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Presents a study which defined normal values of P wave analysis indices in young healthy men and examined possible associations between P wave indices and clinical variables. Methods; Results and discussion.

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. [ABSTRACT FROM AUTHOR]

Background: The prolongation of P-wave duration has long been shown to indicate the presence of high risk for atrial fibrillation. The circadian variation of P-wave characteristics and their dynamic adaptation to heart rate changes was not tested before.Methods: To evaluate the diurnal pattern of P-wave duration, P area, and PR interval and of their linearly fitted relation with RR interval, 50 healthy volunteers (25 men, mean age 34 +/- 10 years) underwent 24-hour ambulatory electrocardiographic (ECG) recording with digital 12-lead Holter recorders. The median P-wave duration, P area, and PR interval were calculated from the average 12-lead ECG constructed from each 10-second ECG recording. Single harmonic regression analysis was performed to reveal the presence of circadian variation in the aforementioned ECG parameters.Results: The P area (P < 0.0001, R(2) = 0.78), the PR interval (P < 0.0001, R(2) = 0.92), the P area / RR slope (P < 0.0001, R(2) = 0.55), and the PR/RR slope (P < 0.0001, R(2) = 0.42) showed a highly significant circadian variation while the periodic nature of P-wave duration (P = 0.016, R(2) = 0.32) and of the P duration / RR slope (P = 0.011, R(2) = 0.18) was only indicated by harmonic regression analysis.Conclusions: P-wave duration, P area, and PR interval show a significant circadian variation in healthy subjects. The relations between P area/RR,PR/ RR, and P duration/RR also demonstrate a significant diurnal pattern. [ABSTRACT FROM AUTHOR]

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 ECC 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. [ABSTRACT FROM AUTHOR]

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) con 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. [ABSTRACT FROM AUTHOR]

Background Cigarette smoking is strongly related to decreased vagal cardiac activity and increased cardiac death. We sought to examine the short-term effects of smoking on heart rate variability (HRV) in healthy young subjects in the sitting position to investigate the influence of smoking on autonomic cardiac control. Methods Thirty-two healthy volunteers (18 males, 14 females, 21 habitual smokers and 11 nonsmokers, mean age 30 ± 3 years, range 24-36 years) were studied. Smokers were asked not to smoke for 8 hours prior to examination. Mean, SDNN, rMSSD, pNN50, total power, LF, HF, and LF/HF ratio were measured for 30 minutes, divided into six periods of 5 minutes each. Smoking of a single cigarette took place during the second period. Results Smoking caused a significant increase of the LF/HF ratio and of the normalized values of the LF component. A significant decrease in absolute values of total power, LF, and HF components was noticed. All time-domain indices were significantly decreased. We also noticed that although the changes appeared during smoking (second period) the maximal changes were documented 5 to 10 minutes after smoking cessation (third and fourth periods). Conclusions Cigarette smoking in the sitting position causes a transient decrease in vagal cardiac control and a moderate sympathetic activation. These changes last for at least 30 minutes and are compatible with a modulation of the autonomic control of the sinoatrial node toward sympathetic predominance. Despite the differences concerning the baseline HRV measures between nonsmokers and habitual smokers, an almost identical pattern of sympathovagal modulation was observed. [ABSTRACT FROM AUTHOR]

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 (GAD) and typical angina pectoris and 15 controls with anginalike 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. [ABSTRACT FROM AUTHOR]

Background: The prolongation of atrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiological characteristics in patients with paroxysmal atrial fibrillation. Methods: The aim of this study was to test the ability of a new ECG marker to discriminate between patients with a prior history of paroxysmal lone atrial fibrillation and healthy controls. Maximum P wave duration (Pmax) and the difference between the maximum and the minimum P wave duration, which was defined as P-wave dispersion (Pdisp) were calculated from the 12-lead surface ECGs of 75 patients with a history of paroxysmal lone atrial fibrillation and 50 age-matched healthy controls. Results: Pmax was in patients 122 ± 17 ms and in controls 101 ± 10 ms (t = 7.935, P > 0.001). Pdisp was in patients 48 ± 16 ms and in controls 29 ± 8 ms (t = 7.616, P > 0.001). A Pmax value of 110 ms separated patients from controls with a sensitivity 85%, a specificity 72%, and a positive predictive accuracy of 82%. A Pdisp value of 40 ms separated patients from controls with a sensitivity of 81%, a specificity of 80%, and a positive predictive accuracy of 85%. Conclusions: (1) Pmax and Pdisp values were found to be significantly higher in patients with a prior history of paroxysmal lone atrial fibrillation than in age-matched healthy controls, and (2) Pdisp is a new simple ECG marker that could be possibly used for the identification of patients with a previous history of paroxysmal lone atrial fibrillation. A.N.E. 1999;4(1):39-45 [ABSTRACT FROM AUTHOR]