Role of interatrial block in modulating cryptogenic stroke risk in patients with patent foramen ovale: a retrospective study.

BACKGROUND: The patent foramen ovale (PFO) and interatrial block (IAB) are associated with cryptogenic stroke (CS). However, the role of the interaction between PFO and IAB in CS remains unclear. METHODS: This case-control study enrolled 256 patients with CS and 156 individuals without a history of stroke or transient ischemic attack. IAB was defined as P wave duration > 120 ms. PFO was evaluated by contrast transesophageal echocardiography, and classified as no-PFO, low-risk PFO and high-risk PFO. Multiplicative and additive interaction analysis were used to assess the interaction between PFO and IAB in CS. RESULTS: Multiplicative interaction analysis unveiled a significant interaction between IAB and low-risk PFO in CS (OR for interaction = 3.653, 95% CI, 1.115-12.506; P = 0.037). Additive interaction analysis indicated that 68.4% (95% CI, 0.333-1.050; P < 0.001) of the increased risk of CS related to low-risk PFO was attributed to the interaction with IAB. The results were robust in multivariate analysis. However, but no significant multiplicative or additive interaction was observed between IAB and high-risk PFO. When stratified by IAB, high-risk PFO was associated with CS in both patients with IAB (OR, 4.186; 95% CI, 1.617-10.839; P = 0.003) and without IAB (OR, 3.476; 95% CI, 1.790-6.750; P < 0.001). However, low-risk PFO was only associated with CS in patients with IAB (OR, 2.684; 95% CI, 1.007-7.149; P = 0.048) but not in those without IAB (OR, 0.753; 95% CI, 0.343-1.651; P = 0.479). CONCLUSION: The interaction between IAB and PFO might play an important role in CS, particularly in cases with low-risk PFO.

Advanced Interatrial Block across the Spectrum of Renal Function.

Background and Objective: Interatrial block (IAB) is defined as a conduction delay between the right and left atria. No data are available about the prevalence of both partial IAB and advanced IAB among the different stages of chronic kidney disease. The aim of this study was to describe the prevalence and type of advanced IAB across the spectrum of renal function, including patients on dialysis and the clinical characteristics associated with advanced IAB. Materials and Methods: Retrospective, single-center study of 151 patients consecutively admitted to the Nephrology and Ophthalmology Unit for 3 months. The study population was divided into three groups according to stages of chronic kidney disease. We evaluated the prevalence and pattern of IAB among the groups and the clinical characteristics associated with advanced IAB. Results: The prevalence of partial IAB was significantly lower in end-stage kidney disease (ESKD) group compared to control group (36.7% vs. 59.6%; p = 0.02); in contrast the prevalence of advanced IAB was significantly higher in both chronic kidney disease (CKD) (17.8% vs. 5.3%, p = 0.04) and ESKD group (24.5% vs. 5.3%, p = 0.005) compared to control group. The atypical pattern of advanced IAB was more frequent in both the ESKD and CKD group than in the control group (100% and 75% vs. 33.3%; p = 0.02). Overall, among patients that showed advanced IAB, 17 (73.9%) showed an atypical pattern by morphology and 2 (8.7%) showed an atypical pattern by duration of advanced IAB. The ESKD group was younger than the control group (65.7 ± 12.3 years vs. 71.3 ± 9.9 years; p = 0.01) and showed a higher prevalence of beta blockers (42.9% vs. 19.3%; p = 0.009), as in the CKD group (37.8% vs. 19.3%; p= 0.04). Conclusions: The progressive worsening of renal function was associated with an increasing prevalence of advanced IAB. Advanced IAB may be a sign of uremic cardiomyopathy and may suggest further evaluation with long-term follow-up to investigate its prognostic significance in chronic kidney disease.

Multi-parametric system for risk stratification in mitral regurgitation: A multi-task Gaussian prediction approach.

BACKGROUND: We hypothesized that a multi-parametric approach incorporating medical comorbidity information, electrocardiographic P-wave indices, echocardiographic assessment, neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI) calculated from laboratory data can improve risk stratification in mitral regurgitation (MR). METHODS: Patients diagnosed with mitral regurgitation between 1 March 2005 and 30 October 2018 from a single centre were retrospectively analysed. Outcomes analysed were incident atrial fibrillation (AF), transient ischemic attack (TIA)/stroke and mortality. RESULTS: This study cohort included 706 patients, of whom 171 had normal inter-atrial conduction, 257 had inter-atrial block (IAB) and 266 had AF at baseline. Logistic regression analysis showed that age, hypertension and mean P-wave duration (PWD) were significant predictors of new-onset AF. Low left ventricular ejection fraction (LVEF), abnormal P-wave terminal force in V1 (PTFV1) predicted TIA/stroke. Age, smoking, hypertension, diabetes mellitus, hypercholesterolaemia, ischemic heart disease, secondary mitral regurgitation, urea, creatinine, NLR, PNI, left atrial diameter (LAD), left ventricular end-diastolic dimension, LVEF, pulmonary arterial systolic pressure, IAB, baseline AF and heart failure predicted all-cause mortality. A multi-task Gaussian process learning model demonstrated significant improvement in risk stratification compared to logistic regression and a decision tree method. CONCLUSIONS: A multi-parametric approach incorporating multi-modality clinical data improves risk stratification in mitral regurgitation. Multi-task machine learning can significantly improve overall risk stratification performance.

Interatrial block can occur in the absence of left atrial enlargement: New experimental model.

We present the surface electrocardiogram of an open-chest anesthetized healthy adult swine after direct application of ice at the transversus sinus of the pericardium where the Bachmann's region is located. Gradual and transient interatrial block (IAB) in the absence of structural atrial disease is described. This new experimental model demonstrated that IAB is an independent entity from left atrial enlargement.

Coexistence of increased arterial stiffness and interatrial block in overweight subjects.

BACKGROUND: Interatrial block (IAB) is an electrical conduction delay between the right and left atrium and is associated with some cardiovascular disorders. Arterial stiffness is a useful prognostic marker for cardiovascular events. In the present study, we aimed to investigate the coexistence of increased arterial stiffness and IAB in overweight subjects. METHODS: A total of 110 overweight people were enrolled (56 subjects with IAB, and 54 age- and gender-matched subjects without IAB) into the study. Surface 12-lead standard ECGs were recorded. I.E.M. Mobil-O-Graph ambulatory blood pressure monitor device was used to assess the arterial stiffness. RESULTS: The mean age of the patients was 54.1 ± 11.5 years, and 53.6% were male. PWV and Aix were significantly higher in IAB (+) group than IAB (-) group (9.34 ± 1.5 vs. 7.86 ± 1.3, p < .001; 29.18 ± 11.2 vs. 22.75 ± 10.4, p < .001, respectively), and also, positive linear correlation was observed between arterial stiffness parameters and P-wave duration (r = .758 for PWV; r = .682 for Aix, respectively). CONCLUSION: The present study is the first to focus on evaluating the relationship between the presence of IAB and arterial stiffness in overweight subjects. If there is a coexistence of increased arterial stiffness and IAB in overweight subjects, it should be considered as requiring clinically closer follow-up.

Bayés' Syndrome-A Comprehensive Short Review.

Prediction and early detection of atrial fibrillation (AF) remain a permanent challenge in everyday practice. Timely identification of an increased risk for AF episodes (which are frequently asymptomatic) is essential in the primary and secondary prevention of cardioembolic events. One of the noninvasive modalities of AF prediction is represented by the electrocardiographic P-wave analysis. This includes the study and diagnosis of interatrial conduction block (Bachmann's bundle block). Bayés' Syndrome (named after its first descriptor) denotes the association between interatrial conduction defect and supraventricular arrhythmias (mainly AF) predisposing to cardioembolic events. Our short review presents an update of the most important data concerning this syndrome: brief history, main ECG features, pathophysiological background and clinical implications.

Effect of PR interval and pacing mode on persistent atrial fibrillation incidence in dual chamber pacemaker patients: a sub-study of the international randomized MINERVA trial.

AIMS: Per standard of care, dual-chamber pacemakers are programmed in DDDR mode with fixed atrioventricular (AV) delay or with long AV delay to minimize ventricular pacing. We aimed to evaluate whether the PR interval may be a specific criterion of choice between standard DDDR, to preserve AV synchrony in long PR patients, and managed ventricular pacing (MVP), to avoid ventricular desynchronization imposed by right ventricle apical pacing, in short PR patients. METHODS AND RESULTS: In the MINERVA trial, 1166 patients were randomized to Control DDDR, MVP, or atrial anti-tachycardia pacing plus MVP (DDDRP + MVP). We evaluated the interaction of PR interval with pacing mode by comparing the risk of atrial fibrillation (AF) longer than 7 consecutive days as a function of PR interval. Out of 906 patients with available data, the median PR interval was 180 ms. The PR interval was found to significantly (P = 0.012) interact with pacing mode for AF incidence: the risk of AF > 7 days was lower [hazard ratio (HR) 0.58, 95% confidence interval (95% CI) 0.34-0.99; P = 0.047] in patients with short PR (shorter than median PR) if programmed in MVP mode compared with DDDR mode and it was lower (HR 0.65, 95% CI 0.43-0.99; P = 0.049) in patients with long PR (equal to or longer than median PR) if programmed in DDDR mode compared with MVP. CONCLUSION: Our data show that PR interval may be used as a selection criterion to identify the optimal physiological pacing mode. Persistent AF incidence was lower in short PR patients treated by right ventricular pacing minimization and in long PR patients treated by standard dual-chamber pacing.

Interatrial block in prediction of all-cause mortality after first-ever ischemic stroke.

BACKGROUND: Interatrial block (IAB) is an ECG indicator of atrial fibrosis related to atrial remodeling and thrombus formation thus leading to embolic stroke and increasing mortality. We aimed to assess weather IAB predicted all-cause mortality during 10 years after ischemic stroke. METHODS: The study sample comprised 235 patients (median age 74 (interquartile range 25-75% 65-81) years, 95 female) included in the Lund Stroke Register in 2001-2002, who had sinus rhythm ECGs at stroke admission. IAB was defined as a P-wave duration ≥120 ms without = partial IAB (n = 56) or with = advanced IAB (n = 41) biphasic morphology (±) in the inferior ECG leads. All-cause mortality was assessed via linkage with the Swedish Causes of Death Register. RESULTS: During follow-up 126 patients died (54%). Advanced IAB, but not partial, was associated with all-cause mortality in univariate Cox regression analysis (hazard ratio (HR) 1.98, 95% CI 1.27-3.09, p = 0.003). After adjustment for age, gender, severity of stroke measured by NIHSS scale and smoking status in patients without additional comorbidities advanced IAB independently predicted all-cause mortality (HR 7.89, 95% CI 2.01-30.98, p = 0.003), while in patients with comorbidities it did not (HR 1.01 95% CI 0.59-1.72, p = 0.966). CONCLUSION: Advanced IAB predicted all-cause mortality after ischemic stroke, but mostly in patients without additional cardiovascular comorbidities.

Advanced interatrial block is a surrogate for left atrial strain reduction which predicts atrial fibrillation and stroke.

BACKGROUND: The association between advanced interatrial block (aIAB) and atrial fibrillation (AF) is known as "Bayes' Syndrome." There is little information on the prognostic role that new speckle tracking echocardiographic (STE) imaging techniques could play in it. We have examined the relationship between left atrial (LA) STE and the prediction of new-onset AF and/or stroke in IAB patients. METHODS: This is an observational prospective and unicentric cohort study with 98 outpatients: 55 (56.2%) controls with normal ECG without IAB, 21 (21.4%) with partial IAB (pIAB) and 22 (22.4%) with aIAB. The end point was new-onset AF, ischemic stroke and the composite of both. RESULTS: During a mean follow-up of 1.9 (1.7-2.3) years, 20 patients presented the end point (18 new-onset AF and two strokes): 8 (14.5%) in the control group, 3 (14.3%) in pIAB and 9 (40.9%) in aIAB, p = 0.03. In multivariable comprehensive Cox regression analyses, a decrease in absolute value of strain rate during the booster pump function phase (SRa) was the only variable independently related to the appearance in the evolution of the end point, in the first model (age, P-wave duration and SRa): HR 19.9 (95% CI, 3.12-127.5), p = 0.002 and in the second (age, presence of aIAB and SRa): HR 24.2 (95% CI, 3.15-185.4), p = 0.002. CONCLUSIONS: In patients with IAB, a decrease in absolute value of LA SRa with STE predicts new-onset AF and ischemic stroke. Future studies should confirm our results and assess the prognostic usefulness of LA STE in patients with IAB.

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.

Predictive value of interatrial block for atrial fibrillation in elderly subjects enrolled in the PREDICTOR study.

AIMS: The principal aims of this prospective multicentre study were to relate the presence of interatrial block (IAB) with a late occurrence of atrial fibrillation (AF) and to demonstrate the independence of the IAB effect on risk of AF from structural cardiac alterations. METHODS: This prospective study was the follow-up of subjects included in the PREDICTOR cross-sectional population-based study. Subjects were divided into groups according to IAB status. Socio-demographic and health characteristic were collected during enrolment in the PREDICTOR along with ECGs, echocardiograms and NT-proBNP dosages. Follow up was performed on administrative data. The mean time of follow up was 6.6 years. RESULTS: 1626 subjects were included in the analysis. Four hundred-fifteen subjects out of 1626 (25.5%) had IAB. The survival analysis suggests an association between IAB alone and AF (HR = 1.50, p = 0.058) and, in normal-weight subjects, IAB strongly predicted AF indicating more than triple the risk (HR = 3.05; p = 0.002 95% CI: 1.51-6.18). The association seems to be independent of possible confounders such as history of IHD, left ventricular hypertrophy, CHA2DS2-VASc, left atrial dimension, or NT-proBNP dosage. CONCLUSION: Our analysis suggests that IAB is an electric condition that can increase the risk of AF independently of any structural cardiac alterations, at least in normal-weight subjects.

Interatrial block and atrial remodeling assessed using speckle tracking echocardiography.

BACKGROUND: To evaluate the possibility of left atrial (LA) remodeling using speckle tracking echocardiography (STE) in patients with interatrial block (IAB). METHODS: We performed a cross-sectional study with three groups of patients: 56 without IAB, 21 with partial IAB (pIAB), and 22 with advanced IAB (aIAB). Transthoracic echocardiographic (TTE) STE was performed and clinical and echocardiographic findings were analyzed. RESULTS: TTE showed higher LA volume/body surface area in the patients with IAB. With STE, the absolute value of strain rate during atrial booster pump function (SRa) and early reservoir period (SRs) decreased in the pIAB group and even more in the aIAB group, compared to the group without IAB. The independent variables were the echocardiographic measures of LA size and function. After adjusting for confounders, both multiple linear regression and multivariate multinomial regression showed good correlation with dependent variables: longer P-wave duration on electrocardiography and with the type of IAB, respectively. SRa (p < 0.001), SRs (p < 0.001), and maximal peak LA longitudinal strain in the reservoir period (p = 0.009) were independently associated with P-wave duration. SRa was also associated with the presence of pIAB (OR = 11.5; 95% confidence interval (CI): 2.7-49.0; p = 0.001) and aIAB, (OR = 98.2; 95% CI: 16-120.4; p < 0.001) and SRs was associated with pIAB (OR: 0.03; CI: 0.003-0.29; p = 0.003) and with aIAB (OR: 0.008; CI: 0.001-0.12; p = 0.004). CONCLUSIONS: IAB correlates directly with structural remodeling and a decrease in the absolute value of LA SRa and SRs determined using STE.

P-wave and interatrial block: New predictor for atrial high rate episodes in patients with cardiac implantable electronic devices.

BACKGROUND: The presence of interatrial block (IAB) is associated with the development of atrial fibrillation (AF). The aim of this study was to determine whether P-wave duration and presence of IAB before the implantation of a cardiac implantable electronic device (CIED) are associated with the presence of atrial high rate episodes (AHRE), during long-term follow-up. METHODS: 380 patients (57% men; 75 ± 10 years) were included. IAB was defined according to the International Consensus Criteria. AHRE was defined as an episode of atrial rate ≥225 beats/min with a minimum duration of 5 minutes. RESULTS: Documented paroxysmal AF before the implantation was present in 24% of the patients; 80% had hypertension and 32% structural heart disease. Mean P-wave duration was 123 ± 23 ms, and 39% of the patients had IAB (32% partial, 7% advanced). After a mean follow-up of 18 ± 12 months, 33% of the patients presented AHRE. Patients with AHRE had a P-wave duration significantly longer (130 ± 24 ms vs 119 ± 21 ms; P < 0.001) and a greater prevalence of IAB (53% vs 32%; P < 0.001). In a multivariate analysis, predictors of AHRE were: IAB (odds ratio [OR] 2.1; 95% confidence interval [CI] [1.3-3.4], P < 0.001) and previous paroxysmal AF (OR 2.6; 95% CI [1.5-4.3], P < 0.001). In patients without previous AF, the presence of IAB was also a significant predictor of AHRE (OR 3.1; 95% CI [1.8-5.5], P < 0.001). CONCLUSIONS: IAB is a strong predictor of AHRE in patients with CIED. This finding is independent of the presence of prior paroxysmal AF.

Second-degree interatrial block: Brief review and concept.

The advanced interatrial block (A-IAB) (P ≥ 120 ms plus ± pattern in II, III and aVF) corresponds at atrial level, to right or left advanced bundle branch block at ventricular level, and it is well known that these patterns may be seen transiently in relation to taquicardia or bradycardia (tachycardia or bradycardia dependent right or left bundle branch block). We present for the first time, the same phenomenon at atrial level. In one case, the A-IAB appears in relation to tachycardization and in the other disappears during a pause induced by ventricular premature complex.

[Interatrial block and its clinical relevance. Renaissance of an ECG change]. / Az interatrialis blokk és klinikai jelentosége. Egy EKG-entitás reneszánsza.

Interatrial block involves conduction delay between the right and left atria during sinus rhythm. The review describes the classification, pathomechanism and clinical significance of this under-recognised ECG sign, nominated Bayés syndrome. The presented ECGs help to recognise the differentypes of interatrial blocks. Orv Hetil. 2018; 159(3): 91-95.

Surface ECG interatrial block-guided treatment for stroke prevention: rationale for an attractive hypothesis.

Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with stroke, cognitive impairment, and cardiovascular death. Some predisposing factors - as aging, diabetes, hypertension - induce and maintain electrophysiological and ultrastructural remodeling that usually includes fibrosis. Interatrial conduction disturbances play a crucial role in the initiation of atrial fibrosis and in its associated complications. The diagnosis of interatrial blocks (IABs) is easy to perform using the surface ECG. IAB is classified as partial when the P wave duration is ≥120 ms, and advanced if the P wave also presents a biphasic pattern in II, III and aVF. IAB is very frequent in the elderly and, particularly in the case of the advanced type, is associated with AF, AF recurrences, stroke, and dementia. The anticoagulation in elderly patients at high risk of AF without documented arrhythmias is an open issue but recent data suggest that it might have a role, particularly in elderly patients with structural heart disease, high CHA2DS2VASc (Congestive heart failure/left ventricular dysfunction, Hypertension, Age ≥ 75 [doubled], Diabetes, Stroke [doubled] - Vascular disease, Age 65-74, and Sex category [female]), and advanced IAB. In this debate, we discuss the association of surface ECG IAB, a marker of atrial fibrosis, with AF and stroke. We also present the rationale that justifies further studies regarding anticoagulation in some of these patients.

Evaluation of Electrocardiographic Parameters and the Presence of Interatrial Block in Patients with Mad Honey Intoxication.

Mad honey intoxication (MHI) is a food-induced clinical condition that usually presents with cardiovascular symptoms and can lead to life-threatening arrhythmias if not diagnosed and treated early. No data exist in the literature on the presence of interatrial block (IAB) after food intoxication. In our study, we sought to investigate atrioventricular electrocardiography (ECG) parameters and determine the frequency of IAB in patients with MHI. In total, 76 patients diagnosed with MHI were included in our retrospective study. Twelve-lead ECGs were performed and participants were divided into two groups according to the presence of IAB in the reference ECG. The P maximum (Pmax), P minimum (Pmin), P dispersion (Pdisp), T peak to T end (Tp-Te) interval and QT dispersion (QTdisp) values were compared between the two groups. IAB was detected in 28 (35.5%) of 76 MHI patients included in the final analysis. Pmax duration (122 ± 8; p < 0.001) and PD (69 ± 11; p < 0.001) were significantly higher in the IAB ( +) group. During regression analysis, Pmax [odds ratio (OR) 1.158, 95% confidence interval (CI) 1.036-1.294; p = 0.010] and Pd (OR 1.086, 95% CI 1.001-1.017; p = 0.046) were independently associated with IAB. Pmax and Pd area under the receiver operating characteristic curve values for IAB prediction were 0.926 (95% CI 0.841-1,000; p < 0.001) and 0.872 (95% CI 0.765-0.974; p < 0.001), respectively. ECG changes are common in patients presenting with MHI. These patients need to be followed up clinically in terms of progression to arrhythmic events that may occur in the future.

Comparison of clinical features and conventional echocardiographic characteristics of patients with heart failure with mid-range ejection fraction with and without interatrial block.

OBJECTIVE: Heart failure with mid-range ejection fraction (HFmrEF) has been proposed as a distinct heart failure (HF) phenotype. Interatrial block (IAB) is a conduction delay between the atria and is associated with cardiovascular disease. Although there are several studies examining the effect of IAB in patients with HF with reduced ejection fraction and HF with preserved ejection fraction, a literature review did not reveal any study investigating the clinical importance of the presence of IAB in patients with HFmrEF. Thus, the aim of this research was to evaluate clinical characteristics of HFmrEF with and without IAB. METHODS: A total of 520 consecutive patients with HFmrEF in sinus rhythm who were examined at outpatient clinics were enrolled in the study (244 patients with IAB and 276 patients without IAB). Surface 12-lead standard electrocardiograms (ECGs) were recorded. Clinical characteristics, echocardiographic examination results, and laboratory values of the patients were recorded. RESULTS: The mean age of the patients was 67.4±11.1 years, and 76.1% were male. The patients with IAB had more comorbidities, including hypertension, diabetes mellitus, and stroke/transient ischemic attack. A statistically significant, strong, positive linear correlation was observed between P-wave duration and age, systolic blood pressure, and left atrial volume index (r=0.718, p<0.001; r=0.704, p<0.001; and r=0.725, p<0.001, respectively). CONCLUSION: To the best of our knowledge, the present study is the first to evaluate the clinical relevance of IAB in HFmrEF. Adding this simple ECG marker to the clinical evaluation could add significantly to the management of HFmrEF. IAB can be used to identify high-risk HFmrEF patients, as well as to guide follow-up and appropriate treatment.