Advanced interatrial block: A predictor of covert atrial fibrillation in embolic stroke of undetermined source.

AIMS: One third of ischemic strokes are of unknown etiology. Interatrial block (IAB) is a marker of atrial electromechanical dysfunction that may predispose to the development of atrial fibrillation (AF). We hypothesized that IAB, especially in its advanced form, could be a marker of covert AF in patients with embolic stroke of undetermined source (ESUS). METHODS: We reviewed a single center cohort of ESUS patients with no prior history of AF. According to P-wave analysis of baseline ECG we distinguished 3 groups: normal P-wave duration (P-wave < 120 ms), partial IAB (P-IAB, P-wave ≥ 120 ms) and A-IAB (A-IAB, P-wave ≥ 120 ms with biphasic morphology in inferior leads). Follow-up was done 1, 6 and 12 months after discharge; then every 6 months. AF episodes, frequent premature atrial contractions (PACs) (>1%) and atrial tachyarrhythmias (runs of >3 consecutive PACs) were detected on 24 h Holter. The primary endpoint was new-onset AF detection on follow-up by any means. RESULTS: A high prevalence of both P-IAB (n = 30, 40%) and A-IAB (n = 23, 31%) was found in 75 ESUS patients. After a 521 day mean follow-up, 14 patients (19%) were diagnosed of AF. A-IAB independently predicted AF diagnosis (p =0.042) on follow-up. 24 h Holter analysis showed greater frequency of PACs and atrial tachyarrhythmia episodes in patients with IAB (p = 0.0275). CONCLUSIONS: In this hypothesis-generating study, A-IAB in the setting of ESUS is an independent risk predictor of covert AF. Although additional randomized clinical trials are warranted, A-IAB identifies ESUS patients with advanced atrial disease that could potentially benefit from early oral anticoagulation in secondary prevention.

Old teaching tools should not be forgotten: The value of the Lewis ladder diagram in understanding bigeminal rhythms.

As medical education evolves, some traditional teaching methods often get forgotten. For generations, the Lewis ladder diagram (LLD) has helped students understand the mechanisms of cardiac arrhythmias and conduction disorders. Similarly, clinicians have used LLDs to communicate their proposed mechanisms to their colleagues and trainees. In this article, we revisit this technique of constructing the LLD and demonstrate this process by describing the mechanisms of various bigeminal rhythms.

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.

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.

Atypical advanced interatrial blocks: Definition and electrocardiographic recognition.

The diagnosis of advanced interatrial block (A-IAB) is done by surface ECG analysis when the P-wave ≥120 ms with biphasic (±) morphology in leads II, III and aVF. In this brief communication, we advance a new concept involving atypical patterns of A-IAB due to changes about the morphology or duration of the P-wave. It remains to be determined its real prevalence in different clinical scenarios, and whether these atypical ECG patterns should be considered as predictors of atrial fibrillation/stroke.

A novel method for the noninvasive estimation of cardiac output with brachial oscillometric blood pressure measurements through an assessment of arterial compliance.

OBJECTIVE: To propose and validate a new method for estimating cardiac output based on the total arterial compliance (Ct) formula that does not need an arterial waveform and to apply it to brachial oscillometric blood pressure measurements (OBPMs). METHODS: One hundred subjects with normal heart anatomy and function were included. Reference values for cardiac output were measured with echocardiography, and Ct was calculated with a two-element Windkessel model. Then, a statistical model of arterial compliance (Ce) was used to estimate cardiac output. Finally, the measured and estimated cardiac output values were compared for accuracy and reproducibility. RESULTS: The model was derived from the data of 70 subjects and prospectively tested with the data from the remaining 30 individuals. The mean age of the whole group was 43.4 ± 12.8 years, with 46% women. The average blood pressure (BP) was 107.1/65.0 ± 15.0/9.6 mmHg and the average heart rate was 67.7 ± 11.4 beats/min. The average Ct was 1.39 ± 0.27 mL/mmHg and the average cardiac output was 5.5 ± 1.0 L/min. The mean difference in the cardiac output estimated by the proposed methodology vs. that measured by Doppler echocardiography was 0.022 L/min with an SD of 0.626 L/min. The intraclass correlation coefficient was 0.93, and the percentage error was 19%. CONCLUSION: Cardiac output could be reliably and noninvasively obtained with brachial OBPMs through a novel method for estimating Ct without the need for an arterial waveform. The new method could identify hemodynamic factors that explain BP values in an ambulatory care setting.

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.

Advanced interatrial block predicts new-onset atrial fibrillation and ischemic stroke in patients with heart failure: The "Bayes' Syndrome-HF" study.

AIMS: Advanced interatrial block (IAB) is characterized by a prolonged (≥120 ms) and bimodal P wave in the inferior leads. The association between advanced IAB and atrial fibrillation (AF) is known as "Bayes' Syndrome", and there is scarce information about it in heart failure (HF). We examined the prevalence of IAB and whether advanced IAB could predict new-onset AF and/or stroke in HF patients. METHODS AND RESULTS: The prospective observational "Bayes' Syndrome-HF" study included consecutive outpatients with chronic HF. The primary endpoints were new-onset AF, ischemic stroke, and the composite of both. A secondary endpoint included all-cause death alone or in combination with the primary endpoint. Comprehensive multivariable Cox regression analyses were performed. Among 1050 consecutive patients, 536 (51.0%) were in sinus rhythm, 464 with a measurable P wave are the focus of this study. Two-hundred and sixty patients (56.0%) had normal atrial conduction, 95 (20.5%) partial IAB, and 109 (23.5%) advanced IAB. During a mean follow-up of 4.5 ±â€¯2.1 years, 235 patients experienced all-cause death, new-onset AF, or stroke. In multivariable comprehensive Cox regression analyses, advanced IAB was associated with new-onset AF (HR 2.71 [1.61-4.56], P < 0.001), ischemic stroke (HR 3.02 [1.07-8.53], P = 0.04), and the composite of both (HR 2.42 [1.41-4.15], P < 0.001). CONCLUSIONS: In patients with HF advanced IAB predicts new-onset AF and ischemic stroke. Future studies must assess whether anticoagulant treatment in Bayes' Syndrome leads to better outcomes in HF.

Analysis of the Association Between Electrocardiographic P-wave Characteristics and Atrial Fibrillation in the REGICOR Study.

INTRODUCTION AND OBJECTIVES: Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia. P-wave duration and interatrial blocks (IAB) have been reported to be associated with AF. Our aim was to determine the individual and combined association of P-wave duration and advanced IAB morphology with AF. METHODS: We designed an age-, sex-, and survey-matched case-control study nested in a population-based cohort (REGICOR: REgistre GIroní del COR). Two different surveys recruited a total of 9380 participants from 1999 to 2005; all participants were invited to a second examination between 2009 and 2013. For the present study, we selected participants aged 25 to 79 years with follow-up through the end of the study. All electrocardiograms were analyzed by 2 observers to determine P-wave duration and morphology (normal, partial, or advanced IAB). RESULTS: The median follow-up was 7.12 years. Eighty participants presented with AF, had a legible baseline electrocardiogram, and were included in the study, along with 160 controls. P-wave duration and the presence of partial or advanced IAB were associated with AF. When P-wave duration and morphology were considered together, only P-wave duration (≥ 110 milliseconds) showed an independent and strong association with AF. The odds ratio for AF of P-wave duration between 110-119, 120-129 and ≥ 130 milliseconds vs < 110 milliseconds were 5.33; 95%CI, 1.74-16.33, 5.08; 95%CI, 1.73-14.90 and 5.44; 95%CI, 1.95-15.15, respectively. CONCLUSIONS: A P-wave longer than 110 milliseconds increases the risk of AF. Advanced IAB morphology did not seem to provide an additional AF risk beyond that of P-wave duration.