P wave dispersion and short-term vs. late atrial fibrillation recurrences after cardioversion

Electromechanical Cycle Length Mapping for atrial arrhythmia detection and cardioversion success assessment

BACKGROUND

Direct current cardioversion (DCCV) is an established treatment to acutely convert atrial fibrillation (AF) to normal sinus rhythm. Yet, more than 70% of patients revert to AF shortly thereafter. Electromechanical Cycle Length Mapping (ECLM) is a high framerate, spectral analysis technique shown to non-invasively characterize electromechanical activation in paced canines and re-entrant flutter patients. This study assesses ECLM feasibility to map and quantify atrial arrhythmic electromechanical activation rates and inform on 1-day and 1-month DCCV response.

METHODS

Forty-five subjects (30 AF; 15 healthy sinus rhythm (SR) controls) underwent transthoracic ECLM in four standard apical 2D echocardiographic views. AF patients were imaged within 1 h pre- and post-DCCV. 3D-rendered atrial ECLM cycle length (CL) maps and spatial CL histograms were generated. CL dispersion and percentage of arrhythmic CLs≤333ms across the entire atrial myocardium were computed transmurally. ECLM results were subsequently used as indicators of DCCV success.

RESULTS

ECLM successfully confirmed the electrical atrial activation rates in 100% of healthy subjects (R2=0.96). In AF, ECLM maps localized the irregular activation rates pre-DCCV and confirmed successful post-DCCV with immediate reduction or elimination. ECLM metrics successfully distinguished DCCV 1-day and 1-month responders from non-responders, while pre-DCCV ECLM values independently predicted AF recurrence within 1-month post-DCCV.

CONCLUSIONS

ECLM can characterize electromechanical activation rates in AF, quantify their extent, and identify and predict short- and long-term AF recurrence. ELCM constitutes thus a noninvasive arrhythmia imaging modality that can aid clinicians in simultaneous AF severity quantification, prediction of AF DCCV response, and personalized treatment planning.

Long-term single-lead electrocardiogram monitoring to detect new-onset postoperative atrial fibrillation in patients after cardiac surgery

Background

Postoperative atrial fibrillation (POAF) is often associated with serious complications. In this study, we collected long-term single-lead electrocardiograms (ECGs) of patients with preoperative sinus rhythm to build statistical models and machine learning models to predict POAF.

Methods

All patients with preoperative sinus rhythm who underwent cardiac surgery were enrolled and we collected long-term ECG data 24 h before surgery and 7 days after surgery by single-lead ECG. The patients were divided into a POAF group a no-POAF group. A clinical model and a clinical + ECG model were constructed. The ECG parameters were designed and support vector machine (SVM) was selected to build a machine learning model and evaluate its prediction efficiency.

Results

A total of 100 patients were included. The detection rate of POAF in long-term ECG monitoring was 31% and that in conventional monitoring was 19%. We calculated 7 P-wave parameters, Pmax (167 ± 31 ms vs. 184 ± 37 ms, P = 0.018), Pstd (15 ± 7 vs. 19 ± 11, P = 0.031), and PWd (62 ± 28 ms vs. 80 ± 35 ms, P = 0.008) were significantly different. The AUC of the clinical model (sex, age, LA diameter, GFR, mechanical ventilation time) was 0.86. Clinical + ECG model (sex, age, LA diameter, GFR, mechanical ventilation time, Pmax, Pstd, PWd), AUC was 0.89. In the machine learning model, the accuracy (Ac) of the train set and test set was above 80 and 60%, respectively.

Conclusion

Long-term ECG monitoring could significantly improve the detection rate of POAF. The clinical + ECG model and the machine learning model based on P-wave parameters can predict POAF.

Risk Factors of Early Atrial Fibrillation Recurrence Following Electrical Cardioversion When Left Ventricular Ejection Fraction Is Preserved

Background and objectives: To identify clinical, echocardiographic, and laboratory parameters that affect the early recurrence of atrial fibrillation (AF) after restoring sinus rhythm (SR) by electrical cardioversion (ECV), and to determine whether left atrial (LA) strain, as a noninvasive indicator reflecting fibrosis, is associated with laboratory indicators affecting the development of fibrosis, interleukin 6 (IL-6) or tumor necrosis factor α (TNF-α). Materials and Methods: The study included 92 persistent AF patients who underwent elective ECV. The effective maintenance of SR was evaluated after 40 ± 10 days of ECV. Echocardiography, inflammatory markers (high-sensitivity c-reactive protein (hs-CRP), IL-6, and TNF-α), and natriuretic peptides (N-terminal pro b-type natriuretic peptide (NT-proBNP) and N-terminal pro a-type natriuretic peptide (NT-proANP)) were assessed. Results: After a 40 ± 10 days observation period, 51 patients (55.4%) were in SR. Patients with AF recurrence had a significantly longer duration of AF (p = 0.008) and of arterial hypertension (p = 0.035), lower LA ejection fraction (p = 0.009), lower LA strain (p < 0.0001), higher left ventricular global longitudinal strain (p = 0.001), and a higher E/e‘ ratio (p < 0.0001). LA strain was an independent predictor of early AF recurrence (OR: 0.65; 95% Cl 0.5−0.9, p = 0.004). LA strain < 11.85% predicted AF recurrence with 70% sensitivity and 88% specificity (AUC 0.855, 95% CI 0.77−0.94, p < 0.0001). LA strain demonstrated the association with NT-proBNP (r = −0.489, p < 0.0001) and NT-proANP (r = −0.378, p = 0.002), as well as with hs-CRP (r = −0.243, p = 0.04). Conclusions: LA strain appeared to be the most accurate predictor of early AF recurrence after ECV in patients with persistent AF. LA strain inversely correlated with NT-proBNP and NT-proANP, but no significant association with any of the inflammatory markers was identified.

Long P-wave duration immediately after pulmonary vein isolation on radiofrequency catheter ablation for atrial fibrillation predicts clinical recurrence: correlation with atrial remodeling in persistent atrial fibrillation

P-wave morphology reflects atrial remodeling and indicates prognosis after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). The impact of p-wave morphology after excluding the effect of pulmonary vein (PV) substrate on outcomes is unknown. We evaluated the p-wave morphology on electrocardiography immediately after PV isolation for clinical outcomes. Eighty-four consecutive patients (47 with paroxysmal AF and 37 with persistent AF) who underwent RFCA were included. P-wave duration (PWD) and amplitude in all leads were examined during sinus rhythm immediately after PV isolation. We evaluated the relationship between electrocardiogram parameters and AF recurrence, according to the type of AF and following ablation, and the correlation with left atrial (LA) volume, low voltage ratio, and fixed conduction time. During 12 months of follow-up, 20 patients experienced recurrence. The cut-off value of PWD > 120 ms in lead I showed a sensitivity of 75% and specificity of 69% for predicting recurrence. PWD was significantly correlated with LA volume, low voltage, and conduction velocity. Significantly higher recurrence rates were observed in patients with PWD > 120 ms than in those with PWD ≤ 120 ms (p < 0.001), and the difference was more pronounced in patients with persistent AF. Multivariate analysis demonstrated that PWD > 120 ms was independently associated with recurrence in the total population (hazard ratio 2.00; 95% confidence interval 1.27-3.22; p = 0.003) and in patients with persistent AF. In conclusion, long PWD after PV isolation predicts AF recurrence, which might be associated with the extent of the LA substrate in persistent AF.

The effects of gender on electrical therapies for the heart: physiology, epidemiology, and access to therapies

The difference between men and women is clear even just by looking at an electrocardiogram: females present higher resting heart rate, a shorter QRS complex length and greater corrected QT interval. The development of these differences from pubertal age onward suggests that sexual hormones play a key role, although their effect is far from being completely understood. Different incidences between sexes have been reported for many arrhythmias, both ventricular and supraventricular, and also for sudden cardiac death. Moreover, arrhythmias are an important issue during pregnancy, both for diagnosis and treatment. Interestingly, cardiovascular structural and electrophysiological remodelling promoted by exercise training enhances this 'gender effect'. Despite all these relevant issues, we lack gender specific recommendations in the current guidelines for electrical therapies for heart rhythm disorders and heart failure. Even more, we continue to see that fewer women are included in clinical trials and are less referred than men for these treatments.

Predictive role of P-wave axis abnormalities in secondary cardiovascular prevention

Background Abnormal P-wave axis has been correlated with an increased risk of all-cause and cardiovascular mortality in a general population. We aimed to evaluate the prognostic role of abnormal P-wave axis in patients undergoing myocardial revascularisation or cardiac valve surgery. Methods We considered data of 810 patients with available P-wave axis measure from a prospective monocentric registry of patients undergoing cardiovascular rehabilitation. A total of 436 patients (54%) underwent myocardial revascularisation, 253 (31%) valve surgery, 71 (9%) combined valve and coronary artery bypass graft surgery and 50 (6%) cardiac surgery for other cardiovascular disease. Mean follow-up was 47 ± 27 months. Results Over the whole group, P-wave axis was 43.8° ± 27.5° and an abnormal P-wave axis was found in 94 patients (12%). The risk of overall (hazard ratio (HR) 2.5, 95% confidence interval (CI) 1.6-4.0, P < 0.001) and cardiovascular mortality (HR 2.9, 95% CI 1.5-5.8, P = 0.002) was significantly higher in patients with abnormal P-wave axis even after adjustment for age, other electrocardiographic variables (PR, QRS, QTc intervals), left ventricular ejection fraction and left atrial volume index. After dividing the population according to the type of disease, patients with abnormal P-wave axis and ischaemic heart disease had 3.9-fold higher risk of cardiovascular mortality (HR 3.9, 95% CI 1.3-12.1, P = 0.017), while a 2.2-fold higher risk of cardiovascular mortality (HR 3.6, 95% CI 1.3-10.1, P = 0.015) was found in those with cardiac valve disease. Conclusion An abnormal P-wave axis represents an independent predictor of both overall and cardiovascular mortality in patients undergoing myocardial revascularisation or cardiac valve surgery.

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.

Beat-to-beat variability of P-wave in patients suffering from atrial fibrillation

The aim of this paper was to analyze the P-wave variability over time in patients suffering from Atrial Fibrillation (AF). Behind some time-domain and morphological features of the P-wave template, two novel indexes of P-wave variability have been estimated: one based on the cross-correlation coefficients among the P-waves (Correlation Index, CI), and one associated to variation of P-waves amplitude (Amplitude Index, AI). These indexes were estimated in two experimental models: patients suffering from persistent AF respect to control subjects and patients developing post-operative AF (POAF) after coronary artery bypass grafting respect to patients without POAF. The control group resulted to be characterized by shorter P-wave duration and by a less amount of fragmentation and variability, respect to AF patients (with a sensitivity and specificity of 98.4% and 95 % respectively). Also P-wave features resulted to be different for patients with POAF respect to patients without. In conclusion the quantification of the P-wave variability over time can add information in the understanding of the association between the anatomical atrial substrate and atrial arrhythmias.

P-wave Variability and Atrial Fibrillation

The analysis of P-wave template has been widely used to extract indices of Atrial Fibrillation (AF) risk stratification. The aim of this paper was to assess the potential of the analysis of the P-wave variability over time in patients suffering from atrial fibrillation. P-wave features extracted from P-wave template together with novel indices of P-wave variability have been estimated in a population of patients suffering from persistent AF and compared to those extracted from control subjects. We quantify the P-wave variability over time using three algorithms and we extracted three novel indices: one based on the cross-correlation coefficients among the P-waves (Cross-Correlation Index, CCI), one associated to variation in amplitude of the P-waves (Amplitude Dispersion Index, ADI), one sensible to the phase shift among P-waves (Warping Index, WI). The control group resulted to be characterized by shorter P-wave duration and by a less amount of fragmentation and variability, respect to AF patients. The parameter CCI shows the highest sensitivity (97.3%) and a good specificity (95%).

P-wave dispersion: What we know till now?

P-wave dispersion is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different-surface ECG leads. It has been known that increased P-wave duration and P-wave dispersion reflect prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses, which are well-known electrophysiologic characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation. Extensive clinical evaluation of P-wave dispersion has been performed in the assessment of the risk for atrial fibrillation in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease, in patients undergoing coronary artery bypass surgery, in patients with congenital heart diseases, as well as in other groups of patients suffering from various cardiac or non-cardiac diseases. In this paper, we aimed to summarize the measurement methods, current use in different clinical situations, strengths and limitations of the of P-wave dispersion.

Influence of Zoledronic Acid on Atrial Electrophysiological Parameters and Electrocardiographic Measurements

INTRODUCTION

Our objective was to determine effects of zoledronic acid (ZA) on atrial electrophysiological parameters and electrocardiographic measurements.

METHODS AND RESULTS

Ex vivo perfusion study: Isolated guinea pig hearts were perfused with modified Krebs-Henseleit (K-H) buffer with or without ZA 0.07 mg/kg/L (each n = 6). In ZA-perfused hearts, atrial action potential at 90% repolarization (APD90 ) decreased more from baseline than in controls (-23.2% ± -5.1% vs. -2.1% ± -8.1%, P < 0 .0001), as did APD30 (-28.8% ± -3.8% vs. -2.1% ± -2.1%, P < 0.0001). In vivo dose-response study: Guinea pigs underwent intraperitoneal injections every 2 weeks in 1 of 4 groups (each n = 8): ZA 0.007 mg/kg (low-dose), ZA 0.07 mg/kg (medium-dose), ZA 0.7 mg/kg (high-dose), or placebo. Hearts were excised at 8 weeks and perfused with modified K-H. Atrial effective refractory period (ERP) was lower with medium- and high-dose ZA versus placebo (P = 0.004). Atrial APD30 was lower with high-dose ZA versus placebo, low and medium doses (P < 0.001). Canine ECG study: Mature female beagles received intravenous ZA 0.067 mg/kg or saline (placebo; each n = 6) every 2 weeks for 12 weeks. P wave dispersion was greater in the ZA group (7.7 ± 3.7 vs. 3.4 ± 2.6 ms, P = 0.04). There were no significant differences in P wave index, maximum or minimum P wave duration, or PR interval.

CONCLUSION

ZA shortens left atrial APD and ERP and increases P wave dispersion.

P-wave duration in lead aVR and the risk of atrial fibrillation in hypertension

BACKGROUND

Hypertension entails atrial remodeling that affect P-wave (PW) duration on electrocardiogram (ECG). PW indices (e.g., variance, dispersion, and terminal force) are associated with a higher risk for atrial fibrillation (AF), but their calculation requires multiple measurements of PW duration, limiting their use in clinical practice. We evaluated whether PW duration in specific ECG leads may identify patients with increased susceptibility to AF in a population of hypertensive patients.

METHODS

In a case-control study, AF and control subjects were matched for age, sex, and left atrial (LA) dimensions. PW duration was measured from digitally stored ECGs. Logistic regression was used to assess the association of PW duration and indices with AF.

RESULTS

We enrolled 44 hypertensive AF patients (16 paroxysmal and 28 persistent) and 44 hypertensive controls. AF and control subjects were matched for sex (males, n = 27), age (67 ± 8 years), LA diameter (40 ± 5 mm), and were comparable for left ventricular mass (45 ± 11 g/m(2.7) vs 48 ± 12 g/m(2.7) , P = 0.19), ejection fraction (58 ± 7% in both groups), and prevalence of mild valvular heart disease (7% vs 5%; P = 0.64). PW duration in lead aVR was significantly higher in AF patients as compared with controls (115 ± 18 ms vs 101 ± 14 ms; P < 0.0001) and was the best independent predictor of AF in multivariable logistic regression (PW ≥ 100 ms: RR = 3.7; 95% CI: 1.3-10.3; P = 0.02).

CONCLUSIONS

Simple measurement of PW duration in lead aVR allows effective identification of AF patients in a population of hypertensives. Confirmation of this finding in a larger population would provide a simple and effective risk marker of AF in hypertensive patients.

Holter electrocardiography findings and P-wave dispersion in pediatric patients with transcatheter closure of atrial septal defects

BACKGROUND

This study aimed to determine the frequency of postintervention arrhythmia and factors associated with the development of arrhythmia, including the correlation between arrhythmia and P-wave dispersion, and the effects of the latter on transcatheter closure of atrial septal defects (ASDs).

METHODS

Holter ECG recordings were performed before and after the intervention and 6 and 12 months later in 47 of the 59 patients who had undergone transcatheter ASD closure and once in the healthy control subjects.

RESULTS

A statistically significant correlation was identified between the patients' arrhythmia grade according to Lown's system and each of the following: the number of defects, the size of the atrioventricular valve rim, the presence of an atrial septal aneurysm.

CONCLUSION

The frequency of arrhythmia increases after transcatheter ASD closure, gradually decreases within the next year, and is most frequently of a benign nature. Lown's arrhythmia grading of patients occluded with either the Amplatzer septal occluder (ASO) or the Cardio-O-Fix septal occluder (CSO) were compared, and the arrhythmia frequency was higher with the latter. One day after the intervention, the P maximum (Pmax ) and the P dispersion(Pdis ) values were not increased but in fact slightly reduced in patients occluded with either ASO or CSO. An improvement in the electrical system resulting from early anatomical and mechanical healing following transcatheter ASD occlusion may explain the reduction in the Pmax and Pdis values.

P-wave characteristics after electrical external cardioversion: predictive indexes of relapse

Atrial fibrillation (AF) is the most common arrhythmia in the western countries and accounts for hundred thousand strokes per year. Electrocardiographic characteristics of AF have been demonstrated to help identify patients at risk of developing AF. Prolonged and highly fragmented P-waves have been observed in patients prone to AF, and time-domain. Morphological characteristics of the P-wave from surface ECG recordings turned out to significantly distinguish patients at risk of AF. The aim of this study is to evaluate the morphological and time-domain characteristics of the P-wave in patients with AF relapse after cardioversion, respect to patients without. 14 patients who underwent successful electrical cardioversion for persistent AF were enrolled. Five minute ECG recordings were performed for each subject, immediately post-successful cardioversion. ECG signals were acquired by using a 16-lead mapping system for high-resolution biopotential measurements (sample frequency 2 kHz, 31 nV resolution, 0-400 Hz bandwidth). From the 16 recordings, a standard 12-lead ECG was derived and analyzed in terms of signal-averaged P-wave. Time-domain and mor-phological characteristics were estimated from the averaged P-waves of each lead. Time-domain features were quantified as: maximum P-wave duration in any of the 12 leads (Pmax), minimum P-wave duration in any of the leads (Pmin), P-wave dispersion (Pdisp=Pmax-Pmin), and Pindex (standard devia-tion of P-wave duration in any of the 12 leads). Morphological characteristics were extracted from a Gaussian function-based model of the P-wave as: average model order (Nav), maximum number of zero-crossing (PCmax), and maximum and average number of maxima and minima (FCImax and FCIav) in any of the leads. The results obtained so far indicate that the morphological and time-domain characteristics distinguish between patients with AF relapse and patients without.

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.

Factors to predict recurrence of atrial fibrillation in patients with hypertension

BACKGROUND

Patients with essential hypertension had a higher recurrence rate of atrial fibrillation (AF) than patients without hypertension. This study evaluated the role of various parameters for predicting recurrence after conversion of AF in patients with essential hypertension.

METHODS

We retrospectively analyzed 136 patients with essential hypertension and a known history of AF. P-wave duration and dispersion were measured in a 12-lead electrocardiograph. The size and function of the left atrium (LA) and left atrial appendage (LAA) were assessed by transthoracic and transesophageal echocardiography. The time interval from initiation of P-wave to the start of LAA ejection flow (P-LAA) was measured at the same time. All the patients were followed up for a period of 12 +/- 6 months for the recurrence of AF.

RESULTS

In the follow-up period, 38.2%of patients underwent AF recurrence. Age, P-LAA, P(max), P-wave dispersion, left atrium diameter (LAD), and maximum and minimum LAA volume were significantly higher in patients with AF recurrence than in patients without AF recurrence, while EF-LAA and LAA peak emptying velocity were much lower in patients with AF recurrence. P-LAA had positive correlation with LAD and P-wave dispersion (r = 0.501, p < 0.0001; r = 0.713, p < 0.0001).

CONCLUSION

These results indicated that increased P-wave dispersion, P-LAA in addition to the dilated LA, and the depressed LAA function may be useful to identify patients with hypertension at risk of recurrent AF.

P-wave indices, distribution and quality control assessment (from the Framingham Heart Study)

BACKGROUND

P-wave indices of maximum P-wave duration and P-wave dispersion have been examined in a broad array of cardiovascular and noncardiovascular disease states. The P-wave indices literature has been highly heterogeneous in measurement methodologies, described quality control metrics, and distribution of values. We therefore sought to determine the reproducibility of P-wave indices in a community-based cohort.

METHODS

P-wave indices were measured in sequential subjects enrolled in the Framingham Heart Study. Electrocardiograms were obtained at the 11th biennial visit of the Original Cohort (n = 250) and the initial visit of the Offspring Cohort (n = 252). We determined the mean P-wave durations, interlead correlations, and P-wave indices. We then chose 20 ECGs, 10 from each cohort, and assessed intrarater and interrater variability.

RESULTS

The maximum P-wave duration ranged from 71 to 162 ms with mean of 112 + or - 12 ms. The minimum P-wave duration ranged from 35 to 103 ms with mean of 65 + or - 10 ms. P-wave dispersion ranged from 12 to 82 ms. The mean P-wave dispersion was 48 + or - 12 ms (40-56). The intrarater intraclass correlation coefficient (ICC) was r = 0.80 for maximum P-wave duration and r = 0.82 for P-wave dispersion. The interrater ICC was 0.56 for maximum P-wave duration and 0.70 for P-wave dispersion.

CONCLUSIONS

We demonstrated excellent intrarater reproducibility and fair interrater reproducibility for calculating P-wave indices. Reproducibility is frequently lacking in studies of P-wave indices, but is an essential component for the field's growth and epidemiologic contribution.

Duration and dispersion of the P wave after the Senning operation

We studied the duration and dispersion of the P wave in patients after a Senning operation, assessing its value in detecting the risk of atrial tachycardias.We measured the duration and dispersion of the wave in surface 12 lead electrocardiograms obtained from 18 patients with sinus rhythm, having a mean age of 12.8 years, with 13 being males and 5 females, who had undergone a Senning operation, comparing the values obtained in 35 age and gender-matched healthy people. The patients had undergone repair at a mean age of 13.4 months, and had a mean duration of follow-up of 12.8 years after the procedure. We also made 24 hour Holter recordings.The maximal duration of the P wave, at a mean of 129.3 milliseconds, and dispersion with a mean of 78 milliseconds, were both significantly increased in the patients compared with their controls, the mean values for the normal subjects being 103.7 and 54 milliseconds. Supraventricular tachycardia was detected in 1 of 3 patients with dispersion greater than 100 milliseconds, and in 2 of 15 patients (13%) with dispersion less than 100 milliseconds as measured from the Holter recordings (p > 0.05).Thus, the maximum duration and dispersion of the P wave were increased in patients after a Senning operation, but we were unable to establish any relationship between these measurements and atrial tachycardias as observed using Holter monitoring.

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.

Electrocardiographic predictors of atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most prevalent arrhythmia in the United States and accounts for more than 750,000 strokes per year. Noninvasive predictors of AF may help identify patients at risk of developing AF. Our objective was to identify the electrocardiographic characteristics associated with onset of AF.

METHODS

This was a retrospective cohort analysis of 42,751 patients with electrocardiograms (ECGs) ordered by physician's discretion and analyzed using a computerized system. The population was followed for detection of AF on subsequent ECGs. Cox proportional hazard regression analysis was performed to test the association between these ECG characteristics and development of AF.

RESULTS

For a mean follow-up of 5.3 years, 1,050 (2.4%) patients were found to have AF on subsequent ECG recordings. Several ECG characteristics, such as P-wave dispersion (the difference between the widest and narrowest P waves), premature atrial contractions, and an abnormal P axis, were predictive of AF with hazard ratio of approximately 2 after correcting for age and sex. P-wave index, the SD of P-wave duration across all leads, was one of the strongest predictors of AF with a concordance index of 0.62 and a hazard ratio of 2.7 (95% CI 2.1-3.3) for a P-wave index >35. These were among the several independently predictive markers identified on multivariate analysis.

CONCLUSIONS

Several ECG markers are independently predictive of future onset of AF. The P index, a measurement of disorganized atrial depolarization, is one of the strongest predictors of AF. The ECG contains valuable prognostic information that can identify patients at risk of AF.

P-wave duration and dispersion in patients with obstructive sleep apnea

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 Pd in patients with obstructive sleep apnea (OSA) and to determine its relationship with severity of the disease.

METHODS

The study population included 67 patients referred to sleep laboratory. The Apnea-Hypopnea Index (AHI) was defined as the number of apneas and hypopneas per hour of sleep. Of the sixty-seven patients, 48 had AHI5 and were diagnosed as OSA. Nineteen of the patients had AHI<5 and were diagnosed as OSA (-) (Group 1), 32 of the patients had AHI between 5-30 (mild and moderate, group 2), 16 of the patients had AHI>30 (severe, group 3). The P-wave duration was calculated in all leads of the surface electrocardiogram. The difference between the maximum (Pmax) and minimum P (Pmin) wave duration was calculated and was defined as the P-wave dispersion (Pd). Echocardiographic examination was also performed.

RESULTS

Pmax was longer in group 3 compared to group 2 and group 1 (p=0.002, p<0.001 respectively). Pmax was longer in group 2 compared to group 1 (s<0.001). Pd was greater in group 3 compared to group 2 and group 1 (p<0.001 for both comparison). Pd was greater in group 2 compared to group 1 (p<0.001). Pmin did not differ between the groups. In patients with OSA, Pd was positively correlated with AHI (r=0.56, p<0.001), BMI (r=0.43, p=0.03), and mitral early diastolic to late diastolic velocity (E/A) ratio (r=0.37, p=0.01). Multiple linear regression analysis showed that only AHI was independently associated with Pd (beta=0.39, p=0.02).

CONCLUSION

Pd was found to be greater in patients with OSA than patients without OSA and to be associated with severity of the disease.

The effect of diabetes mellitus on the P-wave dispersion

BACKGROUND

P-wave dispersion (PD), a measure of heterogeneity of atrial refractoriness, is defined as the difference between the minimum (P min) and maximum P-wave (P max) durations on standard 12-lead electrocardiography (ECG). Increase in PD shows the intra-atrial and inter-atrial non-uniform conduction. In the present study the evaluation of the effect of diabetes mellitus (DM) on PD in patients without coronary artery disease and hypertension was carried out.

METHODS AND RESULTS

Seventy-six diabetic patients who had no coronary artery disease or hypertension (group 1; mean age 48+/-9) and 40 healthy volunteer individuals (group 2; mean age 46+/-13) were enrolled in the study. After obtaining 12-lead surface ECG of all cases, P max and P min P-wave durations were measured and the differences between them were taken as PD (PD=P max-P min). Left atrium diameter, left ventricular end systolic and end diastolic diameters were measured and left ventricular ejection fraction was determined by echocardiography. Pulse wave mitral flow velocities were measured from the apical 4-chamber view. Mitral early diastolic velocity (E), late diastolic velocity (A), E/A, E deceleration time and isovolumetric relaxation time were determined. In comparison of the 2 groups there was no statistically significant difference among age, sex, systolic and diastolic blood pressure, resting heart rate and body mass index of the cases. Although PD and P max were significantly higher in diabetic patients, there was no difference between P min values (33+/-12 vs 28+/-10, p=0.02; 99+/-12 vs 93+/-10, p=0.011; 66+/-9 vs 65+/-10, p=NS; respectively).

CONCLUSIONS

DM might increase PD even without ischemia, hypertension and left ventricular hypertrophy.

P-wave dispersion in patients with rheumatic mitral stenosis

It has previously been shown that maximum P-wave duration and P-wave dispersion in 12-lead surface electrocardiogram (ECG) are significantly increased in patients prone to developing atrial fibrillation. Because patients with mitral stenosis (MS) are also susceptible to developing atrial fibrillation, the present study was carried out to determine whether maximum P-wave duration and P-wave dispersion are prolonged in MS patients during normal sinus rhythm. In addition, the correlation between these P-wave variables and the left atrial size, transmitral valve gradient and mitral valve area were determined. Fifty consecutive patients (40 women and 10 men; mean age 35.76±6.59 years) with MS who were in normal sinus rhythm, and a control group of 50 age- and sex-matched healthy persons were studied.A 12-lead ECG was obtained for each subject. All ECGs were scanned through a Cannon scanner at 300 dpi and saved as images in a personal computer. The minimum and maximum P-wave durations, as well as P-wave dispersion, were subsequently calculated. In addition, all patients were evaluated by echocardiography to measure the left atrial size, transmitral valve gradient and mitral valve area by planimetry. The P-wave parameters were compared between the two groups and the correlation between these parameters and the echocardiographic variables were determined in patients with MS. The most important findings included a significant prolongation of maximum P-wave duration in patients with MS compared with controls (P<0.001), and a strong correlation between the maximum P-wave duration and left atrial size (r=0.505, P<0.001), transmitral valve gradient (r=0.371, P=0.01) and a significant negative correlation with mitral valve area (r=-0.379, P=0.007). There was no correlation between the P-wave dispersion and echocardiographic parameters.

Assessment of Atrial Conduction in Patients with Scleroderma by Tissue Doppler Echocardiography and P Wave Dispersion

BACKGROUND

Atrial conduction abnormalities in patients with scleroderma have not been evaluated in terms of P wave duration, P wave dispersion (P(d)) and electromechanical coupling measured by tissue Doppler echocardiography.

METHODS

Twenty-four patients with scleroderma and 24 control subjects underwent resting electrocardiogram (ECG), M mode and tissue Doppler echocardiography. The P wave duration was calculated in all leads of the surface ECG. The difference between the maximum (P(max)) and minimum P wave duration was calculated and defined as P(d). Interatrial and intraatrial electromechanical delays were measured with tissue Doppler tissue echocardiography.

RESULTS

The left ventricular dimensions, fractional shortening, and left atrial diameter did not differ between the patients and the controls. P(d) and P(max) were significantly higher in patients with scleroderma compared with controls: 51 +/- 17 versus 28 +/- 7 ms (p < 0.01) and 109 +/- 10 versus 93 +/- 6 ms (p < 0.01), respectively. There was a delay between the onset of the P wave on surface ECG and the onset of the late diastolic wave (A wave; PA) obtained by tissue Doppler echocardiography in patients with scleroderma compared with controls measured at lateral septal annulus (lateral PA; 122 +/- 8 vs. 105 +/- 7 ms, p = 0.001), septal mitral annulus (104 +/- 11 vs. 93 +/- 10 ms, p = 0.01) and tricuspid annulus (right ventricular PA; 71 +/- 9 vs. 64 +/- 7 ms, p = 0.05). Interatrial conduction time (lateral PA - right ventricular PA) was delayed in patients with scleroderma compared with controls (88 +/- 13 vs. 76 +/- 11 ms, p = 0.01). A positive correlation was detected between interatrial electromechanical delay (lateral PA - right ventricular PA) and P(d) (r = 0.5, p = 0.03).

CONCLUSION

Atrial conduction abnormalities as estimated with P(d) and P(max) are significantly higher in patients with scleroderma compared with controls. There is a delay in both intraatrial and interatrial electromechanical coupling intervals in patients with scleroderma.