P Wave Indices-Advancing Our Understanding of Atrial Fibrillation-Related Cardiovascular Outcomes

The effect of high-power short-duration pulmonary vein isolation on PWPT-a predictor of paroxysmal atrial fibrillation

BACKGROUND

The P wave peak time (PWPT) is a predictor of paroxysmal atrial fibrillation (PAF). High-power short-duration ablation has been associated with improved durability of circumferential pulmonary vein electrical isolation (PVI). We investigated the effect of high-power short-duration PVI on PWPT in patients with PAF.

METHODS

Out of 111 patients with PAF, 91 received radiofrequency ablation (ablation group) and 20 received medication treatment (control group). A VIZIGO sheath and an STSF catheter (Biosense Webster, CA, USA) were used together for high-power short-duration circumferential PVI at ablation index values of 500 and 400 for the anterior and posterior walls, respectively. The patients were followed up for 12 months.

RESULTS

The preoperative PWPT in the ablation group was similar to that in the control group: PWPT II = 54.38 ± 6.18 ms vs. 54.35 ± 6.12 ms (p > 0.05), PWPT V1 = 54.19 ± 6.21 ms vs. 54.31 ± 6.08 ms (p > 0.05), respectively. Circumferential PVI was achieved for all patients in the ablation group during the operation. At the 12-month follow-up, there were seven cases of AF recurrence. The PWPT in the ablation group 12 months postoperatively was shorter than the preoperative value: PWPT II = 49.39 ± 7.11 ms vs. 54.38 ± 6.18 ms (p < 0.001), PWPT V1 = 47.69 ± 7.01 ms vs. 54.19 ± 6.21 ms (p < 0.001). The PWPT in the patients with AF recurrence was significantly longer than that in the non-recurrence patients: PWPT II = 50.48 ± 7.12 ms vs. 47.33 ± 6.21 ms (p < 0.001), PWPT V1 = 50.84 ± 7.05 ms vs. 47.19 ± 6.27 ms, (p < 0.001). The PWPT of the control group at the 12-month follow-up was similar to the baseline level: PWPT II = 54.32 ± 6.20 ms vs. 54.35 ± 6.12 ms (p > 0.05), PWPT V1 = 53.89 ± 6.01 ms vs. 54.31 ± 6.08 ms (p > 0.05).

CONCLUSION

The results showed that high-power short-duration PVI had a positive effect on PWPT, which is a predictor of PAF.

Cardioprotective role of a magnolol and honokiol complex in the prevention of doxorubicin-mediated cardiotoxicity in adult rats

Doxorubicin (DOXO) induces marked cardiotoxicity, though increased oxidative stress while there are some documents related with cardioprotective effects of some antioxidants against organ-toxicity during cancer treatment. Although magnolia bark has some antioxidant-like effects, its action in DOXO-induced heart dysfunction has not be shown clearly. Therefore, here, we aimed to investigate the cardioprotective action of a magnolia bark extract with active component magnolol and honokiol complex (MAHOC; 100 mg/kg) in DOXO-treated rat hearts. One group of adult male Wistar rats was injected with DOXO (DOXO-group; a cumulative dose of 15 mg/kg in 2-week) or saline (CON-group). One group of DOXO-treated rats was administered with MAHOC before DOXO (Pre-MAHOC group; 2-week) while another group was administered with MAHOC following the 2-week DOXO (Post-MAHOC group). MAHOC administration, before or after DOXO, provided full survival of animals during 12-14 weeks, and significant recoveries in the systemic parameters of animals such as plasma levels of manganese and zinc, total oxidant and antioxidant statuses, and also systolic and diastolic blood pressures. This treatment also significantly improved heart function including recoveries in end-diastolic volume, left ventricular end-systolic volume, heart rate, cardiac output, and prolonged P-wave duration. Furthermore, the MAHOC administrations improved the structure of left ventricles such as recoveries in loss of myofibrils, degenerative nuclear changes, fragmentation of cardiomyocytes, and interstitial edema. Biochemical analysis in the heart tissues provided the important cardioprotective effect of MAHOC on the redox regulation of the heart, such as improvements in activities of glutathione peroxidase and glutathione reductase, and oxygen radical-absorbing capacity of the heart together with recoveries in other systemic parameters of animals, while all of these benefits were observed in the Pre-MAHOC treatment group, more prominently. Overall, one can point out the beneficial antioxidant effects of MAHOC in chronic heart diseases as a supporting and complementing agent to the conventional therapies.

Markers of Atrial Myopathy in the General Population: Prevalence, Predictors, and Inter-Relations

BACKGROUND

Atrial myopathy refers to structural and functional cardiac abnormalities associated with atrial fibrillation and stroke, but appropriate diagnostic criteria are lacking.

OBJECTIVES

This study aimed to assess prevalence, clinical correlates, and overlap between potential atrial myopathy markers.

METHODS

The population-based SCAPIS (Swedish CArdioPulmonary bioImage Study) prospectively included 6,013 subjects without atrial fibrillation with 24-hour electrocardiograms. Resting electrocardiograms measuring P-wave indices were collected at 1 screening site (n = 1,201), and a random sample (n = 385) had echocardiographic left atrial volume index (LAVi). Atrial myopathy markers were defined as ≥500 premature atrial complexes/24 h, LAVi ≥34 mL/m2, P-wave duration >120 milliseconds, or P-wave terminal force in V1 >4,000 ms·s. Clinical correlates included age, sex, body mass index, height, smoking, physical activity, coronary artery disease, diabetes, systolic blood pressure, antihypertensive medication, and low education.

RESULTS

Atrial myopathy was common; 42% of the sample with all diagnostic modalities available had ≥1 atrial myopathy marker, but only 9% had 2 and 0.3% had ≥3. Only P-wave duration and LAVi were correlated (ρ = 0.10; P = 0.04). Clinical correlates of premature atrial complexes, P-wave indices, and LAVi differed; current smoking (34% increase; P < 0.001), systolic blood pressure (4%/mm Hg increase; P = 0.01), diabetes (35% increase; P = 0.001), and coronary artery disease (71% increase; P = 0.003) were associated with premature atrial complexes, physical activity ≥2 h/wk was associated with increased LAVi (β-coefficient = 3.1; P < 0.0001) and body mass index was associated with P-wave duration (β-coefficient = 0.4/kg/m2; P < 0.0001).

CONCLUSIONS

In the general population, indirect markers of atrial myopathy are common but only weakly correlated, and their risk factor patterns are different. More studies are needed to accurately identify individuals with atrial myopathy with diagnostic methods.

Assessment of the efficacy of the electrocardiographic P-wave peak time in predicting atrial high rate episode in patients with cardiac implantable electronic devices

INTRODUCTION & OBJECTIVE

The incidence of atrial high-rate episode (AHRE) is high among patients with cardiac implantable electronic devices (CIEDs). In this context, the objective of this study is to evaluate the efficacies of P-wave indices (PWIs) obtained from the surface electrocardiography (ECG) in predicting future AHRE development.

MATERIAL & METHOD

The study sample consisted of 158 patients with CIEDs. The study group was divided into two subgroups according to the presence of AHRE during device interrogation. PWIs were calculated using the surface ECG.

RESULTS

There was no significant difference between the groups in the P-wave indices (PWIs), i.e., minimum P-wave duration (PWDmin), maximum P-wave duration (PWDmax) and P-wave dispersion (PWDIS). On the other hand, P-wave peak time in V1 lead (PWTV1) and P-wave peak time in D2 lead (PWPTD2) were significantly higher in the AHRE group than in the non-AHRE group.

CONCLUSION

The study findings revealed that novel ECG parameters PWPTV1 and PWPTD2 had high prognostic value in predicting patients likely to develop AHRE.

A randomized clinical trial of omega-3 fatty acid and vitamin D supplementation on electrocardiographic risk profiles

Beneficial and adverse associations with arrhythmias have been reported for omega-3 fatty acids (omega-3 FA) and Vitamin D. The 12 lead electrocardiogram (ECG) contains quantitative measures reflecting diverse aspects of electrophysiology that might provide insights into mechanisms underlying these associations. In a pre-specified ancillary study of the VITaminD and omegA-3 (VITAL) trial, we examined the effect of 1 g of marine omega-3 FA per day, comprised of 460 mg eicosapentanoic acid and 380 mg of docosahexaenoic acid, and 2000 IU VitaminD3 per day on ECG characteristics associated with atrial and ventricular arrhythmias among individuals age 50 years or greater. A total of 911 study participants underwent ECGs at baseline and again at 2 years after the randomization. Individuals randomized to active omega-3 FA demonstrated significant net increase in PR-interval duration (p = 0.005) and P-wave duration (p = 0.03) as well significant net decrease in P-wave amplitude (p = 0.037) as compared to placebo. RMSSD increased to a greater extent in the omega-3 FA arm compared to placebo (p = 0.040). For Vitamin D3, the Cornell voltage increased to a lesser extent in the participants assigned to active treatment as compared to placebo (p = 0.044). There were no other significant differences in QRS, QTc, Cornell voltage or heart rate. Thus, randomized treatment with omega-3 FA supplements resulted in changes on the ECG that are potentially reflective of heightened vagal tone and/or slowing of intraatrial and AV conduction. Vitamin D3 supplementation resulted in modest reductions in progressive LV voltage suggestive of a potential antihypertrophic effect.Trial registration ClinicalTrials.gov Identifiers: NCT01169259, NCT02178410 (06/26/2010 and 06/30/2014).

Inflammatory bowel disease and atrial fibrillation: a contemporary overview

Atrial fibrillation is the most common arrhythmia in clinical practice and it is associated with increased morbidity and mortality. Atrial fibrillation is linked with inflammatory signaling while inflammation and oxidative stress promote atrial remodeling promoting the development and perpetuation of the arrhythmia. On the other hand, inflammatory bowel disease (IBD) is considered a chronic inflammatory condition with flares and remissions. IBD has been associated with an increased risk of atherosclerotic cardiovascular disease but its relationship with atrial fibrillation has not been studied well. Recent epidemiological evidence indicates an association between IBD and atrial fibrillation, especially during flares/hospitalizations. This brief review provides a concise overview of all available data regarding the association between IBD and atrial fibrillation including the predictive role of electrocardiographic and echocardiographic markers. Several unresolved issues including the thromboembolic risk in this setting and the potential role of antiinflammatory interventions are also discussed.

Electrocardiographic markers of atrial cardiomyopathy and risk of heart failure in the multi-ethnic study of atherosclerosis (MESA) cohort

Background

The association of electrocardiographic (ECG) markers of atrial cardiomyopathy with heart failure (HF) and its subtypes is unclear.

Methods

This analysis included 6,754 participants free of clinical cardiovascular disease (CVD), including atrial fibrillation (AF), from the Multi-Ethnic Study of Atherosclerosis. Five ECG markers of atrial cardiomyopathy (P-wave terminal force in V1 [PTFV1], deep-terminal negativity in V1 [DTNV1], P-wave duration [PWD], P-wave axis [PWA], advanced intra-atrial block [aIAB]) were derived from digitally recorded electrocardiograms. Incident HF events through 2018 were centrally adjudicated. An ejection fraction (EF) of 50% at the time of HF was used to classify HF as HF with reduced EF (HFrEF), HF with preserved EF (HFpEF), or unclassified HF. Cox proportional hazard models were used to examine the associations of markers of atrial cardiomyopathy with HF. The Lunn-McNeil method was used to compare the associations in HFrEF vs. HFpEF.

Results

413 HF events occurred over a median follow-up of 16 years. In adjusted models, abnormal PTFV1 (HR (95%CI): 1.56(1.15-2.13), abnormal PWA (HR (95%CI):1.60(1.16-2.22), aIAB (HR (95%CI):2.62(1.47-4.69), DTNPV1 (HR (95%CI): 2.99(1.63-7.33), and abnormal PWD (HR (95%CI): 1.33(1.02-1.73), were associated with increased HF risk. These associations persisted after further adjustments for intercurrent AF events. No significant differences in the strength of association of each ECG predictor with HFrEF and HFpEF were noted.

Conclusions

Atrial cardiomyopathy defined by ECG markers is associated with HF, with no differences in the strength of association between HFrEF and HFpEF. Markers of atrial Cardiomyopathy may help identify individuals at risk of developing HF.

P-wave durations from automated electrocardiogram analysis to predict atrial fibrillation and mortality in heart failure

BACKGROUND

P-wave indices have been used to predict incident atrial fibrillation (AF), stroke, and mortality. However, such indices derived from automated ECG measurements have not been explored for their predictive values in heart failure (HF). We investigated whether automated P-wave indices can predict adverse outcomes in HF.

METHODS

This study included consecutive Chinese patients admitted to a single tertiary centre, presenting with HF but without prior AF, and with at least one baseline ECG, between 1 January 2010 and 31 December 2016, with last follow-up of 31 December 2019.

RESULTS

A total of 2718 patients were included [median age: 77.4, interquartile range (IQR): (66.9-84.3) years; 47.9 males]. After a median follow-up of 4.8 years (IQR: 1.9-9.0 years), 1150 patients developed AF (8.8/year), 339 developed stroke (2.6/year), 563 developed cardiovascular mortality (4.3/year), and 1972 had all-cause mortality (15.1/year). Compared with 101-120 ms as a reference, maximum P-wave durations predicted new-onset AF at ≤90 ms [HR: 1.17(1.11, 1.50), P < 0.01], 131-140 ms [HR: 1.29(1.09, 1.54), P < 0.001], and ≥141 ms [HR: 1.52(1.32, 1.75), P < 0.001]. Similarly, they predicted cardiovascular mortality at ≤90 ms [HR: 1.50(1.08, 2.06), P < 0.001] or ≥141 ms [HR: 1.18(1.15, 1.45), P < 0.001], and all-cause mortality at ≤90 ms [HR: 1.26(1.04, 1.51), P < 0.001], 131-140 ms [HR: 1.15(1.01, 1.32), P < 0.01], and ≥141 ms [HR: 1.31(1.18, 1.46), P < 0.001]. These remained significant after adjusting for significant demographics, past co-morbidities, P-wave dispersion, and maximum P-wave amplitude.

CONCLUSIONS

Extreme values of maximum P-wave durations (≤90 ms and ≥141 ms) were significant predictors of new-onset AF, cardiovascular mortality, and all-cause mortality.

Early atrial remodeling predicts the risk of cardiovascular events in patients with metabolic syndrome: a retrospective cohort study

Background

This study aims to assess the prevalence of atrial cardiomyopathy (ACM) in patients with new-onset metabolic syndrome (MetS) and investigate whether ACM could be a predictor of hospital admission for cardiovascular (CV) events.

Methods

Patients with MetS who were free of clinically proven atrial fibrillation and other CV diseases (CVDs) at baseline were included in the present study. The prevalence of ACM was compared between MetS patients with and without left ventricular hypertrophy (LVH). The time to first hospital admission for a CV event between subgroups was assessed using the Cox proportional hazard model.

Results

A total of 15,528 MetS patients were included in the final analysis. Overall, LVH patients accounted for 25.6% of all newly diagnosed MetS patients. ACM occurred in 52.9% of the cohort and involved 74.8% of LVH patients. Interestingly, a significant percentage of ACM patients (45.4%) experienced MetS without LVH. After 33.2 ± 20.6 months of follow-up, 7,468 (48.1%) patients had a history of readmission due to CV events. Multivariable Cox regression analysis revealed that ACM was associated with an increased risk of admission for CVDs in the MetS patients with LVH [hazard ratio (HR), 1.29; 95% confidence interval (CI), 1.142-1.458; P < 0.001]. Likewise, ACM was found to be independently associated with hospital readmission due to CVD-related events in MetS patients without LVH (HR, 1.175; 95% CI, 1.105-1.250; P < 0.001).

Conclusion

ACM is a marker of early myocardial remodeling and predicts hospitalization for CV events in patients with MetS.

Analysis of the amplified p-wave enables identification of patients with atrial fibrillation during sinus rhythm

Aim

This study sought to develop and validate diagnostic models to identify individuals with atrial fibrillation (AF) using amplified sinus-p-wave analysis.

Methods

A total of 1,492 patients (491 healthy controls, 499 with paroxysmal AF and 502 with persistent AF) underwent digital 12-lead-ECG recording during sinus rhythm. The patient cohort was divided into training and validation set in a 3:2 ratio. P-wave indices (PWI) including duration of standard p-wave (standard PWD; scale at 10 mm/mV, sweep speed at 25 mm/s) and amplified sinus-p-wave (APWD, scale at 60-120 mm/mV, sweep speed at 100 mm/s) and advanced inter-atrial block (aIAB) along with other clinical parameters were used to develop diagnostic models using logistic regression. Each model was developed from the training set and further tested in both training and validation sets for its diagnostic performance in identifying individuals with AF.

Results

Compared to standard PWD (Reference model), which achieved an AUC of 0.637 and 0.632, for training and validation set, respectively, APWD (Basic model) importantly improved the accuracy to identify individuals with AF (AUC = 0.86 and 0.866). The PWI-based model combining APWD, aIAB and body surface area (BSA) further improved the diagnostic performance for AF (AUC = 0.892 and 0.885). The integrated model, which further combined left atrial diameter (LAD) with parameters of the PWI-based model, achieved optimal diagnostic performance (AUC = 0.916 and 0.902).

Conclusion

Analysis of amplified p-wave during sinus rhythm allows identification of individuals with atrial fibrillation.

Obesity as a risk factor for cardiac arrhythmias

Obesity is global health problem with an estimated three billion people worldwide being classified as overweight or obese. In addition to being associated with a range of adverse health outcomes, obesity is linked to higher risks of atrial and ventricular arrhythmias, as well as sudden cardiac death. Obesity is a multifactorial disease that often co-exists with hypertension, diabetes, and sleep apnoea, which are also independent risk factors for cardiac arrhythmias. Nevertheless, compelling evidence suggests that increasing adiposity is an independent proarrhythmic risk factor and that weight loss can be a mitigating and preventative intervention to reduce arrhythmia incidence. This review briefly outlines the economic and social burden of obesity and summarises evidence for the direct and indirect effects of increasing adiposity on risk of atrial and ventricular arrhythmias. The paper also summarises the evidence for electrocardiographic changes indicative of obesity-related atrial and ventricular remodelling and how weight reduction and management of comorbidity might reduce arrhythmic burden.

Development and Validation of an Algorithm for the Digitization of ECG Paper Images

The electrocardiogram (ECG) signal describes the heart's electrical activity, allowing it to detect several health conditions, including cardiac system abnormalities and dysfunctions. Nowadays, most patient medical records are still paper-based, especially those made in past decades. The importance of collecting digitized ECGs is twofold: firstly, all medical applications can be easily implemented with an engineering approach if the ECGs are treated as signals; secondly, paper ECGs can deteriorate over time, therefore a correct evaluation of the patient's clinical evolution is not always guaranteed. The goal of this paper is the realization of an automatic conversion algorithm from paper-based ECGs (images) to digital ECG signals. The algorithm involves a digitization process tested on an image set of 16 subjects, also with pathologies. The quantitative analysis of the digitization method is carried out by evaluating the repeatability and reproducibility of the algorithm. The digitization accuracy is evaluated both on the entire signal and on six ECG time parameters (R-R peak distance, QRS complex duration, QT interval, PQ interval, P-wave duration, and heart rate). Results demonstrate the algorithm efficiency has an average Pearson correlation coefficient of 0.94 and measurement errors of the ECG time parameters are always less than 1 mm. Due to the promising experimental results, the algorithm could be embedded into a graphical interface, becoming a measurement and collection tool for cardiologists.

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.

Atrial cardiopathy and cognitive impairment

Cognitive impairment involves complex interactions between multiple pathways and mechanisms, one of which being cardiac disorders. Atrial cardiopathy (AC) is a structural and functional disorder of the left atrium that may be a substrate for other cardiac disorders such as atrial fibrillation (AF) and heart failure (HF). The association between AF and HF and cognitive decline is clear; however, the relationship between AC and cognition requires further investigation. Studies have shown that several markers of AC, such as increased brain natriuretic peptide and left atrial enlargement, are associated with an increased risk for cognitive impairment. The pathophysiology of cognitive decline in patients with AC is not yet well understood. Advancing our understanding of the relationship between AC and cognition may point to important treatable targets and inform future therapeutic advancements. This review presents our current understanding of the diagnosis of AC, as well as clinical characteristics and potential pathways involved in the association between AC and cognitive impairment.

Secondhand smoke exposure is associated with abnormal P-wave axis

OBJECTIVES

Secondhand smoke exposure (SHSE) is associated with increased risk of cerebrovascular accident (CVA). Abnormal P-wave axis (aPWA) is a marker for atriopathy that is also associated with CVA risk. We hypothesized that SHSE is associated with aPWA.

METHODS

This analysis included 5986 non-smokers (age 61.7 ± 13.8 years, 45.8% men, 77.4% Whites) from the Third National Health and Nutrition Examination Survey. SHSE was defined as serum cotinine ≥1 ng/ml aPWA was defined as any P-wave axis outside of 0-75°. Multivariable logistic regression was used to examine the association between SHSE and aPWA, overall and among subgroups stratified by demographics and comorbidities.

RESULTS

About 18.5% (n = 1109) of the participants had SHSE. aPWA was more prevalent among those with SHSE than those without (23.9% versus 19.8%, respectively, P-value = 0.003). In a model adjusted for sociodemographic and potential confounders, presence (versus absence) of SHSE was associated with increased odds of aPWA (odds ratio [95% confidence interval]: 1.28 [1.09, 1.50]; P-value = 0.003). This association was stronger among Whites vs non-Whites (interaction P-value = 0.04) and non-obese versus obese (interaction P-value = 0.04). Higher levels of serum cotinine were associated with increased odds of aPWA. Compared with serum cotinine level <1 ng/ml, serum cotinine ≥3 ng/ml and ≥6 ng/ml were associated with 35% (P-value = 0.002) and 38% (P-value = 0.002) increased odds of aPWA, respectively.

CONCLUSIONS

SHSE is associated with abnormal atrial conduction, measured as aPWA, with possible effect modification by ethnicity and obesity. These findings underscore the harmful effects of SHSE on cardiovascular health which merits a personalized risk assessment when counseling patients on SHSE.

Enhancing electrocardiographic analysis by combining a high-resolution 12-lead ECG with novel software tools

INTRODUCTION

Signal-averaged electrocardiography is a non-invasive, computerized technique that amplifies, filters, and averages cardiac electrical signals reducing contaminating noise to obtain a high-resolution record. The most widely used signal averaging (SA) method involves a bipolar X, Y, and Z orthogonal lead system. Information is limited regarding its application in the standard resting 12-lead ECG. A novel system combining a high-resolution 12-lead ECG (HR-ECG) registered by SA with advanced analysis tools is presented.

HISTORY

Original programming of a commercially available signal-averaged HR-ECG device was modified, introducing more exhaustive electrocardiographic assessment instruments.

DESCRIPTION

Using SA techniques and placing surface electrodes in the standard 12-lead ECG positions, a HR-ECG is acquired within a bandwidth of 0.25 to 262 Hz at a rate of 1000 samples per second. It is advisable to average at least 200 cycles, taking three to five minutes to record. The package includes different optional high-frequency filters, manual calipers, zoom/superimposing/amplification functions.

CLINICAL ROLE

The main strength lies in obtaining a low noise HR-ECG with zooming capabilities without definition loss. Other potential advantages are the greater ease in performing high precision analysis and comparing different ECG leads simultaneously.

CURRENT PROBLEMS

The primary limitation is the inability to document intermittent or dynamic electrocardiographic disorders because of averaging similar electrical cardiac cycles.

FUTURE DEVELOPMENTS

Adding artificial intelligence and further refinements in the averaging process could lead to software upgrades.

CONCLUSION

Integrating HR-ECG, obtained through SA techniques, with novel advanced analysis tools can enhance the ability to detect electrocardiographic disorders of permanent expression expeditiously.

The Effect of Medication on P-wave Beat-to-Beat Variability in Atrial Fibrillation during Sinus Rhythm

Atrial Fibrillation (AF) is the most common cardiac arrhythmia, and its progressive nature is associated with gradual atrial remodeling. The P-wave in the surface Electrocardiogram (ECG) reflects the atrial activation, while the modification of the atrial pathophysiological properties leads to P-wave morphology (PWM) alternations. In paroxysmal AF (pAF), the modifications of the PWM may have a spontaneous rather than permanent presence in the ECG signal. The analysis of the P-waves, during sinus rhythm, on a beat-to-beat basis, has revealed the existence of at least two PWM. In addition, the wavelet characteristics of the P-wave matching the main morphology can accurately distinguish the patients with pAF from healthy volunteers. In this work, we examine the hypothesis that there is an effect of the anti-arrhythmic medication on beat-to-beat PWM alternations of pAF patients. ECG signals of high frequency (1000Hz), in the three orthogonal leads, were collected for 81 pAF patients of minimal and mild AF burden, 47 of which receiving antiarrhythmic medication treatment, and from 56 healthy volunteers. Kruskal-Wallis test was performed, and the preliminary results denote the existence of statistically significant differences between the groups. A 3-class Random Forest classifier was trained, using the forward wrapper approach, resulting in a high overall classification performance (AUC = 85.75%). This analysis is a step towards improving understanding of medication effect on the variability of P-wave.Clinical Relevance- The methodology presented in this paper can be used to perform a non-invasive characterization of low burden pAF patients using the ECG recording.

Abnormal P-wave terminal force in lead V1 is associated with low left atrial appendage ejection velocity

BACKGROUND

Sinus P-wave abnormalities have been associated stroke in people with atrial fibrillation (AF). The majority of AF-related strokes occur from left atrial appendage (LAA) thromboembolism. Dysfunction of the left atrium (LA) and left atrial appendage (LAA) can increase rates of thromboembolic stroke. We studied whether abnormal P wave terminal force in V1 (aPTFV1) is associated with decreased LAA ejection velocity (LAAV) on transesophageal echocardiography (TEE).

METHODS

We conducted a retrospective cross-sectional study reviewing patients at a tertiary care medical center who underwent TEE in sinus rhythm and had an interpretable sinus ECG within 12 months of TEE. Participants were excluded for complex congenital heart disease, age <18, cardiac transplantation, and chronic atrial pacing. Logistic regression analysis was used to estimate the odds ratios of LAAV<40 cm/s for aPTFV1.

RESULTS

In our final cohort of 169 patients (28% of which had LAAV <40), the multivariate odds ratio of aPTFV1 for LAAV<40 cm/s after adjustment for CHA₂DS₂VASc variables, heart rate during TEE, history of atrial arrhythmias, and left atrial volume index was 2.24 (95% CI of 1.13-6.00).

CONCLUSION

Abnromal P-wave terminal force in lead V1 is associated with low LAAV after adjustment for potential confounders. Future research is needed for validation of our findings and determination of clinical utility.

Impaired Left Atrial Performance Resulting From Age-Related Arial Fibrillation Is Associated With Increased Fibrosis Burden: Insights From a Clinical Study Combining With an in vivo Experiment

Background: Atrial fibrillation (AF) is increasingly considered an age-related degenerative disease, whose process is associated with the development of impaired left atrial (LA) performance. However, the subtle dynamic changes of LA performance in AF during aging have yet to be fully elucidated. Atrial fibrosis is a key substrate for the development of AF, but the progression of fibrosis during aging and its relationship with LA dysfunction need to be further explored. Methods: A total of 132 control individuals and 117 persistent AF patients were prospectively studied. Subjects were further stratified into three age groups (age group 1: younger than 65 years, age group 2: between 65 and 79 years old, and age group 3: older than 80 years). The two-dimensional speckle tracking imaging was carried out for analyzing the alterations in LA function underlying LA remodeling, whereas electroanatomic mapping was performed to investigate LA fibrosis burden. In animal study, aged mice and young mice served as research subjects. Echocardiography and histological staining were used to assess LA performance and fibrosis burden, respectively. Results: Echocardiography showed progressive increases in LA dimension and LA stiffness index, and progressive decreases in LA global longitudinal strain and LA strain rates with advancing age in both AF and control cohorts, which was more prominent in AF cohort. Electroanatomic mapping showed progressive decrease in mean LA voltage and progressive increases in LA surface area, low-voltage area %, and LA volume with advancing age, whereas more significant alterations were observed in AF patients. Moreover, left atrial global longitudinal strain was positively correlated with mean LA voltage, whereas LA stiffness index was negatively related to mean LA voltage. In animal experiment, increased LA size and pulmonary artery dimension as well as longer P-wave duration and more prominent LA fibrosis were found in aged mice. Conclusions: This study provides new evidence of subtle changes in structure and performance of left atrium and their association with atrial fibrosis in both AF and non-AF subjects during physiological aging. In addition, our study also provides normal values for LA structure and performance in both AF and non-AF conditions during aging. These measurements may provide an early marker for onset of AF and LA adverse remodeling.

New Parameter of the Second Half of the P-Wave, P-Wave Duration, and Atrial Conduction Times Predict Atrial Fibrillation during Electrophysiological Studies

OBJECTIVE

Several P-wave parameters reflect atrial conduction characteristics and have been used to predict atrial fibrillation (AF). The aim of this study was to determine the relationship between maximum P-wave duration (PMax) and new P-wave parameters, with atrial conduction times (CT), and to assess their predictive value of AF during electrophysiological studies (AF-EPS).

SUBJECTS AND METHODS

This was a cross-sectional study in 153 randomly selected patients aged 18-70 years, undergoing EPS. The patients were divided into 2 groups designated as no AF-EPS and AF-EPS, depending on whether AF occurred during EPS or not. Different P-wave parameters and atrial CT were compared for both study groups. Subsequently, the predictive value of the P-wave parameters and the atrial CT for AF-EPS was evaluated.

RESULTS

The values of CT, PMax, and maximum Ppeak-Pend interval (Pp-eMax) were significantly higher in patients with AF-EPS. Almost all P-wave parameters were correlated with the left CT. PMax, Pp-eMax, and CT were univariate and multivariate predictors of AF-EPS. The largest ROC area was presented by interatrial CT (0.852; p < 0.001; cutoff value: ≥82.5 ms; sensitivity: 91.1%; specificity: 81.1%). Pp-eMax showed greater sensitivity (79.5%) to discriminate AF-EPS than PMax (72.7%), but the latter had better specificity (60.4% vs. 41.5%).

CONCLUSIONS

Left atrial CT were directly and significantly correlated with PMax and almost all the parameters of the second half of the P-wave. CT, PMax, and Pp-eMax (new parameter) were good predictors of AF-EPS, although CT did more robustly.

The relationship between heart disease and cognitive impairment

Neurodegenerative dementias, such as Alzheimer's disease, and vascular cognitive impairment were once considered unrelated processes. Emerging evidence, however, shows that both conditions often coexist and that vascular risk factors in midlife predispose to the development of cognitive decline later in older adults. In addition, recent advanced in basic science research have elucidated key underpinnings of this association. In this chapter, we review the clinical and basic science data that explain the relationship between vascular risk factors, heart disease, and cognitive decline.

Atrial conduction explains the occurrence of the P-wave dispersion phenomenon, but weakly

BACKGROUND

P-wave dispersion (PWD) is believed to be caused by inhomogeneous atrial conduction. This statement, however, is based on limited little solid evidence. The aim of this study was to determine the relationship between atrial conduction and PWD by means of invasive electrophysiological studies.

METHODS

Cross-sectional study in 153 patients with accessory pathways and atrioventricular node reentry tachycardia (AVNRT) undergoing an electrophysiological study. Different atrial conduction times were measured and correlated with PWD.

RESULTS

Only the interatrial (P-DCS) and left intra-atrial conduction times (ΔDCS-PCS) showed a significant correlation with PWD, but this correlation was weak. Multivariate linear regression analysis determined that both P-DCS (β = 0.242; P = .008) and ΔDCS-PCS (β = 0.295; P < .001) are independent predictors of PWD. Performing the multivariate analysis for arrhythmic substrates, it is observed that only ΔDCS-PCS continued to be an independent predictor of PWD. Analysis of the receiver operating characteristic curves showed that regardless of the types of arrhythmic substrates, PWD discriminates significantly, but moderately, to patients with P-DCS and ΔDCS-PCS ≥75 percentile.

CONCLUSIONS

Interatrial and intraleft atrial conduction times were directly and significantly correlated with PWD, but only weakly, and were independent predictors of PWD. In general, PWD correctly discriminates patients with high values in interatrial and intraleft atrial conduction times, but moderately. This is maintained in cases with accessory pathways; however, in patients with AVNRT it only does so for intraleft atrial conduction times. Interatrial and intraleft atrial conduction times weakly explains PWD.

The effect of P wave indices on new onset atrial fibrillation after trans-catheter aortic valve replacement

OBJECTIVES

Data is scarce regarding the relation between P wave indices and new onset atrial fibrillation (NOAF) after trans-catheter aortic valve replacement (TAVR).

AIMS

The present study aimed to find out certain characteristics of P wave that may predict NOAF after TAVR procedure.

METHOD

Patients with severe calcific aortic stenosis who had undergone TAVR procedure between 2013 and 2019 in two centers were investigated. P wave abnormalities that have been resumed to reflect impaired atrial conduction; partial and advanced inter atrial block (IAB), P-wave terminal force in lead V1, P wave dispersion, reduced amplitude of P- wave in lead I, P wave peak time in D2 and V1 were evaluated on pre- procedural 12 derivation surface electrocardiography (ECG). The relationship between these parameters and incidence of NOAF during index hospitalization was evaluated.

RESULTS

A total of 227 consecutive patients (median age 79 [74-83]; 134 [59%] female) were included in the study. NOAF occurred in 46 (20.3%) patients. P wave duration, P wave dispersion, number of patients with partial and advanced IAB, left atrium diameter, STS score were higher in NOAF patients. Use of general anesthesia and history of prior open heart surgery were also more frequent in NOAF group. In multivariable logistic regression analysis; advanced IAB (OR 6.413 [2.555-16.095] p < 0.01), P wave dispersion (OR 3.544 [1.431-8.780] p = 0.006) and use of general anesthesia (OR 2.736 [1.225-6.109] p = 0.014) were independent predictors of NOAF.

CONCLUSION

Among P wave abnormalities evaluated on pre-procedural 12-derivation surface ECG, advanced IAB and P wave dispersion may predict NOAF after TAVR procedure.

Interatrial block and its association with an increased risk of ischemic stroke: A systematic review and meta-analysis

INTRODUCTION

Several studies have suggested the association between interatrial block (IAB) and ischemic stroke. As no prior collective study has been discerned in this issue, we hence conducted systemic review and meta-analysis to assess the relationship between IAB and ischemic stroke.

METHODS

We comprehensively searched the databases of MEDLINE, EMBASE, PUBMED, and the Cochrane from inception to January 2020. Included studies were published observational studies that compared the risk of ischemic stroke among patients with and without IAB. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate risk ratios and 95% confidence intervals (CIs). Subgroup analyses and meta-regression were performed to explore heterogeneity.

RESULTS

Ten studies were included in this analysis, involving total 177,249 participants. Our study demonstrated no association between partial IAB and an increased risk of ischemic stroke with OR 1.19 (95% CI 0.99-1.43 p = 0.054),but a statistical correlation with an increased risk of stroke with OR 1.85 (95% CI 1.37-2.50, p < 0.001) in advanced IAB. Interestingly, our subgroup analysis of patients with prior stroke suggested higher risk of recurrent stroke in both advanced IAB (OR 4.73) and partial IAB (OR 1.65). Meta-regression suggested a history of stroke as an effect modifier in the interplay between IAB and risk of recurrent stroke.

CONCLUSION

Only advanced IAB is associated with an increased risk of stroke. However, further studies are warranted to further support this finding to confirm its clinical feasibility in stroke risk stratification.

Association of Abnormal P-Wave Indices With Dementia and Cognitive Decline Over 25 Years: ARIC-NCS (The Atherosclerosis Risk in Communities Neurocognitive Study)

Background Abnormal P-wave indices (PWIs)-reflecting underlying left atrial abnormality-are associated with increased risk of stroke independent of atrial fibrillation. We assessed whether abnormal PWIs are associated with incident dementia and greater cognitive decline, independent of atrial fibrillation and ischemic stroke. Methods and Results We included 13 714 participants (mean age, 57±6 years; 56% women; 23% black) who were followed for dementia through the end of 2015. (Abnormal P-wave terminal force in lead V1, ≥4000 μV×ms), abnormal P-wave axis (>75° or <0°), prolonged P-wave duration (>120 ms), and advanced interatrial block were determined from ECGs at visits 2 to 4. Dementia was adjudicated by an expert panel using data from cognitive tests and hospitalization International Classification of Diseases codes. Cognitive function was measured longitudinally using 3 neuropsychological tests. Cox proportional hazards models were used to assess the association between time-dependent abnormal PWIs with incident dementia. Linear regression models were used to evaluate PWIs with cognitive function over time. At the conclusion of the study, 19%, 16%, 28%, and 1.9% of participants had abnormal P-wave terminal force in lead V1, abnormal P-wave axis, prolonged P-wave duration, and advanced interatrial block, respectively. During mean follow-up of 18 years, there were 1390 (10%) dementia cases. All abnormal PWIs except advanced interatrial block were associated with an increased risk of dementia even after adjustment for incident atrial fibrillation and stroke: multivariable hazard ratio of abnormal P wave terminal force in lead V1=1.60, 95% CI, 1.41 to 2.83; abnormal P-wave axis, hazard ratio =1.36, 95% CI, 1.17 to 2.57; prolonged P-wave duration, hazard ratio=1.60, 95% CI, 1.42 to 1.80. Only abnormal P-wave terminal force in lead V1 was associated with greater decline in global cognition. Conclusions Abnormal PWIs are independently associated with an increased risk of dementia. This novel finding should be replicated in other cohorts and the underlying mechanisms should be evaluated.