Interatrial blocks. A separate entity from left atrial enlargement: a consensus report

Atrial electrofunctional predictors of incident atrial fibrillation in cardiac amyloidosis

BACKGROUND

Atrial fibrillation (AF) is common in patients with cardiac amyloidosis (CA) and is a significant risk factor for heart failure hospitalization and thromboembolic events.

OBJECTIVE

This study was designed to investigate the atrial electrofunctional predictors of incident AF in CA.

METHODS

A multicenter, observational study was conducted in 4 CA referral centers including sinus rhythm patients with light-chain (AL) and transthyretin (ATTR) CA undergoing electrocardiography and cardiac magnetic resonance imaging. The primary end point was new-onset AF occurrence.

RESULTS

Overall, 96 patients (AL-CA, n = 40; ATTR-CA, n = 56) were enrolled. During an 18-month median follow-up (Q1-Q3, 7-29 months), 30 patients (29%) had incident AF. Compared with those without AF, patients with AF were older (79 vs 73 years; P = .001). They more frequently had ATTR (87% vs 45%; P < .001); electrocardiographic interatrial block (IAB), either partial (47% vs 21%; P = .011) or advanced (17% vs 3%; P = .017); and lower left atrial ejection fraction (LAEF; 29% vs 41%; P = .004). Age (hazard ratio [HR], 1.059; 95% CI, 1.002-1.118; P = .042), any type of IAB (HR, 2.211; 95% CI, 1.03-4.75; P = .041), and LAEF (HR, 0.967; 95% CI, 0.936-0.998; P = .044) emerged as independent predictors of incident AF. Patients exhibiting any type of IAB, LAEF <40%, and age >78 years showed a cumulative incidence for AF of 40% at 12 months. This risk was significantly higher than that carried by 1 (8.5%) or none (7.6%) of these 3 risk factors.

CONCLUSION

In patients with CA, older age, IAB on 12-lead electrocardiography, and reduced LAEF on cardiac magnetic resonance imaging are significant and independent predictors of incident AF. A closer screening for AF is advisable in CA patients carrying these features.

Effect of pacing site on P wave parameters: Within-patient comparison of right atrial appendage and Bachmann's bundle

BACKGROUND

Conventional right atrial appendage pacing (RAAp) is associated with adverse clinical outcomes mediated in part by electromechanical atrial delays. Bachmann's bundle pacing (BBp) offers more physiologic atrial activation; however, detailed analysis of pacing site on paced P wave parameters is lacking.

METHODS

Intraprocedural electrocardiograms of 21 consecutive patients undergoing atrial lead implantation were retrospectively analyzed and within-patient comparisons of 7 P wave parameters (P wave duration, P wave voltage, P wave area, PR interval, PR segment, PTFV1 and P wave axis) during sinus rhythm, RAAp and BBp performed.

RESULTS

The median basal P wave duration was prolonged at 134.5 ms (Q1,Q3: 120.5, 150.5) and similarly prolonged during RAAp at 144.0 ms (127.0, 176.0) but was significantly reduced with BBp at 98.0 ms (93.0, 116.0; p = 0.005 and p < 0.001, respectively). The median basal P wave voltage in lead II was normal at 0.11 mV (0.08, 0.15) but significantly reduced during RAAp at 0.08 mV (0.04, 0.11) and greatest during BBp at 0.16 mV (0.09, 0.19; p < 0.001 and p = 0.003, respectively). The median basal PR interval was top normal at 185.0 ms (163.0, 213.0) and similarly prolonged during RAAp at 204.0 ms (166.5, 221.0) but was significantly shortened during BBp at 163.0 ms (142.0, 208.0; p = 0.03 and p = 0.001, respectively).

CONCLUSIONS

BBp has favorable effects on the paced P wave parameters including marked shortening in P wave duration, increase in P wave voltage in lead II and increase in PR segment which may offer significant hemodynamic advantages over conventional RAAp.

Understanding the Underlying Mechanism of an Abnormal P Wave

This case report describes a patient in their 70s presenting to the hospital with dyspnea and fatigue.

Novel electrocardiographic classification for stroke prediction in atrial fibrillation patients undergoing cardioversion

BACKGROUND

Abnormal conduction, structure, and function of the atrial myocardium predispose to atrial fibrillation (AF) and stroke. The usefulness of electrocardiographic indices in predicting stroke or systemic embolism (SSE) in patients undergoing cardioversion (CV) for AF remains unknown, especially in those at low estimated risk.

OBJECTIVE

We systematically evaluated the performance of various P-wave abnormalities (PWAs) in predicting SSE 30 days after CV (derivation cohort) and in the long term (validation cohort).

METHODS

Electrocardiograms (n = 1773) of AF patients undergoing an acute CV were manually reviewed. The 30-day post-CV data were used to derive a composite PWA variable. The electrocardiographic findings were validated by the long-term follow-up of patients with no anticoagulation. Electrocardiograms of 27 CAREBANK study patients with right atrial appendage biopsies were further analyzed for histopathologic validation.

RESULTS

During data derivation, the best performance was found with a combination of prolonged P-wave (≥180 ms), deflected P-wave morphology in lead II, biphasic P-waves in inferior leads, or increased P-terminal force (≥80 mm·ms) as markers for extensive PWA. In the validation cohort, 219 of 874 (25.1%) had extensive PWA. During a median follow-up of 4.9 years, there were 51 patients (5.8%) with SSE in total. In a competing risk model, PWA predicted SSE (adjusted hazard ratio, 2.1 per category; 95% CI, 1.4-3.1; P < .001). Areas under the curve for SSE at 3 years were 0.77, 0.79, and 0.86 for PWA, CHA2DS2-VASc, score, and their combination, respectively. On histologic evaluation, extensive PWA was associated with interstitial fibrosis (P = .033).

CONCLUSION

Novel electrocardiographic PWA classification provided additional prognostic insight in AF patients.

Association of the interatrial block and left atrial fibrosis in the patients without history of atrial fibrillation

Presence of left atrial (LA) fibrosis reflects underlying atrial cardiomyopathy. Interatrial block (IAB) is associated with LA fibrosis in patients with atrial fibrillation (AF). The association of IAB and LA fibrosis in the patients without history of AF is unknown. We examined association of IAB and LA fibrosis in the patients without AF history. This is a retrospective analysis of 229 patients undergoing cardiac magnetic resonance imaging (CMR). LA fibrosis was reported from spatial extent of late gadolinium enhancement of CMR. IAB was measured from 12-lead electrocardiography using digital caliper. Of 229 patients undergoing CMR, prevalence of IAB was 50.2%. Patients with IAB were older (56.9±13.9 years vs. 45.9±19.2 years, p<0.001) and had higher prevalence of co-morbidities. Left ventricular ejection fraction was lower in IAB group. LA volume index (LAVI) was greater in IAB group (54.6±24.9 ml/m2 vs. 43.0±21.1 ml/m2, p<0.001). Patients with IAB had higher prevalence of LA fibrosis than those without IAB (70.4% vs. 21.2%; p<0.001). After multivariable analysis, only IAB and LAVI were independent factors that predict LA fibrosis. Prevalence of IAB in patients undergoing CMR was high. IAB was highly associated with LA fibrosis and larger LA size in patients without AF history.

Paradoxical interatrial conduction recovery after cavotricuspid isthmus ablation: A case report

We present a case of a patient with advanced interatrial block who was admitted for cavotricuspid isthmus ablation as treatment of typical atrial flutter. A baseline advanced interatrial block pattern turned into partial interatrial block pattern and prolonged PR interval after the procedure. We discuss the mechanism underlying that change.

P-wave Indices as Predictors of Atrial Fibrillation: The Lion from a Claw

The P wave, representing the electrical fingerprint of atrial depolarization, contains information regarding spatial and temporal aspects of atrial electrical-and potentially structural-properties. However, technical and biological reasons, including-but not limited to-the low amplitude of the P wave and large interindividual variations in normal or pathologic atrial electrical activity, make gathering and utilizing this information for clinical purposes a rather cumbersome task. However, even crude ECG descriptors, such as P-wave dispersion, have been shown to be of predictive value for assessing the probability that a patient already has or will shortly present with AF. More sophisticated methods of analyzing the ECG signal, on a single- or multi- beat basis, along with novel approaches to data handling, namely machine learning, seem to be leading up to more accurate and robust ways to obtain clinically useful information from the humble P wave.

P-wave characteristics as electrocardiographic markers of atrial abnormality in prediction of incident atrial fibrillation - The Malmö Preventive Project

BACKGROUND

P-wave indices reflect atrial abnormalities contributing to atrial fibrillation (AF). We aimed to assess a comprehensive set of P-wave characteristics for prediction of incident AF in a population-based setting.

METHODS

Malmö Preventative Project (MPP) participants were reexamined in 2002-2006 with electrocardiographic (ECG) and echocardiographic examinations and followed for 5 years. AF-free subjects (n = 983, age 70 ± 5 years, 38% females) with sinus rhythm ECGs were included in the study. ECGs were digitally processed using the Glasgow algorithm. P-wave duration, axis, dispersion, P-terminal force in lead V1 and interatrial block (IAB) were evaluated. ECG risk score combining the morphology, voltage and length of P-wave (MVP score) was calculated. New-onset diagnoses of AF were obtained from nation-wide registers.

RESULTS

During follow up, 66 patients (7%) developed AF. After adjustment for age and gender, the independent predictors of AF were abnormal P-wave axis > 75° (HR 1.63 CI95% 1.95-11.03) and MVP score 4 (HR 6.17 CI 95% 1.76-21.64), both correlated with LA area: Person r - 0.146, p < 0.001 and 0.192, p < 0.001 respectively. Advanced IAB (aIAB) with biphasic P-wave morphology in leads III and aVF was the most prevalent variant of aIAB and predicted AF in a univariate model (HR 2.59 CI 95% 1.02-6.58).

CONCLUSION

P-wave frontal axis and MVP score are ECG-based AF predictors in the population-based cohort. Our study provides estimates for prevalence and prognostic importance of different variants of aIAB, providing a support to use biphasic P-wave morphology in lead aVF as the basis for aIAB definition.

Interatrial block as a first clinical presentation of atrial cardiomyopathy related to a novel LMNA variant: a case report

Background

Interatrial block (IAB) is a conduction delay in Bachmann's bundle with a well-described association with structural heart disease, supraventricular arrhythmias, and cardiovascular events.

Case summary

We report the case of an asymptomatic 35-year-old man in whom the presence of IAB at electrocardiogram led to a comprehensive evaluation including speckle-tracking echocardiography, 24 h Holter monitoring, and genetic testing. Speckle-tracking echocardiography demonstrated a decrease in the longitudinal strain of interventricular septum, a typical feature of LMNA-related cardiomyopathy, and decreased indices of left atrial deformation. A diagnosis of cardiac laminopathy related to the frame shift variant c.1367 (p.Asn456Thrfs*24) of the LMNA gene was made. A dual-chamber implantable cardioverter defibrillator implantation was performed for the high risk of life-threatening ventricular tachyarrhythmias.

Discussion

This case demonstrates that IAB could be a rare presentation of a life-threatening laminopathy. Strain echocardiography is an essential tool to evaluate the deposition of fibrosis tissue in subclinical cardiomyopathies. Our report describes a novel variant of LMNA gene associated with a high risk of sudden cardiac death.

New pattern of atypical advanced interatrial block

INTRODUCTION

Interatrial block (IAB) is defined as prolonged P-wave duration (≥ 120 ms) due to delayed conduction in the Bachmann bundle. This is readily identifiable using surface electrocardiogram (ECG). Advanced IAB can be classified as typical and atypical. Atypical IAB can be further categorized by (i) duration or (ii) morphology. In this report, we have identified a new pattern of atypical IAB with triphasic morphology of the P-wave in the inferior leads.

METHODS

Two clinical cases were evaluated including surface ECGs. P-wave durations and amplitudes were measured with digital calipers using ECG analysis software (MUSE, GE HealthCare). Comparisons were made using prior data to evaluate IAB and P-wave duration and morphology.

RESULTS

A new pattern of atypical advanced IAB shows prolonged P-wave duration (P wave >160 ms) and triphasic morphology in all inferior leads with P +/+/- and P +/-/+, respectively. We speculate that triphasic P-waves in the inferior leads represent three moments of atrial depolarization; from right to left.

CONCLUSION

This study describes a novel pattern of atypical advanced IAB. Further investigation regarding the increased risk of atrial fibrillation and stroke associated with this new pattern is warranted in the future.

Alternative atrial pacing site to improve cardiac function: focus on Bachmann's bundle pacing

Pacing from the right atrial appendage (RAA) prolongs the P wave duration and can induce interatrial and especially left-sided atrio-ventricular dyssynchrony. Pacing from Bachmann's bundle closely reproduces normal physiology and has the potential to avoid the electromechanical dysfunction associated with conventional RAA pacing. Interatrial conduction delay is associated with an increased risk of stroke, heart failure, and death. In addition to a reduction in atrial fibrillation, Bachmann's bundle pacing has emerging applications as a hemodynamic pacing modality. This review outlines the pathophysiology of atrial conduction disturbances and their potential remedies and provides the reader with a practical guide to implementing Bachmann's bundle pacing with an emphasis on the recapitulation of normal electrical and mechanical function.

Research progress on predicting atrial fibrillation recurrence after radiofrequency ablation based on electrocardiogram-related parameters

Atrial fibrillation (AF) is the most common arrhythmia. It is associated with increased stroke risks, thromboembolism, and other complications, which are great life and economic burdens for patients. In recent years, with the maturity of percutaneous catheter radiofrequency ablation (RFA) technology, it has become a first-line therapy for AF. However, some patients still experience AF recurrence (AFR) after RFA, which can cause serious consequences. Therefore, it is critical to identify appropriate parameters that are predictive of prognosis and to be able to translate the parameters easily into the clinical setting. Here, we reviewed possible predicting indicators for AFR, focusing on all the electrocardiogram indicators, such as P wave duration, PR interval and so on. It may provide valuable information for guiding clinical works.

The Role of Electrocardiographic Markers for Predicting Atrial Fibrillation in Patients with Acute Ischemic Stroke: Data from the BIOSIGNAL Cohort Study

BACKGROUND AND AIMS

P-wave abnormalities in the 12-lead electrocardiogram (ECG) have been associated with a higher risk of acute ischemic stroke (AIS) as well as atrial fibrillation (AF). This study aimed to assess pre-determined ECG criteria during sinus rhythm in unselected AIS patients and their value for predicting newly diagnosed atrial fibrillation (NDAF) after hospital admission.

METHODS

P-wave alterations were measured on 12-lead ECG on admission in all consecutively enrolled patients without known AF between October 2014 and 2017. The outcome of interest was NDAF, identified by prolonged electrocardiographic monitoring within one year after the index AIS. Univariable and multivariable logistic regression was applied to assess the magnitude and independence of the association between pre-selected ECG markers and NDAF. The discriminatory accuracy was evaluated with the area under the receiver operating characteristic curve (AUC), and the incremental prognostic value was estimated with the net reclassification index.

RESULTS

NDAF was detected in 87 (10%) of 856 patients during a follow-up of 365 days. Out of the pre-selected ECG parameters, advanced interatrial block (aIAB) and PR interval in lead II were independently associated with NDAF in univariable regression analysis. Only aIAB remained a significant predictor in multivariable analysis. Adding aIAB to the best-performing multivariable regression model improved the discriminatory accuracy to predict NDAF from an AUC of 0.78 (95%-CI 0.77-0.80) to 0.81 (95%-CI 0.80-0.83, p < 0.001).

CONCLUSION

aIAB is independently and highly associated with NDAF in patients with AIS, has high inter-rater reliability, and therefore may be helpful to refine diagnostic work-up to search for AF in AIS.

Predictive value of interatrial block on electrocardiogram among obese patients undergoing atrial fibrillation ablation

BACKGROUND

Determine a predictive value of interatrial block (IAB) on atrial fibrillation (AF) ablation outcomes in obese patients.

METHODS

Medical records were retrospectively reviewed for 205 consecutive patients with body mass indices (BMI) ≥ 30 kg/m2 who underwent initial AF ablation. Evidence of partial IAB defined as P-wave duration (PWD) ≥ 120 ms and advanced IAB with PWD ≥ 120 ms and biphasic or negative P-wave in inferior leads was examined from sinus electrocardiograms (ECGs) within 1-year pre-ablation. The primary outcome was recurrent atrial arrhythmia after 3-month blanking period post-ablation.

RESULTS

The mean BMI was 36.9 ± 5.7 kg/m2. Partial IAB and advanced IAB were observed in 155 (75.61%) and 42 (20.49%) patients, respectively. During the median follow-up of 1.35 (interquartile range 0.74, 2.74) years, 115 (56.1%) patients had recurrent atrial arrhythmias. In multivariable analysis adjusting for age, gender, persistent AF, use of antiarrhythmic drugs (AADs), left atrial volume index (LAVI), partial IAB, and advanced IAB were independent predictors of recurrent arrhythmia with hazard ratio (HR) of 2.80 (95% confidence interval [CI] 1.47-6.05; p = 0.001) and HR 1.79 (95% CI 1.11-2.82; p = 0.017), respectively. The results were similar in a subgroup analysis of patients who had no severe left atrial enlargement and a subgroup analysis of patients who were not on AADs.

CONCLUSIONS

IAB is highly prevalent in patients with obesity and AF. Partial IAB, defined as PWD ≥ 120 ms, and advanced IAB with evidence of biphasic P-wave in inferior leads were independently associated with increased risk of recurrent arrhythmia after AF ablation. Its predictive value is independent of other traditional risk factors, LAVI, or use of AADs.

P-wave duration as a marker of atrial remodeling in patients referred to ablation for atrial fibrillation: A new stratification tool emerging?

Ablation of atrial fibrillation is one of the most widely applied invasive procedures in cardiovascular medicine, and populations with atrial fibrillation continuously rise. Recurrence rates are, however, consistently high, even in patients without severe comorbidities. Robust stratification algorithms to distinguish patients suitable for ablation are generally lacking. This is a fact caused by the inability to incorporate evidence of atrial remodeling and fibrosis, e.g., atrial remodeling, in the decision pathways. Cardiac magnetic resonance is a powerful tool in identifying fibrosis; however, it is costly and not routinely used. Electrocardiography has been generally underutilized in clinical practice during pre-ablative screening. One of the characteristics of the electrocardiogram that can give us valuable data depicting the existence and the extent of atrial remodeling and fibrosis is the duration of the P-wave. Currently, many studies support the implementation of P-wave duration in the routine practice of patient evaluation as a surrogate marker of existing atrial remodeling, that in turn predicts recurrence after ablation of atrial fibrillation. Further research is guaranteed to establish this electrocardiographic characteristic in our stratification quiver.

Asymmetric remodeling between the left and right atria in patients with advanced interatrial block and atrial fibrillation

BACKGROUND

Advanced interatrial block (A-IAB) on electrocardiography (ECG) represents the conduction delay between the left and right atria. We investigated the association of A-IAB with left and right atrial (LA/RA) remodeling in patients with atrial fibrillation (AF).

METHODS

We enrolled 74 patients who underwent ECG, cardiac computed tomography (CCT), and echocardiography during sinus rhythm before catheter ablation of AF. A-IAB was defined as P-wave duration ≥120 ms with a biphasic morphology in leads III and aVF or notched morphology in lead II. We compared the maximum and minimum LA/RA volume indices (max and min LAV/RAVI), LA/RA expansion index (LAEI/RAEI), and total, passive, and active LA/RA emptying fraction (LAEF/RAEF) between patients with and without A-IAB.

RESULTS

Of the 74 patients (mean age, 64.3 ± 9.6 years), 35 (47%) showed A-IAB. Patients with A-IAB had a significantly higher likelihood of hypertension and left ventricular diastolic dysfunction than those without. Patients with A-IAB had significantly larger max (69.2 [60.7-79.7]mL/m2 vs. 60.9 [50.4-68.3]mL/m2, P < 0.01) and min (44.0 [37.2-52.1]mL/m2 vs. 34.1 [29.2-43.5]mL/m2, P < 0.01) LAVI than those without. The max and min RAVI were not significantly different between groups. LAEI (55.1 [48.2-78.5]% vs. 72.1 [57.8-84.8]%, P < 0.05), total LAEF (35.5 [32.5-44.0]% vs. 41.9 [36.6-45.9]%, P < 0.05), and passive LAEF (12.2 [10.0-14.4]% vs. 15.5 [11.2-19.6]%, P < 0.05) were significantly lower in patients with A-IAB than without.

CONCLUSIONS

A-IAB was associated with LA, but not RA enlargement, in patients with AF. A-IAB may indicate LA functional remodeling in the reservoir and conduit phases.

Interatrial Block Association With Adverse Cardiovascular Outcomes in Patients Without a History of Atrial Fibrillation

BACKGROUND

Interatrial block (IAB) is associated with thromboembolism and atrial arrhythmias. However, prior studies included small patient cohorts so it remains unclear whether IAB predicts adverse outcomes particularly in context of atrial fibrillation (AF)/atrial flutter (AFL).

OBJECTIVES

This study sought to determine whether IAB portends increased stroke risk in a large cohort in the presence or absence of AFAF/AFL.

METHODS

We performed a 5-center retrospective analysis of 4,837,989 electrocardiograms (ECGs) from 1,228,291 patients. IAB was defined as P-wave duration ≥120 ms in leads II, III, or aVF. Measurements were extracted as .XML files. After excluding patients with prior AF/AFL, 1,825,958 ECGs from 458,994 patients remained. Outcomes were analyzed using restricted mean survival time analysis and restricted mean time lost.

RESULTS

There were 86,317 patients with IAB and 355,032 patients without IAB. IAB prevalence in the cohort was 19.6% and was most common in Black (26.1%), White (20.9%), and Hispanic (18.5%) patients and least prevalent in Native Americans (9.2%). IAB was independently associated with increased stroke probability (restricted mean time lost ratio coefficient [RMTLRC]: 1.43; 95% CI: 1.35-1.51; tau = 1,895), mortality (RMTLRC: 1.14; 95% CI: 1.07-1.21; tau = 1,924), heart failure (RMTLRC: 1.94; 95% CI: 1.83-2.04; tau = 1,921), systemic thromboembolism (RMTLRC: 1.62; 95% CI: 1.53-1.71; tau = 1,897), and incident AF/AFL (RMTLRC: 1.16; 95% CI: 1.10-1.22; tau = 1,888). IAB was not associated with stroke in patients with pre-existing AF/AFL.

CONCLUSIONS

IAB is independently associated with stroke in patients with no history of AF/AFL even after adjustment for incident AF/AFL and CHA2DS2-VASc score. Patients are at increased risk of stroke even when AF/AFL is not identified.

Left atrial epicardial adipose tissue exacerbates electrical conduction disturbance in normal-weight patients undergoing pulmonary vein isolation for atrial fibrillation

INTRODUCTION

Epicardial adipose tissue (EAT) exacerbates both electrical and structural remodeling in obese atrial fibrillation (AF) patients, but the impacts of EAT on atrial arrhythmogenicity remain unclear in normal-weight AF patients. Therefore, we sought to investigate this issue using electroanatomic mapping.

METHODS AND RESULTS

We enrolled drug-refractory 105 paroxysmal AF patients in the normal body mass index range (18.5-24.9 kg/m² ), who had undergone electroanatomic mapping after pulmonary vein isolation (PVI). One day before PVI, we assessed P-wave duration in a 12-lead electrocardiogram and left atrial (LA)-EAT volumes using contrast-enhanced computed tomography. The patients were divided into two groups based on the median LA-EAT volume (16.0 ml); the high LA-EAT group (≥16.0 ml, n = 53) and low LA-EAT group (<16.0 ml, n = 52). We compared P-wave duration, LA conduction velocity and bipolar voltage, the presence of low-voltage zone (<0.5 mV), and LA volume index on echocardiography between the two groups. The LA bipolar voltage, low-voltage zone, and LA volume index were not different between the high and low LA-EAT groups. However, P-wave duration was significantly longer in the high group than in the low group (p < .001). Additionally, the LA conduction velocity was significantly more depressed in the high group than in the low group (p < .001). Multivariate linear regression analysis revealed that LA-EAT volume was correlated with P-wave duration (β = .367, p < .001) and conduction velocity (β = -.566, p < .001), respectively.

CONCLUSIONS

Increased LA-EAT volumes were associated with electrical conduction disturbance after PVI in normal-weight patients with AF. P-wave duration may be a clinically useful predictor of LA-EAT.

New electrocardiographic aspects of the P wave: Its value in clinical cardiology

In this article, we will comment on new aspects of P-wave morphology that help us to better diagnose atrial blocks and atrial enlargement, and their clinical implications. These include: (1) Atypical ECG patterns of advanced interatrial block; (2) The ECG diagnosis of left atrial enlargement versus interatrial block; (3) Atrial fibrillation and advanced interatrial block: The two sides of the same coin; and (4) P-wave parameters: Clinical implications.

Epicardial high-resolution mapping of advanced interatrial block: Relating ECG, conduction abnormalities and excitation patterns

Background

Impairment of conduction across Bachmann's Bundle (BB) may cause advanced interatrial block (a-IAB), which in turn is associated with development of atrial fibrillation. However, the exact relation between a complete transverse line of conduction block (CB) across BB and the presence of a-IAB has not been studied.

Objective

The aims of this study are to determine whether (1) a complete transversal line of CB across BB established by high resolution mapping correlates with a-IAB on the surface ECG, (2) conduction abnormalities at the right and left atria correlate with a-IAB, and (3) excitation patterns are associated with ECG characteristics of a-IAB.

Methods

We included 40 patients in whom epicardial mapping revealed a complete transverse line of CB across BB. Pre-operative ECGs and post-operative telemetry were assessed for the presence of (a) typical a-IAB and de novo early post-operative AF (EPOAF), respectively. Total atrial excitation time (TAET) and RA-LA delay were calculated. Entry site and trajectory of the main sinus rhythm wavefront at the pulmonary vein area (PVA) were assessed.

Results

Thirteen patients were classified as a-IAB (32.5%). In the entire atria and BB there were no differences in conduction disorders, though, patients with a-IAB had an increased TAET and longer RA-LA delay compared to patients without a-IAB (90.0 ± 21.9 ms vs. 74.9 ± 13.0 ms, p = 0.017; 160.0 ± 27.0 ms vs. 136.0 ± 24.1 ms, p = 0.012, respectively). Patients with typical a-IAB solely had caudocranial activation of the PVA, without additional cranial entry sites. Prevalence of de novo EPOAF was 69.2% and was similar between patients with and without a-IAB.

Conclusion

A transverse line of CB across BB partly explains the ECG characteristics of a-IAB. We found atrial excitation patterns underlying the ECG characteristics of both atypical and typical a-IAB. Regardless of the presence of a-IAB, the clinical impact of a complete transverse line of CB across BB was reflected by a high incidence of de novo EPOAF.

The "Bayés Spirit" as a guide for new generations: How to combine one's personal life and friendships with science and profession

Recent studies suggest that up to a quarter of physicians in training suffer from burnout and psychological disorders. Scientist-physicians, cardiologists, cardiology residents, and first-year medical residents seem to be more prone to developing varying degrees of emotional distress. Concerned about the new generations of clinicians and researchers, the authors aim to provide guidelines for reconciling professional success with a fulfilling and satisfying personal life. The figure of Antonio Bayés de Luna (cardiology and electrocardiology guru) is used as the ideal example to learn how to combine one's personal life, family, and friendships with science and their professional career. This can be done in a healthy and balanced way, prioritizing the former while continuing to have an intense dedication to the latter.

Unusual Electrocardiogram Findings After Cardioversion

This case report considers electrocardiogram findings in an older patient with a history of metastatic carcinoma and tuberculosis presenting with palpitations at rest and 2 months of breathlessness.

Noteworthy P Waves in an Elderly Woman

This case report describes a patient in their 70s who was referred to the emergency department for worsening shortness of breath, chest tightness, and episodes of palpitations. What is your diagnosis?

Atrial cardiomyopathy: Diagnosis, clinical implications and unresolved issues in anticoagulation therapy

Atrial cardiomyopathy (AC) is an evolving pathophysiological entity that has expanded our understanding regarding the atrium and its role in arrhythmogenesis and cardiac thromboembolism. The pathological myocardium in AC promotes arrhythmogenesis through mechanical dysfunction (hypocontractility, fibrosis), adverse alterations of the endothelium and secretion of prothrombotic factors (IL-6, IL-8, TNF-a). 'Red flags', indicative of AC, can be recognized either non-invasively by electrocardiography, echocardiography and cardiac magnetic resonance imaging or invasively by high-density electroanatomical mapping as low bipolar voltage areas of the affected myocardium. Signs of AC have been strongly associated with an increased risk of ischemic stroke, even embolic strokes of undetermined source, regardless of the coexistence of atrial fibrillation (AF). The underlying existence of AC has been negatively correlated with the success rate of catheter ablation of AF. The clinical value of AC is the provision of a novel pathway regarding the potential mechanisms of cerebrovascular events of cardiac thromboembolic origin. In addition, AC may serve as a risk stratification tool to predict the long-term responders of AF catheter ablation.

P-wave duration and atrial fibrillation recurrence after catheter ablation: a systematic review and meta-analysis

AIMS

Atrial fibrillation (AF) is a global health problem with high morbidity and mortality. Catheter ablation (CA) can reduce AF burden and symptoms, but AF recurrence (AFr) remains an issue. Simple AFr predictors like P-wave duration (PWD) could help improve AF therapy. This updated meta-analysis reviews the increasing evidence for the association of AFr with PWD and offers practical implications.

METHODS AND RESULTS

Publication databases were systematically searched and cohort studies reporting PWD and/or morphology at baseline and AFr after CA were included. Advanced interatrial block (aIAB) was defined as PWD ≥ 120 ms and biphasic morphology in inferior leads. Random-effects analysis was performed using the Review Manager 5.3 and R programs after study selection, quality assessment, and data extraction, to report odds ratio (OR) and confidence intervals. : Among 4175 patients in 22 studies, 1138 (27%) experienced AFr. Patients with AFr had longer PWD with a mean pooled difference of 7.8 ms (19 studies, P < 0.001). Pooled OR was 2.04 (1.16-3.58) for PWD > 120 ms (13 studies, P = 0.01), 2.42 (1.12-5.21) for PWD > 140 ms (2 studies, P = 0.02), 3.97 (1.79-8.85) for aIAB (5 studies, P < 0.001), and 10.89 (4.53-26.15) for PWD > 150 ms (4 studies, P < 0.001). There was significant heterogeneity but no publication bias detected.

CONCLUSION

P-wave duration is an independent predictor for AF recurrence after left atrium ablation. The AFr risk is increasing exponentially with PWD prolongation. This could facilitate risk stratification by identifying high-risk patients (aIAB, PWD > 150 ms) and adjusting follow up or interventions.

Prognostic significance of atrial cardiopathy in patients with acute ischemic stroke

Introduction:

Whether atrial cardiopathy is associated with stroke prognosis remains unclear. We evaluated the association between atrial cardiopathy markers and outcomes in patients with ischemic stroke using a nationwide prospective registry.

Patients and methods:

Based on the Third China National Stroke Registry, we evaluated different atrial cardiopathy markers including increased P-wave terminal force in V1 (PTFV1), advanced interatrial block (aIAB), prolonged P-wave duration, prolonged P-wave dispersion, paroxysmal supraventricular tachycardia, premature atrial contractions, prolonged PR interval, and severe left atrial enlargement in ischemic stroke patients. The outcomes were death and ischemic stroke recurrence at 1 year. The association between atrial cardiopathy markers and outcomes was analyzed using Cox regression models.

Results:

At 1-year follow-up, 486 (3.4%) patients had died and 1317 (9.3%) patients had experienced ischemic stroke recurrence. After adjustment for clinical risk factors including atrial fibrillation, PTFV1 > 5000 μV·ms (adjusted hazard ratio [HR] 1.70, 95% confidence interval [CI]: 1.18–2.45, p = 0.004) and aIAB (adjusted HR 1.47, 95% CI: 1.14–1.91, p = 0.003) were significantly associated with mortality. PTFV1 > 5000 μV·ms was significantly associated with ischemic stroke recurrence (adjusted HR 1.54, 95% CI: 1.22–1.96, p = 0.0004). This association was observed although we excluded patients diagnosed with atrial fibrillation.

Discussion and Conclusion:

Atrial cardiopathy markers, especially PTFV1 and aIAB, are significantly associated with a higher risk of poor prognosis in patients with ischemic stroke.

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.

Utility of P-wave abnormalities for distinguishing embolic stroke from non-embolic stroke

BACKGROUND

Our aim was to analyze the incidence of P-wave abnormalities in embolic and non-embolic strokes, and evaluate its clinical usefulness for predicting stroke etiology.

METHODS

We included 376 consecutive patients hospitalized for acute ischemic stroke from January 2015 to September 2021. Among the patients in sinus rhythm at admission, 31 had ischemic stroke due to atrial fibrillation (AF)-related embolism, 59 had embolic stroke of unknown source (ESUS), and 143 had non-embolic stroke. P-wave abnormalities were defined as 1. P-wave axis abnormality (PWAA); 2. P-wave terminal force in V₁ (PTFV1) ≤ -4000 μV*ms; 3. advanced inter-atrial block (A-IAB).

RESULTS

The prevalence of each type of abnormality was consistently lower in patients with non-embolic stroke than in those with AF-related embolism (AF-related vs. ESUS vs. non-embolic; PWAA, 45% vs. 20% vs. 14%; PTFV1, 36% vs. 37% vs. 15%; and A-IAB, 55% vs. 31% vs. 13%, respectively). The identification of at least one type of P-wave abnormality improved the sensitivity compared to using a single abnormality parameter (sensitivity 72%, specificity 62%), while at least two types of abnormality had low sensitivity, but high specificity (sensitivity 29%, specificity 95%). Multivariate regression analysis revealed that identification of at least one type of P-wave abnormality was independently associated with embolic stroke (odds ratio 3.11, 95%CI 1.46-6.63).

CONCLUSIONS

The incidence of each type of P-wave abnormality was significantly lower in patients with non-embolic stroke. A combination of PWAA, PTFV1, and A-IAB parameters could be useful for distinguishing embolic from non-embolic stroke.

The prognostic role of interatrial block among COVID-19 patients hospitalized in medicine wards

INTRODUCTION

Some abnormal electrocardiographic findings were independently associated with increased mortality in patients admitted for COVID-19; however, no studies have focussed on the prognosis impact of the interatrial block (IAB) in this clinical setting. The aim of our study was to assess the prevalence and clinical implications of IAB, both partial and advanced, in hospitalized COVID-19 patients.

MATERIALS

We retrospectively evaluated 300 consecutive COVID-19 patients (63.22 ± 15.16 years; 70% males) admitted to eight Italian Hospitals from February 2020 to April 2020 who underwent twelve lead electrocardiographic recording at admission. The study population has been dichotomized into two groups according to the evidence of IAB at admission, both partial and advanced. The differences in terms of ARDS in need of intubation, in-hospital mortality and thromboembolic events (a composite of myocardial infarction, stroke and transient ischaemic attack) have been evaluated.

RESULTS

The presence of IAB was noticed in 64 patients (21%). In the adjusted logistic regression model, the partial interatrial block was found to be an independent predictor of ARDS in need of intubation (HR: 1.92; p: .04) and in-hospital mortality (HR: 2.65; p: .02); moreover, the advanced interatrial block was an independent predictor of thrombotic events (HR: 7.14; p < .001).

CONCLUSIONS

Among COVID-19 patients hospitalized in medical wards, the presence of interatrial block is more frequent than in the general population and it might be useful as an early predictor for increased risk of incident thrombotic events, ARDS in need of intubation and in-hospital mortality.

Atrial myxoma surgery and p-wave remodeling

INTRODUCTION

Data regarding atrial electrocardiographic parameters in patients with atrial myxomas are scarce.

METHODS

We aimed to study atrial electrocardiographic features in patients with atrial myxomas, before and after surgery. We also analyze the incidence of atrial fibrillation during follow-up and its correlation with different P-wave indexes. 32 patients in sinus rhythm that underwent atrial myxoma surgery were included.

RESULTS

Mean age was 55.0±12.6 years and 18 (56.3%) were women. Ten patients had left atrial enlargement (31.3%). Only one myxoma was located in the right atrium. At baseline 7 cases of partial interatrial block (IAB) were detected (21.9%), two in the absence of left atrial enlargement. There were significant differences in atrial electrocardiographic indexes before and after surgery, including P-wave duration (108.9±17.9 ms vs. 93.0±12.4 ms; p < 0.001), partial IAB (21.9% vs 3.1%; p = 0.012) and duration of P-wave terminal force in lead V1 negativity (-0.6±0.3 vs -0.5±0.3 mm; p = 0.034). At a mean follow up of 10.0±5.5 years, 10 patients (31.3%) had experienced at least one episode of atrial fibrillation. Post-operative P-wave duration was associated with atrial fibrillation occurrence during follow-up (Hazard ratio: 0.90, 95% confidence interval: 0.83-0.98; p = 0.020).

CONCLUSIONS

Abnormalities in atrial electrocardiographic indexes are common in atrial myxomas and frequently improve after surgery. Post-operative P-wave duration is associated with atrial fibrillation occurrence during follow-up. This article is protected by copyright. All rights reserved.

Interatrial Block Predicts Life-Threatening Arrhythmias in Dilated Cardiomyopathy

Background Interatrial block (IAB) has been associated with supraventricular arrhythmias and stroke, and even with sudden cardiac death in the general population. Whether IAB is associated with life-threatening arrhythmias (LTA) and sudden cardiac death in dilated cardiomyopathy (DCM) remains unknown. This study aimed to determine the association between IAB and LTA in ambulant patients with DCM. Methods and Results A derivation cohort (Maastricht Dilated Cardiomyopathy Registry; N=469) and an external validation cohort (Utrecht Cardiomyopathy Cohort; N=321) were used for this study. The presence of IAB (P-wave duration>120 milliseconds) or atrial fibrillation (AF) was determined using digital calipers by physicians blinded to the study data. In the derivation cohort, IAB and AF were present in 291 (62%) and 70 (15%) patients with DCM, respectively. LTA (defined as sudden cardiac death, justified shock from implantable cardioverter-defibrillator or anti-tachypacing, or hemodynamic unstable ventricular fibrillation/tachycardia) occurred in 49 patients (3 with no IAB, 35 with IAB, and 11 patients with AF, respectively; median follow-up, 4.4 years [2.1; 7.4]). The LTA-free survival distribution significantly differed between IAB or AF versus no IAB (both P<0.01), but not between IAB versus AF (P=0.999). This association remained statistically significant in the multivariable model (IAB: HR, 4.8 (1.4-16.1), P=0.013; AF: HR, 6.4 (1.7-24.0), P=0.007). In the external validation cohort, the survival distribution was also significantly worse for IAB or AF versus no IAB (P=0.037; P=0.005), but not for IAB versus AF (P=0.836). Conclusions IAB is an easy to assess, widely applicable marker associated with LTA in DCM. IAB and AF seem to confer similar risk of LTA. Further research on IAB in DCM, and on the management of IAB in DCM is warranted.

Embolic stroke of undetermined source: beyond atrial fibrillation

INTRODUCTION

Embolic stroke of undetermined source (ESUS) accounts for 25% of all cerebral infarcts; only 30% are associated with paroxysmal atrial fibrillation (AF). Various biochemical, electrocardiographic, and echocardiographic findings may suggest left atrial damage and increased risk of embolism in the absence of clinically documented AF or atrial flutter. In this review, we analyse the available evidence on atrial cardiopathy or atrial disease, its involvement in ESUS, and its identification through electrocardiographic, echocardiographic, and serum markers and its possible therapeutic implications.

DEVELOPMENT

A systematic search was conducted on MEDLINE (PubMed) using the following MeSH terms: MeSH [ESUS]+[atrial cardiopathy]+[atrial fibrillation]+[interatrial block]+[treatment]. We selected what we considered to be the most useful original prospective or retrospective studies and systematic reviews. We then read the full texts of the articles and checked the references cited in each article. We analyse epidemiological and demographic variables of patients with ESUS, as well as recent evidence related to presentation and prognosis and factors associated with recurrence and mortality. We review the contribution of atrial cardiopathy diagnosis prior to the detection of AF and the clinical, electrocardiographic, and echocardiographic variables and the biochemical markers associated with its development and its potential contribution to cerebral embolism.

CONCLUSIONS

The systematic search of biochemical and electrocardiographic, and echocardiographic alterations can be useful to identify ESUS patients at higher risk of recurrence.

Embolic stroke of undetermined source: Beyond atrial fibrillation

INTRODUCTION

Embolic stroke of undetermined source (ESUS) accounts for 25% of all cerebral infarcts; only 30% are associated with paroxysmal atrial fibrillation (AF). Various biochemical, electrocardiographic, and echocardiographic findings may suggest left atrial damage and increased risk of embolism in the absence of clinically documented AF or atrial flutter. In this review, we analyse the available evidence on atrial cardiopathy or atrial disease, its involvement in ESUS, and its identification through electrocardiographic, echocardiographic, and serum markers and its possible therapeutic implications.

DEVELOPMENT

A systematic search was conducted on MEDLINE (PubMed) using the following MeSH terms: MeSH [ESUS]+[atrial cardiopathy]+[atrial fibrillation]+[interatrial block]+[treatment]. We selected what we considered to be the most useful original prospective or retrospective studies and systematic reviews. We then read the full texts of the articles and checked the references cited in each article. We analyse epidemiological and demographic variables of patients with ESUS, as well as recent evidence related to presentation and prognosis and factors associated with recurrence and mortality. We review the contribution of atrial cardiopathy diagnosis prior to the detection of AF and the clinical, electrocardiographic, and echocardiographic variables and the biochemical markers associated with its development and its potential contribution to cerebral embolism.

CONCLUSIONS

The systematic search of biochemical and electrocardiographic, and echocardiographic alterations can be useful to identify ESUS patients at higher risk of recurrence.

Paced P-wave duration as a significant predictor for atrial high-rate episodes in patients with cardiac implantable electronic devices

BACKGROUND

Atrial pacing can unmask or aggravate a preexisting interatrial block (IAB). The aim of our study was to determine whether atrial pacing is associated with the development of atrial high-rate episodes (AHRE) during follow-up.

METHODS

Patients with dual-chamber cardiac implantable electronic devices (CIED), no previous documented atrial fibrillation, and with a 6-month minimum follow-up were included. In all patients, sinus and paced P-wave duration were measured. AHRE was defined as an episode of atrial rate ≥ 225 bpm with a minimum duration of 5 min, excluding those documented during the first three months after implantation.

RESULTS

Two hundred twenty patients were included (75 ± 10 years, 61% male). After a mean follow-up of 59±25 months, 46% of patients presented AHRE. Mean paced P-wave duration was significantly longer than the sinus P-wave duration (154±27 vs 115±18 ms; p < 0.001). Sinus and paced P-waves were significantly longer in those who developed AHRE (sinus: 119±20 vs 112±16; p  =  0.006; paced: 161±29 vs 148±23; p < 0.001). A paced P-wave ≥160 ms was the best predictor of AHRE, especially those lasting >24 h (OR 4.2 (95% CI) [1.6-11.4]; p  =  0.004).

CONCLUSIONS

Atrial pacing significantly prolongs P-wave duration and is associated with further development of AHRE. A paced P-wave ≥160 ms is a strong predictor of AHRE and should be taken into consideration as a new definition of IAB in the presence of atrial pacing. This article is protected by copyright. All rights reserved.

P Wave Parameters and Indices: A Critical Appraisal of Clinical Utility, Challenges, and Future Research-A Consensus Document Endorsed by the International Society of Electrocardiology and the International Society for Holter and Noninvasive Electrocardiology

Atrial cardiomyopathy, characterized by abnormalities in atrial structure and function, is associated with increased risk of adverse cardiovascular and neurocognitive outcomes, independent of atrial fibrillation. There exists a critical unmet need for a clinical tool that is cost-effective, easy to use, and that can diagnose atrial cardiomyopathy. P wave parameters (PWPs) reflect underlying atrial structure, size, and electrical activation; alterations in these factors manifest as abnormalities in PWPs that can be readily ascertained from a standard 12-lead ECG and potentially be used to aid clinical decision-making. PWPs include P wave duration, interatrial block, P wave terminal force in V₁, P wave axis, P wave voltage, P wave area, and P wave dispersion. PWPs can be combined to yield an index (P wave index), such as the morphology-voltage-P-wave duration ECG risk score. Abnormal PWPs have been shown in population-based cohort studies to be independently associated with higher risks of atrial fibrillation, ischemic stroke, sudden cardiac death, and dementia. Additionally, PWPs, either individually or in combination (as a P wave index), have been reported to enhance prediction of atrial fibrillation or ischemic stroke. To facilitate translation of PWPs to routine clinical practice, additional work is needed to standardize measurement of PWPs (eg, via semiautomated or automated measurement), confirm their reliability and predictive value, leverage novel approaches (eg, wavelet analysis of P waves and machine learning algorithms), and finally, define the risk-benefit ratio of specific interventions in high-risk individuals. Our ultimate goal is to repurpose the ubiquitous 12-lead ECG to advance the study, diagnosis, and treatment of atrial cardiomyopathy, thus overcoming critical challenges in prevention of cardiovascular disease and dementia.

Cardiovascular Complications of Interatrial Conduction Block: JACC State-of-the-Art Review

Interatrial block (IAB) is an electrocardiographic pattern describing the conduction delay between the right and left atria. IAB is classified into 3 degrees of block that correspond to decreasing conduction in the region of Bachmann's bundle. Although initially considered benign in nature, specific subsets of IAB have been associated with atrial arrhythmias, elevated thromboembolic stroke risk, cognitive impairment, and mortality. As the pathophysiologic relationships between IAB and stroke are reinforced, investigation has now turned to the potential benefit of early detection, atrial imaging, cardiovascular risk factor modification, antiarrhythmic pharmacotherapy, and stroke prevention with oral anticoagulation. This review provides a contemporary overview of the epidemiology, pathophysiology, diagnosis, and management of IAB, with a focus on future directions.

P-Wave Beat-to-Beat Analysis to Predict Atrial Fibrillation Recurrence after Catheter Ablation

The identification of patients prone to atrial fibrillation (AF) relapse after catheter ablation is essential for better patient selection and risk stratification. The current prospective cohort study aims to validate a novel P-wave index based on beat-to-beat (B2B) P-wave morphological and wavelet analysis designed to detect patients with low burden AF as a predictor of AF recurrence within a year after successful catheter ablation. From a total of 138 consecutive patients scheduled for AF ablation, 12-lead ECG and 10 min vectorcardiogram (VCG) recordings were obtained. Univariate analysis revealed that patients with higher B2B P-wave index had a two-fold risk for AF recurrence (HR: 2.35, 95% CI: 1.24–4.44, p: 0.010), along with prolonged P-wave, interatrial block, early AF recurrence, female gender, heart failure history, previous stroke, and CHA₂DS₂-VASc score. Multivariate analysis of assessable predictors before ablation revealed that B2B P-wave index, along with heart failure history and a history of previous stroke or transient ischemic attack, are independent predicting factors of atrial fibrillation recurrence. Further studies are needed to assess the predictive value of the B2B index with greater accuracy and evaluate a possible relationship with atrial substrate analysis.

Atrial High-Rate Episodes Detected by Cardiac Implantable Electronic Devices: Dynamic Changes in Episodes and Predictors of Incident Atrial Fibrillation

Simple Summary

Atrial high rate episodes (AHRE) detected by cardiac implantable electronic devices (CIEDs) may be associated with a risk of progression towards long-lasting episodes (≥24 h) and clinical atrial fibrillation (AF). Identification of this subset of patients is key to promptly starting oral anticoagulant therapy and possibly avoiding stroke and systemic thromboembolism. In the present study, we describe the clinical characteristics of 104 retrospectively enrolled patients with AHRE episodes lasting 5 min–23 h 59 min, no AF at 12-lead ECG, and no history of prior clinical AF. Moreover, we define predictors of the composite outcome of clinical AF and/or AHRE episodes lasting ≥24 h. Over a median follow-up of 24.3 (10.6–40.3) months, 31/104 (29.8%) patients experienced the composite outcome. Baseline CHA₂DS₂-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were independently associated with the composite outcome and with incident clinical AF as well. To conclude, in patients with AHRE, the incidence of clinical AF or AHRE episodes lasting ≥24 h is high. Baseline patients’ characteristics (CHA₂DS₂-VASc score) and AHRE duration may help to intensify monitoring and decision-making, being independently associated with clinical AF in a two-year follow-up.

Abstract

Background. Atrial high rate episodes (AHRE) detected by cardiac implantable electronic devices (CIEDs) may be associated with a risk of progression towards long-lasting episodes (≥24 h) and clinical atrial fibrillation (AF). Methods. Consecutive CIED patients presenting AHRE (with confirmation of an arrhythmia lasting 5 min–23 h 59 min, atrial rate ≥175/min, with no AF at 12-lead ECG and no prior clinical AF) were retrospectively enrolled. The aims of this study were to describe patients’ characteristics and the incidence of adverse events, and second, to identify potential predictors of the composite outcome of clinical AF and/or AHRE episodes lasting ≥24 h. Results. 104/107 (97.2%) patients (median age 79.7 (74.0–84.2), 33.7% female) had available follow-up data. Over a median follow-up of 24.3 (10.6–40.3) months, 31/104 (29.8%) patients experienced the composite outcome of clinical AF or AHRE episodes lasting ≥24 h. Baseline CHA₂DS₂-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were independently associated with the composite outcome (Hazard ratio (HR); 95% CI: 1.40; 1.07–1.83 and HR: 8.15; 95% CI 2.32–28.65, respectively). Baseline CHA₂DS₂-VASc score and the longest AHRE episode at enrollment lasting 12 h–23 h 59 min were the only independent predictors of incident clinical AF (HR: 1.45; 95% CI 1.06–2.00 and HR: 4.25; 95% CI 1.05–17.20, respectively). Conclusions. In patients with AHRE, the incidence of clinical AF or AHRE episodes lasting ≥24 h is high in a two-year follow-up. Baseline patients’ characteristics (CHA₂DS₂-VASc score) and AHRE duration may help to intensify monitoring and decision-making, being independently associated with clinical AF at follow-up.

Dissimilar Atrial Rhythms Seen by Transesophageal Echocardiography During an Electrophysiology Study

Dissimilar atrial rhythms describe the coexistence of atrial fibrillation in one atrium and a more regular rhythm in the other. Electrograms are typically used to diagnose this rare entity. The use of transesophageal echocardiography in this context has not been described previously. We present a case of an 88-year-old woman with paroxysmal atrial fibrillation and new-onset, symptomatic atrial flutter who underwent electrophysiology study that confirmed dissimilar atrial rhythms. Transesophageal echocardiography images reveal differential function of the left and right atrial appendages, a novel finding that may be useful in diagnosing this rhythm disorder.

Strain Echocardiography to Predict Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (POAF) complicates 15% to 40% of cardiovascular surgeries. Its incidence progressively increases with aging, reaching 50% in octogenarians. This arrhythmia is usually transient but it increases the risk of embolic stroke, prolonged hospital stay, and cardiovascular mortality. Though many pathophysiological mechanisms are known, POAF prediction is still a hot topic of discussion. Doppler echocardiogram and, lately, strain echocardiography have shown significant capacity to predict POAF. Alterations in oxidative stress, calcium handling, mitochondrial dysfunction, inflammation, fibrosis, and tissue aging are among the mechanisms that predispose patients to the perfect “atrial storm”. Manifestations of these mechanisms have been related to enlarged atria and impaired function, which can be detected prior to surgery. Specific alterations in the atrial reservoir and pump function, as well as atrial dyssynchrony determined by echocardiographic atrial strain, can predict POAF and help to shed light on which patients could benefit from preventive therapy.

Risk of New-Onset Atrial Fibrillation Post-cavotricuspid Isthmus Ablation in Typical Atrial Flutter Without History of Atrial Fibrillation

Aims: The aim was to describe the incidence of atrial fibrillation (AF) after cavotricuspid isthmus (CTI) ablation in patients with typical atrial flutter (AFL) without history of AF and to identify risk factors for new-onset AF after the procedure.

Methods: A total of 191 patients with typical AFL undergoing successful CTI ablation were enrolled. Patients who had history of AF, structural heart disease, cardiac surgery, or ablation or who received antiarrhythmic drug after procedure were excluded. Clinical and electrophysiological data were collected.

Results: There were 47 patients (24.6%) developing new AF during a follow-up of 3.3 ± 1.9 years after CTI ablation. Receiver operating characteristic (ROC) curves indicated that the cut-off values of left atrial diameter (LAD) and CHA₂DS₂-VASc score were 42 mm and 2, with area under the curve of 0.781 and 0.550, respectively. The multivariable Cox regression analysis revealed that obstructive sleep apnea (OSA) [hazard ratio (HR) 3.734, 95% confidence interval (CI) 1.470–9.484, P = 0.006], advanced interatrial block (aIAB) (HR 2.034, 95% CI 1.017–4.067, P = 0.045), LAD > 42 mm (HR 2.710, 95% CI 1.478–4.969, P = 0.001), and CHA₂DS₂-VASc score > 2 (HR 2.123, 95% CI 1.118–4.034, P = 0.021) were independent risk factors of new-onset AF.

Conclusion: A combination of OSA, aIAB, LAD > 42 mm, and CHA₂DS₂-VASc > 2 was a strongly high risk for new-onset AF after ablation for typical AFL, and it had significance in postablation management in clinical practice.