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

Notched P-wave on digital electrocardiogram predicts the recurrence of atrial fibrillation in patients who have undergone catheter ablation

Background

A notched P-wave is associated with the occurrence of atrial fibrillation (AF). However, the association between a notched P-wave and AF recurrence in patients who have undergone a catheter ablation for AF is unclear.

Methods

We enrolled 100 subjects who underwent catheter ablation for AF (paroxysmal AF: 60 cases; persistent AF: 40 cases). Twelve-lead electrocardiography (ECG) was conducted, and the peak-to-peak distance in the M shape was calculated automatically using a 12-lead ECG analysis system. A notched P-wave was defined as a P-wave with an M-shape and a peak-to-peak distance of ≥20 ms in lead II. We compared the recurrence of AF in the patients with notched P-wave and the others.

Results

The mean follow-up period was 12 ± 8 months, and a recurrence of AF was observed in 28 patients. The recurrence of AF in the notched P-wave group was significantly higher than that in the controls (log rank 5.14, p = .023). A notched P-wave was a significant predictor of the recurrence of AF after adjustment for age, gender, history of heart failure, history of catheter ablation, persistent AF, use of antiarrhythmic drugs, and the left atrial volume index (hazard ratio 2.470, 95% confidence interval 1.065-5.728, p = .035).

Conclusions

Automatically identified notched P-waves with peak-to-peak distance ≥20 ms were associated with AF recurrence in patients who had undergone catheter ablation.

The Effect of Glycemic Status on P Wave Dispersion

Background and aim The growing number of people with diabetes mellitus (DM) across the world is a public health concern. The diabetes epidemic involves enormous health costs to the patients, their careers, and society at large. Cardiovascular diseases such as atrial fibrillation (AF) often develop in the diabetic population. An increase in the P wave dispersion (PWD) has been established as an independent risk factor for the occurrence of AF, hence the present study was conducted to establish a possible relationship between PWD and the glycemic status of the individual to predict the occurrence of AF ahead of clinical symptomology. Methodology A comparative cross-sectional study was conducted at a tertiary care hospital after obtaining approval from the institutional ethics committee and written consent of each study subject. The main steps included the selection and categorization of the study population based on their glycemic status, collection of demographic data, performing ECGs calculating PWD using digital calipers, and recording the data systematically for evaluation. Results In this study, 234 patients with a mean age of 53.3 ± 13.1 years were studied, of which 121 (51.7%) were male and 113 (48.29%) were female. The 234 patients were divided into four groups based on their glycemic status - 74 uncontrolled DM patients (31.62%), 51 type 2 DM (T2DM) patients (21.78%), 56 prediabetes patients (23.93%), and 53 patients in the control group (22.64%; not a known case of diabetes with normal HbA1c and fasting blood sugar (FBS) levels). Minimal correlation was observed between FBS with PWD (r value 0.175) and age with PWD (r value 0.161), but statistical significance was observed only between age and PWD (p-value 0.014). The difference in means between the four different study groups was found to be not statistically significant (p-value- 0.104); hence, no intergroup variation was noted. Conclusion Advancing age and higher fasting blood sugars have shown minimal correlation with widening P-wave dispersion. With further studies involving larger populations, this can be a promising aid in identifying PWD as a probable early predictor of atrial arrhythmias among diabetic patients.

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.

Investigating the association between P wave duration and atrial fibrillation recurrence after radiofrequency ablation in early persistent atrial fibrillation patients

BACKGROUND

In the present study, we aimed to explore the association between P wave duration, as the measured time from the start point of the P wave to the end point, and atrial fibrillation recurrence after transcatheter radiofrequency ablation in patients with early persistent atrial fibrillation.

METHODS

Patients with early persistent atrial fibrillation who underwent the first radiofrequency ablation procedure were retrospectively analyzed. The electrocardiographic, echocardiographic and clinical data of the enrolled patients before and after operation were collected and recorded. After adjusting confounding factors and performing stratified analysis, the association between the P wave duration and the atrial fibrillation recurrence of patients with early persistent atrial fibrillation after radiofrequency ablation was explored.

RESULTS

The proportions of atrial fibrillation recurrence of the low, medium, and high P wave duration groups were 6.4%, 19.7%, and 47.0%, respectively. After potential confounding factors were adjusted, the risk of atrial fibrillation recurrence gradually increased with the increase of P wave duration (odds ratio: 1.093, 95% confidence interval: 1.063-1.124, p < 0.001). This trend was statistically significant (odds ratio: 1.099, 95% confidence interval: 1.052-1.149, p < 0.001), especially in comparison of high vs. low (odds ratio: 16.99, 95% confidence interval: 4.75-60.78, p < 0.001). Curve fitting showed that there was a linear and positive association between the P wave duration and the risk of atrial fibrillation recurrence. This association was consistent in different subgroups based on gender, drinking, history of smoking, hypertension, diabetes mellitus, peripheral artery disease, stroke or transient ischemia attack, hyperlipidemia, heart failure, and heart rate, suggesting that there was no significant interaction between different grouping parameters and the association (p for interaction range = 0.217-0.965).

CONCLUSIONS

In patients with early persistent atrial fibrillation who underwent radiofrequency ablation procedure for the first time and converted to sinus rhythm, the P wave duration within 72 h after the procedure was independently associated with the risk of atrial fibrillation recurrence, and such association was linear and positive.

P wave dispersion and ventricular repolarization changes in children with familial hypercholesterolemia

BACKGROUND

Familial hypercholesterolemia is a genetic disease with plasma total cholesterol especially low-density lipoprotein-cholesterol elevation. In this study, we aimed to examine the changes in the electrocardiographies of children with familial hypercholesterolemia.

MATERIALS AND METHODS

Electrocardiography of 85 patients with a diagnosis of familial hypercholesterolemia, followed up from the Pediatric Metabolism and Pediatric Cardiology outpatient clinic was examined. Electrocardiography of 83 children from the control group who did not have hypercholesterolemia in a similar gender and age range were examined. Heart rate, P wave, PR interval, P wave dispersion, QRS wave, QT interval, corrected QT (calculated with Bazett formula), Tpeak-end interval, QT dispersion, corrected QT dispersion, JT interval, corrected JT (calculated with Bazett formula) were statistically compared.

RESULTS

P wave, PR interval, and P wave dispersion values were significantly higher (p < 0.05) in the children with familial hypercholesterolemia. Corrected QT, QT dispersion, corrected QT dispersion, JT interval, corrected JT, Tpeak-end interval were significantly higher than the control group (p < 0.05) in children with familial hypercholesterolemia. These statistical differences in electrocardiography parameters support the risk of atrial and/or ventricular arrhythmia in children with familial hypercholesterolemia.

CONCLUSION

We found that high total cholesterol and low-density lipoprotein-cholesterol variables are associated with an increased risk of cardiac atrial and/or ventricular arrhythmia. The findings suggest that total cholesterol and low-density lipoprotein-cholesterol variability can be used as a new marker for the risk of cardiac arrhythmia. In this case, decreasing total cholesterol and low-density lipoprotein-cholesterol variability below certain thresholds may decrease the risk of cardiac arrhythmia.

Synthetic Cannabinoids and Cardiac Arrhythmia Risk: Review of the Literature

Synthetic cannabinoids (SCBs) are widely used recreational substances especially among adults. Although they have been considered as safe during the marketing process, our knowledge about their adverse effects has evolved since years. SCBs are associated with various cardiac events including acute myocardial infarction and sudden cardiac death. There is also growing evidence that SCBs are associated with cardiac arrhythmia development both in acute and chronic exposure. SCBs have been shown to be associated with both supraventricular and ventricular arrhythmias. However, the exact mechanism of the SCB related arrhythmia remains unknown. Understanding the exact association and possible mechanisms may help us to identify high risk patients at an early stage and to develop treatment modalities to prevent or reverse the arrhythmic effects of SCBs.

Interatrial conduction times in paroxysmal atrial fibrillation patients with normal atrial volume and their correlation with areas of local prolonged bipolar electrograms

BACKGROUND

Recent evidence has shown that the presence of abnormal substrate can be demonstrated also among patients with "lone" AF.

OBJECTIVES

Interatrial conduction slowing is likely to characterize patients with paroxysmal atrial fibrillation (AF) and it could be correlated to the left atrium area of prolonged local bipolar endocardial electrograms.

METHODS

P-wave duration (PWD), amplified PWD and endocavitary interatrial conduction time (IACT), were analyzed in 60 patients; 30 undergoing de novo ablation for paroxysmal AF with normal atrial volumes and without any other cardiac disease and 30 of similar age undergoing electrophysiological study for atrioventricular nodal reentrant tachycardia or atrioventricular re- entrant tachycardia. In patients with AF, voltage maps and local bipolar electrograms (LBE) duration map were evaluated.

RESULTS

Although PWD was <120 ms in 28 patients with AF and in 29 controls, patients with AF exhibited longer PWD, amplified-PWD and IACT. Although low-voltage areas (<0.5 mV) were not found in the study population, 28 of them demonstrated areas with LBE longer than 60 ms. These LBE were found mainly in the roof of the left atrium and their extension was correlated to IACT (R = 0.51, p = 0.004). IACT >135.5 ms identified the subjects who experienced AF with 90% sensitivity and 97% specificity.

CONCLUSION

A subclinical interatrial conduction disturbance is demonstrable in subjects with paroxysmal AF and normal left atrial volume. IACT has a good correlation to the areas of abnormal LBE in the left atrium. IACT >135 ms identified subjects who have experienced AF.

Effects of epicardial fat reduction on P-wave duration of morbidly obese patients submitted to bariatric surgery: an observational study

Introduction: Epicardial fat (EF) is biologically active and, through its paracrine effect, interacts with the atrial myocardium and may be involved in the atrial remodeling observed in obese individuals. P-wave duration (PWD) is a non-invasive marker of atrial conduction time and reflects changes related to atrial remodeling. The effects of the reduction of EF induced by bariatric surgery on PWD have not yet been defined. Methods: We prospectively recruited 22 morbidly obese patients with no other comorbidities at the Unidade de Cirurgia Bariátrica (Bariatric Surgery Unit) of Unviversidade de São Paulo’s Hospital das Clínicas. The patients were submitted to clinical and laboratorial evaluations, 12-lead eletrocardiography (ECG), two-dimensional echocardiogram and 24 h Holter. The same evaluation was performed 12 months after bariatric surgery. In order to make a comparison of the continuous variables, we used the paired and Wilcoxon T tests. To evaluate the association between independent variables, a regression model was used for repeated measures. Results: A total of 20 patients completed the protocol (age: 36.35 ± 10.26 years, 18 women). There was a significant reduction of PWD, body mass index (BMI) and EF after bariatric surgery (p<0.05). There was also an average reduction of 11.55 ± 8.49 ms in PWD. In the multiple regression analysis, an association was observed between the reduction of PWD and the reduction of EF and BMI. Conclusions: In morbidly obese patients with no other comorbidities, the reduction of EF after bariatric surgery was associated with an improvement in atrial remodeling indicated by a significant reduction in PWD.

Efeitos da Redução da Gordura Epicárdica na Duração da Onda P de Obesos Mórbidos Submetidos à Cirurgia Bariátrica: um Estudo Observacional

Introduction: Epicardial fat (EF) is biologically active and, through its paracrine effect, interacts with the atrial myocardium and may be involved in the atrial remodeling observed in obese individuals. P-wave duration (PWD) is a non-invasive marker of atrial conduction time and reflects changes related to atrial remodeling. The effects of the reduction of EF induced by bariatric surgery on PWD have not yet been defined. Methods: We prospectively recruited 22 morbidly obese patients with no other comorbidities at the Unidade de Cirurgia Bariátrica (Bariatric Surgery Unit) of Unviversidade de São Paulo’s Hospital das Clínicas. The patients were submitted to clinical and laboratorial evaluations, 12-lead eletrocardiography (ECG), two-dimensional echocardiogram and 24 h Holter. The same evaluation was performed 12 months after bariatric surgery. In order to make a comparison of the continuous variables, we used the paired and Wilcoxon T tests. To evaluate the association between independent variables, a regression model was used for repeated measures. Results: A total of 20 patients completed the protocol (age: 36.35 ± 10.26 years, 18 women). There was a significant reduction of PWD, body mass index (BMI) and EF after bariatric surgery (p<0.05). There was also an average reduction of 11.55 ± 8.49 ms in PWD. In the multiple regression analysis, an association was observed between the reduction of PWD and the reduction of EF and BMI. Conclusions: In morbidly obese patients with no other comorbidities, the reduction of EF after bariatric surgery was associated with an improvement in atrial remodeling indicated by a significant reduction in PWD.

ECG analysis in patients with acute coronary syndrome undergoing invasive management: rationale and design of the electrocardiography sub-study of the MATRIX trial

BACKGROUND

The twelve‑lead electrocardiogram (ECG) has become an essential tool for the diagnosis, risk stratification, and management of patients with acute coronary syndromes (ACS). However, several areas of residual controversies or gaps in evidence exist. Among them, P-wave abnormalities identifying atrial ischemia/infarction are largely neglected in clinical practice, and their diagnostic and prognostic implications remain elusive; the value of ECG to identify the culprit lesion has been investigated, but validated criteria indicating the presence of coronary occlusion in patients without ST-elevation are lacking; finally, which criteria among the multiple proposed, better define pathological Q-waves or success of revascularisation deserve further investigations.

METHODS

The Minimizing Adverse hemorrhagic events via TRansradial access site and systemic Implementation of AngioX (MATRIX) trial was designed to test the impact of bleeding avoidance strategies on ischemic and bleeding outcomes across the whole spectrum of patients with ACS receiving invasive management. The ECG-MATRIX is a pre-specified sub-study of the MATRIX programme which aims at analyzing the clinical value of ECG metrics in 4516 ACS patients (with and without ST-segment elevation in 2212 and 2304 cases, respectively) with matched pre and post-treatment ECGs.

CONCLUSIONS

This study represents a unique opportunity to further investigate the role of ECGs in the diagnosis and risk stratification of ACS patients with or without ST-segment deviation, as well as to assess whether the radial approach and bivalirudin may affect post-treatment ECG metrics and patterns in a large contemporary ACS population.

P-wave duration is a predictor for long-term mortality in post-CABG patients

Risk stratification in secondary prevention has emerged as an unmet clinical need in order to mitigate the Number-Needed-to-Treat and make expensive therapies both clinically relevant and cost-effective. P wave indices reflect atrial conduction, which is a sensitive marker for inflammatory, metabolic, and pressure overload myocardial cell remodeling; the three stimuli are traditional mechanisms for adverse clinical evolution. Accordingly, we sought to investigate the predictive role of P-wave indices to estimate residual risk in patients with chronic coronary artery disease (CAD). The cohort included 520 post-Coronary Artery Bypass Grafting patients with a median age of 60 years who were followed for a median period of 1025 days. The primary endpoint was long-term all-cause death. Cubic spline model demonstrated a linear association between P-wave duration and incidence rate of long-term all-cause death (p = 0.023). P-wave >110ms was a marker for an average of 425 days shorter survival as compared with P-wave under 80ms (Logrank p = 0.020). The Cox stepwise regression models retained P-wave duration as independent marker (HR:1.37; 95%CI:1.05–1.79,p = 0.023). In conclusion, the present study suggests that P-wave measurement may constitute a simple, inexpensive and accessible prognostic tool to be added in the bedside risk estimation in CAD patients.

Electrocardiographic alterations in patients consuming synthetic cannabinoids

INTRODUCTION

The aim of this study was to investigate the electrocardiographic parameters in patients consuming synthetic cannabinoids.

METHODS

Thirty-five patients who were consuming synthetic cannabinoids were enrolled to the study, prospectively. The control group included 35 healthy age and sex-matched volunteers. The standard 12-lead surface electrocardiograms of the study population were recorded. P maximum (P_max), P minimum (P_min), P wave dispersion, interatrial duration, P wave area in D2 derivation, abnormal P terminal force in V1 derivation, heart rate, QT interval, corrected QT, QT dispersion, PR interval duration and macrovolt T-wave alternans were evaluated by two experienced cardiologists. The intra-observer and inter-observer variations for all measurements were non-significant.

RESULTS

P_max and P_min duration was not different between the groups ( p=0.96, p=0.15, respectively). However, P wave dispersion was higher in the patient group compared to control group (34±9.4, 29.5±6.6, p=0.02, respectively). QT interval was significantly higher in the patient group than the control group (380.3±25, 365.6±22.8, p=0.01, respectively). Besides, corrected QT was higher in the patient group compared to control group (415±36.8, 392±15.5, p=0.001, respectively). QT dispersion was also higher in the patient group than the control group (39.8±10.0, 29.2±5.4, p<0.001, respectively).

CONCLUSION

Altered electrocardiography parameters linked with atrial and ventricular arrhythmia development may be observed in patients consuming synthetic cannabinoids. These patients should be evaluated regularly for cardiovascular disease and arrhythmia development. The electrocardiogram, which is a cheap and easy test to apply, can be used to determine the pro-arrythmic risk in patients consuming synthetic cannabinoids.

Reduced P-wave Voltage in Lead I is Associated with Development of Atrial Fibrillation in Patients with Coronary Artery Disease

Background

Reduced P-wave voltage in lead 1 (PVL1) has been associated with atrial fibrillation (AF) recurrence.This study sought to determine the association between reduced PVL1 and AF in the NSTEMI population and the correlation between reduced PVL1 and interatrial block (IAB)/coronary artery disease (CAD).

Methods

Data were recorded for clinical, echocardiographic, angiographic, electrocardiographic and outcome variables. Patients were followed for a minimum of one year. Chi-square tests, independent samples t-tests and one-way ANOVA were used for the analysis, which was done using IBM SPSSResults:: A total of 322 consecutive patients were included in the analysis. Patients with new-onset AF had a significantly lower PVL1 (0.085 ± 0.030mV vs. 0.103 ± 0.037mV; p=0.007). There was a significant difference in mean PVL1 between those with no IAB, partial IAB and advanced IAB (p = <0.001). Those with any type of IAB had a significantly lower mean PVL1 than those without (0.094 ± 0.032 mV vs. 0.106 ± 0.038 mV; p=0.005). Patients who developed AF had a significantly longer P-wave duration (126 ± 20ms vs. 119 ± 17ms; p=0.022). Patients with IAB were more likely to develop new-onset AF (15.4% versus 7.5%, p=0.025). There were significant co-linear associations between reduced PVL1 and IAB (p=0.005); reduced PVL1 and diffuse CAD (p=0.031) and IAB and diffuse CAD (p=0.022).

Reversible Increases in Qt Dispersion and P Wave Dispersion during Carbon Monoxide Intoxication

Objectives

Carbon monoxide (CO) is a potent myocardial toxin. We investigated the association between acute CO intoxication and electrocardiographic QT interval (QTmax/QTmin), corrected QT interval (cQTmax/cQTmin), QT dispersion (QTd) and corrected QT dispersion (cQTd), P wave duration (Pmax/Pmin) and P wave dispersion (Pd), which were known as predictors of ventricular arrhythmias, atrial fibrillation and sudden death.

Methods

Electrocardiography with 12-leads and blood gas were taken from 65 patients with CO intoxication as well as 65 control patients with similar age and gender distribution at the admission time to the emergency department and at the 4th hour post-therapy. The carboxyhaemoglobin (COHb) levels and the relationships with electrocardiographic parameters were studied.

Results

The mean COHb levels were 21.43±6.85% and 1.37±0.98% in intoxicated patients and in the control group respectively. QTmax, QTd, cQTmax, cQTd, Pmax, and Pd were found significantly higher in intoxicated patients when compared to the control group (373.98±40.35 vs. 355.98±32.88, p=0.006; 49.29±22.66 vs. 20.43±11.16, p<0.001; 455.38±30.72 vs. 419.57±22.27, p<0.001; 60.88±25.99 vs. 25.75±13.13, p<0.001; 107.91±13.28 vs. 96.65±12.65, p<0.001, 46.85±13.49 vs. 35.22±10.07, p<0.001 respectively). In Pearson correlation analysis, there were significant correlations between COHb level and QTmax, QTd, cQTmax, cQTd, Pmax and Pd (r=0.211, p=0.016; r=0.610, p<0.001; r=0.599, p<0.001; r=0.628, p<0.001; r=0.458, p<0.001; r=0.414, p<0.001 respectively).

Conclusion

A correlation between reversible increases in QTd, cQTmax, cQTd, Pmax and Pd in the electrocardiogram and COHb can be observed in acute CO intoxication patients.

Utility of P-Wave Dispersion in the Prediction of Atrial Fibrillation

Prevention is important in the case of the most common sustained arrhythmia-atrial fibrillation, with the intention of obtaining both medical and economic benefits. Electrocardiographic parameters have been tested as predictors of atrial fibrillation in different settings, and indices of P-wave have been assiduously studied.Increased P-wave dispersion has been described in different illnesses and correlated with several echocardiographic and clinical parameters. Several studies have demonstrated the relationship between P-wave dispersion with the first episode or paroxysmal atrial fibrillation, as well as with the recurrence of atrial fibrillation after conversion to sinus rhythm. Despite of some critics, the current evidencesentitleus to continue studying P-wave dispersion and use it for identifying patients with risk for atrial fibrillation.

Diagnostic accuracy of electrocardiographic P wave related parameters in the assessment of left atrial size in dogs with degenerative mitral valve disease

The purpose of this research was to compare the accuracy of newly described P wave-related parameters (P wave area, Macruz index and mean electrical axis) with classical P wave-related parameters (voltage and duration of P wave) for the assessment of left atrial (LA) size in dogs with degenerative mitral valve disease. One hundred forty-six dogs (37 healthy control dogs and 109 dogs with degenerative mitral valve disease) were prospectively studied. Two-dimensional echocardiography examinations and a 6-lead ECG were performed prospectively in all dogs. Echocardiography parameters, including determination of the ratios LA diameter/aortic root diameter and LA area/aortic root area, were compared to P wave-related parameters: P wave area, Macruz index, mean electrical axis voltage and duration of P wave. The results showed that P wave-related parameters (classical and newly described) had low sensitivity (range=52.3 to 77%; median=60%) and low to moderate specificity (range=47.2 to 82.5%; median 56.3%) for the prediction of left atrial enlargement. The areas under the curve of P wave-related parameters were moderate to low due to poor sensitivity. In conclusion, newly P wave-related parameters do not increase the diagnostic capacity of ECG as a predictor of left atrial enlargement in dogs with degenerative mitral valve disease.

Effect of Aging on Left Atrial Compliance and Electromechanical Properties in Subjects Without Structural Heart Disease

Aging is associated with changes in left atrial (LA) structure and function. The present study aimed at describing the effect of aging on LA properties in a large cohort of subjects without structural heart disease. We divided 386 subjects (mean age 58 years [range 16 to 91]; 188 men [49%]) clinically referred for echocardiography according to age groups. The P-wave dispersion (PWD), reflecting total atrial conduction time, was measured on a 12-lead surface electrocardiogram as the difference between maximum and minimum P-wave duration. The PA-TDI duration reflecting the total atrial conduction time was measured on tissue Doppler imaging (TDI) as the time between onset of P wave on surface electrocardiogram to peak A'-wave velocity. Two-dimensional speckle-tracking echocardiography was used to assess LA reservoir function, reflecting LA compliance. In the overall population, mean PWD, PA-TDI, and LA reservoir strain were 43 ± 12 ms, 129 ± 27 ms, and 36 ± 13%, respectively. Increasing age was independently associated with prolonged PWD (β = 0.161; p <0.001), PA-TDI (β = 0.476; p <0.001), and reduced LA reservoir strain (β = -0.259; <0.001), suggesting age-related fibrotic changes of the LA myocardium. The association between age and LA reservoir strain was modulated by body mass index (β = -0.582; p <0.001) and LA volume index (β = -0.117; p = 0.014). In conclusion, aging is associated with longer PWD and PA-TDI duration along with a decrease in LA reservoir function. Obesity and larger LA volumes are independently associated with reduced LA compliance.

Reverse atrial electrical remodeling induced by cardiac resynchronization therapy

PURPOSE

Cardiac resynchronization therapy (CRT) has been shown to improve left atrial function; however the effect on reverse electrical remodeling has been poorly evaluated. We hypothesized that CRT might induce reverse atrial electrical remodeling manifesting in the surface ECG as a shortening in P-wave duration.

METHODS

Patients with CRT and more than 92% biventricular pacing at minimum follow-up of 1 year were included in the analysis. Those with prior history of atrial fibrillation (AF) were excluded. Data were recorded for clinical, echocardiographic and ECG variables prior to implant and at least 12 months post implantation. Semiautomatic calipers and scanned ECGs at 300 DPI maximized × 8 were used to measure P-wave duration and diagnose advanced interatrial block (aIAB) during sinus rhythm. The occurrence of AF was assessed through analyses of intracardiac electrograms and clinical presentations.

RESULTS

41 patients were included in the study with mean age of 67.4 ±9.6 years, 71% were male, left atrial diameter 41.1 ± 8.5 mm and LV EF 28.5 ± 6.5%. Over a mean follow up of 55 months, a significant reduction in P-wave duration (142.7 ms vs. 133.1 ms; p < 0.001) was noted. The presence of aIAB was significantly reduced (36% vs. 17%; p = 0.03). The incidence of new onset AF was 36%. Time to AF onset after CRT implantation was not influenced by a reduction in P-wave duration.

CONCLUSION

CRT induces atrial reverse electrical remodeling manifested as a reduction in P-wave duration. Larger studies are needed to determine the impact on AF incidence after CRT implantation.

P-wave dispersion measurement: Methodological considerations

Well-known difficulties in defining P-wave onset and offset may restrict the accuracy and reproducibility of P-wave dispersion measurements. To achieve greater precision in measuring P-wave dispersion, simultaneous digital recording of all 12 ECG leads and onscreen measurement of P wave characteristics is mandatory to examine atrial fibrillation risk.

Electrophysiological Mechanisms of Bayés Syndrome: Insights from Clinical and Mouse Studies

Bayés syndrome is an under-recognized clinical condition characterized by inter-atrial block (IAB). This is defined electrocardiographically as P-wave duration > 120 ms and can be categorized into first, second and third degree IAB. It can be caused by inflammatory conditions such as systemic sclerosis and rheumatoid arthritis, abnormal protein deposition in cardiac amyloidosis, or neoplastic processes invading the inter-atrial conduction system, such as primary cardiac lymphoma. It may arise transiently during volume overload, autonomic dysfunction or electrolyte disturbances from vomiting. In other patients without an obvious cause, the predisposing factors are diabetes mellitus, hypertensive heart disease, and hypercholesterolemia. IAB has a strong association with atrial arrhythmogenesis, left atrial enlargement (LAE), and electro-mechanical discordance, increasing the risk of cerebrovascular accidents as well as myocardial and mesenteric ischemia. The aim of this review article is to synthesize experimental evidence on the pathogenesis of IAB and its underlying molecular mechanisms. Current medical therapies include anti-fibrotic, anti-arrhythmic and anti-coagulation agents, whereas interventional options include atrial resynchronization therapy by single or multisite pacing. Future studies will be needed to elucidate the significance of the link between IAB and atrial tachyarrhythmias in patients with different underlying etiologies and optimize the management options in these populations.

Vessel heterogeneity of TIMI frame count and its relation to P-wave dispersion in patients with coronary slow flow

BACKGROUND

The vessel heterogeneity of thrombolysis in myocardial infarction (TIMI) frame count (TFC) in patients with coronary slow flow (CSF) remains to be further evaluated, and the correlation between TFC heterogeneity and P-wave dispersion (PWD) has not been elucidated. We aim to investigate the vessel heterogeneity of TFC in coronary arteries, and its relation to PWD in patients with CSF and otherwise normal coronary arteries.

METHODS

We studied 72 patients with angiographically documented CSF and 66 age- and gender-matched control subjects. The coefficient of variation (CV) and mean TFC of the three vessels were calculated. P-wave duration and PWD were measured on the standard electrocardiograms (ECGs).

RESULTS

The mean TFC and CV were both significantly higher in CSF patients than in controls (P<0.001 for both comparisons). The maximum P-wave duration (Pmax) and PWD were found to be significantly higher in CSF patients than in controls (P<0.001 for both comparisons). In patients with CSF, both Pmax and PWD were mildly correlated to mean TFC (r=0.318, P=0.009; and r=0.307, P=0.010), and were more significantly correlated to CV (r=0.506, P<0.001; and r=0.579, P<0.001).

CONCLUSIONS

These data demonstrate that variability of TFC in three coronary arteries is increased in CSF patients, and that the vessel heterogeneity in coronary flow might be intimately associated with PWD.

Effects of Nasal Septum Deviation and Septoplasty on Cardiac Arrhythmia Risk

OBJECTIVE

Upper airway obstruction (UAO) can result in cardiac complications, including arrhythmias and sudden cardiac death. Nasal septum deviation (NSD) is a common cause of UAO. The aim of this study was to assess the risk of cardiac arrhythmias in patients with NSD. To assess this risk, we measured noninvasive indicators of atrial arrhythmia (P-wave dispersion [Pd]) and ventricular arrhythmia (corrected QT dispersion [QTcd]) and compared these values between NSD patients and healthy subjects.

STUDY DESIGN

Prospective study.

SETTINGS

Tertiary referral center.

SUBJECTS AND METHODS

This study included 53 consecutive patients who had underwent septoplasty due to marked NSD. Electrocardiographic records were used to determine Pd and QTcd values preoperatively and 6 months postoperatively. Fifty-three consecutive age- and sex-matched subjects without any UAO were also examined as a control group.

RESULTS

Preoperative Pd and QTcd values were significantly higher in NSD patients than in the control group (Pd: 57.40 ± 14.21 vs 34.11 ± 7.12 milliseconds, P < .001; QTcd: 81.77 ± 16.39 vs 50.25 ± 11.51 milliseconds, P < .001, respectively). In addition, Pd and QTcd values were significantly greater in preoperative NSD patients when compared with the same patients postoperatively (Pd: 57.40 ± 14.21 vs 36.32 ± 8.9 milliseconds, P = .013; QTcd: 81.77 ± 16.39 vs 55.76 ± 11.4 milliseconds, P = .012, respectively).

CONCLUSION

In conclusion, NSD patients are at risk for both atrial and ventricular cardiac arrhythmias; however, septoplasty in these patients can relieve UAO and reduce the risk of arrhythmias.

Effects of balanced propofol sedation on QT, corrected QT, and P-wave dispersion on upper endoscopy

Objective:

Combined sedation with propofol and benzodiazepines, known as balanced propofol sedation (BPS), was developed to increase patient comfort during endoscopy. However, the effects of BPS on P-wave dispersion (Pwd), QT interval, and corrected QT (QTc) interval after endoscopy have not been investigated.

Methods:

The study population consisted of 40 patients with BPS and 42 without sedation who were scheduled to undergo upper endoscopy in this cross-sectional prospective study. Patients with hypertension, diabetes mellitus, renal failure, chronic obstructive pulmonary disease, coronary artery disease, or valvular heart disease and those on medications that interfere with cardiac conduction times were excluded. Electrocardiograms (ECGs) was recorded in all patients pre-endoscopy and 10 min post-endoscopy. QT, QT dispersion (QTd), and Pwd were defined from 12-lead ECG. The QTc interval was calculated using Bazett’s formula. All analyses were performed using SPSS 15.0.

Results:

Post-endoscopy P max duration and Pwd were prolonged compared with baseline values (86±13 ms vs. 92±10 ms and 29±12 ms vs. 33±12 ms, respectively; p<0.05). Post-endoscopy QTc and QTd were decreased compared with baseline values, but these decreases were not statistically significant (431±25 ms vs. 416±30 ms and 62±28 ms vs. 43±22 ms, respectively; p>0.05).

Conclusion:

The present study showed that P-wave duration and Pwd values increased after endoscopy with a combination of midazolam and propofol sedation. Physicians should be made aware of the potential effects of BPS in terms on P-wave duration and Pwd values.

Left atrial appendage ligation in patients with atrial fibrillation leads to a decrease in atrial dispersion

Background

Left atrial appendage (LAA) exclusion has been performed in patients with atrial fibrillation (AF) to prevent thrombus formation and subsequent cardioembolic events. Left atrial electrical remodeling is a recognized factor in the recurrence of AF. The effects of LAA exclusion on P-wave characteristics and left atrial electrical remodeling have not been well described. The purpose of this study was to evaluate the effect of LAA ligation on P-wave morphology in patients with AF.

Methods and Results

Fifteen patients who were in sinus rhythm during the LAA ligation procedure were included in the study. We evaluated the P-wave characteristics, including P-wave duration, P-wave amplitude, PQ interval, and P-wave dispersion, before and after ligation. Eleven patients had paroxysmal AF and 4 patients had persistent AF (12 male patients and 3 female patients). P-wave duration immediately after ligation was significantly shorter compared with baseline in all limb leads except lead aVR (P<0.05). P-wave amplitude immediately after ligation was significantly greater compared with baseline in inferior leads; however, P-wave amplitude after 1 to 3 months was significantly lower compared with immediately after ligation. PQ interval immediately after ligation was significantly shorter compared with baseline (P=0.01), and P-wave dispersion after 1 to 3 months was significantly shorter compared with baseline (P=0.02).

Conclusions

LAA exclusion produces consistent P-wave changes consistent with decreased atrial mass and decreased atrial dispersion that may represent reverse electrical atrial remodeling. This is a potential mechanism to explain the role of LAA ligation in maintaining sinus rhythm in patients with AF.

Advanced Interatrial Block Predicts New Onset Atrial Fibrillation in Patients with Severe Heart Failure and Cardiac Resynchronization Therapy

BACKGROUND

Advanced interatrial block (aIAB) on the surface electrocardiogram (ECG), defined as a P-wave duration ≥120 milliseconds with biphasic (±) morphology in inferior leads, is frequently associated with atrial fibrillation (AF). The aim of this study was to determine whether preoperative aIAB could predict new-onset AF in patients with severe congestive heart failure (CHF) requiring cardiac resynchronization therapy (CRT).

METHODS

Retrospective analysis of consecutive patients with CHF and no prior history of AF undergoing CRT for standard indications. A baseline 12-lead ECG was obtained prior to device implantation and analyzed for the presence of aIAB. ECGs were scanned at 300 DPI and maximized 8×. Semiautomatic calipers were used to determine P-wave onset and offset. The primary outcome was the occurrence of AF identified through analyses of intracardiac electrograms on routine device follow-up.

RESULTS

Ninety-seven patients were included (74.2% male, left atrial diameter 45.5 ± 7.8 mm, 63% ischemic). Mean P-wave duration was 138.5 ± 18.5 milliseconds and 37 patients (38%) presented aIAB at baseline. Over a mean follow-up of 32 ± 18 months, AF was detected in 29 patients (30%) and the incidence was greater in patients with aIAB compared to those without it (62% vs 28%; P < 0.003). aIAB remained a significant predictor of AF occurrence after multivariate analysis (OR 4.1; 95% CI, 1.6-10.7; P < 0.003).

CONCLUSION

The presence of aIAB is an independent predictor of new-onset AF in patients with severe CHF undergoing CRT.

Left atrial dyssynchrony time measured by tissue Doppler imaging to predict atrial fibrillation recurrences after pulmonary vein isolation

OBJECTIVE

In this study we assess the value of left atrial dyssynchrony time measured by tissue Doppler imaging (TDI) to predict recurrences after pulmonary vein isolation (PVI) in patients with paroxysmal and persistent atrial fibrillation (AF).

METHODS

One hundred sixty patients (57 ± 7.5 years, 122 males) with symptomatic drug-refractory paroxysmal and persistent AF, undergoing PVI were enrolled in our study. PA peak time by tissue Doppler imaging (PApeak-TDI) is defined as the time measured from the start of P wave in lead II to the peak of A wave on the tissue Doppler tracing. Left atrial dyssynchrony was measured by subtracting the PApeak-TDI time measured at the mid-inter atrial septum from the PA peak-TDI time measured at the left atrial midlateral free wall, (LA dyssynchrony = PApeak TDI lateral-PApeak TDI septal).

RESULTS

During a mean follow-up of 12 ± 3 months, recurrences occurred in 50 out of 160 patients. Patients with recurrence of atrial fibrillation had larger left atrial dyssynchrony time (26.5 ± 2.4 ms vs. 23.5 ± 2.3 ms, p < 0.001). Left atrial dyssynchrony time of 25 ms has the best combined sensitivity and specificity (74% and 63% respectively) along with positive predictive value 53% and negative predictive value 85.5%. LA dyssynchrony time ≥ 25 ms was found to discriminate patients prone to AF recurrences over time. Multivariate regression analysis showed that left atrial dyssynchrony time (HR per ms: 1.69, p<0.001) was identified as independent predictor of AF recurrence.

CONCLUSION

Left atrial dyssynchrony time is good clinical predictor of recurrence of AF after PVI in patients with paroxysmal and persistent AF.

Electrocardiographic P-wave Indices as a Useful Tool to Predict Successful Percutaneous Balloon Mitral Valvotomy in Patients with Mitral Stenosis

Introduction : Patients with hemodynamically significant mitral stenosis (MS) have prolonged P-wave duration and increased P-wave dispersion (PWD) that decrease after successful percutaneous balloon mitral valvotomy (PBMV). The purpose of this study was to investigate if the changes in these indices may predict a successful procedure. Methods : Fifty two patients with MS in sinus rhythm underwent PBMV (90.4% female; mean age 38±10 years). Mitral valve area (MVA), valve score, mean diastolic mitral gradient (mMVG), mitral regurgitation severity, and systolic pulmonary artery pressure (sPAP) were evaluated by echocardiography before PBMV and repeated after one month. P-wave duration (Pmax /Pmin) and PWD were measured before and immediately after PBMV, at discharge, and at the end of the first month after discharge. Results : Among all procedures, 38 (73.1%) were defined as successful. Mean age, valve score, mMVG, and MVA before PBMV were similar for both groups. MVA was significantly greater in the successful PBMV group (1.65±0.27 vs. 1.41±0.22; P= 0.003). sPAP was reduced after PBMV in all patients and there were no significant differences in the mean sPAP before and after PBMV in both successful and unsuccessful groups. Pmax and PWD were significantly decreased immediately after the procedure (P= 0.035), the next day (P= 0.005) and at one month (P= 0.002) only in patients with successful PBMV. Pmin did not change significantly in either group. Conclusion : Only is successful PBMV associated with a decrease in Pmax and PWD. These simple electrocardiographic indices may predict the success of the procedure immediately after PBMV.

P-wave dispersion: an indicator of cardiac autonomic dysfunction in children with neurocardiogenic syncope

Neurocardiogenic syncope is the most frequent cause of fainting in childhood and adolescence. Although head-up tilt table testing (HUTT) was previously considered as the reference standard in the diagnosis of syncope, in children with a typical history of reflex syncope, normal physical examination, and electrocardiogram (ECG) are sufficient to cease investigation; however, according to recent reports, TT is indicated in patients in whom this diagnosis cannot be proven by initial evaluation. The hypothesis of this study is that P-wave dispersion (PWD) can be a useful electrocardiographic predictor of cardiac autonomic dysfunction in children with vasovagal syncope (VVS). The study was designed prospectively and included 50 children with positive and 50 children with negative HUTT who presented with at least two previous unexplained episodes of syncope as well as 50 sex- and age-matched healthy children as the control group. All standard 12-lead ECGs were obtained in patients and controls, and the difference between maximum and minimum durations of the P wave was defined as the PWD. A total of 100 children with VVS and 50 healthy controls were evaluated for the study. The P maximum values of HUTT-positive (HUTT[+]) patients were significantly greater than those in the HUTT-negative (HUTT[-]) and control groups(p < 0.05). In addition, mean PWD values were 50.2 ± 18.5, 39.6 ± 11.2 and 32.0 ± 11.2 ms in the HUTT(+), HUTT(-), and control groups, respectively. The difference between groups was statistically significant (p < 0.05). We suggest that PWD is an early sign of cardiac autonomic dysfunction in children with neurally mediated syncope and can be used as a noninvasive electrocardiographic test to evaluate orthostatic intolerance syndromes.

Assessment of atrial electromechanical delay in patients with polycystic ovary syndrome in both lean and obese subjects

AIM

Even though polycystic ovary syndrome (PCOS) is characterized by increased inflammatory activity and insulin resistance, there is no clinical data about whether risk of atrial fibrillation are increased in these patients. We aimed to evaluate atrial conduction parameters predicting atrial involvement in this patient group.

METHODS

The study population comprised 50 women 18-40 years of age who had been diagnosed with PCOS. The patients were divided into two groups: lean women (L-PCOS) with a body mass index (BMI) under 25 kg/m² and obese women (O-PCOS) with a BMI greater than 30 kg/m². Twenty-five age-matched lean healthy women were enrolled voluntarily as the control group. Difference between maximum and minimum P-wave duration was calculated and was defined as P-wave dispersion (Pd). Inter- and intra-atrial electromechanical delays (inter-AED, intra-AED, respectively) were measured with tissue Doppler imaging.

RESULTS

Inter- and intra-AED parameters were higher in the L-PCOS group when compared with control subjects (anova, P=0.004 and P=0.013, respectively), and were also significantly higher in the O-PCOS group compared with other groups (anova, P<0.001 for both). The regression analyses indicated that Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR) (β=0.603, P<0.001) and BMI (β=0.379, P<0.001) were the independent predictors of inter-AED, HOMA-IR (β=0.835, P<0.001) was an independent predictor of intra-AED, and BMI (β=0.457, P=0.006) and the left atrial diameter (β=0.350, P<0.034) were independent predictors of Pd.

CONCLUSION

Consequently, our findings provide data regarding prolonged atrial conduction parameters in PCOS patients, especially when accompanied by obesity.

P-wave abnormality predicts recurrence of atrial fibrillation after electrical cardioversion: a prospective study

BACKGROUND

Maintenance of atrial fibrillation (AF) is related to atrial electrical inhomogeneity and resultant chaotic reentry. Our aim was to test the hypothesis that abnormalities of P morphology on the surface electrocardiogram (ECG) predict recurrent AF following electrical cardioversion (ECV).

METHODS

A 12-lead ECG was recorded after ECV for persistent AF in 77 patients (51 men, 65 ± 10 years) and repeated 1 month later. P-wave duration was obtained in each lead using blinded on-screen measurement. Maximum P-wave duration (P-max) was defined as the longest measurable P-wave duration in any lead. P-wave dispersion (PWd) was calculated as the maximum-minimum P-wave duration.

RESULTS

One month after ECV, 29 (38%) patients maintained sinus rhythm. Compared with the sinus rhythm group, those with recurrent AF had significantly greater PWd (66 ± 19 vs 57 ± 16 ms, P = 0.024) and included more patients with P-max ≥142 ms (65% vs 38%, P = 0.023). Using a cutoff of ≥62 ms for PWd and ≥142 ms for P-max, both indices had similar predictive value (sensitivity 66.7 and 64.6%, specificity 58.6 and 62.1%, respectively). In multiple regression analysis, including established clinical predictors, P-max ≥142 ms was the only independent predictor of AF recurrence (P = 0.025).

CONCLUSION

A prolonged P-wave duration measured by 12-lead ECG predicts recurrent AF within 1 month after ECV.

P wave indices to predict atrial fibrillation recurrences post pulmonary vein isolation

Background

P-wave indices are appealing markers for predicting atrial fibrillation (AF) recurrences post ablation.

Objective

This study evaluates the value of P wave indices to predict recurrences post pulmonary vein isolation (PVI) in patients with paroxysmal AF.

Methods

We selected 198 patients (57 ± 8 years, 150 males) with symptomatic drug-refractory paroxysmal AF undergoing PVI in our hospital. A 12-lead electrocardiogram was used to measure P wave duration in lead II, P wave terminal force (PWTF) in lead V1, P wave axis and dispersion.

Results

During a follow-up of 9 ± 3 months, recurrences occurred in 60 (30.3%) patients. The patients that had AF recurrence had longer mean P wave duration (122.9 ± 10.3 vs 104.3 ± 14.2 ms, p < 0.001), larger P wave dispersion (40.7 ± 1.7 ms vs 36.6 ± 3.2 ms, p < 0.001). P wave duration ≥ 125 ms has 60% sensitivity, 90% specificity, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 83.7%, whereas P wave dispersion ≥ 40 ms has 78% sensitivity, 67% specificity, PPV of 51% and NPV of 87.6% 48/66 (72.7%) patients with PWTF ≤ - 0.04 mm/second vs 12/132(9%) with PWTF > -0.04 mm/second showed recurrence of AF (p < 0.001). P wave axis was not different between two groups. On multivariate analysis, P wave indices were not independent from left atrial size and age.

Conclusions

P wave duration ≥ 125 ms, P wave dispersion ≥ 40 ms and PWTF in V1 ≤ - 0.04 mm/sec are good clinical predictors of AF recurrences post PVI in patients with paroxysmal atrial fibrillation; however they were not independent from left atrial size and age.

Personalization of atrial anatomy and electrophysiology as a basis for clinical modeling of radio-frequency ablation of atrial fibrillation

Multiscale cardiac modeling has made great advances over the last decade. Highly detailed atrial models were created and used for the investigation of initiation and perpetuation of atrial fibrillation. The next challenge is the use of personalized atrial models in clinical practice. In this study, a framework of simple and robust tools is presented, which enables the generation and validation of patient-specific anatomical and electrophysiological atrial models. Introduction of rule-based atrial fiber orientation produced a realistic excitation sequence and a better correlation to the measured electrocardiograms. Personalization of the global conduction velocity lead to a precise match of the measured P-wave duration. The use of a virtual cohort of nine patient and volunteer models averaged out possible model-specific errors. Intra-atrial excitation conduction was personalized manually from left atrial local activation time maps. Inclusion of LE-MRI data into the simulations revealed possible gaps in ablation lesions. A fast marching level set approach to compute atrial depolarization was extended to incorporate anisotropy and conduction velocity heterogeneities and reproduced the monodomain solution. The presented chain of tools is an important step towards the use of atrial models for the patient-specific AF diagnosis and ablation therapy planing.

Relationship between atrial conduction delay and obstructive sleep apnea

Prolonged P-wave duration, indicating atrial conduction delay, is a marker of left atrial abnormality and is reported as a potent precursor of atrial fibrillation (AF). Several studies have shown that obstructive sleep apnea (OSA) is associated with AF. We evaluated the relationship between OSA and prolonged P-wave duration. Consecutive subjects who underwent overnight polysomnography and showed a normal sinus rhythm, had no history of AF or ischemic heart disease, and showed no evidence of heart failure were enrolled. Apnea-hypopnea index (AHI) is defined as the number of apnea and hypopnea events per hour of sleep. P-wave duration was determined on the basis of the mean duration of three consecutive beats in lead II from a digitally stored electrocardiogram. A total of 250 subjects (middle-aged, predominantly male, mildly obese, with a mean P-wave duration of 106 ms) were enrolled. In addition to age, male gender, body mass index (BMI), hypertension, dyslipidemia, and uric acid and creatinine levels, AHI (r = 0.56; P < 0.001) had significant univariable relationship with P-wave duration. Multivariate regression analysis showed that age, BMI, male gender, and AHI (partial correlation coefficient, 0.47; P < 0.001) were significantly independently correlated to P-wave duration. Severity of OSA is significantly associated with delayed atrial conduction time. Obstructive sleep apnea may lead to progression of atrial remodeling as an AF substrate.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Tissue Doppler atrial conduction times and electrocardiogram interlead P-wave durations with varying severity of obstructive sleep apnea

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.

Homocysteine and P wave dispersion in patients with heart transplantation

BACKGROUND

Hyperhomocysteinemia (HHcy), a putative independent risk factor for the development of atherotrombosis in the general population, represents a very common finding in orthotopic heart transplantation (OHT) patients. Starting from previous studies suggesting a pro-arrhythmogenic activity of homocysteine (Hcy), we evaluated the possible correlation among Hcy plasma levels and P wave dispersion (PWD), corrected QT interval (QTc), and QTc dispersion (QTcD) as parameters of electric instability of the myocardium in patients undergone OHT whose hearts are therefore completely denervated, thus unresponsive to autonomic influences.

METHODS AND RESULTS

Homocysteine plasma levels, PWD, QTc, QTcD, and QTc dynamics were measured in 32 patients, who underwent OHT, and in 20 control subjects. In OHT patients, PWD (39.5 ± 11 vs. 34 ± 6 ms, p = 0.04) and QTc interval (438 ± 20 vs. 410 ± 10 ms, p < 0.001) were significantly higher in comparison with control subjects. Moreover, OHT subjects with HHcy had higher PWD values than those with normal Hcy plasma levels (44.1 ± 10.7 vs. 33.9 ± 8.8 ms, p = 0.007), but no difference was found between this latter OHT group and controls. Accordingly, in OHT patients, plasma Hcy level correlated significantly with PWD (Spearman r = 0.70; p < 0.0001), whereas no correlation was found with QTc, QTcD, and QTc circadian dynamics.

CONCLUSION

HHcy seems associated with an alteration in the electrical atrial conduction, possibly contributing, at least in part, to the increased risk of cardiac arrhythmias in the denervated hearts of OHT patients.

Effect of obesity on p-wave parameters in a Chinese population

OBJECTIVE

To study the association between obesity and P-wave duration and dispersion (P(d)) in order to evaluate the potential risk for atrial fibrillation development in Chinese subjects using the definitions applied for Asian populations.

METHODS

The study population consisted of 40 obese (body mass index (BMI) > or = 25 Kg/m(2), according to the World Health Organization classification for the Asian population) subjects and 20 age- and sex-matched normal weight controls. Maximum P-wave duration (P(max)), minimum P-wave duration (P(min)), and P(d) were carefully measured using a 12-lead electrocardiogram, while the presence of interatrial block (IAB; P > or = 110 ms) was assessed.

RESULTS

There were no significant differences between the two groups regarding age, sex, history of hypertension or diabetes, and hyperlipidemia. Compared to controls, BMI, left atrial diameter (LAD), and interventricular septal thickness were increased, while P(max) (111.9 +/- 9.3 vs 101.1 +/- 6.0 ms, P < 0.01) and P(d) (47.9 +/- 9.3 vs 31.8 +/- 6.9 ms, P < 0.01) were significantly prolonged in the obese group. P(min) was similar between the two groups. The prevalence of IAB was significantly greater in the obese subjects. Pearson's correlation analysis showed that there were positive correlations between P(d) and BMI (r = 0.6, P < 0.001), as well as between P(d) and LAD (r = 0.366, P < 0.05).

CONCLUSION

Our data suggest that obesity is associated with increased P(max) and P(d), and increased prevalence of IAB, parameters that have been associated with atrial fibrillation. The correlation of these electrocardiogram parameters with LAD indicates an association between increased BMI and atrial remodeling in Asian subjects.

Prevalence of interatrial block in healthy school-aged children: definition by P-wave duration or morphological analysis

BACKGROUND

P waves > or = 110 ms in adults and > or = 90 ms in children are considered abnormal, signifying interatrial block, particularly in the first case.

METHODS

To evaluate the prevalence of interatrial block in healthy school-aged children, we obtained 12-lead digital ECGs (Cardioperfect 1.1, CardioControl NV, Delft, The Netherlands) of 664 healthy children (349 males/315 females, age range 6-14 years old). P-wave analysis indices [mean, maximum and minimum (in the 12 leads) P-wave duration, P-wave dispersion, P-wave morphology in the derived orthogonal (X, Y, Z) leads, as well the amplitude of the maximum spatial P-wave vector] were calculated in all study participants.

RESULTS

P-wave descriptor values were: mean P-wave duration 84.9 + or - 9.5 ms, maximum P-wave duration 99.0 + or - 9.8 ms, P dispersion 32.2 + or - 12.5 ms, spatial P amplitude 182.7 + or - 69.0 microV. P-wave morphology distribution in the orthogonal leads were: Type I 478 (72.0%), Type II 178 (26.8%), Type III 1 (0.2%), indeterminate 7 (1%). Maximum P-wave duration was positively correlated to age (P < 0.001) and did not differ between sexes (P = 0.339). Using the 90-ms value as cutoff for P-wave duration, 502 (75.6%) children would be classified as having maximum P-wave duration above reference range. The 95th and the 99th percentiles were in the overall population 117 ms and 125 ms, respectively. P-wave morphology type was not in any way correlated to P-wave duration (P = 0.715).

CONCLUSIONS

Abnormal P-wave morphology signifying the presence of interatrial block is very rare in a healthy pediatric population, while widened P waves are quite common, although currently classified as abnormal.

P-wave dispersion and its relationship to aortic elasticity in young prehypertensive patients

BACKGROUND

Prolonged P-wave duration (P(dur)) and increased P-wave dispersion (PWD) are independent predictors of atrial fibrillation (AF) in patients with hypertension. This study was designed to evaluate the possible relationship between aortic elasticity and PWD in young prehypertensive patients.

METHODS

Twenty-five newly diagnosed prehypertensive patients (18 men, mean age = 34 +/- 6 years) and 25 healthy control subjects (16 men, mean age = 33 +/- 6 years) were enrolled in the study. The P(dur) measurements were calculated using a 12-lead surface electrocardiogram (ECG). Aortic elasticity parameters were derived from aortic diameters measured by echocardiography, and simultaneous blood pressure (BP) measurements by sphygmomanometry.

RESULTS

The baseline characteristics of patients with prehypertension were homogeneous with those of the controls. PWD and P(maximum) values were found to be higher in patients with prehypertension as compared to those of the controls (PWD; 65 ms vs. 35 ms, P < 0.001; P(maximum); 110 ms vs. 80 ms, P < 0.001). However, P(minimum) values were not significantly different between the two groups (40 ms vs. 45 ms, P = 0.358). Also, a moderate positive correlation was found between stiffness index (SI) and PWD (r = 0.500, P = 0.011), and a moderate negative correlation between aortic elasticity parameters (aortic distensibility and strain indexes) and PWD (for aortic distensibility, r = -0.498, P = 0.011; for strain index, r = -0.578, P = 0.002), in patients with prehypertension.

CONCLUSIONS

Young patients with prehypertension have increased PWD and arterial stiffness. These parameters are correlated and may pose additional risk factors for future cardiovascular events.