Prolonged P-wave Duration Research Articles

Atrial protective effects of n-3 polyunsaturated fatty acids: A long-term study in ovine chronic heart failure

It has been suggested that omega-3 polyunsaturated fatty acids (n-3 PUFAs) may prevent the development of atrial fibrillation (AF). The purpose of this study was to evaluate the impact of these agents on development of the AF substrate in heart failure (HF). In this study, HF was induced by intracoronary doxorubicin infusions. Twenty-one sheep [7 with n-3 PUFAs treated HF (HF-PUFA), 7 with olive oil-treated HF controls (HF-CTL), 7 controls (CTL)] were studied. Open chest electrophysiologic study was performed with assessment of biatrial effective refractory period (ERP) and conduction. Cardiac function was monitored by magnetic resonance imaging. Atrial n-3 PUFAs levels were quantified using chromatography. Structural analysis was also performed. Atrial n-3 PUFAs levels were twofold to threefold higher in the HF-PUFA group. n-3 PUFAs prevented the development of HF-related left atrial enlargement (P = .001) but not left ventricular/atrial dysfunction. Atrial ERP was significantly lower in the HF-PUFA group (P <.001), but ERP heterogeneity was unchanged. In addition, n-3 PUFAs suppressed atrial conduction abnormalities seen in HF of prolonged P-wave duration (P = .01) and slowed (P <.001) and heterogeneous (P <.05) conduction. The duration of induced AF episodes in HF-PUFA was shorter (P = .02), although AF inducibility was unaltered (P = NS). A 20% reduction of atrial interstitial fibrosis was seen in the HF-PUFA group (P <.05). In this ovine HF study, chronic n-3 PUFAs use protected against adverse atrial remodeling by preventing atrial enlargement, fibrosis, and conduction abnormalities leading to shorter AF episodes despite lower ERP.

Abnormal atrial activation is common in patients with arrhythmogenic right ventricular cardiomyopathy

Structural right atrial abnormalities have been described in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). However, little is known about electrocardiographic signs of atrial involvement in ARVC because no systematic studies have been conducted. P-wave-triggered signal-averaged orthogonal electrocardiogram from 40 ARVC patients (46 ± 15 years, 16 females) was compared with recordings from age- and sex-matched healthy control subjects for assessment of P-wave duration and morphology. P-wave morphology was classified with regard to the P-wave polarity in leads X, Y, and Z. P-wave duration was longer in patients (135 ± 18 vs 124 ± 12 milliseconds; P = .003). Two typical P-wave morphologies were identified in the controls: positive in X and Y and negative (45%) or biphasic (55%) in Z. In patients with ARVC , typical P waves were seen in only 60%, whereas 15 patients (37%) had atypical P-wave positive in all 3 leads (P < .0001). The presence of atypical P waves in the ARVC group was not associated with the presence of either structural or functional right ventricular abnormality. Patients with ARVC commonly demonstrate deteriorated atrial activation expressed either as prolonged P-wave duration or abnormal P-wave morphology. The P-wave abnormalities were not secondary to right ventricular dilatation. These findings show that atrial involvement is common in ARVC and may represent yet another manifestation of the disease to be considered for inclusion in ARVC diagnostic workup.

Chronologic changes in P-wave characteristics after the Fontan procedure: The effect of surgical modification

The Fontan-type procedure has undergone 2 major modifications, including intra-atrial baffling and extracardiac conduit. To clarify the effect of these modifications on arrhythmia propensity, we analyzed chronologic changes in P-wave characteristics after atriopulmonary connection, intra-atrial baffling, or extracardiac conduit. A retrospective analysis was conducted on electrocardiographic data from 40 patients with tricuspid atresia who underwent the Fontan-type procedure and follow-up for greater than 5 years: 18 had atriopulmonary connection, 13 had intra-atrial baffling, and 9 had extracardiac conduit. The mean follow-up period in years was 19.8 for atriopulmonary connection, 13.3 for intra-atrial baffling, and 8.0 for extracardiac conduit. We analyzed chronologic changes in P-wave duration, dispersion, and amplitude and prevalence of sinus node dysfunction. Atrial tachyarrhythmia was documented in 9 patients with atriopulmonary connection but not in any patients with extracardiac conduit or intra-atrial baffling. Both P-wave maximum duration and dispersion decreased slightly over time with extracardiac conduit but increased progressively in the intra-atrial baffling and atriopulmonary connection groups. Intra-atrial baffling resulted in significantly shorter P-wave duration than atriopulmonary connection, whereas extracardiac conduit had significantly shorter P-wave duration and smaller dispersion than atriopulmonary connection and intra-atrial baffling. P-wave amplitude decreased markedly immediately after surgical intervention with intra-atrial baffling and extracardiac conduit but remained unchanged in patients undergoing atriopulmonary connection. Sinus node dysfunction was found commonly in all 3 groups. After intra-atrial baffling, patients increasingly had prolonged P-wave duration and larger dispersion associated with sinus node dysfunction, suggesting a propensity to arrhythmia, although less progressive than seen in those undergoing atriopulmonary connection. In contrast, despite an equal prevalence of sinus node dysfunction after extracardiac conduit, the lack of important changes in P-wave characteristics over time suggests that the extracardiac conduit procedure is the preferred option for optimal rhythm prognosis.

P-Wave Dispersion and Its Relationship to Aortic Elasticity in Young Prehypertensive Patients

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

Right ventricular apical lead position is associated with prolonged signal-averaged P-wave duration

Aim The study aimed to determine if right ventricular apical pacing is associated with adverse change in atrial substrate compared with right ventricular septal pacing. Methods Patients with septal leads and dual-chamber devices with more than 3 months of follow-up and 70% or higher cumulative percentage of ventricular pacing were compared with a matched group of apically implanted leads with a cumulative percentage ventricular pacing of 70% or higher. Device parameters were recorded, and high-resolution recordings were obtained for signal-averaged P-wave (SAPW) analysis. Previously obtained SAPW recordings taken from 49 healthy patients and 73 patients with paroxysmal atrial fibrillation were used as negative and positive controls, respectively. Results Ten patients with septal leads (mean age, 71.9 ± 12.1 years; mean months implanted, 10.5 ± 3.2 months) and 9 patients with apical leads (mean age, 71.9 ± 5.7 years; mean months implanted, 11.4 ± 6.4 months) were enrolled. The SAPW duration was longer in the apical cohort compared with the septal cohort (144.8 ± 6.9 and 133.0 ± 5.5 milliseconds, respectively; P = .001), whereas there was no significant difference between septal and normal cohorts (133.0 ± 5.5 and 129.3 ± 7.1 milliseconds, respectively; P = .08). Conclusions Apical pacing is associated with prolonged P-wave duration relative to septal pacing and controls: this may manifest as increased risk of atrial tachycardias and presents a potentially novel benefit of septal pacing.

Left atrial remodeling in patients with atrial septal defects

Information regarding left atrial (LA) substrate in conditions predisposing to atrial fibrillation (AF) is limited. This study sought to characterize the left atrial remodeling that results from chronic atrial stretch caused by atrial septal defect (ASD). Eleven patients with hemodynamically significant ASDs and 12 control subjects were studied. The following were evaluated using multipolar catheters: effective refractory period (ERP) at 7 sites, P-wave duration (PWD), conduction time, and inducibility of AF. LA electroanatomic maps were created to determine atrial activation, and regional conduction and voltage abnormalities. Patients with ASDs showed significant LA enlargement (P <0.001), unchanged or prolonged atrial ERPs, increase in LA conduction times (P = 0.03), prolonged PWD (P <0.001), regional conduction slowing (P <0.001), greater number of double potentials or fractionated electrograms (P <0.0001), reduced atrial voltage (P <0.001), and more frequent electrical scar (P = 0.005) compared with control subjects. In addition, patients with ASDs showed a greater propensity for sustained AF with single extrastimuli (4 of 11 vs. 0 of 12, P = 0.04). ASDs are associated with chronic left atrial stretch, which results in remodeling characterized by LA enlargement, loss of myocardium, and electrical scar that results in widespread conduction abnormalities but with no change or an increase in ERP. These abnormalities were associated with a greater propensity for sustained AF.

Long‐term Follow‐up of P‐wave Duration and Dispersion in Patients with Mitral Stenosis

Patients with mitral stenosis have prolonged P-wave duration and increased P-wave dispersion (PWD) that have been associated with increased risk for atrial fibrillation. Thirty mild-to-moderate mitral stenosis patients were followed for 38.4+/-10.7 (23-48) months. Baseline and last 12-lead electrocardiographic and transthoracic echocardiographic measurements were evaluated. Maximum and minimum P-wave durations (Pmax and Pmin) and PWD were calculated. Pmax and PWD were significantly higher in patients compared to control group. Left atrial (LA) size, mitral gradient, and pulmonary artery systolic pressure (PASP) were significantly increased and mitral valve area (MVA) was decreased during follow-up. There were significant increases in Pmax and PWD and significant decrease in Pmin (Pmax: 101.0+/-12.5 ms vs 105.0+/-16.5 ms, P=0.005; Pmin: 59.3+/-8.5 ms vs 55.0+/-12.3 ms P=0.004; PWD: 41.7+/-5.5 ms vs 50.0+/-6.2 ms, P<0.001). Baseline Pmax, Pmin, and PWD were significantly correlated with MVA (Pmax: r=-0.605, P<0.001, Pmin: r=-0.632, P<0.001, PWD: r=-0.402, P=0.0028) and mean mitral gradient (Pmax: r=0.412, P=0.024, Pmin: r=0.632, P=0.049, PWD: r=0.378, P=0.039). In addition to MVA and mean mitral gradient follow-up P-wave variables were significantly correlated with LA size (Pmax: r=0.573, P=0.001, Pmin: r=0.636, P=0.001, PWD: r=0.265, P=0.046) and PASP (Pmax: r=0.462, P=0.011, Pmin: r=0.472, P=0.008 PWD: r=0.295, P=0.047). P-wave duration and PWD increase progressively in accordance with the progression of mitral stenosis.

Acute Sleep Deprivation is Associated with Increased Electrocardiographic P‐Wave Dispersion in Healthy Young Men and Women

Sleep deprivation (SD) is associated with worse cardiovascular outcome including mortality. Prolonged P-wave duration and P-wave dispersion (Pd) are known to represent inhomogeneous conduction of sinus impulses and are known to be electrophysiologic predictors of atrial fibrillation. Pd in normal subjects has been reported to be influenced by the autonomic tone. Because autonomic tone is affected by sleep and sleep duration, we evaluated the effect of acute SD on P-wave duration and Pd in healthy young adults and whether the effect was gender selective. We obtained electrocardiograms of 37 healthy young volunteers (age: 28.45 +/- 7.97; 11 women) after a night of regular sleep and repeated after a night with sleep debt. We measured minimum and maximum P-wave durations (Pmin, Pmax) and Pd in milliseconds. Average sleep time of the subjects were 7.7 +/- 0.8 hours during regular sleep and 1.7 +/- 1.6 hours during a night of sleep debt (P < 0.001). Subjects had significantly lower values of Pmin in milliseconds after a night of sleep debt when compared to regular sleep (65.13 +/- 8.03 vs 74.86 +/- 10.95; P < 0.001), whereas they had significantly higher values of Pmax and Pd (102.16 +/- 9.46 vs 95.13 +/- 11.21; P < 0.001 and 37.02 +/- 8.11 vs 20.27 +/- 11.42; P < 0.001, respectively). In Pearson's correlation analysis Pmin was positively and Pmax and Pd were negatively correlated with sleep time (P < 0.001, r = 0.465; P = 0.003, r =-0.336 and P < 0.001, r =-0.698 respectively). Effect of SD on P-wave duration and Pd was similar for both men and women. In conclusion, prolongation of Pmax and Pd in acute SD suggests that acute SD might contribute to development and/or recurrence of atrial fibrillation.

Risk Stratification for Recurrent Heart Failure in Patients Post-Myocardial Infarction With Electrocardiographic and Echocardiographic Left Atrial Abnormality

Left atrial enlargement is predictive of cardiovascular events. The predictive power, however, of the combination of electrocardiographic (LAE-ECG) and echocardiographic left atrial enlargement (LAE-Echo) has not been extensively evaluated. We prospectively identified patients admitted with non-ST-segment elevation myocardial infarction (NSTEMI) who developed new-onset heart failure during admission. Baseline electrocardiograms obtained < or =12 months before admission were evaluated for LAE-ECG, such as prolonged P-wave duration or positive P-wave terminal force in lead V1, and in-hospital echocardiographic reports obtained < or =1 month after admission were assessed for linear, anteroposterior LAE-Echo. Follow-up was directed toward pertinent cardiovascular events and death. Of the 462 patients with NSTEMI, 108 developed new-onset heart failure (23%); 71 patients had LAE-Echo. Follow-up was 23.2 months (mean 22.1 months). Although in-hospital (early) cardiovascular complications (other than heart failure) were not significantly higher in patients with LAE-Echo, these patients demonstrated more postdischarge (late) cardiovascular complications, predominantly recurrent heart failure. In addition, those with a combination of LAE-Echo and LAE-ECG demonstrated significantly higher recurrence of heart failure (hazard ratio 1.52, 95% confidence interval 1.12 to 4.35; p = 0.02 for interatrial conduction delay, and hazard ratio 1.07, 95% confidence interval 1.01 to 3.27 for P-wave terminal force in lead V1; p = 0.03) and increased mortality compared with those with LAE-Echo alone. In conclusion, our data suggest that a combination of electrical and mechanical left atrial dysfunction is significantly more predictive of increased cardiovascular events and mortality compared with left atrial mechanical dysfunction alone.

Electrical remodelling of the left and right atria due to rheumatic mitral stenosis

To characterize the atrial remodelling in mitral stenosis (MS). Twenty-four patients with severe MS undergoing commissurotomy and 24 controls were studied. Electrophysiological evaluation was performed in 12 patients in each group by positioning multi-electrode catheters in both atria to determine the following: effective refractory period (ERP) at 10 sites at 600 and 450 ms; conduction time; conduction delay at the crista terminalis (CT); and vulnerability for atrial fibrillation (AF). P-wave duration (PWD) was determined on the surface ECG. In the remaining 12 patients in each group, electroanatomic maps of both atria were created to determine conduction velocity and identify regions of low voltage and electrical silence. Patients with MS had larger left atria (LA) (P < 0.0001); prolonged PWD (P = 0.0007); prolonged ERP in both LA (P < 0.0001) and right atria (RA) (P < 0.0001); reduced conduction velocity in the LA (P = 0.009) and RA (P < 0.0001); greater number (P < 0.0001) and duration (P< 0.0001) of bipoles along the CT with delayed conduction; lower atrial voltage in the LA (P < 0.0001) and RA (P < 0.0001); and more frequent electrical scar (P = 0.001) compared with controls. Five of twelve with MS and none of the controls developed AF with extra-stimulus (P = 0.02). Atrial remodelling in MS is characterized by LA enlargement, loss of myocardium, and scarring associated with widespread and site-specific conduction abnormalities and no change or an increase in ERP. These abnormalities were associated with a heightened inducibility of AF.

Atrial myocardial pathoelectrophysiology in adults with a secundum atrial septal defect is unaffected by closure of the defect. A study using high resolution signal-averaged orthogonal P-wave technique

Background In patients with atrial septal defect (ASD) the P-wave is prolonged as a marker of delayed atrial conduction which is associated with atrial fibrillation. The study aim was to analyse the impact of ASD closure in adults on P-wave duration and morphology by means of signal-averaged P-waves (PSA-ECG) and to investigate potential mechano–electrical interactions. Methods PSA-ECG was obtained before and 8 ± 6 months after ASD closure in 35 adult patients (age 53 ± 15 years). Heart chamber sizes and pulmonary artery pressure levels were assessed by echoDopplercardiography. Results P-wave duration and morphology did not change after ASD closure (148 ± 16 vs 144 ± 16 ms, P = 0.07). P-wave duration did not relate to age at repair, preclosure atrial sizes or pulmonary artery pressure. Pre- or postclosure atrial fibrillation propensity was associated with longer P-wave duration both before and after ASD closure. Conclusion Atrial conduction disturbances in middle-aged patients with ASD, manifested as a prolonged P-wave duration, do not change after ASD closure and are not related to the dilatation of the right and left atria. It is suggestive that atrial conduction disturbance associated with ASD develop early and early intervention is required to prevent the development of late atrial fibrillation.

Relation of Recurrence of Atrial Fibrillation After Non–ST-Elevation Acute Myocardial Infarction to Left Atrial Abnormality

Atrial fibrillation (AF) is common during the course of acute myocardial infarction and is associated with left atrial (LA) dilatation. However, the role of LA depolarization abnormality on the electrocardiogram (ECG) in the setting of LA dilatation was not studied in this context. Patients admitted with non-ST-segment elevation myocardial infarction (NSTEMI) who developed new-onset AF (International Classification of Diseases, Ninth Revision code 427.31) were prospectively identified. Baseline ECGs and echocardiograms before the admission event were reviewed. Follow-up was directed toward pertinent cardiovascular events, atrial tachyarrhythmias, and death as end points. Of 101 patients with NSTEMI who had new-onset AF, 88 had current echocardiograms and 69 had LA dilatation (78%). Total follow-up was 24 months (mean 21.4). Prolonged P-wave duration (> or =110 ms) and decreased left ventricular fractional shortening were most significant in those with LA dilatation and were independently associated with AF. In those with LA dilatation, the prevalence of such abnormal atrial depolarization on ECGs was 56%. AF (43% vs 15%; p = 0.03) and heart failure (63% vs 35%; p = 0.03) occurred more often in this subset, but there was no difference in mortality. However, the overall prevalence of late cardiovascular complications in this subset was higher (71% vs 45%; p = 0.02) compared with that of immediate complications (20% vs 26%; p = 0.60). In conclusion, there is higher recurrence of AF in patients with NSTEMI who have a combination of electrocardiographic and echocardiographic LA abnormalities compared with those without.

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.

Incremental prevalence of fractionated and inhomogeneous propagation of sinus impulses with increasing atrial depolarization abnormality among outpatients

Introduction Prolonged P-wave duration (P-dur) and excessive P-wave dispersion (P-disp) are purported arrhythmogenic substrates for atrial fibrillation. However, the extent of involvement of inhomogeneous, sinus impulse propagation demonstrated by excessive P-disp (> 40 ms) has not been evaluated in relation to increasing P-dur. Methods We appraised our previously studied sample of 500 consecutively numbered, otherwise unselected, electrocardiograms (ECGs) of outpatients from the University of Massachusetts, Worcester, Massachusetts for P-disp, P-dur and P-wave axis (P-axis). P-disp, defined as the difference of the duration between the widest and narrowest P wave, and the greatest P-dur after a 12-lead ECG search, was measured manually to the nearest 10 ms. Normal P-axis was considered 0 to + 75 degrees by manually constructing the mean frontal plane electrical P-axis from the limb leads. Results After excluding those with atrial arrhythmias, paced rhythms, errors in lead placement, P waves with low amplitude or overall technically poor tracing, 428 ECGs depicting sinus rhythm formed our final sample. P-dur was strongly associated with P-disp ( p < 0.0001) but the correlation remained weak ( r = 0.42). However, when P-dur was divided into 10 ms increments, the prevalence of abnormal P-disp rose incrementally with P-dur, with or without consideration of the P-axis. The prevalence of abnormal P-disp doubled from 30% in those with P-dur of 100 ms to > 60% in those with P-dur of 120 ms. Further, the prevalence exceeded 80% with P-dur of 130 ms and reached 100% with P-dur > 160 ms. Conclusion With increasingly prolonged atrial depolarization, the associated inhomogeneity of sinus impulse propagation across the atria increases. P-dur and P-disp are associated with each other and are consistent with abnormal atrial conduction properties.

Effect of Slow Coronary Flow on P-Wave Duration and Dispersion

The slow coronary flow (SCF) phenomenon is often considered to be an incidental angiographic finding; however, several reports have shown it to be associated with cardiac events. In this study we aimed to assess P-wave duration and dispersion (PWD) in patients with SCF and to compare it with that of healthy subjects. Thus, 40 patients with angiographically proven SCF and otherwise normal coronary arteries (group 1) and 36 sex-age-matched healthy subjects (group 2) were included in this study. A 12-lead surface ECG, recorded at a paper speed of 50-mm/s and 2 mV/cm standardization, was obtained from each subject. P-wave duration was measured manually by use of a caliper. The difference between the maximum (Pmax) and minimum P (Pmin)-wave duration was calculated and defined as PWD. All subjects had undergone echocardiographic examination to exclude valvular disorders and wall motion abnormalities. There was no significant difference between the 2 groups in demographies of age, sex, heart rate, or blood pressure. Maximum P-wave duration and PWD were significantly higher in group 1 than in group 2 (120 +/-7 vs 115 +/-5, p = 0.003; 44 +/-12 vs 38 +/-9, p = 0.01, respectively). However, there was no significant difference in Pmin duration (75 +/-9 vs 78 +/-7, p = 0.4). In conclusion; SCF and otherwise normal epicardial coronary artery was found to be associated with prolonged P-wave duration and increased PWD. This may result from microvascular ischemia and/or altered autonomic control of cardiovascular system observed in this group of patients.

Predictors of post Coronary Artery Bypass Grafting Atrial Fibrillation

Objective To investigate the incidence and relative risk factors of post coronary artery bypass grafting (post-CABG) atrial fibrillation (AF). Methods: 312 patients with CABG were reviewed and divided into an AF group and a non-AF group. Statistical analysis was used to compare the data between the two groups and screen for risk factors of post-CABG AF. Results: 103/312 (33.01%) patients developed post-CABG AF. Univariate analysis showed that patients in AF group compared with those in non-AF group were more likely to have advanced age (≥70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement (≥40mm), a history of AF, pro-longed p-wave duration (≥120ms) and increased number of grafts (≥3). Multivariate logistic regression analysis showed that advanced age (≥70 years), early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement (≥40mm) and a history of AF were highly related to post-CABG AF. Conclusion: The incidence of AF in patients following CABG was 33.01% in this study. Advanced age, early postoperative withdrawal of β-blockers, hypertension, left atrial enlargement and a history of AF were independent risk factors of post-CABG AF.

Optimal timing of the Fontan conversion: Change in the P-wave characteristics precedes the onset of atrial tachyarrhythmias in patients with atriopulmonary connection

Atrial tachyarrhythmia is a common complication late after the atriopulmonary connection Fontan procedure. The P-wave duration and dispersion have been regarded as useful markers for its prediction. The purpose of this study was to analyze change in the P-wave characteristics over time after the atriopulmonary connection Fontan procedure, with a special emphasis on the timing of the Fontan conversion. We reviewed clinical and electrocardiographic data in 18 patients with classic tricuspid atresia who underwent the atriopulmonary connection Fontan procedure. Their median age at operation was 4.1 years (range, 1.1-22 years), and the median follow-up period was 18.1 years (range, 10-25 years). We measured the P-wave duration, dispersion, and axis from consecutive 12-lead electrocardiograms in each patient. There was a significant increase in the maximum P-wave duration as well as the P-wave dispersion over time. Transient ectopic atrial rhythm was observed in 16 patients during follow-up. Atrial tachyarrhythmia developed subsequent to transient ectopic atrial rhythm in 8 patients. Ten patients underwent the conversion. Atrial tachyarrhythmia recurred in 2 patients who had sustained arrhythmia (6.0 and 8.0 years) before the conversion. In contrast, the other 8 patients with transient ectopic atrial rhythm alone or nonsustained atrial tachyarrhythmia have been free from arrhythmia after the conversion. Patients commonly and increasingly had prolonged P-wave duration, larger P-wave dispersion, and ectopic atrial rhythm, along with an atrial tachyarrhythmia propensity, late after the atriopulmonary connection Fontan procedure. These P-wave characteristics were informative when considering the Fontan conversion before a sustained atrial tachyarrhythmia ensued.

P-Wave Signal-Averaged Electrocardiogram for Predicting Atrial Arrhythmia After Cardiac Surgery

Atrial arrhythmias (AF) are usually benign, but occur frequently after cardiac surgery. P-wave signal-averaged electrocardiogram has been used to characterize atrial conduction delay as a marker of risk of AF during sinus rhythm. Ninety-five patients undergoing either primary isolated coronary artery bypass grafting or aortic valve replacement were enrolled. The duration and the root mean square voltage for the last 20 ms of filtered (40 to 300 Hz) P-wave of the spatial magnitude were recorded before surgery. Any episode of postoperative atrial fibrillation, atrial flutter, or paroxysmal atrial fibrillation lasting longer than 1 hour was considered as AF. Twenty-eight patients (29%) exhibited AF 3.0 +/- 2.3 days after surgery. The P-wave duration recorded with P-wave signal-averaged electrocardiogram was significantly prolonged in patients with AF (135 +/- 14 ms versus 127 +/- 9 ms; p = 0.002). Patients with AF more often had dilated left atrium (p = 0.003), left ventricular hypertrophy (p = 0.03), and advanced age (p = 0.02). Logistic regression analysis identified the following three variables as predictive of AF: P-wave duration of 135 ms or greater (p = 0.02; odds ratio, 3.5), patients 70 years of age and older (p = 0.03; odds ratio, 3.2), and left atrial dimension of 35 mm or greater (p = 0.03; odds ratio, 3.2). If a patient had two or more of these three risk factors, the occurrence of AF was predicted with a sensitivity of 75%, specificity of 76%, positive predictive accuracy of 57%, and negative predictive accuracy of 88%. The prolonged P-wave duration recorded with P-wave signal-averaged electrocardiogram, together with advanced age and left atrial enlargement, is a potent and independent predictor of AF after cardiac surgery. Patients with these risk factors may benefit from prophylactic antiarrhythmic treatment.

Genome-wide linkage scan identifies a novel genetic locus on chromosome 5p13 for neonatal atrial fibrillation associated with sudden death and variable cardiomyopathy.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and patients with AF have a significantly increased risk for ischemic stroke. Approximately 15% of all strokes are caused by AF. The molecular basis and underlying mechanisms and pathophysiology of AF remain largely unknown. We have identified a large AF family with an autosomal recessive inheritance pattern. The AF in the family manifests with early onset at the fetal stage and is associated with neonatal sudden death and, in some cases, ventricular tachyarrhythmias and waxing and waning cardiomyopathy. Genome-wide linkage analysis was performed for 36 family members and generated a 2-point logarithm of the odds (LOD) score of 3.05 for marker D5S455. The maximum multipoint LOD score of 4.10 was obtained for 4 markers: D5S426, D5S493, D5S455, and D5S1998. Heterozygous carriers have significant prolongation of P-wave duration on ECGs compared with noncarriers (107 versus 85 ms on average; P=0.000012), but no differences between these 2 groups were detected for the PR interval, QRS complex, ST-segment duration, T-wave duration, QTc, and R-R interval (P>0.05). Our findings demonstrate that AF can be inherited as an autosomal recessive trait and define a novel genetic locus for AF on chromosome 5p13 (arAF1). A genetic link between AF and prolonged P-wave duration was identified. This study provides a framework for the ultimate cloning of the arAF1 gene, which will increase the understanding of the fundamental molecular mechanisms of atrial fibrillation.

Clinical prediction rule for atrial fibrillation after coronary artery bypass grafting

This study was designed to devise and validate a practical prediction rule for atrial fibrillation/atrial flutter (AF) after coronary artery bypass grafting (CABG) using easily available clinical and standard electrocardiographic (ECG) criteria. Reported prediction rules for postoperative AF have suffered from inconsistent results and controversy surrounding the added predictive value of a prolonged P-wave duration. In 1,851 consecutive patients undergoing CABG with cardiopulmonary bypass, preoperative clinical characteristics and standard 12-lead ECG data were examined. Patients were continuously monitored for the occurrence of sustained postoperative AF while hospitalized. Multiple logistic regression was used to determine significant predictors of AF and to develop a prediction rule that was evaluated through jackknifing. Atrial fibrillation occurred in 508 of 1,553 patients (33%). Multivariate analysis showed that greater age (odds ratio [OR] 1.1 per year [95% confidence intervals (CI) 1.0 to 1.1], p < 0.0001), prior history of AF (OR 3.7 [95% CI 2.3 to 6.0], p < 0.0001), P-wave duration >110 ms (OR 1.3 [95% CI 1.1 to 1.7], p = 0.02), and postoperative low cardiac output (OR 3.0 [95% CI 1.7 to 5.2], p = 0.0001) were independently associated with AF risk. Using the prediction rule we defined three risk categories for AF: <60 points, 61 of 446 (14%); 60 to 79 points, 330 of 908 (36%); and >or=80 points, 117 of 199 (59%). The area under the receiver-operator characteristic curve for the model was 0.69. These data show that post-CABG AF can be predicted with moderate accuracy using easily available patient characteristics and may prove useful in prognostic and risk stratification of patients after CABG. The presence of intraatrial conduction delay on ECG contributed least to the prediction model.