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Objective: To evaluate the role of the CT‐derived angle between the intra‐atrial septum (IAS) and the left atrial appendage (LAA) on procedural complexity and clinical outcomes in left atrial appendage occlusion (LAAO) procedures. Background: Given the broad variations in anatomy, LAAO remains one of the most challenging interventional procedures in structural heart disease. In recent years, preprocedural cardiac tomography (CT) has evolved as a valuable tool; however, prediction of procedural complexity remains cumbersome. Methods: We retrospectively analyzed 47 patients that underwent LAAO at our center in whom pre‐procedural cardiac CT‐scans were available. Among other baseline parameters, we measured the angle between the LAA ostium and the preferred transseptal puncture site at the IAS. We compared patients with an angle above and below the median regarding procedural characteristics and procedural outcome. Results: The median angle between the LAA and the IAS was 127.3° (IQR: 120.9–141.3). LAAO took longer in patients with a measured angle below the median (55.0 ± 22.7 min vs. 41.3 ± 17.5 min; p =.04), resulting in longer radiation times (13.0 ± 5.3 min vs. 9.8 ± 5.7 min; p =.04) and more contrast use (61.1 ± 47.5 mL vs. 33.6 ± 24.7 mL; p =.05). Moreover, the necessity for a sheath exchange was significantly higher (30.4% vs. 4.2%, p =.02) and device repositioning or device resizing trended to be more frequent (26.1% vs. 8.3%; p =.1 and 21.7% vs. 8.3%; p =.2). There were no differences in procedural outcome, device‐position and peri‐device leak (PDL). Conclusions: The angle between the transseptal puncture site and the LAA ostium may serve as a predictor for more demanding LAAO interventions. In our study a steeper angle led to a prolonged procedure resulting in higher doses of contrast and radiation, but was not associated with a worse procedural outcome. [ABSTRACT FROM AUTHOR]

Background: Left atrial reservoir strain (LARS) is an early sensor of left ventricular (LV) diastolic dysfunction. Still, the clinical implications of LARS in patients with well‐functioning bicuspid aortic valve (BAV) remain unknown. Materials: The study recruited 103 patients with well‐functioning BAV and 50 controls with tricuspid aortic valves. LARS, LV global longitudinal strain (LVGLS) and aortic elasticity indices (aortic strain, aortic distensibility and stiffness index) were acquired. This study aimed to analyze the changes of LARS and further explore the influential factors of LARS in patients with well‐functioning BAV. Results: Patients with BAV had lower LARS (34.17 ± 4.85 vs. 44.72 ± 6.06 %, P <.001) and LVGLS (20.53 ± 1.28 vs. 22.30 ±.62 %, P <.001), and abnormal aortic elasticity indices (aortic strain:7.14 ± 1.57 vs. 10.99 ± 1.03 %, aortic distensibility: 5.82 ± 1.50 vs. 8.98 ± 2.42 (10−6 cm2 dyne−1), and stiffness index: 6.30 ± 2.30 vs. 3.92 ±.98, all P <.05) compared with controls. LARS was associated with LVGLS (r =.799), interventricular septum index (r = −.232), lateral e' (r =.290), septal e' (r =.308), E/e' ratio (r = −.392), aortic strain (r =.829), aortic distensibility (r =.361), and stiffness index (r = −.724) (all P <.05). LVGLS, aortic strain and E/e' ratio were independent influencers of LARS in the multifactorial analysis model (all P <.05). Conclusion: In patients with well‐functioning BAV, decreased LARS may provide evidence of subclinical LV diastolic function impairment. LARS may be helpful for clinical risk stratification in such a population. [ABSTRACT FROM AUTHOR]

The article describes the case of a 55-year-old man with arrhythmogenic cardiomyopathy with biventricular involvement who was referred for subcutaneous defibrillator (S-ICD) removal and dual chamber implantable cardioverter defibrillator (ICD) implanation. Topics discussed include his left ventricular ejection fraction on echocardiography, his medical therapy, and advantage of antitachycardia pacing (ATP) offered by transvenous ICDs over S-ICDs.

Introduction: Electrophysiological characteristics of epicardial connections (ECs) in atria and pulmonary veins (PVs) are unclear despite their important contributions to atrial fibrillation (AF). Unidirectional conduction associated with source‐sink mismatch can occur in ECs due to their fine fibers with abrupt changes in orientation. We detailed the prevalence and electrophysiological characteristics of unidirectional conduction in the atria and investigated its association with the clinical manifestation of AF. Methods: This study retrospectively reviewed electrophysiological studies and radiofrequency catheter ablation in 261 consecutive patients with AF. Results: Unidirectional conduction was observed during ablation encircling the PVs in eight (3.1%) patients, and all occurred in the suspected (N = 4) or definitively (N = 4) recognized ECs. These ECs included three intercaval bundles, four septopulmonary bundles, and one Marshall bundle, and were first manifested in a second procedure in 6 (75%) patients. The unidirectional property was from PV to atrium (exit conduction) in all intercaval bundles and three septopulmonary bundles, and from atrium to PV (entrance conduction) in the remaining two bundles. Intercaval bundles acted as a limb of bi‐atrial macro‐reentrant tachycardia (50%, three of the six including previous cases). Ablation of the exit outside the PVs, including the right atrium, eliminated ECs in three (38%) patients. All patients remain free from arrhythmia recurrence after a mean 13‐month follow‐up. Conclusion: A unidirectional conduction property was closely associated with the EC, as estimated by histological findings. Recognition of this fact by electrophysiologists may help to clarify mechanisms for AF and atrial tachycardia and guide the creation of efficient and safe ablation lesion sets. [ABSTRACT FROM AUTHOR]

Background: Dual occlusive closure mechanism (disc and lobe type), Amulet device (Abbott; a second‐generation device that has replaced Amplatzer Cardiac Plug) was approved by the Food and Drug Administration (FDA) in August 2021 for percutaneous left atrial appendage occlusion (LAAO). However, real‐world safety data on the delivery system (Amplatzer Cardiac Plug and Amplatzer Amulet device) are lacking. Objective: We sought to assess the type of adverse events associated with the Amplatzer LAAO delivery system using the FDA Manufacturer and User Facility Device Experience (MAUDE) database. Methods: A MAUDE database search was conducted on March 31, 2023, for reports received between February 2013 and March 2023 to capture all adverse events. Results: A total of 59 adverse events were reported, of which 58 were sheath‐related events, and one was a wire‐related event. The most commonly encountered issue was air embolism (19%, 11 events), followed by sheath thrombosis (13.8%, eight events, two of which were also associated with device thrombosis), kinked sheath (10.3%, six events), and sheath deformation (8.6%, five events). Patient‐related adverse events included pericardial effusion requiring pericardiocentesis (22.4%, 13 events), vascular complications (20.7%, 12 events), and device dislodgement (5.2%, three events). Conclusion: LAAO‐related adverse events are increasingly being reported using the Amplatzer LAAO delivery sheath. It is anticipated that improvements in device technology, the advent of steerable sheaths, and operator experience will minimize these complications. [ABSTRACT FROM AUTHOR]

Mapping and ablation of atrial tachycardia (AT) in patients who have had prior cardiac surgery can be a challenge for clinical electrophysiologists. High density mapping (HDM) technology has been widely used in these patients because it provides a better characterization of the substrate and the mechanisms with an unprecedented high resolution. In this review, we summarize how the latest HDM technologies can reveal the mechanism of AT in different types of patients post‐cardiac surgery and guide a specifically tailored ablation strategy. [ABSTRACT FROM AUTHOR]

Background: High‐power‐short‐duration (HPSD) radiofrequency (RF) ablation is a viable alternative to low‐power‐long‐duration (LPLD) RF for pulmonary vein isolation (PVI). Nevertheless, trials showed conflicting results regarding atrial fibrillation (AF) recurrences and few data concerning complications. Therefore, we conducted a meta‐analysis of randomized trials comparing HPSD versus LPLD. Methods: We systematically searched the electronic databases for studies published from inception to March 31, 2023 focusing on HPSD versus LPLD. The study endpoints were AF recurrence, procedural times and overall complications. Results: Five studies enrolling 424 patients met the inclusion criteria (mean age 61.1 years; 54.3% paroxysmal AF; mean LVEF 58.2%). Compared to LPLD, HPSD showed a significantly lower AF recurrence rate [16.3% vs. 30,1%; RR: 0.54 (95% CI: 0.38–0.79); p = 0.001] at a mean 10.9 months follow‐up. Moreover, HPSD led to a significant reduction in total procedural time [MD: −26.25 min (95%CI: −42.89 to −9.61); p = 0.002], PVI time [MD: −26.44 min (95%CI: −38.32 to −14.55); p < 0.0001], RF application time [MD: −8.69 min (95%CI: −11.37 to −6.01); p < 0.00001] and RF lesion number [MD: −7.60 (95%CI: −10.15 to −5.05); p < 0.00001]. No difference was found in either right [80.4% vs. 78.2%; RR: 1.04 (95% CI: 0.81–1.32); p = 0.77] or left [92.3% vs. 90.2%; RR: 1.02 (95% CI: 0.94–1.11); p = 0.58] first‐pass isolation and overall complications [6% vs. 3.7%; RR: 1.45 (95%CI: 0.53–3.99); p = 0.47] between groups. Conclusion: In our metanalysis of randomized trials, HPSD ablation appeared to be associated to a significantly improved freedom from AF and shorter procedures, without increasing the risk of complications. [ABSTRACT FROM AUTHOR]

To provide an overview of the current application of high‐density mapping (HDM) in the mechanism of complex atrial tachycardias (ATs). Complex ATs are frequently scar‐related, after history of previous cardiac surgery and large scars. These scar‐related ATs are difficult to manage medically and frequently recur after electrical cardioversion. HDM technologies have enabled rigorous elucidation of AT mechanisms in patients post cardiac surgery. This article showed the application of HDM technology in complex ATs from the mechanisms of complex ATs, the development of HDM technology, and the identification of scars or critical isthmus from HDM. HDM‐guided approach is highly effective for identifying the ATs mechanism and critical isthmus. [ABSTRACT FROM AUTHOR]

Automatic pacing threshold adjustment algorithms and remote monitoring are widely used to improve the utility of pacemakers and ensure patient safety. However, healthcare providers involved in the management of permanent pacemakers should know the potential pitfalls of these functions. In this report, we present a case of atrial pacing failure induced by the automatic pacing threshold adjustment algorithm that went unnoticed even under remote monitoring. [ABSTRACT FROM AUTHOR]

Aims Atrial functional mitral regurgitation (AFMR) has been associated with atrial fibrillation (AF) and heart failure with preserved ejection fraction. However, data on incident AFMR are scarce. We aimed to study the incidence, risk factors, and clinical significance of AFMR in AF or sinus rhythm (SR). Methods and results Adults with new diagnosis of AF and adults in SR were identified. Patients with >mild MR at baseline, primary mitral disease, cardiomyopathy, left-sided valve disease, previous cardiac surgery, or with no follow-up echocardiogram were excluded. Diastolic dysfunction (DD) was indicated by ≥2/4 abnormal diastolic function parameters [mitral medial e ′, mitral medial E / e ′, tricuspid regurgitation velocity, left atrial volume index (LAVI)]. Overall, 1747 patients with AF and 29 623 in SR were included. Incidence rate of >mild AFMR was 2.6 per 100 person-year in new-onset AF and 0.7 per 100 person-year in SR, P < 0.001. AF remained associated with AFMR in a propensity score-matched analysis based on age, sex, and comorbidities between AF and SR [hazard ratio: 3.80 (95% confidence interval 3.04–4.76)]. Independent risk factors associated with incident AFMR were age ≥65 years, female sex, LAVI, and DD in both AF and SR, in addition to rate (vs. rhythm) control in AF. Incident AFMR was independently associated with all-cause death in both groups (both P < 0.001). Conclusions AF conferred a three-fold increase in the risk of incident AFMR. DD, older age, left atrial size, and female sex were independent risk factors in both SR and AF, while rhythm control was protective. AFMR was universally associated with worse mortality. [ABSTRACT FROM AUTHOR]

Aims We aim to evaluate the clinical relevance and the prognostic value of arterial and venous renal Doppler in acute decompensated precapillary pulmonary hypertension (PH). Methods and results The renal resistance index (RRI) and the Doppler-derived renal venous stasis index (RVSI) were monitored at admission and on Day 3 in a prospective cohort of precapillary PH patients managed in intensive care unit for acute right heart failure (RHF). The primary composite endpoint included death, circulatory assistance, urgent transplantation, or rehospitalization for acute RHF within 90 days following inclusion. Ninety-one patients were enrolled (58% female, age 58 ± 16 years). The primary endpoint event occurred in 32 patients (33%). In univariate logistic regression analysis, variables associated with RRI higher than the median value were non-variable parameters (age and history of hypertension), congestion (right atrial pressure and renal pulse pressure), cardiac function [tricuspid annular plane systolic excursion (TAPSE) and left ventricular outflow tract- velocity time integral], systemic pressures and NT-proBNP. Variables associated with RVSI higher than the median value were congestion (high central venous pressure, right atrial pressure, and renal pulse pressure), right cardiac function (TAPSE), severe tricuspid regurgitation, and systemic pressures. Inotropic support was more frequently required in patients with high RRI (P = 0.01) or high RVSI (P = 0.003) at the time of admission. At Day 3, a RRI value <0.9 was associated with a better prognosis after adjusting to the estimated glomerular filtration rate. Conclusion Renal Doppler provides additional information to assess the severity of patients admitted to the intensive care unit for acute decompensated precapillary PH. [ABSTRACT FROM AUTHOR]

Background. Bachmann's bundle (BB) is the main pathway of interatrial connection that could be involved in the development of atrial fibrillation (AF). Based on this hypothesis, we raised a novel ablation strategy, BB modification in addition to circumferential pulmonary vein isolation (CPVI-BB) in patients with AF. Methods. A retrospective cohort of patients with AF who underwent CPVI-BB or CPVI alone from March 2018 to July 2021 was enrolled in our study. Propensity score matching was performed in patients with paroxysmal AF and persistent AF, respectively, to reduce the risk of selection bias between the treatment strategies (CPVI-BB or CPVI alone). The primary endpoint was overall freedom from atrial arrhythmia recurrence through 12 months of follow-up. Results. Our propensity score-matched cohort included 82 patients with paroxysmal AF (CPVI group: n = 41; CPVI-BB group: n = 41) and 168 patients with persistent AF (CPVI group: n = 84; CPVI-BB group: n = 84). Among patients with persistent AF, one-year freedom from atrial arrhythmia recurrence rate was 83.3% in the CPVI-BB group and 70.2% in the CPVI group (log-rank P = 0.047). Among patients with paroxysmal AF, no significant difference was found in the primary endpoint between two groups (85.4% in the CPVI-BB group vs. 80.5% in the CPVI group; log-rank P = 0.581). In addition, procedure-related complications and recurrence of atrial tachycardia or atrial flutter were similar between the two treatment groups, regardless of the type of AF. Conclusions. BB modification in addition to CPVI is an effective approach in increasing the maintenance of sinus rhythm in patients with persistent AF, while it does not improve the clinical outcomes of radiofrequency catheter ablation in patients with paroxysmal AF. [ABSTRACT FROM AUTHOR]

Hemiplegic migraine (HM) can cause significant functional impairment and negatively affect the quality of life of affected individuals. Emerging evidence suggests an association between migraines and congenital patent foramen ovale (PFO), which is a small opening between the atria of the heart that normally closes shortly after birth. This report describes a 34 years-old woman with sporadic hemiplegic migraine (SHM) who was diagnosed with PFO. Following percutaneous PFO closure, her hemiplegic symptoms disappeared, but her headache exacerbated. After 3 years of follow-up, her headache severity gradually reduced, and the frequency remained consistent at 2-3 times per year with no aura symptoms. This case highlights the dissociation between the resolution of hemiplegic symptoms and the persistence of headaches after PFO closure in sporadic HM. Patients with HM may experience changes in aura symptoms and headache severity after PFO closure. Before performing PFO closure in patients with hemiplegic migraine, the indications should be thoroughly understood. [ABSTRACT FROM AUTHOR]

Background: The increasing global prevalence of atrial fibrillation (AF) has led to a growing demand for stroke prevention strategies, resulting in higher healthcare costs. High-quality economic evaluations of stroke prevention strategies can play a crucial role in maximising efficient allocation of resources. In this systematic review, we assessed the methodological quality of such economic evaluations. Methods: We searched electronic databases of PubMed, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and Econ Lit to identify model-based economic evaluations comparing the left atrial appendage closure procedure (LAAC) and oral anticoagulants published in English since 2000. Data on study characteristics, model-based details, and analyses were collected. The methodological quality was evaluated using the modified Economic Evaluations Bias (ECOBIAS) checklist. For each of the 22 biases listed in this checklist, studies were categorised into one of four groups: low risk, partial risk, high risk due to inadequate reporting, or high risk. To gauge the overall quality of each study, we computed a composite score by assigning + 2, 0, − 1 and − 2 to each risk category, respectively. Results: In our analysis of 12 studies, majority adopted a healthcare provider or payer perspective and employed Markov Models with the number of health states varying from 6 to 16. Cost-effectiveness results varied across studies. LAAC displayed a probability exceeding 50% of being the cost-effective option in six out of nine evaluations compared to warfarin, six out of eight evaluations when compared to dabigatran, in three out of five evaluations against apixaban, and in two out of three studies compared to rivaroxaban. The methodological quality scores for individual studies ranged from 10 to − 12 out of a possible 24. Most high-risk ratings were due to inadequate reporting, which was prevalent across various biases, including those related to data identification, baseline data, treatment effects, and data incorporation. Cost measurement omission bias and inefficient comparator bias were also common. Conclusions: While most studies concluded LAAC to be the cost-effective strategy for stroke prevention in AF, shortcomings in methodological quality raise concerns about reliability and validity of results. Future evaluations, free of these shortcomings, can yield stronger policy evidence. [ABSTRACT FROM AUTHOR]

Isolated congenital anomalous drainage of the inferior vena cava (IVC) and partial hepatic veins (HV) into the left atrium (LA) via an interatrial communication (IAC), associated with the normal connection of the IVC to the right atrium is exceedingly rare. Therefore, there is a dearth of knowledge regarding the management of these cases. To date, there has been no report of abnormal IVC drainage caused by abnormal IVC‐IAC alignment. Much more frequently, patients have an abnormal connection or abnormal drainage mediated by a persistent Eustachian valve that allows blood to pass from the inferior vena cava to the left atrium. Herein, we report an 8‐year‐old boy with anomalous IVC and hepatic vein drainage into the LA due to IVC‐IAC malalignment. We describe the findings of multimodality imaging, including transthoracic, transesophageal, contrast, and speckle‐tracking echocardiography, cardiac angiography, and cardiac magnetic resonance imaging. We go over the diagnostic and therapeutic pitfalls and caveats of this case that can apply to similar patients. [ABSTRACT FROM AUTHOR]

Background: Relaxation, restoring forces, myocardial stiffness and atrial function determine left ventricular (LV) diastolic function. This study aims to provide a comprehensive assessment of diastolic function in preterm infants using conventional echocardiography and speckle tracking imaging and determine the diagnostic accuracy of various algorithms to detect high left atrial pressure (LAP). Methods: Preterm infants received an echocardiogram 1 week after birth and diastolic reference values were derived from the outer percentiles of stable preterm infants. Impaired relaxation, LV stiffness and high LAP were defined by using algorithms where at least half of the parameters were outside the normal range. Diastolic function was graded using the 2016 American Society of Echocardiography algorithm and expanded with the EA ratio and left atrial strain. The diagnostic accuracy of various algorithms to detect high LAP was determined with sensitivity analysis. Results: We studied 146 infants (59 stable) with a mean of 27(1) weeks gestation. Impaired relaxation, LV stiffness and high LAP were found in 8%, 7%, and 14% of infants. The patent ductus arteriosus was a contributing factor to high LAP and LV stiffness, not impaired relaxation. Diagnostic accuracy improved from 90% to 96% and sensitivity from 40% to 90% by adding left atrial strain to the 2016 algorithm. Conclusion: Various grades of diastolic dysfunction could be appreciated in preterm infants using a multi‐parameter approach. Adding left atrial strain improved sensitivity to detect infants with high LAP. [ABSTRACT FROM AUTHOR]

A 3‐year‐old female patient presented with symptoms of cyanosis and intermittent eyelid edema, leading to the discovery of a lobulated mass in the right atrium, obstructing the superior vena cava. Despite the inability to entirely remove the mass due to its origins in the right atrium myocardium and its extension towards the sinoatrial node, successful surgical intervention and subsequent histopathological evaluation identified the mass as a fibroma, and postoperative symptoms were significantly alleviated. [ABSTRACT FROM AUTHOR]

Background: Recurrence rates of atrial fibrillation (AF) remain high even after complete wide area circumferential pulmonary vein isolation (PVI). In recent years adjunct posterior wall isolation (PWI) has been performed in patients with more persistent forms of AF but the benefits remain unclear. Aim: The objective of this meta‐analysis was to evaluate the efficacy of adjunct posterior wall isolation in reducing recurrence rates of AF using cryoballoon ablation (CBA). Methods: We searched PubMed, Google Scholar, Clinicaltrials.gov and Cochrane CENTRAL. We included studies comparing PVI to PVI + PWI in patients with either persistent or paroxysmal AF (PAF) undergoing CBA. After data extraction and quality assessment of the studies, we assessed recurrence rates of atrial tachy‐arrhythmias (AF, atrial flutter, and atrial tachycardia) as well as total ablation time and procedural adverse events. Risk ratio (RR), mean difference (MD), and 95% confidence interval (CI) were calculated using Review Manager. Results: Concomitant PWI exhibited a substantial reduction in the risk of AF recurrence (RR: 0.51; 95% CI: 0.42–0.63, p <.00001), as well as all atrial arrhythmias (RR: 0.58; 95% CI: 0.49–0.68, p <.00001). On subgroup analysis, in patients with only PAF, adjunct PWI resulted in significant reduction in recurrence risk of AF (RR: 0.56; 95% CI: 0.41–0.76, p =.0002) as well. There was no significant difference in adverse events between both groups (RR: 0.90; 95% CI: 0.44–1.86; p =.78), whereas total ablation time was significantly increased in PVI + PWI group (MD: 21.75; 95% CI: 11.13–32.37, p <.0001). Conclusion: Adjunct PWI when compared to PVI alone decreases recurrence rates of atrial fibrillation after CBA of patients with persistent as well as paroxysmal atrial fibrillation. [ABSTRACT FROM AUTHOR]

Catheter ablation (CA) of left atrial tachycardia adjacent to implanted septal closure devices represents a multifaceted challenge. We describe the case of a 57‐year‐old patient with remote percutaneous closure of atrial septal defect who underwent successful CA of left atrial tachycardia adjacent to the septal device using a transaortic approach and RF energy. Besides the technical difficulties and associated risks, interference between the device and applied RF parameters may limit ablation efficiency. Further research is required to evaluate the safety, efficacy, and optimal energy type/parameters when ablating arrhythmias adjacent to these devices. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is the most common arrhythmia encountered, especially in the elderly. AF leads to fivefold risk of stroke. However, there is a no temporal association found when we compare the onset of AF and stroke suggesting that the presence of AF is not mandatory for stroke occurrence. This has led to concept of atrial myopathy suggesting that a diseased atrium can provoke stroke without AF. Atrial interstitial fibrosis, inflammation, and extracellular matrix deposition can initiate and perpetuate atrial myopathy leading to stasis of blood flowing through the atria and may lead to stroke without intervening AF. AF may be just a marker of atrial myopathy. The present paper reviews the emerging concept of atrial myopathy, its pathogenesis, precursors, and diagnosis. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 69-year-old woman with a wide complex tachycardia (WCT) and a suggestion diagnosis of supraventricular tachycardia (SVT). Examinations showed the correct diagnosis of atrial tachycardia (AT) with the site of origin inside the coronary sinus (CS) ostium that was successfully ablated. No changes were noted in atriohis (AH) interval after ablation.

Introduction: Sinus node location, function, and atrial activation are often abnormal in patients with congenital heart disease (CHD), due to anatomical, surgical, and acquired factors. We aimed to perform noninvasive electrocardiographic imaging (ECGI) of the intrinsic atrial pacemaker and atrial activation in patients with surgically repaired or palliated CHD, compared with control patients with structurally normal hearts. Methods and Results: Atrial ECGI was performed in eight CHD patients with prespecified diagnoses (Fontan circulation, dextro transposition of the great arteries post Mustard/Senning, tetralogy of Fallot), and three controls. Activation and propagation maps were constructed in presenting rhythm. Wavefront propagation was analyzed to identify (1) intrinsic atrial pacemaker breakout site, (2) morphological right atrial (RA) activation pattern, (3) morphological left atrial (LA) breakout sites (i.e., interatrial connections), (4) LA activation pattern, and (5) putative lines of block. Physiologically appropriate atrial activation and propagation maps were able to be constructed. In the majority of patients, atrial breakouts were in keeping with the sinus node, observed in a crescent‐shaped distribution from the anterior superior vena cava to the posterior RA. Ectopic atrial pacemaker sites were demonstrated in the atriopulmonary (AP) Fontan patient (very diffuse posterolateral RA) and Mustard patient (very posterior RA competing with a low RA focus). RA propagation was laminar in controls, but suggested either a line of block or conduction slowing consistent with an atriotomy scar in the tetralogy of Fallot (TOF) patients. Putative lines of block were more complex and RA propagation more abnormal in the atrial switch and AP Fontan patients, compared with the TOF patients. RA activation in the extracardiac Fontan patients was relatively laminar. Earliest LA breakout was most commonly observed in the region of Bachmann's Bundle in both controls and CHD patients, except for posterior LA breakouts in two patients. LA activation was typically more homogeneous than RA activation in CHD patients. Conclusion: ECGI can be utilized to create a noninvasive mapping model of atrial activation in postsurgical CHD, demonstrating atrial pacemaker location, putative lines of block and interatrial connections. Once validated invasively, this may have clinical implications in predicting risk of sinus node dysfunction and atrial arrhythmias, or in guiding catheter ablation. [ABSTRACT FROM AUTHOR]

Introduction: To investigate the optimal range of quantitative ablation index (AI) value during superior vena cava (SVC) electrical isolation by radiofrequency catheter ablation (RFCA). Methods: First, in a development cohort of patients with atrial fibrillation (AF), the RFCA with 40 W was performed to complete SVC isolation guided by the conduction breakthrough point from the right atrium to SVC. Then, the range of AI value was calculated by offline analysis on different segments of SVC. Lastly, for the validation of AF patients, the safety and effectiveness of SVC isolation with the optimized target range of AI value were evaluated with an additional adenosine test. Results: A total of 101 patients with AF were included in the study (44 patients in the development cohort/57 in the validation cohort). The segmental ablation strategy was applied in 70% of the patients. According to the offline analysis of the AI values in the development cohort, the target AI value range was set as 350–400. The success rate of SVC isolation in the validation cohort was significantly higher than that in the exploration cohort (100% vs. 90.9%, p =.02), and no complications occurred in the exploration cohort. During the adenosine test, the recovery rate of electrical conduction in SVC was significantly lower than that in the pulmonary vein (3.5% vs. 17.5%). Conclusion: The target AI value with a range from 350 to 400 is safe and effective for high‐power RFCA to complete SVC isolation. [ABSTRACT FROM AUTHOR]

Focused ultrasound can be used to rapidly diagnose COVID‐19 disease, assess disease severity, and inform management of COVID‐19 and associated pathologies, reducing radiation exposure from other imaging modalities and minimizing spread of infection. Ultrasound examinations performed by trained nurses in the intensive care unit (ICU) enable more patients to receive these assessments. This case series evaluates the use of nurse‐led focused cardiac and lung ultrasound for clinical management of ICU patients with COVID‐19. We describe common pathophysiological findings and how findings were used to inform clinical decision‐making. An ultrasound trained ICU nurse performed Focused Ultrasound in Intensive Care (FUSIC) cardiac and lung scans enabling calculation of a lung severity score on adult ICU patients with a confirmed COVID‐19 diagnosis in a single‐centre setting. Fifteen scans were performed on 15 patients. Thirteen (87%) patients had normal left ventricular function; 12 (80%) normal right ventricular function. All 15 (100%) scans identified abnormal lung findings including irregular thickened pleura, B‐lines, sub‐pleural consolidation and hepatization. Worse lung severity scores were correlated with higher Acute Physiology and Chronic Health Evaluation (APACHE II) scores (r = 0.70; p =.003). Of the 15 scans, 10 (67%) identified abnormal pathology contributing to a change in clinical management. This included targeted fluid removal (4, 27%), change in respiratory management (3, 20%) and need for formal echocardiographic assessment (3, 20%). Findings from five (33%) scans required no intervention. This case series demonstrates nurse‐led ultrasound could be a useful adjunct in the management of the COVID‐19 patient. [ABSTRACT FROM AUTHOR]

Suppression of atrial fibrillation (AF) arising within the superior vena cava (SVC) requires SVC electric isolation (SVCI) without sinus node (SN) injury. If an ectopic rhythm and AF trigger coexist within the SVC, the intra‐SVC ectopic rhythm complicates the pre‐SVCI search for the SN. This coexistence is without precedent; however, it is important to carefully locate the SN to prevent injury during SVCI. This case shows a paroxysmal AF with both phenomena coexisting in the SVC. Moreover, outpatient electrocardiographic assessment for tall P‐waves in inferior leads before catheter ablation could predict these phenomena and enable safer SVCI. [ABSTRACT FROM AUTHOR]

Atrial echo beats due to a dual‐atrioventricular nodal pathway are a possible cause of fluctuating tachycardia in cycle length (CL) but have not been reported so far. Here, we present a case of an 82‐year‐old man with symptomatic atrial tachycardia (AT), which was accompanied by periodic fluctuations in atrial sequence at the coronary sinus. Electrophysiological study (EPS) for atrioventricular conduction and three‐dimensional (3D) electro‐anatomical mapping system explained that the mechanism of periodic fluctuations was due to atrial echo beats through a dual‐atrioventricular nodal pathway. [ABSTRACT FROM AUTHOR]

The article discusses the initial experience with a dual-chamber leadless pacemaker system, addressing the limitations of single-chamber leadless systems by offering atrial pacing and atrioventricular synchrony. The study demonstrated successful implantation, reliable atrial pacing and atrioventricular synchrony for three months after implantation, with complication rates similar to conventional lead-based systems.

The article discusses the use of catheter ablation as a treatment for atrial fibrillation (AF) and explores the potential role of artificial intelligence (AI) in improving ablation strategies. Topics include the effectiveness of pulmonary vein isolation for treating paroxysmal and persistent AF, the need for additional left atrial modification in persistent AF cases, and the development of an AI-based model to predict low-voltage areas in the left atrium from a 12-lead ECG before ablation.

A study published in the Journal of General Physiology reveals that Kv1.1 channels, although present at low levels and generating small currents in the sinoatrial node (SAN), have a significant impact on cardiac pacemaking. The SAN is responsible for initiating every heartbeat, and the firing frequency is determined by outward K+ currents that repolarize SAN myocytes. Kv1.1 channels play a role in regulating SAN firing frequency and the intrinsic heart rate. Mutations in the gene encoding Kv1.1 channels have been linked to epilepsy and may contribute to cardiac arrhythmias and sudden unexpected death in epilepsy (SUDEP). Further research is needed to understand the neural and cardiac effects of Kv1.1 channels. [Extracted from the article]

The article describes the case of a 41-year-old-female who underwent double lung transplantation 42 days prior and developed a massive pulmonary embolism requiring vasopressor support with hypotension, fluctuating levels of consciousness and tachypnea.

Cardiac myxoma is the most common primary benign cardiac tumors, mostly found in the left atrium. It was previously reported that the main component of myxoma was myxoid stroma riched in acid‐mucopolysaccharide, the blood vessels in which were sparsely distributed, being characterized as hypovascular tumor by contrast echocardiography (CE) and computed tomography angiography (CTA). There are few reports of myxoma with rich blood supply and we report one in the left atrium. [ABSTRACT FROM AUTHOR]

The article presents a case of a 60-year-old woman with recurrent narrow QRS tachycardia and a structurally normal heart. Through an electrophysiology study, the authors diagnose the patient with both typical atrioventricular nodal reentrant tachycardia (AVNRT) and atrial tachycardia, highlighting the challenges in identifying and treating dual tachycardias.

Purpose This article, the first in a 2-part review, aims to reinforce current literature on the pathophysiology of cardiac arrhythmias and various evidence-based treatment approaches and clinical considerations in the acute care setting. Part 1 of this series focuses on atrial arrhythmias. Summary Arrhythmias are prevalent throughout the world and a common presenting condition in the emergency department (ED) setting. Atrial fibrillation (AF) is the most common arrhythmia worldwide and expected to increase in prevalence. Treatment approaches have evolved over time with advances in catheter-directed ablation. Based on historic trials, heart rate control has been the long-standing accepted outpatient treatment modality for AF, but the use of antiarrhythmics is often still indicated for AF in the acute setting, and ED pharmacists should be prepared and poised to help in AF management. Other atrial arrhythmias include atrial flutter (AFL), atrioventricular nodal reentry tachycardia (AVNRT), and atrioventricular reentrant tachycardia (AVRT), which warrant distinction due to their unique pathophysiology and because each requires a different approach to utilization of antiarrhythmics. Atrial arrhythmias are typically associated with greater hemodynamic stability than ventricular arrhythmias but still require nuanced management according to patient subset and risk factors. Since antiarrhythmics can also be proarrhythmic, they may destabilize the patient due to adverse effects, many of which are the focus of black-box label warnings that can be overreaching and limit treatment options. Electrical cardioversion for atrial arrhythmias is generally successful and, depending on the setting and/or hemodynamics, often indicated. Conclusion Atrial arrhythmias arise from a variety of mechanisms, and appropriate treatment depends on various factors. A firm understanding of physiological and pharmacological concepts serves as a foundation for exploring evidence supporting agents, indications, and adverse effects in order to provide appropriate care for patients. [ABSTRACT FROM AUTHOR]

Investigating native human cardiac tissue with preserved 3D macro- and microarchitecture is fundamental for clinical and basic research. Unfortunately, the low accessibility of the human myocardium continues to limit scientific progress. To overcome this issue, utilizing atrial appendages of the human heart may become highly beneficial. Atrial appendages are often removed during open-heart surgery and can be preserved ex vivo as living tissue with varying durability depending on the culture method. In this study, we prepared living thin myocardial slices from left atrial appendages that were cultured using an air-liquid interface system for overall 10 days. Metabolic activity of the cultured slices was assessed using a conventional methyl thiazolyl tetrazolium (MTT) assay. To monitor the structural integrity of cardiomyocytes within the tissue, we implemented our recently described super-resolution microscopy approach that allows both qualitative and quantitative in-depth evaluation of sarcomere network based on parameters such as overall sarcomere content, filament size and orientation. Additionally, expression of mRNAs coding for key structural and functional proteins was analyzed by real-time reverse transcription polymerase chain reaction (qRT-PCR). Our findings demonstrate highly significant disassembly of contractile apparatus represented by degradation of α -actinin filaments detected after three days in culture, while metabolic activity was constantly rising and remained high for up to seven days. However, gene expression of crucial cardiac markers strongly decreased after the first day in culture indicating an early destructive response to ex vivo conditions. Therefore, we suggest static cultivation of living myocardial slices derived from left atrial appendage and prepared according to our protocol only for short-termed experiments (e.g. medicinal drug testing), while introduction of electro-mechanical stimulation protocols may offer the possibility for long-term integrity of such constructs. [ABSTRACT FROM AUTHOR]

Aim: we sought to test the inter‐center reproducibility of 16 echo laboratories involved in the EACVI‐Afib Echo Europe. Methods: This was done on a dedicated setting of 10 patients with sinus rhythm (SR) and 10 with persistent atrial fibrillation (AF), collected by the Principal Investigator. Images and loops of echo‐exams were stored and made available for labs. The tested measurements included main echo‐Doppler parameters, global longitudinal strain (GLS) and peak atrial longitudinal strain (PALS). Results: Single measures interclass correlation coefficients (ICCs) of left ventricular mass and ejection fraction were suboptimal in both patients with SR and AF. Among diastolic parameters, ICCs of deceleration time were poor, in particular in AF (=.50). ICCs of left atrial size and function, besides optimal in AF, showed an acceptable despite moderate concordance in SR. ICC of GLS was.81 and.78 in SR and AF respectively. ICCs of PALS were suitable but lower in 4‐chamber than in 2‐chamber view. By depicting the boxplot of the 16 laboratories, GLS distribution was completely homogeneous in SR, whereas GLS of AF and PALS of both SR and AF presented a limited number of outliers. GLS mean ± SE of the 16 labs was 19.7 ±.36 (95% CI: 18.8‐20.4) in SR and 16.5 ±.29 (95% CI: 15.9‐17.1) in AF, whereas PALS mean ± SE was 43.8 ±.70 (95% CI: 42.3‐45.3) and 10.2 ±.32 (95% CI: 9.5‐10.9) respectively. Conclusion: While the utilization of some standard‐echo variables should be discouraged in registries, the application of GLS and PALS could be largely promoted because their superior reproducibility, even in AF. [ABSTRACT FROM AUTHOR]

Introduction: Use of sodium glucose cotransporter 2 inhibitors (SGLT2i) was associated with a reduction in atrial fibrillation hospitalizations. Therefore, we aim to evaluate the effects of SGLT2i on atrial tachy‐arrhythmias (ATA) in patients with cardiac implantable electronic devices (CIEDs). Methods: All 13 888 consecutive patients implanted with a CIED in two tertiary medical centers were enrolled. Treatment with SGLT2i was assessed as a time dependent variable. The primary endpoint was the total number of ATA. Secondary endpoints included total number of ventricular tachy‐arrhythmias (VTA), ATA and VTA, and death. All events were independently adjudicated blinded to the treatment. Multivariable propensity score modeling was performed. Results: During a total follow‐up of 24 442 patient years there were 62 725 ATA and 10 324 VTA events. Use of SGLT2i (N = 696) was independently associated with a significant 22% reduction in the risk of ATA (hazard ratio [HR] = 0.78 [95% confidence interval {CI} = 0.70–0.87]; p <.001); 22% reduction in the risk of ATA/VTA (HR = 0.78 [95% CI = 0.71–0.85]; p <.001); and with a 35% reduction in the risk of all‐cause mortality (HR = 0.65 [95% CI = 0.45–0.92]; p =.015), but was not significantly associated with VTA risk (HR = 0.92 [95% CI = 0.80–1.06]; p =.26). SGLT2i were associated with a lower ATA burden in heart failure (HF) patients but not among diabetes patients (HF: HR = 0.68, 95% CI = 0.58–0.80, p <.001 vs. Diabetes: HR = 0.95, 95% CI = 0.86–1.05, p =.29; p <.001 for interaction between SGLT2i indication and ATA burden). Conclusion: Our real world findings suggest that in CIED HF patients, those with SGLT2i had a pronounced reduction in ATA burden and all‐cause mortality when compared with those not on SGLT2i. [ABSTRACT FROM AUTHOR]

Introduction: We describe the first case of the use of pulsed‐field ablation (PFA) to treat focal atrial tachycardia (FAT) in a pediatric patient. Methods: An 11‐year‐old girl with obesity was referred to our center for ablation of incessant atrial tachycardia. The earliest atrial activation was shown to be present in the left superior pulmonary vein. Radiofrequency ablation of FAT seems to be associated with a lower success rate and, especially, with a higher complication rate than in adult patients. Results: We performed ablation by means of a novel nonthermal energy source (PFA) that is able to reduce the risk of complications due to injury to anatomic structures surrounding the heart. After the first application, stable sinus rhythm was restored. Conclusions: PFA can be used to treat FAT arising from pulmonary veins in young children as a good alternative to RFA ablation, thereby reducing the risk of potential procedure‐related complications. [ABSTRACT FROM AUTHOR]

Introduction: Ethanol infusion into the vein of Marshall (EIVOM) is expected to be an adjunctive therapy for mitral isthmus (MI) ablation. Additionally, EIVOM can widely ablate the epicardium via the branches that extend to the left atrial posterior wall (LAPW) and facilitate LAPW isolation. This study aimed to investigate the efficacy and durability of LAPW isolation with EIVOM. Methods: Our cohort consisted of 413 patients with atrial fibrillation (AF) who underwent both LAPW and MI ablations. EIVOM was first attempted in 177 (35%) patients with adequate VOMs. The VOM was infused with 5 mL of ethanol with a double coaxial guiding catheter technique. Both ablations were performed only by radiofrequency ablation (the RF group) in the remaining 236 (57%) patients. Results: EIVOM with 5 mL of ethanol was completely achieved in 106 patients (the EIVOM group). The application duration of LAPW isolation did not differ significantly between the two groups (718 ± 276 vs. 709 ± 288 s; p =.78). LAPW debulking ablation was required in 64/106 (60%) and 176/236 (75%) patients in the EIVOM and RF groups, respectively (p <.05). However, AF‐ or atrial tachycardia‐free survival analyses revealed no significant differences between the two groups (log‐rank p =.70). Among the cases of recurrence, 17 and 38 patients underwent subsequent ablation sessions; LAPW was reconnected in 9/17 (53%) and 25/38 (53%) patients (p =.36) in the EIVOM and RF groups, respectively. Conclusion: EIVOM reduced the number of cases that required LAPW debulking ablation but did not improve the durability of LAPW isolation or clinical outcomes. [ABSTRACT FROM AUTHOR]

Introduction: The efficacy and safety of leadless cardiac pacemakers (LPMs) as an alternative to conventional transvenous cardiac pacing have been largely reported. The first generation of the MicraTM transcatheter pacing system (VR; Medtronic) was able to provide single‐chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A second‐generation system (AV) now provides atrioventricular synchrony through atrial mechanical (Am) sensing capability (VDD mode). Objective: We sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block. Methods: All consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or Vp burden <20% at 1 month postimplantation were excluded. Patients were systematically followed with a visit at 1 month, and then at least once a year. Results: A total of 93 patients—45 VR (2015–2020) and 48 AV (2020–2021)—were included. VR and AV patients had similar baseline characteristics, except for VR patients being older (80 ± 8 vs. 77 ± 9 years, p = 0.049). The mean Vp burden was 77% in the VR and 82% in the AV group (p = 0.38). In AV patients, the median AV synchronous beats rate was 78%, with 65% having a >66% rate. An E/A ratio <1.2 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (p = 0.01). One‐year survival rate was similar in both groups. Five patients in the VR and 0 in the AV group eventually developed pacemaker syndrome within 1 year post‐implantation (p = 0.02). Conclusion: In sinus rhythm patients with chronic Vp for complete atrioventricular block implanted with an LPM, the atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients and was associated with no occurrence of—otherwise rare—pacemaker syndrome. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to assess atrial conduction time and P-wave dispersion (PWD) in gestational diabetes mellitus (GDM) patients. Methods: Thirty patients with GDM and 30 healthy pregnant women were included to the study. Atrial conduction times (PA) were calculated by the time interval from the onset of the P wave on the electrocardiography (ECG) to the onset of the late diastolic flow (Am wave) on echocardiography and from the lateral mitral annulus (PA lateral), septal mitral annulus (PA septum), and right ventricular tricuspid annulus (PA tricuspid). The difference between (PA lateral-PA tricuspid) was defined as interatrial electromechanical delay (EMD); the difference between (PA septum-PA tricuspid) as intra-atrial EMD; and the difference between (PA lateral-PA septal) as intraleft atrial EMD. Results: Mean PWD was higher in GDM (52.7 ± 5.1 ms vs. 28.9 ± 4.2 ms, p < 0.001). PA lateral, PA septal and PA tricuspid were significantly higher in the GDM patients compared to the control group (65.7 ± 4.2 ms vs. 47.7 ± 4.7 ms, p < 0.001; 56.1 ± 3.4 ms vs. 40.8 ± 3.7 ms, p < 0.001 and 48.4 ± 3.9 ms vs. 36.0 ± 3.6 ms, p < 0.001, respectively). Interatrial, intra-atrial, and intraleft atrial EMDs were also significantly higher in the GDM group (median values: 18 ms vs. 12 ms; 10 ms vs 7.5 ms; 8 ms vs. 4 ms, respectively, p < 0.001 for all). There was a positive correlation between intra-atrial delay time and PWD in GDM group (r = 0.39, p = 0.033). Conclusion: We suggest that patients with GDM have higher PWD and higher atrial conduction and EMD times compared to otherwise healthy pregnant control group. [ABSTRACT FROM AUTHOR]

Epidemiological studies have established that exposure to tungsten increases the risk of developing cardiovascular diseases. However, no studies have investigated how tungsten affects cardiac function or the development of cardiovascular disease. Inhalation of tungsten particulates is relevant in occupational settings, and inhalation of particulate matter has a known causative role in driving cardiovascular disease. This study examined if acute inhalation to tungsten particulates affects cardiac function and leads to heart tissue alterations. Female BALB/c mice were exposed to Filtered Air or 1.5 ± 0.23 mg/m3 tungsten particles, using a whole-body inhalation chamber, 4 times over the course of two weeks. Inhalation exposure resulted in mild pulmonary inflammation characterized by an increased percentage and number of macrophages and metabolomic changes in the lungs. Cardiac output was significantly decreased in the tungsten-exposed group. Additionally, A′, an indicator of the amount of work required by the atria to fill the heart was elevated. Cardiac gene expression analysis revealed, tungsten exposure increased expression of pro-inflammatory cytokines, markers of remodeling and fibrosis, and oxidative stress genes. These data strongly suggest exposure to tungsten results in cardiac injury characterized by early signs of diastolic dysfunction. Functional findings are in parallel, demonstrating cardiac oxidative stress, inflammation, and early fibrotic changes. Tungsten accumulation data would suggest these cardiac changes are driven by systemic consequences of pulmonary damage. • Inhalation of tungsten particulates results in mild inflammation and metabolomic changes in the lungs. • Inhalation of tungsten results in early signs of cardiac injury (decreased cardiac output and increased atrial workload). • Tungsten increases expression of pro-inflammatory, cardiac remodeling, and oxidative stress genes in the heart. • Tungsten accumulation data would suggest these cardiac changes are driven by systemic consequences of pulmonary damage. [ABSTRACT FROM AUTHOR]

Hemodynamics play a vital role for the risk of thrombosis in the left atrial appendage (LAA) and left atrium (LA) for patients with atrial fibrillation. Accurate prediction of hemodynamics in the LA can provide important guidance for assessing the risk of thrombosis in the LAA. Patient specificity is a crucial factor in representing the true hemodynamic fields. In this study, we investigated the effects of blood rheology (as a function of hematocrit and shear rate), as well as patient-specific mitral valve (MV) boundary conditions (MV area and velocity profiles measured by ultrasound) on the hemodynamics and thrombosis potential of the LAA. Four scenarios were setup with different degrees of patient specificity. Though using a constant blood viscosity can classify the thrombus and non-thrombus patients for all the hemodynamic indicators, the risk of thrombosis was underestimated for all patients compared with patient-specific viscosities. The results with least patient specificities showed that patients prone to thrombosis predicted by three hemodynamic indicators were inconsistent with clinical observations. Moreover, though patients had the same MV inlet flow rate, different MV models lead to different trends in the risk of thrombosis in different patients. We also found that endothelial cell activation potential and relative residence time can effectively distinguish thrombus and non-thrombus patients for all the scenarios, relatively insensitive to patient specificities. Overall, the findings of this study provide useful insights on patients-specific hemodynamic simulations of the LA. [ABSTRACT FROM AUTHOR]

Background: Surface ECG is a useful tool to guide mapping of focal atrial tachycardia (AT). Objectives: We aimed to construct 12‐lead ECG templates for P‐wave morphology (PWM) during endocardial pacing from different sites in both atria in patients with no apparent structural heart disease (derivation cohort), with the goal of creating a localization algorithm, which could subsequently be validated in a cohort of patients undergoing catheter ablation of focal AT (validation cohort). Methods: We prospectively enrolled consecutive patients who underwent electrophysiology study, had no structural heart disease and no atrial enlargement. Atrial pacing, at twice diastolic threshold, was carried out at different anatomical sites in both atria. Paced PWM and duration were assessed. An algorithm was generated from the constructed templates of each pacing site. The algorithm was applied on a retrospective series of successfully ablated AT patients. Overall and site‐specific accuracy were determined. Results: Derivation cohort included 65 patients (25 men, age 37 ± 13 years). Atrial pacing was performed in 1025 sites in 61 patients (95%) in RA and in 15 patients (23%) in LA. The validation cohort included 71 patients (28 men, age 52 ± 19 years). AT were right atrial in 66.2%. The algorithm successfully predicted AT origin in 91.5% of patients (100% in LA and 87.2% in RA). It was off by one adjacent segment in the remaining 8.5%. Conclusions: A simple ECG algorithm based on paced PWM templates was highly accurate in localizing site of origin of focal AT in patients with structurally normal hearts. [ABSTRACT FROM AUTHOR]

Ivabradine is used to reduce heart rate in children with chronic heart failure and dilated cardiomyopathy, it has recently been used off‐label to treat tachyarrhythmias such as ectopic atrial tachycardia and junctional ectopic tachycardia (JET) in children. We report a successful ivabradine experience in a male neonate with refractory focal atrial tachycardia (FAT). [ABSTRACT FROM AUTHOR]

Bi‐atrial tachycardia (BiAT) is not rare after extensive atrial ablation or cardiac surgery. The complexity of bi‐atrial reentrant circuits poses a great challenge for clinical practice. With recent advances in mapping technologies, we are now able to characterize atrial activation in detail. However, given the involvement of both atria and multiple epicardial conductions, endocardial mapping for BiATs is not easy to understand. Knowledge of the atrial myocardial architecture is the foundation for the clinical management of BiATs; as it is required to understand the possible mechanism of the tachycardia and identify the optimal target of ablation. In this review we summarize current knowledge about the anatomy of interatrial connections as well as other epicardial fibers and discuss the interpretation of electrophysiological findings and ablation strategies for BiATs. [ABSTRACT FROM AUTHOR]

Background: The canine sterile pericarditis model associated with atrial inflammation is an experimental counterpart of postoperative atrial fibrillation (POAF). However, the use of canines for research is restricted by ethics committees in many countries, and social acceptance is declining. Objective: To validate the feasibility of the swine sterile pericarditis model as an experimental counterpart to study POAF. Methods: Seven domestic pigs (35–60 kg) underwent initial pericarditis surgery. On two or more postoperative days in the closed‐chest state, we performed electrophysiological measurements of pacing threshold and atrial effective refractory period (AERP) while pacing from the right atrial appendage (RAA) and the posterior left atrium (PLA). The inducibility of POAF (>5 min) by burst pacing was determined in both the conscious and anesthetized closed‐chest state. These data were compared to previously published canine sterile pericarditis data for validation. Results: The pacing threshold increased from day 1 to day 3 (2 ± 0.1 to 3.3 ± 0.6 mA in the RAA, 2.5 ± 0.1 to 4.8 ± 0.2 mA in the PLA). Also, the AERP increased from day 1 to day 3 (118 ± 8 to 157 ± 16 ms in the RAA; 98 ± 4 to 124 ± 2 ms in the PLA, both p <.05). Induction of sustained POAF occurred in 43% (POAF CL range 74–124 ms). All electrophysiologic data from the swine model were consistent with the canine model with respect to (1) the range of both pacing threshold and AERP; (2) the progressive increase in threshold and AERP over time; (3) a 40%–50% incidence of POAF. Conclusion: A newly developed swine sterile pericarditis model demonstrated electrophysiologic properties consistent with the canine model and patients after open heart surgery. [ABSTRACT FROM AUTHOR]

We report a case of recurring, persistent atrial fibrillation (AF) in a patient with a unidirectional epicardial connection (EC) between the right‐sided pulmonary venous (PV) carina and the right atrium detected using a high‐density mapping catheter with a steerable introducer support, but not a conventional circular mapping catheter. This unidirectional EC could be steadily abolished by a radiofrequency delivery. Finally, we were able to successfully achieve complete PV antrum isolation. Thereafter, he has remained well without any AF. [ABSTRACT FROM AUTHOR]