people living at high altitude and sea level. Twelve-lead electrocardiographies of 38 healthy people living at sea level (Antalya,Turkey) and 38 healthy people living at high altitude (Van, Turkey; 1,700-1,800 m) were obtained. Minimum and maximum P-wave durations, P-wave dispersion, minimum and maximum corrected QT intervals, and corrected QT dispersion were calculated. There was no significant difference between the two groups in respect to heart rate and QT variables. Mean Pminimum values were slightly but significantly lower in the high altitude group (P = 0.029). Mean Pmaximum values tended to be lower at high altitude but did not reach statistical significance (P = 0.085). However, there was no significant difference in respect to P-wave dispersion values. In a sample of men and women living at high altitude in Turkey, significant reduction of Pminimum and borderline reduction of Pmaximum duration, but no significant change of P-wave and QT dispersion, were observed.

Acute Sleep Deprivation is Associated with Increased Electrocardiographic P‐Wave Dispersion in Healthy Young Men and Women

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

Short-term effects of cilazapril and atenolol on P-wave dispersion in patients with hypertension

P-wave dispersion (PWD) has been shown to be a non-invasive electrocardiographic predictor for development of atrial fibrillation (AF). Thus, it may be possible to decrease AF risk through improvement in PWD. Our objective was to compare the effects of cilazapril and atenolol on P-wave duration and dispersion in patients with hypertension. A total of 38 newly diagnosed hypertensive patients were enrolled in the study. The patients were randomly assigned to receive treatment with either cilazapril (5 mg) or atenolol (50 mg). Doppler echocardiographic examination, P-wave durations and PWD were measured before and 1 mo after treatment Both drugs reduced blood pressure significantly (P<0.001). Posttreatment heart rate was significantly lower in the atenolol group (P=0.01). The change in maximum P-wave duration was not significant. However, both agents decreased PWD (P=0.001 and P<0.001) and increased the minimum P-wave duration (P=0.004 and P=0.02). Both cilazapril and atenolol treatments resulted in improvement in PWD.

P‐Wave Duration and Dispersion in Obese Subjects

Although previous studies have documented a variety of electrocardiogram (ECG) abnormalities in obesity, P-wave alterations, which represent an increased risk for atrial arrhythmia, have not been studied very well in these patients. The aim of the present study was to evaluate P-wave duration and P dispersion (Pd) in obese subjects, and to investigate the relationship between P-wave measurements, and the clinical and echocardiographic variables. The study population consisted of 52 obese and 30 normal weight control subjects. P-wave duration and P-wave dispersion were calculated on the 12-lead ECG. As echocardiographic variables, left atrial diameter (LAD), left ventricular end-diastolic, and end-systolic diameters (LVDD and LVSD), left ventricular ejection fraction (LVEF), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), and left ventricular mass (LVM) of the obese and the control subjects were measured by means of transthoracic echocardiography. There were statistically significant differences between obese and controls as regards to Pmax (maximum P-wave duration) and Pd (P dispersion) (P < 0.001 and P < 0.001, respectively). Pmin (minimum P wave duration) was similar in both groups. Correlation analysis showed that Pd in the obese patients was related to any the clinical and echocardiographic parameters including BMI, LAD, LVDD, IVST, LVPWT, and LVM. Our data suggest that obesity affects P-wave dispersion and duration, and changes in P dispersion may be closely related to the clinical and the echocardiographic parameters such as BMI, LAD, IVST, LVPWT, and LVM.

Effect of Ongoing Inflammation in Rheumatoid Arthritis on P-Wave Dispersion

It has been emphasized recently that there is a strong association between atrial fibrillation and inflammation. Rheumatoid arthritis (RA), characterized by ongoing inflammatory activity, can increase the risk of atrial arrhythmia. P-wave dispersion has been encountered as a risk factor for atrial fibrillation and the effect of inflammation on P-wave dispersion has not been studied thoroughly. The aim of this study was to examine the effect of ongoing inflammatory activity in RA on P-wave dispersion. The study comprised 82 patients diagnosed with RA and 41 healthy volunteers as controls. Systolic functions of all participants were evaluated by echocardiography. Maximum P-wave duration and dispersion were calculated and found to be significantly increased in the RA group compared with the healthy controls. These parameters were also significantly correlated with C-reactive protein levels. The findings of this study suggest that RA may be associated with increases in P-wave dispersion and maximum P-wave duration, and that this association may result from ongoing inflammation.

Effect of Slow Coronary Flow on P-Wave Duration and Dispersion

The slow coronary flow (SCF) phenomenon is often considered to be an incidental angiographic finding; however, several reports have shown it to be associated with cardiac events. In this study we aimed to assess P-wave duration and dispersion (PWD) in patients with SCF and to compare it with that of healthy subjects. Thus, 40 patients with angiographically proven SCF and otherwise normal coronary arteries (group 1) and 36 sex-age-matched healthy subjects (group 2) were included in this study. A 12-lead surface ECG, recorded at a paper speed of 50-mm/s and 2 mV/cm standardization, was obtained from each subject. P-wave duration was measured manually by use of a caliper. The difference between the maximum (Pmax) and minimum P (Pmin)-wave duration was calculated and defined as PWD. All subjects had undergone echocardiographic examination to exclude valvular disorders and wall motion abnormalities. There was no significant difference between the 2 groups in demographies of age, sex, heart rate, or blood pressure. Maximum P-wave duration and PWD were significantly higher in group 1 than in group 2 (120 +/-7 vs 115 +/-5, p = 0.003; 44 +/-12 vs 38 +/-9, p = 0.01, respectively). However, there was no significant difference in Pmin duration (75 +/-9 vs 78 +/-7, p = 0.4). In conclusion; SCF and otherwise normal epicardial coronary artery was found to be associated with prolonged P-wave duration and increased PWD. This may result from microvascular ischemia and/or altered autonomic control of cardiovascular system observed in this group of patients.

Reduction of P‐Wave Duration and Successful Pulmonary Vein Isolation in Patients with Atrial Fibrillation

We hypothesize that successful pulmonary vein (PV) isolation can shorten the P-wave duration in patients with atrial fibrillation (AF). We recorded magnified surface electrocardiogram (ECG) and P-wave signal-averaged ECG using 12 electrode leads before and after 31 PV isolation procedures in 27 patients with AF. The patients were followed for 16 +/- 4 months. Repeat ablation studies documented failed PV isolation in seven patients with AF recurrences. At baseline, the maximal P-wave duration in patients without AF recurrence (161 +/- 7 msec) was slightly shorter than that in patients with AF recurrence (168 +/- 10 msec, P < 0.05). After ablation, patients without recurrence showed a significant reduction of P-wave duration from 161 +/- 7 msec to 151 +/- 8 msec (P < 0.0001). In contrast, no change of P-wave duration was noted in patients with recurrences. These findings were confirmed with signal averaged ECG of the P-waves. Three-dimensional (3-D) computer simulation using an atrial cell model showed that elimination of the muscle sleeves inside the PV resulted in a shortening of the P-wave duration and change of the terminal portion of the P-wave morphology. A significant shortening of P-wave duration by P-wave signal-averaged ECG can be used as an indicator for successful PV isolation. These findings suggest that activation of the PV muscle sleeves may be an important component of the terminal portion of the P-wave on surface ECG.

Long-Term Prognostic Value of P-Wave Characteristics for the Development of Atrial Fibrillation in Subjects Aged 55 to 74 Years at Baseline

Atrial fibrillation (AF) is the most prevalent arrhythmia in the elderly, associated with high mortality and morbidity rates. Changes in electrocardiographic P waves were associated with AF in patient series, but the long-term prognostic value of P-wave characteristics in the development of AF was not shown. The aim was to evaluate P-wave duration and morphologic characteristics as potential independent risk markers for the long-term development of AF in the general population. A nested case-control design was adopted in subjects aged 55 to 74 years and apparently healthy at baseline. Baseline P-wave items of 40 patients who developed AF within the 10-year period were compared retrospectively with those of 120 matched controls. Broad maximum P waves (>/=120 ms) at baseline were observed in 70% of patients with AF and 41% of controls (p = 0.002). Maximum P-wave duration proved to be a significant risk marker independent of blood pressure, body mass index, and other electrocardiographic findings. However, this association seems overruled by the predictive value of morphologic changes defined as notched or deflected P waves (p = 0.0002). The joint occurrence of longer duration in combination with morphologic changes in the P wave proved a very important risk indicator for the development of AF over 10 years, with an adjusted odds ratio of 13.4 (95% confidence interval 3.3 to 46.6). In conclusion, enhanced clinical appreciation of P-wave items on the standard electrocardiogram at rest, preferably evaluated in all 12 leads, may help identify a group at high risk of the development of AF at an early stage.