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Background: Local theory and the vectorial theory are used to explain the origin of P-wave dispersion (PWD). There are no previous studies that analyze both at the same time.Objectives: We set out to determine the implication of local and vectorial theories in the origin of PWD.Methods: Cross-sectional study in 153 randomly selected patients aged 18-70 years, undergoing electrophysiological study. Inhomogeneous atrial conduction was evaluated by atrial electrogram dispersion in terms of duration (EGMdurdis) and morphology (EGMmorph dis). P-distal coronary sinus interval (P-DCS) was also measured. P-wave was measured twice, firstly at a calibration of 20 mm/mV and a sweep speed of 50 mm/s, enhancement 10× (basic measurement [BM]), and second time at sweep speed of 150 mm/s, enhancement 80-160× (high precision measurement [HPM]).Results: PWD with BM was 48 ms [36-54 ms] while with HPM it was 4 ms [0-10 ms], p < 0.001. With BM, maximum and minimum P- wave duration presented a moderate correlation (r = 0.342; p < 0.001), using HPM it becomes strong (r = 0.750; p < 0.001). In cases with P-DCS < 80 ms (r = 0.965; p < 0.001), but not with P-DCS ≥ 80 ms (r = 0.649; p < 0.001), the previous correlation became almost perfect with HPM. EGMdurdis and EGMmorphdis were weak but significantly correlated with PWD. This correlation became moderate in patients with P-DCS ≥ 80 ms and disappeared in those with P-DCS, using BM and HPM.Conclusion: Vectorial theory explains almost entirely the PWD phenomenon. Inhomogeneous conduction could be an additional mechanism to explain PWD, but its contribution is small. [ABSTRACT FROM AUTHOR]

Introduction: Long-time exposure to high altitude leads to changing at the respiratory, cardiovascular and hematological systems. There is no sufficient study about cardiovascular changes in moderate altitude. The distance between the peak and the end of the T wave (Tp-e) is a measure of transmyocardial distribution of repolarization and may be associated to dangerous rhythm disorders and ventricular arrhythmias. Again, P-wave dispersion (PWD) described as the extension of interatrial and intraatrial conduction time and inhomogeneous spread of sinus pulses are well recognized electrophysiologic features in patients with atrial fibrillation. We aimed to compare repolarization parameters (Tp-e interval, Tp-e/QT ratio, QT, cQT) and P wave dispersion between healthy people living at moderate altitude and sea level.Methods: In this study included 80 healthy people living at moderate altitude (1600 m, Group I) and 90 people living at sea level (0-4 m, Group II). All people were born and grew up at the same altitude area. Being migrant to living area, people with structural heart disease, rhythm disorders, pulmonary diseases or any systemic chronic disease were excluded criteria in the study. Tp-e interval, QT interval, cQT, Tp-e/QT ratio, P wave durations and PWD were measured from D2 and V5 leads with 20 mm/mV amplitude and 50 mm/s rate. All the measurements were repeated three times and were evaluated manually with a magnifying glass.Results: There were no differences in baseline demographic, laboratory, echocardiographic parameters and coronary artery risk factors. The QRS duration (94.2 ± 14.8 msn and 90.2 ± 9.3 msn, p = 0.05) and corrected QT time (415.8 ± 20.1 msn and 403.9 ± 20.5 msn; p = 0.001), Tp-e interval (86.5 ± 11.7 msn and 80.5 ± 10.4 msn p = 0.001) and Tp-e/QT ratio (0.23 ± 0.03 msn and 0.22 ± 0.03 msn p = 0.011) were statistically significantly higher in the moderate altitude group. P wave maximum, minimum time and PWD were similar in both groups (p > 0.05).Conclusion: Moderate altitude leads to subclinical electrocardiographic changes in healthy individuals such as high altitude. Repolarization parameters (Tp-e interval, Tp-e/QT ratio, and cQT) are prolonged without cardiac structural changes. It should be kept in mind that people living in moderate altitude may be more susceptible to arrhythmia in the future, and findings should be supported in large randomized trials. [ABSTRACT FROM AUTHOR]

Abstract: Background and Purpose: Prolonged P-wave dispersion (PWD) and P-wave duration (PWdur) have been found to be associated with common atrial fibrillation (AF), but the association of P-wave indices with lone atrial fibrillation (LAF) is unclear. Methods: We enrolled 61 paroxysmal LAF cases and 150 controls without AF. P-wave indices were measured from a 12-lead ECG. Multivariable logistic regression was used to assess the association between P-wave indices and LAF. Results: PWD was longer in LAF patients (median, IQR; 54.1 [42.9–63.2] ms) than controls (46.0 [38.5–57.7] ms), P=0.03. MinPWdur was shorter in LAF patients (60.5 [50.7–72.6] ms) than controls (66.0 [55.5–76.4] ms), P=0.03. In multivariable models, only the association between shorter minPWdur and LAF remained statistically significant (OR [95% CI] per tertile increment in minPWdur, 0.64 [0.42–0.95], P=0.03). Conclusions: Unlike common AF, paroxysmal LAF is independently associated with shorter minPWdur. This finding suggests that both shorter and prolonged PWdur may be associated with increased risk of AF. [Copyright &y& Elsevier]

Abstract: Objectives: Obstructive sleep apnea (OSA) has been reported to be associated with an increased risk of atrial fibrillation. The aim of this study was to investigate atrial electromechanical couplings in patients with OSA and the relationship between these parameters and P-wave dispersion (Pd). Methods: One hundred twenty-six patients were enrolled in this study. All patients underwent polysomnographic examination. The apnea-hypopnea index (AHI) was defined as the number of apneas and hypopneas per hour of sleep. An AHI score of 5 or more was diagnosed as OSA, and an AHI score of less than 5 was diagnosed as OSA (−). Thirty-nine of the patients had an AHI score of less than 5 (group 1), 42 of the patients had AHI score between 5 and 30 (mild and moderate, group 2), 45 of the patients had an AHI score more than 30 (severe, group 3). Atrial electromechanical coupling (PA), intra-atrial, and interatrial electromechanical delay were measured with tissue Doppler imaging. P-wave dispersion was calculated from 12-lead electrocardiogram. Results: Maximum P-wave duration was higher in group 3 compared with groups 2 and 1 (126.0 ± 16.7 vs 111.0 ± 12.5 [P < .001] and 126.0 ± 16.7 vs 99.9 ± 10.0 [P < .001], respectively). Maximum P-wave duration was higher in group 2 than in group 1 (111.0 ± 12.5 vs 99.9 ± 10.0, P < .001). P-wave dispersion was higher in group 3 compared with groups 2 and 1 (50.9 ± 11.5 vs 37.0 ± 8.6 [P < .001] and 50.9 ± 11.5 vs 27.9 ± 6.8 [P < .001], respectively). P-wave dispersion was higher in group 2 than in group 1 (37.0 ± 8.6 vs 27.9 ± 6.8, P < .001). Minimum P-wave duration did not differ between the groups. Atrial PA at the left lateral mitral annulus (lateral PA), septal mitral annulus (septal PA), and right ventricular tricuspid annulus (RV PA) were significantly higher in group 3 than in group 2 (P < .001, P = .001, and P = .009, respectively). Lateral PA, septal PA, and RV PA were higher in group 2 compared with group 1 (P < .001, P = .003, and P = .009, respectively). Interatrial electromechanical delay (lateral PA − RV PA) was significantly longer in group 3 compared with groups 2 and 1 (33.6 ± 12.1 vs 22.4 ± 9.4 [P < .001] and 33.6 ± 12.1 vs 14.9 ± 9.2 [P < .001], respectively). Interatrial electromechanical delay was longer in group 2 than in group 1 (22.4 ± 9.4 vs 14.9 ± 9.2, P = .001). There was a positive correlation between AHI and Pd, lateral PA, septal PA, RV PA, interatrial electromechanical delay, and left-sided intra-atrial electromechanical delay. Conclusion: Prolongation of electromechanical delay and increased Pd are associated with apnea-hypopnea index (AHI) and hence the severity of disease. [Copyright &y& Elsevier]

Abstract: Background: Atrial electromechanical delay (AEMD) calculated from tissue Doppler imaging (TDI) echocardiography can be an alternative to invasive electrophysiologic studies. We investigated whether the AEMD obtained from TDI is prolonged in patients with nonischemic dilated cardiomyopathy (DCM). Methods: Fifty-five patients with nonischemic DCM (23 men/32 women; age, 43.9 ± 14.8 years) and 55 controls (20 men/35 women; age, 41.3 ± 13.4 years) were included in this study. Atrial electromechanical delay (the time interval from the onset of P wave on electrocardiogram to the beginning of late diastolic wave [Am wave] on TDI) was calculated from the lateral and septal mitral annulus, and lateral tricuspid annulus (PA lateral, PA septum, and PA tricuspid, respectively). P-wave dispersion was calculated from the 12-lead electrocardiogram. Results: PA lateral and PA septum duration were significantly longer in patients with nonischemic DCM than the controls (78.4 ± 19.7 versus 53.8 ± 6.6 and 55.2 ± 16.3 versus 40.5 ± 6.2, P < .0001 for both; respectively). However, PA tricuspid duration was statistically similar between the 2 groups (36.4 ± 10.9 versus 37.2 ± 5.7, P ≥ .05). P-wave dispersion was significantly higher in nonischemic DCM patients than the controls (53.0 ± 14.4 versus 37.5 ± 5.5, P < .0001). PA lateral was correlated with the left atrial maximal volume (r = 0.64, P < .0001), P-wave dispersion (r = 0.65, P < .0001), and log B-type natriuretic peptide (NT proBNP) (r = 0.63, P < .0001). There was a statistically significant and negative correlation between the PA lateral and left ventricular ejection fraction (r = −0.63, P < .0001) and E-wave deceleration time (r = −0.34, P < .0001). Multivariate analysis revealed that left atrial maximal volume and log NT proBNP were the independent predictors of PA lateral (P < .0001 and P = .003, respectively). Conclusion: The AEMD was significantly prolonged in patients with nonischemic DCM. Left atrial enlargement and log NT proBNP were the independent predictors of this prolongation. [Copyright &y& Elsevier]

Abstract: The aim of our study was to investigate atrial conduction time in patients with mitral annulus calcification (MAC) using P-wave dispersion (PWD) and electromechanical coupling measured with the surface electrocardiogram and the tissue Doppler echocardiography. Fifty-nine patients with MAC and 43 control subjects underwent resting the surface electrocardiogram and tissue Doppler echocardiography. The difference between the maximum (Pmax) and minimum P-wave durations was calculated and defined as PWD. Interatrial and intraatrial electromechanical delays were measured with tissue Doppler echocardiography. Both Pmax and PWD were higher in patients with MAC compared with controls (111.4 ± 15.8 vs 97.3 ± 18.8 milliseconds; P < .0001 and 46.4 ± 14.6 vs 31.4 ± 13.1 milliseconds; P < .0001, respectively). Both interatrial and intraatrial conduction time were also delayed in patients with MAC compared with controls (29.8 ± 13.3 vs 17.6 ± 12.5 milliseconds; P < .0001; 9.4 ± 5.1 vs 6.8 ± 4.0 milliseconds; P < .008, respectively). Left atrial (LA) diameter was significantly higher in patients with MAC compared with controls (35.4 ± 5.0 mm vs 32.3 ± 4.2 mm; P < .001). The LA diameter correlated significantly with both interatrial conduction times and PWD (r = 0.56; P < .0001 and r = 0.47; P < .0001, respectively). There is a delay in both intraatrial and interatrial electromechanical coupling intervals in patients with MAC. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Aim: P-wave dispersion (PD) has been reported to be associated with inhomogeneous and discontinuous propagation of sinus impulses. The purpose of this study was to investigate the PD in patients with stable coronary artery disease (CAD) and to determine its relationship with severity of the disease.Methods: We prospectively analyzed 66 subjects with normal coronary angiogram (group 1) and 68 patients with significant (> or =50%) coronary stenosis; 25 had 1-vessel disease (group 2), 27 had 2-vessel disease (group 3), and 16 had 3-vessel disease (group 4). 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. Angiographic vessel score and Gensini score were used to evaluate the severity of CAD.Results: Pmax was longer in groups 3 and 4 compared with group 1 (P = .001 for both comparison). PD was greater in groups 2, 3, and 4 compared with group 1 ( P < .001 for all comparison), and also in group 4 compared with group 2 (P = .001). However, there was no statistically significant difference among the groups regarding Pmin. In bivariate correlation, increased PD was correlated with presence of hypertension (r = 0.278, P = .013), left ventricular ejection fraction (r = -0.231, P = .044), left atrial diameter (r = 0.223, P = .032), presence of moderate to severe mitral regurgitation (r = 0.284, P = .017), vessel score (r = 0.465, P < .001), and Gensini score (r = 0.338, P = .005). Multiple linear regression analysis showed that only vessel score was independently associated with PD (beta = .471, P = .01).Conclusions: PD was found to be greater in patients with stable CAD than in controls and to be associated with severity of the disease. [ABSTRACT FROM AUTHOR]

Abstract: Hemodialysis (HD) has been associated with an increase in the amplitude of QRS complexes. Experience in a single patient with multiple measurements has shown that HD leads also to augmentation of P-wave amplitude. The objective of this investigation was to evaluate electrocardiogram (ECG) changes with HD in a cohort of patients undergoing this procedure with particular emphasis on the P-wave and QRS complex changes. The sum of amplitudes of P waves (ÓP) and QRS complexes (ÓQRS) in millimeters in the 12 leads of the ECG, along with a host of other ECG parameters, body weight, blood pressure, heart rate, electrolytes, and hemoglobin/hematocrit were measured before and immediately after HD in 47 patients. Hemodialysis resulted in a loss of a mean of 3 kg of weight and an increase in the ΣP, ΣQRS, mean QRS duration, maximum P-wave duration, and P-wave duration measured in lead II, whereas the changes in mean P-wave and corrected QT interval durations were not statistically significant. Percentage change (Δ%) in ΣP and ΣQRS correlated poorly with Δ% in electrolytes, hematocrit, blood pressure, heart rate, and weight. Values for ΣP and ΣQRS vs weight were r = 0.105, P = .48 and r = 0.09, P = .51, respectively. The Δ% in ΣP correlated well with Δ% in ΣQRS (r = 0.42, P = .003). Alterations in P-wave amplitudes and duration commensurate with the ones affecting the corresponding QRS complexes occur in patients undergoing HD and indicate that evaluation of measurements in serial ECGs should take this into account. The mechanisms of these phenomena continue to be elusive, and whether they represent cardiac and/or extracardiac influences has not as yet been unraveled. [Copyright &y& Elsevier]

Abstract: Aim: P-wave durations and P-wave dispersion (PD) are considered to reflect the heterogeneous conduction in atria. The aim of this study was to investigate PD and P-wave duration in different left ventricle geometric patterns of hypertensive patients. Methods: One hundred forty-nine consecutive patients with newly diagnosed essential hypertension and 29 healthy control groups were included in the study. The maximum and minimum P-wave duration (P max and P min, respectively) and PD were measured from the 12-lead surface electrocardiogram. Echocardiographic examination was also performed in all subjects. Four different geometric patterns were identified in hypertensive patients according to left ventricular mass index (LVMI) and relative wall thickness. Results: P-wave dispersion was longer in concentric remodeling (CR), concentric hypertrophy (CH), and eccentric hypertrophy (EH) groups when compared with the control group (P = .009, P < .001, P < .001, respectively). P-wave dispersion of normal left ventricle (NLV) geometric pattern was not different from that of the control group. Patients with NLV geometric pattern had shorter PD than patients who had CH and EH (NLV vs CH, P < .001; NLV vs EH, P = .025). P-wave dispersion of the NLV group was not different from that of the CR group. Patients with CR had also shorter PD than patients who had CH (P = .002). In bivariate analysis, there was a significant correlation between PD with left ventricle geometry, body surface area, LVMI, and relative wall thickness. In multiple linear regression analysis, PD was independently correlated only with LVMI (β = .425, P < .001). Conclusions: P-wave dispersion is independently associated with LVMI rather than left ventricle geometry and relative wall thickness in hypertensive patients. Thus, it is increased particularly in patients with CH and EH. [Copyright &y& Elsevier]