Presystolic wave as a predictor of interatrial block in patients with supraventricular tachycardia

The identification of interatrial block (IAB) through electrocardiography (ECG) has been correlated with an elevated likelihood of developing atrial fibrillation (AF) and stroke. IAB is diagnosed by evaluating P-wave prolongation on a surface ECG. The presystolic wave (PSW) is an echocardiographic marker determined by pulse-wave examination of the aortic root during late diastole. As IAB and PSW share similar pathophysiological mechanisms, we speculated that PSW, as a component of the P wave, might be useful in predicting IAB. In the present study, we aimed to determine the relationship between PSW and IAB. Patients with pre-diagnosis of supraventricular tachycardia (SVT) on electrocardiography or rhythm Holter monitoring between January 2021 and December 2022 were included in the study. Surface 12-lead ECG and transthoracic echocardiography (TTE) were performed for the diagnosis of IAB and PSW. Patients were divided into two groups based on the presence of IAB, and PSW was compared between the groups. In total, 104 patients were enrolled in this study. IAB was diagnosed in 16 patients (15.3%) and PSW was detected in 33 patients (31.7%). The PSW was higher in the IAB ( +) group than in the IAB ( -) group (10 patients (71.4%) vs. 23 patients (32.4%), p = 0.008). PSW may be a useful tool for predicting IAB in patients with SVT. Further studies are needed to determine the clinical utility of PSW in the diagnosis and management of IAB.

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.

P-wave duration and interatrial block as predictors of new-onset atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Early detection of atrial fibrillation (AF) could improve patient outcomes. P-wave duration (PWD) and interatrial block (IAB) are known predictors of new-onset AF and could improve selection for AF screening. This meta-analysis reviews the published evidence and offers practical implications.

METHODS

Publication databases were systematically searched, and studies reporting PWD and/or morphology at baseline and new-onset AF during follow-up were included. IAB was defined as partial (pIAB) if PWD≥120 ms or advanced (aIAB) if the P-wave was biphasic in the inferior leads. After quality assessment and data extraction, random-effects analysis calculated odds ratio (OR) and confidence intervals (CI). Subgroup analysis was performed for those with implantable devices (continuous monitoring).

RESULTS

Among 16,830 patients (13 studies, mean 66 years old), 2,521 (15%) had new-onset AF over a median of 44 months. New-onset AF was associated with a longer PWD (mean pooled difference: 11.5 ms, 13 studies, p < 0.001). The OR for new-onset AF was 2.05 (95% CI: 1.3-3.2) for pIAB (5 studies, p = 0.002) and 3.9 (95% CI: 2.6-5.8) for aIAB (7 studies, p < 0.001). Patients with pIAB and devices had higher AF-detection risk (OR: 2.33, p < 0.001) than those without devices (OR: 1.36, p = 0.56). Patients with aIAB had similarly high risk regardless of device presence. There was significant heterogeneity but no publication bias.

CONCLUSION

Interatrial block is an independent predictor of new-onset AF. The association is stronger for patients with implantable devices (close monitoring). Thus, PWD and IAB could be used as selection criteria for intensive screening, follow-up or interventions.

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.

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.

Advanced interatrial block predicts recurrence of embolic stroke of undetermined source

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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 (P_max), P minimum (P_min), P dispersion (P_disp), T peak to T end (Tp-Te) interval and QT dispersion (QT_disp) values were compared between the two groups. IAB was detected in 28 (35.5%) of 76 MHI patients included in the final analysis. P_max duration (122 ± 8; p < 0.001) and PD (69 ± 11; p < 0.001) were significantly higher in the IAB ( +) group. During regression analysis, P_max [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. P_max 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.

[Clinical, electrical and echocardiographic characteristics of patients with advanced interatrial block]

El haz de Bachmann se compone de un conjunto de fibras miocárdicas paralelas y especializadas, responsables del 80% de la conducción interauricular. Discurre por las paredes anterosuperiores auriculares, y su afectación da lugar al bloqueo interauricular (BIA); éste puede ser: a) parcial (BIA-p) si la conducción está retrasada (en el ECG produce una onda P ≥ 120 ms) o b) avanzado (BIA-a) si está del todo interrumpida y la despolarización auricular izquierda (AI) ocurre en dirección retrógrada caudocraneal (la onda P es ≥ 120 ms y bifásica +/- en las derivaciones inferiores II, III y VF)1.

Interatrial blocks prevalence and risk factors for human immunodeficiency virus-infected persons

Background

Interatrial blocks are considered a new important risk factor for atrial fibrillation and cerebrovascular events. Their prevalence and clinical implications have been reported in general population and several subgroups of patients but no data from HIV-infected populations, with a non-negligible prevalence of atrial fibrillation, has been previously reported.

Methods

We conducted a cross-sectional study in a previously enrolled cohort of randomly selected middle-aged HIV-infected patients who attended our hospital and were clinically stable.

Patients underwent both a 12-lead rest electrocardiogram and clinical questionnaires while epidemiological, clinical and HIV-related variables were obtained from electronic medical records and interviews with the patients. Electrocardiograms were then analyzed and codified using a standardized form by two trained members of the research team who were blinded to clinical variables.

Results

We obtained electrocardiograms from 204 patients with a mean age of 55.22 years, 39 patients (19.12%) presented an interatrial block, 9 (4.41%) advanced and 30 (14.71%) partial. Patients with interatrial block had a lower nadir lymphocyte CD4 count (124 vs 198 cells, p = 0.02) while advanced interatrial blocks were associated to older age (62.16 vs. 54.95 years, p = 0.046) and hypertension (77.8% vs. 32.3%, p = 0.009). We did not find differences regarding baseline CD4 lymphocyte count or CD4/CD8 lymphocyte ratio. Clinical variables and functional capacity among patients with or without interatrial block were similar.

Conclusions

In a cohort of clinically stable HIV infected patients the prevalence of interatrial blocks, specially advanced, is high and associated to previously known factors (age, hypertension) and novel ones (nadir CD4 lymphocyte count).

Bayes Syndrome and Imaging Techniques

BACKGROUND

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