P-wave Signal-averaged Electrocardiogram Research Articles

New parameter of the second part of the P-wave predict atrial fibrillation: comparison with P-wave signal-averaged electrocardiography

Abstract Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): Kyung Hee University Background A study to predict the risk of AF by analyzing the P-wave of the electrocardiogram in detail has been attempted for a long time, and P-wave signal-averaged ECG is also known to be helpful. Recently, the P-wave was analyzed by dividing it into two parts, and when the latter part is extended, it suggests left atrium dilatation or delayed conduction, and it is suggested that this may be a slightly more sensitive parameter. Objective The purpose of this study was to find the best predictor of atrial fibrillation by comparing the characteristics of the P-wave in the subjects with AF and healthy controls using 12-lead ECG and signal-averaged ECG (SAECG). Methods We recruited 58 paroxysmal atrial fibrillation patients in AF group and 57 people in the control group. All subjects underwent 12-lead ECG, P-wave signal-averaged ECG, and transthoracic echocardiography. The total P-wave duration (PWD), the second part of the P-wave were measured with an electronic caliper in lead II. Results The second part of the P-wave was higher in the AF group, which was statistically significant (70.8 ± 20.6 vs. 60.5 ± 12.3ms, respectively, p<0.01). Filtered PWD and the integral of the P-wave were significantly higher in the AF group. The second part of the P-wave, filtered PWD, and the integral of P-wave were univariate and multivariate predictors of AF. The second part of the P-wave showed ROC (Receiver operating characteristic curves) area of 0.635, and the cut-off value was 61.5ms with 59.6% sensitivity and 59.6% of specificity. Of the SAECG parameters, the longer filtered PWD predicted a history of AF with an AUC (Area under the ROC curve) of 0.669. Conclusions We confirmed that second part of the P-wave which reflects the electrophysiological status of the left atrium is a valuable marker for predicting AF. Also, Filtered PWD and the integral of the P-wave among the SAECG parameters were useful predictors of AF.

New Parameter to Predict Recurrence of Paroxysmal Atrial Fibrillation after Pulmonary Vein Isolation by the P-Wave Signal-Averaged Electrocardiogram

New Parameter to Predict Recurrence of Paroxysmal Atrial Fibrillation after Pulmonary Vein Isolation by the P-Wave Signal-Averaged Electrocardiogram

An ECG Index of P-Wave Force Predicts the Recurrence of Atrial Fibrillation after Pulmonary Vein Isolation.

Although several prognostic factors of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) have been investigated, the accurate prediction of AF recurrence remains difficult. We propose an electrocardiogram (ECG) index, the P-wave force (PWF), which is the product of the amplitude of the negative terminal phase of the P wave in the V1 electrode and the filtered P-wave duration, obtained by a signal-averaged P-wave analysis. This study was conducted to evaluate the impact of the PWF on the recurrence of AF after PVI. We retrospectively evaluated 79 paroxysmal AF patients (64 ± 9 years, 56 males) who underwent PVI by cryoballoon ablation. Standard 12-lead ECG and a P-wave signal-averaged electrocardiogram (SAECG) were recorded the day before and 1 month after the PVI procedure. During the mean follow-up of 10.2 months, AF recurred in 11 (14%) patients. The PWF 1 month after ablation was significantly higher in the recurrence group compared to that in the nonrecurrence group (8.8 ± 3.1 mVms vs 6.5 ± 2.9 mVms, P = 0.017). The patients with a PWF value ≥9.3 mVms had a significantly greater risk of recurrence after the ablation compared to the patients with a PWF value <9.3 mVms (log-rank test, P < 0.001). Higher PWF after cryoballoon ablation was associated with poor prognosis during follow-up. The PWF may be a useful and noninvasive marker to predict the recurrence of AF.

THE EFFECT OF ALDOSTERONE ANTAGONISTS ON THE ELECTROPHYSIOLOGICAL PARAMETERS IN RECURRENCE ATRIAL FIBRILLATION

Purpose: to investigate the effect of mineralocorticoid receptor antagonists on atrial electrophysiological parameters and frequency of AF episodes in recurrence AF and left ventricular diastolic dysfunction. Material and methods: prospective cohort study included 89 patients with recurrence non-valvular AF and left ventricular diastolic dysfunction who had sinus rhythm at baseline. All patients received ACE inhibitors, β-blockers, statins, antithrombotic and antiarrhythmic drugs and were randomly assigned to either standard therapy only (Control group, 46 patients) or mineralocorticoid receptor antagonists spironolactone 25 mg titrated to 50 mg (SPRL group, 43 patients) added to standard treatment. At baseline and after 6 months of treatment P-wave duration and dispersion of standard electrocardiogram (ECG), P-wave signal-averaged ECG parameters (total filtered P-wave duration (FiP) and a root-mean-squared voltage of the terminal 20 ms (RMS-20) and atrial late potentials (ALP) were evaluated. The primary endpoint of the study was AF recurrence. Results: at baseline there were no significant differences between groups. After 6 months of treatment significant reduction in P-wave dispersion were found in SPRL group. FiP improved significantly in both groups, but more in the SPRL group, RMS-20 increased only in the SPRL group. At baseline ALP was detected in 38 (82.6%) patients in Control group and in 36 (83.7%) of SPRL group (χ2 = 0.02, p = 0.887). After 6 months the ALP rate was significantly decreased in SPRL group (56.1%, χ2 = 6.4, p = 0.011 compared to baseline) but remained high in Control (76.0%, χ2 = 0.27, p = 0.6). AF recurrences were documented in 33 (71.7%, 95% CI 57.6-84.0%) patients in Control group and in 21 (48.8%, 95% CI 33.7-64.0%) in SPRL group (χ2 = 3.97, p = 0.046). Additional spironolactone intake was associated with 22.9% (95% CI 2.6-40.8%, p = 0,048) risk reduction of AF recurrence. Summary: application of spironolactone for 6 months additionally to standard therapy in patients with recurrent AF and left ventricular diastolic dysfunction leads to significant improvement in the atrial electrophysiological parameters and decrease in AF recurrence.

Effects of eplerenone on P-wave signal-averaged electrocardiogram in hypertensive patients with coronary artery disease

Effects of eplerenone on P-wave signal-averaged electrocardiogram in hypertensive patients with coronary artery disease

Impact of pulmonary vein isolation on atrial late potentials: association with the recurrence of atrial fibrillation

In patients with paroxysmal atrial fibrillation (AF), the P-wave signal-averaged electrocardiogram often demonstrates a low-amplitude potential at the terminal part of filtered P-wave (atrial late potential: ALP), which would originate from delayed pulmonary vein (PV) potentials. The aim of this study was to investigate the impact of PV isolation on P-wave morphology, and explore the association between ALP and AF recurrence after ablation. We enrolled 88 consecutive paroxysmal AF patients scheduled for ablation. The signal-averaged electrocardiogram was obtained at baseline and 1 day after ablation. An ALP was defined as a P-wave duration of ≥ 130 ms and a root-mean-squared voltage of the terminal 20 ms of ≤ 2.0 μV. A pre-procedural ALP was found in 37 (42%) patients and a post-procedural ALP was found in 26 (30%) patients. We completed PV isolation in all patients and followed them for 16 ± 4 months. The AF recurrence rate was 30% (26 patients) and was similar between patients with and without pre-procedural ALP (27 vs. 31%, respectively, P = 0.66); however, AF recurrence was significantly higher in patients with than without post-procedural ALP (54 vs. 19%, respectively, P = 0.001). In multivariate logistic regression analysis, post-procedural ALP was independently associated with AF recurrence (odds ratio = 4.22, 95% confidence interval = 1.52-11.7). Pulmonary vein isolation can modify ALP in a substantial number of patients with paroxysmal AF. Post-procedural ALP is associated with increased risk of future AF recurrence.

Type III procollagen-N-peptide as a predictor of persistent atrial fibrillation recurrence after cardioversion

Fibrosis and inflammation may play a significant role in the pathogenesis of atrial fibrillation (AF) recurrence. Type III procollagen-N-peptide (PIIINP) may be related to atrial fibrosis and play a role in predicting the recurrence of AF. We investigated whether PIIINP as a fibrosis marker predicts the recurrence of AF after cardioversion. Serum PIIINP, interleukin-6, high-sensitivity C-reactive protein, brain natriuretic peptide, renin and aldosterone were measured at baseline and 24 months in 88 patients (62%) with sinus rhythm (SR) maintenance and 54 patients (38%) with AF recurrence. Furthermore, the root mean square voltage in the last 20 ms (RMS20) via P-wave signal-averaged electrocardiogram (P-SAECG) was measured and the relationship between fibrosis biomarkers and RMS20 was examined. Baseline PIIINP with AF recurrence was significantly higher than for those with SR maintenance (0.664 vs. 0.581 U/mL, P = 0.001). However, there were no significant differences in other biomarkers. A logistic regression identified PIIINP (odds ratio 2.61, P = 0.008) as an independent predictor of AF recurrence. The RMS20 as measured by P-SAECG with SR maintenance and PIIINP levels <0.72 U/mL (at baseline) was significantly higher after 24 months than at baseline. Furthermore, the RMS20 with AF recurrence and PIIINP levels >0.72 U/mL (at baseline) was significantly lower after 24 months than baseline. Elevated baseline PIIINP concentration is an independent predictor for AF recurrence after cardioversion. Furthermore, there is a relationship between PIIINP and RMS20 and the fibrosis of AF.

Hemodialysis-Induced P-Wave Signal-Averaged Electrocardiogram Alterations Are Indicative of Vulnerability to Atrial Arrhythmias

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, often occurring during hemodialysis (HD). Prolongation of the total filtered P-wave duration (PWD) and reduction of the root mean square voltages for the last 20 ms of the P wave (RMS20) on a P-wave signal-averaged electrocardiogram (P-SAECG) are predictors of AF. We investigated whether HD induces alterations of P-SAECG, and determined the influential factors. Thirty-three end-stage kidney disease patients (66.7 ± 12.6 years, 23 males) undergoing maintenance HD were enrolled in this study. Digital ambulatory P-SAECG monitoring and laboratory examination of serum proteins and ions were carried out before, during, and after the HD sessions. Data were analyzed by multiple regression analysis. PWD was significantly prolonged, and RMS20 significantly reduced, during HD. These values recovered after completion of HD. Multiple regression analysis showed that prolongation of PWD significantly correlated with HD duration and the rate of removal of body fluid. On the other hand, RMS20 significantly correlated with HD duration and blood urea nitrogen variation. HD resulted in prolongation of PWD and reduction of RMS20, indicating the vulnerability of HD patients to AF. These P-SAECG changes correlated with HD duration and the rate of removal of the body fluid. These findings underline the importance of the control of dialysis variables in the prevention of atrial arrhythmias following HD.

Abstract 9142: Post Procedural Changes of P-wave Duration can Predict Recurrence of Atrial Fibrillation after Circumferential Pulmonary Vein Isolation

Background: It has been reported that the significant shortening of P-wave duration after pulmonary vein isolation was related to successful outcome. However, the impact of the clinical outcomes after circumferential pulmonary vein isolation (CPVI) on the serial changes of P-wave characteristics is not clear. We hypothesized that the recurrence of atrial fibrillation (AF) prolonged P-wave duration and the recurrence of AF after CPVI affected the P-wave parameters by P-wave signal averaged electrocardiogram (P-SAECG). Methods: Fifty-nine patients (65±7years, 41 male) with AF (paroxysmal AF : n=44, persistent AF : n=15) who underwent CPVI alone and received P-SAECG at 2 days, 2 weeks, and 4weeks after CPVI were enrolled in this study. By using P-SAECG, the filtered P-wave duration (FPD) and root mean square voltage for the last 20msec (RMS20) were measured and the serial changes of FPD and RMS20 were calculated. AF recurrence was defined as patient's symptom and any episode of AF lasting &gt; 30 seconds on surface 12-leads ECG or 24-hour Holter ECG during follow-up periods except for 2 months post CPVI. Results: The patients were followed for 6±3 months. The recurrences of AF occurred in 18 of 59 patients (31%). The results of P-SAECG parameters were shown as table. The FPD of 2 days, 2weeks and 4weeks after CPVI in AF recurrence group was significantly longer than that in sinus rhythm (SR) maintenance group and the ΔFPD 4weeks in AF recurrence group was significantly prolonged than that in SR maintenance group. Using FPD 4weeks as cutoff value of &gt; 130.5 msec to predict AF recurrence, the sensitivity and specificity were 65% and 61%, respectively. Using ΔFPD 4weeks as cutoff value of &gt; 3.5 msec to predict AF recurrence, the sensitivity and specificity were 71% and 63%, respectively. Conclusion: The longer FPD and prolongation of FPD for one month after CPVI can predict the recurrence of AF after CPVI.

Aortic stiffness is increased in acromegaly regardless the method of assessment

acid prevents atrial fibrillation associated with heart failure in a rabbit model. Am J Physiol Heart Circ Physiol 2011;300:H1814–21. [19] Michellucci A, Toso A, Mezzani A, et al. Noninvasive recording of sinus node activity by Pwave triggered SAECG. Validation using direct intra-atrial recording of sinus node electrogram. Am J Noninvasive Cardiol 1993;7:132–7. [20] Ehlert F, Gaur A, Steinberg JS. Correlation of the P-wave signal-averaged electrocardiogram to intra-cardiac atrial conduction. Circulation 1996;94:I-70. [21] Nomura M, Kawano T, Nakayasu K, Nakaya Y. The effects of losartan on signalaveraged P wave in patients with atrial fibrillation. Int J Cardiol 2008;126:21–7. [22] Chen J, Shearer GC, Chen Q, et al. Omega-3 fatty acids prevent pressure overloadinduced cardiac fibrosis through activation of cyclic GMP/protein kinase G signaling in cardiac fibroblasts. Circulation 2011;123:584–93. [23] Ciulla MM, Paliotti R, Esposito A, et al. Effects of antihypertensive treatment on ultrasound measures of myocardial fibrosis in hypertensive patients with left ventricular hypertrophy: results of a randomized trial comparing the angiotensin receptor antagonist, candesartan and the angiotensin-converting enzyme inhibitor, enarapril. J Hypertens 2009;27:626–32.

Increased Intraatrial Conduction Abnormality Assessed by P‐Wave Signal‐Averaged Electrocardiogram in Patients with Brugada Syndrome

Atrial fibrillation (AF) is observed in patients with Brugada syndrome (BS), especially those showing coved-type electrocardiogram (ECG) pattern. Using P-wave signal-averaged ECG (P-SAE), we investigated whether increased intraatrial conduction abnormality contributed to AF generation in BS patients. Twenty BS patients and 20 age- and gender-matched healthy controls were enrolled. At the P-SAE recording, 12 of the 20 BS patients showed coved-type (C-BS) and eight showed saddleback-type (S-BS). The total duration (Ad) and root mean square voltage for the terminal 20 ms (LP(20) ) of the filtered P wave were measured. P-wave dispersion (P-disp) was defined as the difference between the maximum and minimum, measured from 16 precordial recording sites. BS patients had a significantly longer Ad (128.2 ± 7.6 vs 116.3 ± 8.2 ms, P < 0.0001), lower LP(20) (2.6 ± 0.9 vs 3.4 ± 0.8 μV, P < 0.01), and greater P-disp (15.5 ± 7.0 vs 7.4 ± 3.2 ms, P < 0.0001) than the controls. C-BS patients had significantly longer Ad (131.0 ± 7.2 vs 124.1 ± 6.8 ms, P < 0.05) and lower LP(20) (2.2 ± 0.6 vs 3.2 ± 1.0 μV, P < 0.05) than S-BS patients. All C-BS patients and only three S-BS patients had atrial late potential (100% vs 38%, P < 0.01). Intraatrial conduction delay and its heterogeneity may exist in BS patients, especially those showing coved-type ECG patterns. These atrial electrical abnormalities could be a substrate for atrial reentrant tachycardia such as AF.

Timing of Atrial Fibrillation Recurrence Following Pulmonary Vein Isolation and Serial Changes of P-Wave Duration

Background: The terminal portion of the P-wave was correlated to the activation of pulmonary vein muscle and the shortening of P wave duration could predict successful outcomes after atrial fibrillation (AF) ablation. However, the mechanism of early recurrence of AF and late recurrence of AF are not clear. We investigated the relation between serial changes of P-wave duration and timing of AF recurrence. Method: Twenty-nine patients (66±7 years, 18 male) with recurrence of AF who underwent circumferential pulmonary vein isolation (CPVI) alone for drug resistant AF and received P-wave signal averaged electrocardiogram (P-SAECG) at 2 days, 2 weeks, and 4 weeks following CPVI were enrolled in this study. By using P-SAECG, the serial changes of the filtered P-wave duration (FPD) (ΔFPD 2 weeks = FPD 2 weeks-FPD 2 days, ΔFPD 4 weeks = FPD 4 weeks-FPD 2 days) were calculated. AF recurrence within 2 months post CPVI was defined as early recurrence. Results: ΔFPD 2 weeks in early recurrence of AF (ERAF group, n=21) was significantly longer than that in late recurrence of AF (LRAF, n=8), (4.2±9 vs. −6.6±11.7, p=0.04). However, ΔFPD 4 weeks in LRAF group was significantly longer than that in ERAF (14.2±7.6 vs. 6.8±9.5, p=0.02). Conclusion: The timing of recurrence of AF affected the serial changes of P-wave duration after CPVI.

Risk Assessment of Asymptomatic Paroxymal Atrial Fibrillation by Using the P-Wave Signal-Averaged Electrocardiogram in Patients with Chronic Kidney Disease

Risk Assessment of Asymptomatic Paroxymal Atrial Fibrillation by Using the P-Wave Signal-Averaged Electrocardiogram in Patients with Chronic Kidney Disease

Remodelagem atrial elétrica reversa após cardioversão de fibrilação atrial isolada de longa duração

Atrial fibrillation (AF) itself promotes electrophysiological changes, termed 'electrical remodeling', facilitating its recurrence and maintenance. There is evidence that the remodeling process is reversible after restoration of the sinus rhythm (SR). However, the timing for the recovery of electrophysiological properties is still undefined.The aim of this study was to assess the atrial electrical activation using P-wave signal-averaged electrocardiogram (P-SAECG) post-cardioversion of long-standing AF, focusing on the reversal remodeling process to identify the timing of the process stabilization.Subjects with lone persistent AF, eligible for cardioversion and successfully converted to SR, were enrolled at the study. SAECG was performed immediately after reversion to SR and repeated on days seven and thirty.Of 31 subjects, nine presented early recurrence of atrial fibrillation, all of them in the first seven days post-cardioversion; 22 remained in SR for at last one month and SAECG was obtained on days seven and thirty after cardioversion. In the latter, P-wave duration progressively abated from the first to the third SAECG (P-wave duration: 185.5+/-41.9 ms vs 171.7+/-40.5 ms vs 156.7+/-34.9 ms, respectively, first, second and third SAECG; p<0.001 for all matches). In the frequency domain analysis, spectral turbulence was not apparent in SAECG immediately post-cardioversion, but sharply increased on day seven and remained unchanged on day thirty.This study suggests that the first seven days post-cardioversion of long standing AF are critical for reversal remodeling process and arrhythmia recurrence.

Effects of angiotensin receptor blockade on serial P-wave signal-averaged electrocardiograms after electrical cardioversion of persistent atrial fibrillation

To evaluate the effects of the angiotensin II type 1 receptor blocker candesartan on P-wave signal-averaged electrocardiogram (P-SAECG) after electrical cardioversion in patients with atrial fibrillation (AF). One hundred and seventy-one patients with persistent AF were randomized to receive candesartan 8 mg/day or placebo for 3-6 weeks before and candesartan 16 mg/day or placebo for 6 months after electrical cardioversion. P-SAECG was recorded in 114 patients (57 in each treatment group) after cardioversion and repeated in those with sinus rhythm at 1 and 6 weeks, and 3 and 6 months. Filtered P-wave duration (FPD), root-mean-squared (RMS) voltages of the terminal 40 ms of the filtered P-wave, RMS voltage of the entire filtered P-wave, and the integral of the voltages in the entire PD were analysed. No effects of candesartan were observed on any P-SAECG parameter at baseline. In the subgroup of patients in sinus rhythm after 6 months, FPD was significantly shorter both at baseline (151 +/- 16 vs. 163 +/- 16 ms) and at 6 months (143 +/- 12 vs. 153 +/- 15 ms) in the candesartan (n = 15) compared with the placebo group (n = 21). Treatment with candesartan was associated with a shorter FPD in patients remaining in sinus rhythm for 6 months.

Reactive oxidative metabolites are associated with atrial conduction disturbance in patients with atrial fibrillation

Oxidative stress is associated with atrial fibrillation (AF). However, little is known about the relationship between serum markers of oxidation and electrical activity in patients with AF. The purpose of this study was to investigate the possible association between serum markers of reactive oxidative metabolism and atrial remodeling in paroxysmal and persistent AF. Derivatives of reactive oxidative metabolites (DROM), an index of oxidative stress, were measured in 306 consecutive patients with AF (225 paroxysmal, 81 persistent) undergoing radiofrequency (RF) catheter ablation. Filtered P-wave duration by P-wave signal-averaged ECG and levels of high-sensitivity C-reactive protein (CRP) as an inflammatory marker also were measured. Patients were followed up for 1.2 +/- 0.8 years. DROM levels in patients with persistent AF were significantly higher than in patients with paroxysmal AF (341.6 +/- 85.5 Carratelli [Carr] units vs 305.0 +/- 77.7 Carr units, P <.001). DROM levels showed a tighter, positive correlation with filtered P-wave duration in persistent AF patients (r = 0.56, P <.001) than in all AF patients (r = 0.13, P <.05). DROM levels also showed a weaker but significant correlation with high-sensitivity CRP in patients with AF. Kaplan-Meier analysis revealed that the highest quartile of basal DROM levels exhibited a significantly higher AF recurrence rate after RF catheter ablation in patients with paroxysmal AF (P <.01). Serum markers of oxidative stress reflect atrial conduction disturbance and predict AF recurrence after RF catheter ablation in paroxysmal AF patients. DROM could serve as a biomarker for predicting risk of AF recurrence after RF catheter ablation.

Mechanical cardiac remodeling and new-onset atrial fibrillation in long-term follow-up of subjects with chronic Chagas' disease

Atrial fibrillation (AF) affects subjects with Chagas' disease and is an indicator of poor prognosis. We investigated clinical, echocardiographic and electrocardiographic variables of Chagas' disease in a long-term longitudinal study as predictors of a new-onset AF episode lasting >24 h, nonfatal embolic stroke and cardiac death. Fifty adult outpatients (34 to 74 years old, 62% females) staged according to the Los Andes classification were enrolled. During a follow-up of (mean +/- SD) 84.2 +/- 39.0 months, 9 subjects developed AF (incidence: 3.3 +/- 1.0%/year), 5 had nonfatal stroke (incidence: 1.3 +/- 1.0%/year), and nine died (mortality rate: 2.3 +/- 0.8%/year). The progression rate of left ventricular mass and left ventricular ejection fraction was significantly greater in subjects who experienced AF (16.4 +/- 20.0 g/year and -8.6 +/- 7.6%/year, respectively) than in those who did not (8.2 +/- 8.4 g/year; P = 0.03, and -3.0 +/- 2.5%/year; P = 0.04, respectively). In univariate analysis, left atrial diameter >/=3.2 cm (P = 0.002), pulmonary arterial hypertension (P = 0.035), frequent premature supraventricular and ventricular contraction counts/24 h (P = 0.005 and P = 0.007, respectively), ventricular couplets/24 h (P = 0.002), and ventricular tachycardia (P = 0.004) were long-term predictors of AF. P-wave signal-averaged ECG revealed a limited long-term predictive value for AF. In chronic Chagas' disease, large left atrial diameter, pulmonary arterial hypertension, frequent supraventricular and ventricular premature beats, and ventricular tachycardia are long-term predictors of AF. The rate of left ventricular mass enlargement and systolic function deterioration impact AF incidence in this population.

Prolonged P wave duration in adults with secundum atrial septal defect: a marker of delayed conduction rather than increased atrial size?

Although atrial fibrillation is a frequent complication of an atrial septal defect (ASD) of the secundum type, the underlying mechanisms are poorly understood. Atrial conduction disturbances, manifested as a prolonged P-wave duration, have been suggested as a substrate for arrhythmia. Prolongation of the P-wave in unrepaired ASD has been demonstrated by means of the conventional ECG, but not by more sophisticated methods. The aim of the study was to analyse P-wave duration and morphology by high-resolution P-wave signal-averaged ECG (PSA-ECG) and to investigate potential atrial mechano-electrical interactions in adults with an unrepaired ASD. P-wave signal-averaged-ECG was obtained in 35 adult patients (age 53 +/- 15 years) with ASD and compared with an equal number of sex- and age-matched healthy controls. Right and left atrial sizes were assessed by echocardiography in the ASD group. P wave duration was significantly longer in the ASD group than in control subjects (148 +/- 16 vs. 128 +/- 15 ms, P < 0.0001). P-wave morphology did not differ significantly between patients and controls. There was no clear relation between P-wave duration and atrial size. Atrial septal defect in the adult is characterized by a prolonged P-wave duration, indicating delayed atrial conduction, which is not related to the enlargement of the atria but rather to conduction delay. The nature and potential reversibility of this warrant further investigation.

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

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

Prediction of the Efficacy of Pulmonary Vein Isolation for the Treatment of Atrial Fibrillation by the Signal‐Averaged P‐Wave Duration

The noninvasive methods for predicting a successful pulmonary vein isolation (PVI) have not been well described. The aim of this study was to assess the usefulness of the P-wave signal-averaged electrocardiogram (P-SAECG) in predicting the chance of a successful PVI in patients with atrial fibrillation (AF). A P-SAECG was recorded before (pre), 1 day after, and 3-4 months after the PVI in 51 AF patients (41, paroxysmal AF; 10, persistent AF). Three-dimensional electroanatomic mapping (3D-EAM) of the right and left atria and left PVs was performed before PVI in 10 patients to analyze the biatrial conduction time (BAT). Fifteen patients suffered from AF recurrences 3 months or more after the PVI. The pre-filtered P-wave duration (FPD) was significantly longer in patients with recurrence than in those without (166.8 +/- 14.8 ms vs 145.9 +/- 12.6 ms, P < 0.0001). In both patient groups, PVI shortened the FPD, which continued for 3-4 months. Multivariate analysis revealed that a pre-FPD >150 ms was a powerful predictor for recurrence, but persistent AF, the left atrial dimension, and structural heart disease were not predictors for recurrence. 3D-EAM showed that the delayed activation point was located within the left PVs and the BAT was identical to the pre-FPD. The pre-FPD may strongly reflect atrial dysfunction, and thus may be useful for predicting a successful PVI. Shortening of the FPD after the PVI and similar FPD and BAT values suggest that the last component of the FPD represents the activation of the left PVs.