Advanced interatrial block as a substrate of supraventricular tachyarrhythmias: a well recognized syndrome

Advanced interatrial block predicts recurrence of embolic stroke of undetermined source

BACKGROUND

Advanced interatrial block (IAB) is an independent risk factor for ischaemic stroke. This study aimed to analyse whether advanced IAB predicts recurrence of embolic stroke of undetermined source (ESUS).

METHODS

104 patients with a confirmed diagnosis of ESUS were followed up for a median period of 15 months (interquartile range, 10-48). We recorded data on clinical variables, P-wave characteristics, and presence of IAB on the electrocardiogram. Electrocardiogram findings were interpreted by a blinded, centralised rater at (XXXX2). ESUS recurrence was the primary outcome variable.

RESULTS

Median age was 47 years (range, 19-85); 50% of patients were women. IAB was detected in 36 patients (34.6%); IAB was partial in 29 cases (27.9%) and advanced in 7 (6.7%). Sixteen patients (15.4%) presented stroke recurrence; of these, 5 had partial and 4 had advanced IAB (P = .01; odds ratio [OR] = 9.44; 95% confidence interval [CI], 1.88-47.46; relative risk [RR] = 4.62; 95% CI, 2.01-10.61). Median P-wave duration was longer in patients with stroke recurrence (P = .009). The multivariate logistic regression analysis identified the following independent risk factors for stroke recurrence: advanced IAB (P < .001; OR = 10.86; 95% CI, 3.07-38.46), male sex (P = .028; OR = 4.6; 95% CI, 1.18-17.96), and age older than 50 years (P = .039; OR = 3.84; 95% CI, 1.06-13.88). In the Cox proportional hazards model, the risk variables identified were age older than 50 years (P = .002; hazard ratio, 7.04; 95% CI, 2.06-23.8) and P-wave duration (per ms) (P = .007; hazard ratio, 1.02; 95% CI, 1.01-1.04).

CONCLUSIONS

Advanced IAB and age older than 50 years predict ESUS recurrence.

Advanced interatrial block predicts recurrence of embolic stroke of undetermined source

BACKGROUND

Advanced interatrial block (IAB) is an independent risk factor for ischaemic stroke. This study aimed to analyse whether advanced IAB predicts recurrence of embolic stroke of undetermined source (ESUS).

METHODS

104 patients with a confirmed diagnosis of ESUS were followed up for a median period of 15 months (interquartile range, 10-48). We recorded data on clinical variables, P-wave characteristics, and presence of IAB on the electrocardiogram (ECG). ECG findings were interpreted by a blinded, centralised rater at (XXXX2). ESUS recurrence was the primary outcome variable.

RESULTS

Median age was 47 years (range, 19-85); 50% of patients were women. IAB was detected in 36 patients (34.6%); IAB was partial in 29 cases (27.9%) and advanced in 7 (6.7%). Sixteen patients (15.4%) presented stroke recurrence; of these, 5 had partial and 4 had advanced IAB (P = .01; odds ratio [OR] = 9.44; 95% confidence interval [CI], 1.88-47.46; relative risk [RR] = 4.62; 95% CI, 2.01-10.61). Median P-wave duration was longer in patients with stroke recurrence (P = .009). The multivariate logistic regression analysis identified the following independent risk factors for stroke recurrence: advanced IAB (P < .001; OR = 10.86; 95% CI, 3.07-38.46), male sex (P = .028; OR = 4.6; 95% CI, 1.18-17.96), and age older than 50 years (P = .039; OR = 3.84; 95% CI, 1.06-13.88). In the Cox proportional hazards model, the risk variables identified were age older than 50 years (P = .002; hazard ratio, 7.04; 95% CI, 2.06-23.8) and P-wave duration (per ms) (P = .007; hazard ratio, 1.02; 95% CI, 1.01-1.04).

CONCLUSIONS

Advanced IAB and age older than 50 years predict ESUS recurrence.

The usefulness of morphology-voltage-P wave duration ECG score for predicting early left atrial dysfunction in hypertensive patients

OBJECTIVE

Left atrial (LA) function is an important predictor of adverse cardiovascular outcomes in patients with hypertension (HT). Therefore, recognition of subtle LA dysfunction in the early stages of HT is essential for controlling modifiable variables. Several electrocardiographic and echocardiographic parameters have been studied to show early LA dysfunction. The goal of this study was to investigate the relationship between newly defined morphology-voltage-P wave duration electrocardiography (MVP ECG) score and early LA dysfunction in hypertensive patients.

MATERIALS AND METHODS

Eighty-nine hypertensive patients were included in this study. Based on speckle tracking echocardiography results, the patients were divided into two groups: 67 patients with normal LA function were included in Group 1, and 22 patients with abnormal LA function in Group 2.

RESULTS

Age, diabetes mellitus history, duration of HT history, left ventricular mass index, E/Em, and MVP ECG score values were statistically significant between the two groups. Based on the results of the multivariate logistic regression test, duration of HT history, E/Em, and MVP ECG score were determined as independent predictive parameters for early LA dysfunction in hypertensive patients.

CONCLUSION

In conclusion, MVP ECG score assessment could be a novel approach to detect early LA dysfunction in hypertensive patients.

Orthogonal P-wave morphology, conventional P-wave indices, and the risk of atrial fibrillation in the general population using data from the Finnish Hospital Discharge Register

AIMS

Identifying subjects at high and low risk of atrial fibrillation (AF) is of interest. This study aims to assess the risk of AF associated with electrocardiographic (ECG) markers linked to atrial fibrosis: P-wave prolongation, 3rd-degree interatrial block, P-terminal force in lead V1, and orthogonal P-wave morphology.

METHODS AND RESULTS

P-wave parameters were assessed in a representative Finnish population sample aged ≥30 years (n = 7217, 46.0% male, mean age 51.4 years). Subjects (n = 5489) with a readable ECG including the orthogonal leads, sinus rhythm, and a predefined orthogonal P-wave morphology type [positive in leads X and Y and either negative (Type 1) or ± biphasic (Type 2) in lead Z; Type 3 defined as positive in lead X and ± biphasic in lead Y], were followed 10 years from the baseline examinations (performed 1978-80). Subjects discharged with AF diagnosis after any-cause hospitalization (n = 124) were defined as having developed AF. Third-degree interatrial block was defined as P-wave ≥120 ms and the presence of ≥2 ± biphasic P waves in the inferior leads. Hazard ratios (HRs) and confidence intervals (CIs) were assessed with Cox models. Third-degree interatrial block (n = 103, HR 3.18, 95% CI 1.66-6.13; P = 0.001) and Type 3 morphology (n = 216, HR 3.01, 95% CI 1.66-5.45; P < 0.001) were independently associated with the risk of hospitalization with AF. Subjects with P-wave <110 ms and Type 1 morphology (n = 2074) were at low risk (HR 0.46, 95% CI 0.26-0.83; P = 0.006), compared to the rest of the subjects.

CONCLUSION

P-wave parameters associate with the risk of hospitalization with AF.

Baseline ECG and Prognosis After Transcatheter Aortic Valve Implantation: The Role of Interatrial Block

Background

The clinical significance of conduction disturbances after transcatheter aortic valve implantation has been described; however, little is known about the influence of baseline ECGs in the prognosis of these patients. Our aim was to study the influence of baseline ECG parameters, including interatrial block (IAB), in the prognosis of patients treated with transcatheter aortic valve implantation.

Methods and Results

The BIT (Baseline Interatrial Block and Transcatheter Aortic Valve Implantation) registry included 2527 patients with aortic stenosis treated with transcatheter aortic valve implantation. A centralized analysis of baseline ECGs was performed. Patients were divided into 4 groups: normal P wave duration (<120 ms); partial IAB (P wave duration ≥120 ms, positive in the inferior leads); advanced IAB (P wave duration ≥120 ms, biphasic [+/–] morphology in the inferior leads); and nonsinus rhythm (atrial fibrillation/flutter and paced rhythm). The mean age of patients was 82.6±9.8 years and 1397 (55.3%) were women. A total of 960 patients (38.0%) had a normal P wave, 582 (23.0%) had partial IAB, 300 (11.9%) had advanced IAB, and 685 (27.1%) presented with nonsinus rhythm. Mean follow‐up duration was 465±171 days. Advanced IAB was the only independent predictor of all‐cause mortality (hazard ratio [HR], 1.48; 95% CI, 1.10–1.98 [P=0.010]) and of the composite end point (death/stroke/new atrial fibrillation) (HR, 1.51; 95% CI, 1.17–1.94 [P=0.001]).

Conclusions

Baseline ECG characteristics influence the prognosis of patients with aortic stenosis treated with transcatheter aortic valve implantation. Advanced IAB is present in about an eighth of patients and is associated with all‐cause death and the composite end point of death, stroke, and new atrial fibrillation during follow‐up.

Association between interatrial block, left atrial fibrosis, and mechanical dyssynchrony: Electrocardiography-magnetic resonance imaging correlation

INTRODUCTION

Advanced interatrial block (IAB) on a 12-lead electrocardiogram (ECG) is a predictor of stroke, incident atrial fibrillation (AF), and AF recurrence after catheter ablation. The objective of this study was to determine which features of IAB structural remodeling is associated with left atrium (LA) magnetic resonance imaging structure and function.

METHODS/RESULTS

We included 152 consecutive patients (23% nonparoxysmal AF) who underwent preprocedural ECG and cardiac magnetic resonance (CMR) in sinus rhythm before catheter ablation of AF. IAB was defined as P-wave duration ≥120 ms, and was considered partial if P-wave was positive and advanced if P-wave had a biphasic morphology in inferior leads. From cine CMR and late gadolinium enhancement, we derived LA maximum and minimum volume indices, strain, LA fibrosis, and LA dyssynchrony. A total of 77 patients (50.7% paroxysmal) had normal P-wave, 52 (34.2%) partial IAB, and 23 (15.1%) advanced IAB. Patients with advanced IAB had significantly higher LA minimum volume index (25.7 vs 19.9 mL/m² , P = .010), more LA fibrosis (21.9% vs 13.1%, P = .020), and lower LA maximum strain rate (0.99 vs 1.18, P = .007) than those without. Advanced IAB was independently associated with LA (minimum [P = .032] and fibrosis [P = .009]). P-wave duration was also independently associated with LA fibrosis (β = .33; P = .049) and LA mechanical dyssynchrony (β = 2.01; P = .007).

CONCLUSION

Advanced IAB is associated with larger LA volumes, lower emptying fraction, and more fibrosis. Longer P-wave duration is also associated with more LA fibrosis and higher LA mechanical dyssynchrony.

Significance of fragmented QRS complexes for predicting new-onset atrial fibrillation after cavotricuspid isthmus-dependent atrial flutter ablation

BACKGROUND

Atrial fibrillation (AF) and cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) are 2 separate entities that coexist in a significant proportion of patients. In patients with CTI ablation of AFL, the decision to hold anticoagulation often becomes an issue.

OBJECTIVES

This study aimed to describe the incidence of the development of AF after CTI ablation in patients without a history of AF and to identify the risk predictors of the occurrence of AF.

METHODS

The present study included 120 consecutive patients (106 men; mean age 68 ± 12 years) who underwent radiofrequency catheter ablation (RFCA) of typical AFL since 2010. Patients with a history of AF before RFCA were excluded. The P-wave and QRS morphology, characteristics, and duration were evaluated by 12-lead electrocardiography the day after ablation.

RESULTS

During 3.6 ± 2.6 years of follow-up after RFCA, 49 patients (41%) developed new-onset AF. A univariate analysis revealed that the presence of fragmented QRS (fQRS) complexes (hazard ratio [HR], 4.63; 95% confidence interval [CI] 2.31-9.29; P < .001) and advanced interatrial block (IAB), defined as P-wave duration > 120 ms and biphasic morphology in the inferior leads (HR 4.44; 95% CI 2.45-8.01; P < .001), were predictors of new-onset AF. A multivariate analysis revealed that fQRS complexes (HR 3.35; 95% CI 1.58-7.10; P = .002) and advanced IAB (HR 2.64; 95% CI 1.38-5.07; P < .004) were independent predictors.

CONCLUSION

The present study indicated that new-onset AF developed in a significant proportion of patients undergoing AFL ablation. The presence of fQRS complexes and advanced IAB were predictors of new-onset AF.

Rational and design of the Baseline Interatrial block and Transcatheter aortic valve implantation (BIT) registry

BACKGROUND

Aortic stenosis (AS) is currently the most frequent heart valve disease. Symptomatic severe AS has a poor prognosis and transcatheter aortic valve implantation (TAVI) is becoming the therapy of choice in these patients. Changes in the conduction tissue after the procedure constitute one of the main limitations of TAVI, with a frequent need for a definitive pacemaker. Interatrial block (IAB) is defined as a prolonged P-wave duration and is related with atrial fibrosis. The presence of IAB could be a marker of conduction tissue abnormalities at other levels. No study has specifically analyzed the role of IAB as a predictor of the need for permanent pacemaker in patients with AS undergoing TAVI.

METHODS

The Baseline Interatrial block and Transcatheter aortic valve implantation (BIT) registry will be performed in approximately 3000 patients with severe AS treated with TAVI. A centralized analysis of baseline ECGs will study the presence and type of IAB and other ECG data (rhythm, P-wave duration, PR and QRS intervals/intraventricular conduction disorders). Clinical follow-up will be carried out by local researchers. The primary endpoint will be the requirement of permanent pacemaker during post-TAVI hospitalization. As secondary objectives, the incidence of new onset AF, stroke, or mortality during follow-up will be analyzed. Secondary endpoints will include the incidence of new onset AF, stroke, or mortality during follow-up.

CONCLUSION

The BIT registry will study, for the first time, the influence of previous IAB in the need of permanent pacemaker after TAVI: This large registry will also provide information regarding the association of this and other ECG parameters with prognosis.

Advanced interatrial block predicts recurrence of atrial fibrillation after accessory pathway ablation in patients with Wolff-Parkinson-White syndrome

BACKGROUND

Paroxysmal atrial fibrillation (AF) frequently occurs in patients with Wolff-Parkinson-White (WPW) syndrome. Although successful ablation of the accessory pathway (AP) eliminates paroxysmal AF in some patients, in other patients it can recur.

HYPOTHESIS

We investigated the clinical utility of advanced interatrial block (IAB) for predicting the risk of AF recurrence in patients with verified paroxysmal AF and WPW syndrome after successful AP ablation.

METHODS

This retrospective study included 103 patients (70 men, 33 women; mean age, 44 ± 16 years) with WPW syndrome who had paroxysmal AF. A resting 12-lead electrocardiogram was performed immediately after successful AP ablation to evaluate the presence of advanced IAB, which was defined as a P-wave duration of >120 ms and biphasic [±] morphology in the inferior leads.

RESULTS

During the mean follow-up period of 30.9 ± 20.0 months (range, 2-71 months), 16 patients (15.5%) developed AF recurrence. Patients with advanced IAB had significantly reduced event-free survival from AF (P < .001). Cox regression analysis with adjustment for the left atrial diameter and CHA₂ DS₂ -VASc score identified advanced IAB (hazard ratio, 9.18; 95% confidence interval [CI], 2.30-36.72; P = .002) and age > 50 years (hazard ratio, 12.64; 95% CI, 1.33-119.75; P = .027) as independent predictors of AF recurrence.

CONCLUSIONS

Advanced IAB was an independent predictor of AF recurrence after successful AP ablation in patients with WPW syndrome.

Electrocardiographic evidence of abnormal atrial phenotype in Brugada syndrome

BACKGROUND

Brugada syndrome (BrS) is an inherited ion channelopathy that may predispose affected individuals to atrial cardiomyopathy. We tested the hypothesis that BrS patients have higher degrees of atrial electrophysiological abnormalities compared to controls, and these can be reflected by changes in P-wave parameters determined on the electrocardiogram (ECG).

METHODS

This was a single-center retrospective study comparing BrS patients to age- and gender-matched control subjects. Mean P-wave duration (PWD_mean), maximum PWD (PWD_max) and minimum PWD (PWD_min), P-wave dispersion (PWD_max - PWD_min), and P-wave terminal force in V1 (PTFV1) were measured. PWD_max ≥ 120 ms, in the presence and absence of biphasic P-waves in the inferior leads, were termed advanced and partial inter-atrial block (IAB), respectively.

RESULTS

The proportion of IAB was significantly higher in BrS patients (28/51; 55%) than in control subjects (14/51; 27%; Fisher's Exact test; P < 0.01). Advanced IAB was observed in two BrS patients but none of the control subjects (P = 0.50). Compared to controls, BrS patients showed higher PWD_mean (107 [98-113] vs. 97 [90-108] ms; KWANOVA, P < 0.01), PWD_max (123 [110-132] vs. 113 [107-121] ms; P < 0.001) but statistically indistinguishable PWD_min (82 [72-92] vs. 77 [69-85]; P = 0.09), and P-wave dispersion (38 [26-52] vs. 37 [23-45] ms; P = 0.14). PTFV1 was significantly higher in BrS patients than in control subjects (24 [0-40] vs. 0 [0-27] mm.ms; P < 0.05).

CONCLUSION

Atrial conduction abnormalities are frequently observed in BrS. These patients may require monitoring for future development of atrial fibrillation and stroke.

Second-degree interatrial block: A case series

Advanced interatrial block (IAB) (P-wave ≥120 ms and biphasic P-wave in leads II, III and aVF) is a prevalent ECG pattern frequently associated with supraventricular arrhythmias and stroke, especially in patients with structural heart disease. Intermittent IAB is a much more poorly defined electrocardiographic entity with uncertain clinical significance. In this case series, we review and analyze eight cases of second degree intermittent IAB. In six cases, there is normalization of advanced IAB after a premature supraventricular or ventricular contraction, suggesting a functional block that temporarily recovers post extra-systolic pause. Recognition of intermittent IAB (second degree) may help further characterize the prognostic and clinical implications of this ECG pattern.

Interatrial block as a predictor of atrial fibrillation in patients with ST-segment elevation myocardial infarction

INTRODUCTION

Interatrial block (IAB) is strongly associated with recurrence of atrial fibrillation (AF) in different clinical scenarios. Atrial fibrosis is considered the responsible mechanism underlying the pathogenesis of IAB. The aim of this study was to investigate whether IAB predicted AF at 12 months follow-up in a population of patients with ST segment elevation myocardial infarction (STEMI).

HYPOTHESIS

We aimed to investigate whether IAB predicted AF at 12 months follow up in a population of patients with STEMI.

METHODS

Prospective, single center, observational study of patients presenting with ST-segment elevation myocardial infarction (STEMI) and referred to primary percutaneous coronary intervention (P-PCI). Surface electrocardiograms (ECG) were recorded on admission and at 6th hour post P-PCI. Patients were screened for the occurrence of AF at a 12-months visit.

RESULTS

A total of 198 patients were included between September 2015 and September 2016. IAB (partial and advanced) was detected in 102 (51.5%) patients on admission. Remodeling of the P-wave and subsequent normalization reduced the prevalence of IAB to 47 (23.7%) patients at 6th hour. AF was detected in 17.7% of study patients at 12 months. Partial IAB (p-IAB) on admission (OR 5.10; 95% CI, 1.46-17.8; P = 0.011) and on 6th hour (OR 4.15; 95% CI, 1.29-13.4; P = 0.017), presence of a lesion in more than one coronary artery (OR 3.29; 95% CI, 1.32-8.16; P = 0.010) found to be independent predictors of AF at 12 months.

CONCLUSION

IAB is common in patients with STEMI and along with the presence of diffuse coronary artery disease is associated with new onset of AF.

Advanced interatrial block is an electrocardiographic marker for recurrence of atrial fibrillation after electrical cardioversion

BACKGROUND

Early recurrence of atrial fibrillation (AF) is common following a successful electrical cardioversion (ECV). The purpose of this study was to investigate the hypothesis that AF recurrence is related to atrial electrical inhomogeneity, which may influence the P wave characteristics.

METHODS

Two hundred ninety-one consecutive persistent AF patients who underwent ECV were enrolled, and evaluated for AF recurrences one month after the ECV. Patients with open-heart surgery, a history of catheter ablation, and an unsuccessful ECV were excluded. The P wave duration, dispersion and P wave morphology were evaluated by 12‑lead ECGs 30 min after the ECV.

RESULTS

In total, 141 patients were investigated. One month after the ECV, 60 (43%) patients maintained sinus rhythm. The advanced interatrial block (aIAB; P wave duration >120 ms and biphasic P waves in the inferior leads) (Hazard ratio [HR], 4.51; 95% confidence interval [CI] 1.45-14.01, P = 0.009), P wave dispersion (HR, 1.06; 95%CI 1.02-1.09, P = 0.001), and duration of AF per month (HR, 1.03; 95%CI 1.01-1.04, P = 0.004) were independent predictors of AF recurrence. An aIAB was not associated with structural parameters such as the left atrial volume index or right atrial area. There were no differences in the serum BNP level and frequency of administering anti-arrhythmic drugs between the patients with and without recurrence.

CONCLUSIONS

The risk of AF recurrence after the ECV can be predicted by the P wave characteristics. A longer P wave dispersion and the duration of AF also had a tendency for recurrence.

Prevalence and clinical significance of interatrial block in very older persons

PURPOSE

The presence in older patients of an interatrial block (IAB) may be a predictor of atrial fibrillation (AF). The objective of the study was to assess in a group of very older participants: the prevalence of IAB, its association with the presence of functional and cognitive status, of new AF diagnosis and mortality after 2-year of follow-up.

METHODS

A prospective subcohort of the OCTABAIX population-based study with 75 inhabitants, all 85-year-olds, at baseline in sinus rhythm were assessed. Functional and cognitive status, nutritional risk, and previous falls were recorded. Participants were classified according to the presence or absence of IAB.

RESULTS

23 patients had IAB (30.7%). We did not observe significant differences regarding gender, comorbidity, functional status, nutritional risk and global geriatric assessment according to interatrial conduction. The patients with IAB had statistically significant better cognitive performance (p = 0.029) and a lower number of previous falls (p = 0.008). During the 2 years follow-up 3 participants (4%) died; without statistical differences between both groups. A non-significant trend to a higher incidence of new-onset AF was observed in patients with IAB (8.7 vs. 6.1%; p = 0.652).

CONCLUSIONS

Nearly one-third of very older patients with sinus rhythm have IAB. They had a tendency to higher incidence of AF and no association with mortality after 2 years of follow-up.

Association of P wave duration index with atrial fibrillation recurrence after cryoballoon catheter ablation

AIM

We aimed to investigate the relationship between the recurrence of AF and P wave duration index (PWDI) in patients with nonvalvular PAF.

METHODS

We included 114 patients who underwent cryoballoon catheter ablation with the diagnosis of paroxysmal atrial fibrillation (PAF) (55 male, 59 female; mean age 55.5±10,9years). PWDI was calculated by dividing the Pwd by the PR interval in DII lead of 12‑lead ECG. Patients had regular follow-up visits with 12-lead ECG, medical history and clinical evaluation. 24h Holter ECG monitoring had been recorded at least 12months after ablation.

RESULTS

AF recurrence was detected in 24 patients after 1year. Patients were divided into two groups according to the AF recurrence. All parameters were compared between the two groups. Age, DM, HT frequency, ACEI-ARB use, CHA2DS2VASc and HAS-BLED score, HsCRP, LA diameter, LA volume, LA volume index, Pwd and PWDI were related to AF recurrence. In binary logistic regression analysis, PWDI (OR=1.143, p=0.001) and HT (OR=0.194, p=0.020) were found to be independent parameters for predicting AF recurrence. Every 0,01 unit increase in PWDI was found to be associated with 14.3% increase in the risk of AF recurrence. The cut-off value of PWDI obtained by ROC curve analysis was 59,9 for prediction of AF recurrence (sensitivity: 75.0%, specificity: 69.0%). The area under the curve (AUC) was 0.760 (p<0.001).

CONCLUSION

Increased PWDI may help to identify those patients in whom electrical remodeling has already occurred and who will get less benefit from cryoablation.

Bayes Syndrome and Imaging Techniques

BACKGROUND

Interatrial block (IAB) is due to disruption in the Bachmann region (BR). According to whether interatrial electrical conduction is delayed or completely blocked through the BR, it can be classified as IAB of first, second or third degree. On the surface electrocardiogram, a P wave ≥ 120 ms (partial IAB) is observed or associated to the prolongation of the P wave with a biphasic (positive / negative) morphology in the inferior leads (advanced IAB). Bayes syndrome is defined as an advanced IAB associated with atrial arrhythmia, more specifically atrial fibrillation. Objective and Conclusion: The purpose of this review is to describe the latest evidence about an entity considered an anatomical and electrical substrate with its own name, which may be a predictor of supraventricular arrhythmia and cardioembolic cerebrovascular accidents, as well as the role of new imaging techniques, such as echocardiographic strain and cardiac magnetic resonance imaging, in characterizing atrial alterations associated with this syndrome and generally in the study of anatomy and atrial function.

Interatrial block and interatrial septal thickness in patients with paroxysmal atrial fibrillation undergoing catheter ablation: Long-term follow-up study

BACKGROUND

Interatrial block (IAB) is a strong predictor of recurrence of atrial fibrillation (AF). IAB is a conduction delay through the Bachman region, which is located in the upper region of the interatrial space. During IAB, the impulse travels from the right atrium to the interatrial septum (IAS) and coronary sinus to finally reach the left atrium in a caudocranial direction. No relation between the presence of IAB and IAS thickness has been established yet.

OBJECTIVE

To determine whether a correlation exists between the degree of IAB and the thickness of the IAS and to determine whether IAS thickness predicts AF recurrence.

METHODS

Sixty-two patients with diagnosis of paroxysmal AF undergoing catheter ablation were enrolled. IAB was defined as P-wave duration ≥120 ms. IAS thickness was measured by cardiac computed tomography.

RESULTS

Among 62 patients with paroxysmal AF, 45 patients (72%) were diagnosed with IAB. Advanced IAB was diagnosed in 24 patients (39%). Forty-seven patients were male. During a mean follow-up period of 49.8 ± 22 months (range 12-60 months), 32 patients (51%) developed AF recurrence. IAS thickness was similar in patients with and without IAB (4.5 ± 2.0 mm vs. 4.0 ± 1.4 mm; p = .45) and did not predict AF. Left atrial size was significantly enlarged in patients with IAB (40.9 ± 5.7 mm vs. 37.2 ± 4.0 mm; p = .03). Advanced IAB predicted AF recurrence after the ablation (OR: 3.34, CI: 1.12-9.93; p = .03).

CONCLUSIONS

IAS thickness was not significantly correlated to IAB and did not predict AF recurrence. IAB as previously demonstrated was an independent predictor of AF recurrence.

Anticoagulation in patients at high risk of stroke without documented atrial fibrillation. Time for a paradigm shift?

Atrial fibrillation (AF) is currently considered a risk factor for stroke. Depending on the severity of clinical factors (risk scores) a recommendation for full anticoagulation is made. Although AF is most certainly a risk factor for ischemic stroke, it is not necessarily the direct cause of it. The causality of association between AF and ischemic stroke is questioned by the reported lack of temporal relation between stroke events and AF paroxysms (or atrial high-rate episodes detected by devices). In different studies, only 2% of patients had subclinical AF > 6 minutes in duration at the time of stroke or systemic embolism. Is it time to consider AF only one more factor of endothelial disarray rather than the main contributor to stroke? In this "opinion paper" we propose to consider not only clinical variables predicting AF/stroke but also electrocardiographic markers of atrial fibrosis, as we postulate this as a strong indicator of risk of AF/stroke. We ask if it is time to change the paradigm and to consider, in some special situations, to protect patients (preventing stroke) who have no evidence of AF.

The P-wave morphology: what does it tell us?

P-wave morphology and duration reveals several aspects of the atria: Proper function, fibrosis, dyssynchrony, and activation paths can be inferred from the surface P-wave analysis. Surface electrocardiogram (ECG) can help differentiating enlargements of the atria from conduction defects including intra- and interatrial block.The purpose of this paper is to review normal atrial morphology and the most relevant abnormal patterns.

The First Report of Bayés Syndrome in Hemodialysis Patient

A chronic hemodialysis patient-known to have advanced interatrial block (IAB)-had reported symptoms suggesting arrhythmias, hence she underwent hemodialysis treatment while on the cardiac monitor. This allowed us to recognize the occurrence of paroxysmal atrial fibrillation and, in turn, disclose the first case of Bayés syndrome. Even though atrial fibrillation and IAB are very frequent in hemodialysis patients, Bayés syndrome, that comprehends both, has never been described, likely because the IAB is often overlooked and undiagnosed. This case could improve the awareness of IAB and of the Bayés syndrome in hemodialysis population.

Interatrial block and atrial arrhythmias in centenarians: Prevalence, associations, and clinical implications

BACKGROUND

Data are lacking on the characteristics of atrial activity in centenarians, including interatrial block (IAB).

OBJECTIVE

The aim of this study was to describe the prevalence of IAB and auricular arrhythmias in subjects older than 100 years and to elucidate their clinical implications.

METHODS

We studied 80 centenarians (mean age 101.4 ± 1.5 years; 21 men) with follow-ups of 6-34 months. Of these 80 centenarians, 71 subjects (88.8%) underwent echocardiography. The control group comprised 269 septuagenarians.

RESULTS

A total of 23 subjects (28.8%) had normal P wave, 16 (20%) had partial IAB, 21 (26%) had advanced IAB, and 20 (25.0%) had atrial fibrillation/flutter. The IAB groups exhibited premature atrial beats more frequently than did the normal P wave group (35.1% vs 17.4%; P < .001); also, other measurements in the IAB groups frequently fell between values observed in the normal P wave and the atrial fibrillation/flutter groups. These measurements included sex preponderance, mental status and dementia, perceived health status, significant mitral regurgitation, and mortality. The IAB group had a higher previous stroke rate (24.3%) than did other groups. Compared with septuagenarians, centenarians less frequently presented a normal P wave (28.8% vs 53.5%) and more frequently presented advanced IAB (26.3% vs 8.2%), atrial fibrillation/flutter (25.0% vs 10.0%), and premature atrial beats (28.3 vs 7.0%) (P < .01).

CONCLUSION

Relatively few centenarians (<30%) had a normal P wave, and nearly half had IAB. Our data suggested that IAB, particularly advanced IAB, is a pre-atrial fibrillation condition associated with premature atrial beats. Atrial arrhythmias and IAB occurred more frequently in centenarians than in septuagenarians.

Bayés' syndrome: the association between interatrial block and supraventricular arrhythmias

The past few years have given rise to extensive research on atrial conduction disorders and their clinical relevance. Most notably, an association between interatrial block and supraventricular arrhythmias has been discovered. This disorder, recently termed 'Bayés' syndrome', has important clinical implications. In this article, the authors review normal atrial conduction and associated disorders. A particular focus is placed on Bayés' syndrome and the relationship between interatrial block and supraventricular arrhythmias in different clinical scenarios. The report also outlines the current progress in the study of this syndrome and highlights areas requiring further investigation.

Advanced interatrial block predicts clinical recurrence of atrial fibrillation after catheter ablation

BACKGROUND

It has been demonstrated that advanced interatrial block (IAB) is associated with an increased risk of atrial fibrillation (AF); however, the impact of advanced IAB on recurrence of paroxysmal AF after catheter ablation is not clear.

METHODS

204 consecutive patients with paroxysmal AF who underwent index circumferential pulmonary vein (PV) isolation were prospectively enrolled. In all patients, a resting electrocardiogram in sinus rhythm was evaluated for the presence of advanced IAB, defined as a P-wave duration >120ms and biphasic (±) morphology in the inferior leads. Advanced IAB was detected in 20.1% of patients. AF recurrence was defined as the occurrence of confirmed atrial tachyarrhythmia lasting more than 30s beyond 3 months after the catheter ablation in the absence of any antiarrhythmic treatment.

RESULTS

During the mean follow-up period of 13.9±6.2 months (range, 3-27 months), 62 patients (30.4%) developed recurrence of AF. The recurrence rate was higher in patients with advanced IAB than those without advanced IAB (46.3% vs. 26.4%, p=0.006). Cox regression analysis with adjustment for age, P-wave duration, CHADS2 score, and PV isolation identified advanced IAB (hazard ratio, 2.111; 95% confidence interval, 1.034-4.308; p=0.040) and left atrial diameter (hazard ratio, 1.051; 95% confidence interval, 1.004-1.100; p=0.034) as two independent predictors of recurrence of AF.

CONCLUSIONS

Patients with advanced IAB were at an increased risk of AF recurrence after catheter ablation.