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AIMS: Prior case series showed promising results for cardioneuroablation in patients with vagally induced atrioventricular blocks (VAVBs). We aimed to examine the acute procedural characteristics and intermediate-term outcomes of electroanatomical-guided cardioneuroablation (EACNA) in patients with VAVB. METHODS AND RESULTS: This international multicentre retrospective registry included data collected from 20 centres. Patients presenting with symptomatic paroxysmal or persistent VAVB were included in the study. All patients underwent EACNA. Procedural success was defined by the acute reversal of atrioventricular blocks (AVBs) and complete abolition of atropine response. The primary outcome was occurrence of syncope and daytime second- or advanced-degree AVB on serial prolonged electrocardiogram monitoring during follow-up. A total of 130 patients underwent EACNA. Acute procedural success was achieved in 96.2% of the cases. During a median follow-up of 300 days (150, 496), the primary outcome occurred in 17/125 (14%) cases with acute procedural success (recurrence of AVB in 9 and new syncope in 8 cases). Operator experience and use of extracardiac vagal stimulation were similar for patients with and without primary outcomes. A history of atrial fibrillation, hypertension, and coronary artery disease was associated with a higher primary outcome occurrence. Only four patients with primary outcome required pacemaker placement during follow-up. CONCLUSION: This is the largest multicentre study demonstrating the feasibility of EACNA with encouraging intermediate-term outcomes in selected patients with VAVB. Studies investigating the effect on burden of daytime symptoms caused by the AVB are required to confirm these findings.

ABSTRACT Aims Methods Results Conclusion In addition to well‐documented tachycardias involving twin atrioventricular (AV) nodes, tachycardias involving a single node have been clinically experienced in right atrial isomerism (RAI). This study aimed to characterize the AV node involvement patterns and evaluate the outcome of ablation therapy in RAI patients with tachycardias.We retrospectively analyzed the medical records of 16 RAI patients who underwent catheter ablation of tachycardias involving twin or single AV nodes at our center between April 2006 and March 2020.A total of 22 ablation procedures were performed in 16 patients. The median age and body weight were 2 years (range 20 months–31 years) and 11.2 kg (range 7.4–42 kg), respectively. Two QRS complexes were confirmed in 11/16 patients, and a single QRS complex in 5/16. The dominant AV node was anterior in 7/16. Four patterns of tachycardias were identified: tachycardias reciprocating between two AV nodes with retrograde conduction through the anterior AV node (3/16) or through the posterior AV node (4/16); and reentrant tachycardias involving the anterior AV node only (3/16) or posterior AV node only (6/16). Ablation successfully eliminated the tachycardias in 15/16 patients (93.8%). Recurrence was reported in 7/16 (44%) during a median follow‐up period of 96.5 months. Five of those 7 patients underwent additional ablation, and the tachycardias were eliminated in 3/5 patients. None of the patients developed ventricular asynchrony after ablation.Transcatheter ablation was effective in RAI patients with tachycardias involving twin or single AV nodes, and deterioration of the cardiac function was rare. [ABSTRACT FROM AUTHOR]

Cardiac rhythms are related to heart electrical activity, being the essential aspect of the cardiovascular physiology. Usually, these rhythms are represented by electrocardiograms (ECGs) that are useful to detect cardiac pathologies. Essentially, the heart activity starts in the sinoatrial node (SA) node, the natural pacemaker, propagating to the atrioventricular node (AV), and finally reaching the His-Purkinje complex (HP). This paper investigates the control of cardiac rhythms in order to induce normal rhythms from pathological responses. A mathematical model that presents close agreement with experimental measurements is employed to represent the heart functioning. The adopted model comprises a network of three nonlinear oscillators that represent each one of the cardiac nodes, connected by delayed couplings. The pathological behavior is induced by an external stimulus in the SA node. An adaptive controller is proposed acting in the SA node considering an strategy based on the signal obtained by the natural pacemaker and its regularization. The incorporation of adaptive compensation in a Lyapunov-based control scheme allows the compensation for the unknown dynamics. The controller ability to deal with interpatient variability is evaluated by assuming that the heart model is not available to the controller design, being used only in the simulator to assess the control performance. Results show that the adaptive term can reduce the control effort by around 3% while reducing the tracking error by 20%, when compared to the conventional feedback approach. Additionally, the controller can avoid abnormal rhythms, turning the ECG closer to the expected normal behavior and preventing critical cardiac responses. Therefore, this work demonstrates that an adaptive controller can be used to regulate the ECG signal without prior information about the system and disregarding inter- and intrapatient variability. [ABSTRACT FROM AUTHOR]

Background: The impact of the His bundle location and distance from the ablation site on ablation efficacy and complication risk remains unexplored. We determined the correlation between age, height, body mass index (BMI), and the His bundle location, and whether the distance between the His bundle and ablation target (DHIS‐ABL) affects ablation safety and efficacy. Methods: Overall, 346 patients with atrioventricular nodal re‐entrant tachycardia (AVNRT) and 96 with atrioventricular re‐entrant tachycardia (AVRT) were retrospectively analyzed. The distance between the His bundle and the coronary sinus ostium (DHis‐CS), the height of the His bundle (HHIS), and DHIS‐ABL were measured. Electrocardiograms were obtained 3 months post‐ablation to assess recurrence and complications. Results: Multiple linear regression showed that HHIS was negatively correlated with age in both groups. In AVNRT patients, DHIS‐ABL was associated with age, height, and BMI; DHIS‐CS was only negatively correlated with age. In AVRT patients, there was no significant correlation between the DHIS‐ABL and age, height, or BMI. The recurrence rates in the AVNRT and AVRT groups were 0.9% and 8.7%, respectively. Subgroup analysis showed that patients with DHIS‐ABL ≤ 10 mm had a higher recurrence rate than those with DHIS‐ABL > 10 mm (p =.013). The incidence of third‐degree atrioventricular block (AVB) complications was 0.2%. Conclusions: HHIS was negatively correlated with age but not with height and BMI. The DHIS‐ABL correlated with age, height, and BMI in AVNRT patients. A short DHIS‐ABL led to a higher rate of supraventricular tachycardia recurrence; whether this affects AVB risk warrants further studies with larger sample sizes. [ABSTRACT FROM AUTHOR]

The atrioventricular node (AVN) is a crucial component of the cardiac conduction system. Despite its pivotal role in regulating the transmission of electrical signals between atria and ventricles, a comprehensive understanding of the cellular electrophysiological mechanisms governing AVN function has remained elusive. This paper presents a detailed computational model of mouse AVN cell action potential (AP). Our model builds upon previous work and introduces several key refinements, including accurate representation of membrane currents and exchangers, calcium handling, cellular compartmentalization, dynamic update of intracellular ion concentrations, and calcium buffering. We recalibrated and validated the model against existing and unpublished experimental data. In control conditions, our model reproduces the AVN AP experimental features, (e.g. rate = 175 bpm, experimental range [121, 191] bpm). Notably, our study sheds light on the contribution of L‐type calcium currents, through both Cav1.2 and Cav1.3 channels, in AVN cells. The model replicates several experimental observations, including the cessation of firing upon block of Cav1.3 or INa,r current. If block induces a reduction in beating rate of 11%. In summary, this work presents a comprehensive computational model of mouse AVN cell AP, offering a valuable tool for investigating pacemaking mechanisms and simulating the impact of ionic current blockades. By integrating calcium handling and refining formulation of ionic currents, our model advances understanding of this critical component of the cardiac conduction system, providing a platform for future developments in cardiac electrophysiology. Key points: This paper introduces a comprehensive computational model of mouse atrioventricular node (AVN) cell action potentials (APs).Our model is based on the electrophysiological data from isolated mouse AVN cells and exhibits an action potential and calcium transient that closely match the experimental records.By simulating the effects of blocking specific ionic currents, the model effectively predicts the roles of L‐type Cav1.2 and Cav1.3 channels, T‐type calcium channels, sodium currents (TTX‐sensitive and TTX‐resistant), and the funny current (If) in AVN pacemaking.The study also emphasizes the significance of other ionic currents, including IKr, Ito, IKur, in regulating AP characteristics and cycle length in AVN cells.The model faithfully reproduces the rate dependence of action potentials under pacing, opening the possibility of use in impulse propagation models.The population‐of‐models approach showed the robustness of this new AP model in simulating a wide spectrum of cellular pacemaking in AVN. [ABSTRACT FROM AUTHOR]

This document is a case presentation and discussion of a patient with narrow QRS regular tachycardia and VA dissociation. The patient underwent catheter ablation for supraventricular tachycardia (SVT 1) and was diagnosed with slow-slow type atrioventricular nodal reentrant tachycardia (AVNRT). However, spontaneous SVT 2 occurred after the ablation. The mechanism of SVT 2 was unclear, but the differential diagnosis included AVNRT with upper common pathway block, nodoventricular (NV) pathway or nodofascicular (NF) pathway mediated orthodromic reciprocating tachycardia (ORT), and junctional tachycardia (JT). Further diagnostic testing and ablation were performed to eliminate the tachycardia. [Extracted from the article]

The atrioventricular node (AVN) is a key component of the cardiac conduction system and takes over pacemaking of the ventricles if the sinoatrial node fails. IP3 (inositol 1,4,5 trisphosphate) can modulate excitability of myocytes from other regions of the heart, but it is not known whether IP3 receptor (IP3-R) activation modulates AVN cell pacemaking. Consequently, this study investigated effects of IP3 on spontaneous action potentials (APs) from AVN cells isolated from rabbit hearts. Immunohistochemistry and confocal imaging demonstrated the presence of IP3-R2 in isolated AVN cells, with partial overlap with RyR2 ryanodine receptors seen in co-labelling experiments. In whole-cell recordings at physiological temperature, application of 10 µM membrane-permeant Bt3-(1,4,5)IP3-AM accelerated spontaneous AP rate and increased diastolic depolarization rate, without direct effects on ICa,L, IKr, If or INCX. By contrast, application via the patch pipette of 5 µM of the IP3-R inhibitor xestospongin C led to a slowing in spontaneous AP rate and prevented 10 µM Bt3-(1,4,5)IP3-AM application from increasing the AP rate. UV excitation of AVN cells loaded with caged-IP3 led to an acceleration in AP rate, the magnitude of which increased with the extent of UV excitation. 2-APB slowed spontaneous AP rate, consistent with a role for constitutive IP3-R activity; however, it was also found to inhibit ICa,L and IKr, confounding its use for studying IP3-R. Under AP voltage clamp, UV excitation of AVN cells loaded with caged IP3 activated an inward current during diastolic depolarization. Collectively, these results demonstrate that IP3 can modulate AVN cell pacemaking rate. [ABSTRACT FROM AUTHOR]

Background An atrioventricular node (AVN) ablation and permanent pacing have been previously reported as effective treatments for patients with atrial tachyarrhythmias. However single-ventricle patients requiring chronic ventricular pacing are at a higher risk of developing ventricular dysfunction and atrioventricular valve regurgitation. We report a case of successful AVN ablation in a 3-month-old infant with hypoplastic left heart syndrome and ectopic atrial tachycardia (EAT). Case summary A boy with hypoplastic left heart syndrome who had a refractory EAT resistant to various medications. At 2 months old, we performed an urgent radiofrequency (RF) catheter ablation of the EAT and the applications delivered at the cavo-atrial junction. Although it disappeared after the first catheter ablation for 2 weeks, it recurred on the next day after the diaphragm plication. At 3 months old and weighed 3.1 kg, we decided to perform an urgent AVN ablation of the EAT. The application was performed on the mid-septum of the tricuspid septum. A permanent pacemaker was implanted after the ablation. After the AVN ablation, the haemodynamics stabilized during the EAT. However, he died from a bacteraemia infection at 4 months. Discussion This patient received an AVN ablation due to failure to previous RF catheter ablation and was haemodynamically stable with the dual-chamber pacemaker. The AV block was successfully created by RF energy on the mid-septum of the tricuspid annulus in this hypoplastic left heart syndrome patient. Pathological findings exhibited that the compact AVN was totally ablated without damage to the tricuspid leaflets or coronary artery. [ABSTRACT FROM AUTHOR]

Background: The growing participation of women in competitive sports necessitates a comprehensive understanding of sex‐specific cardiovascular adaptations and risks. Historically, research has predominantly focused on male athletes, leaving a gap in knowledge about the unique cardiovascular dynamics of female peers. Hypothesis: we hypothesized that female athletes exhibit distinct cardiovascular adaptations and face different risks, influenced by physiological, hormonal, and structural differences. Methods: A systematic review of the literature was conducted, analyzing studies on cardiovascular responses and adaptations in athletes. Data were extracted on hemodynamic changes, autonomic and neural reflex regulation, cardiac remodeling, and arrhythmias. Comparative analyses were performed to identify sex‐specific patterns and discrepancies in cardiovascular health outcomes. Results: We revealed considerable sex differences in cardiovascular adaptations to athletic training. Female athletes generally have longer QT intervals, greater sinoatrial node automaticity, and enhanced atrioventricular node function compared to males. They also exhibit lower sympathetic activity, lower maximal stroke volumes, and a tendency toward eccentric cardiac remodeling. Conversely, male athletes are more prone to concentric hypertrophy and higher incidences of bradyarrhythmia and accessory pathway arrhythmias. Female athletes are more likely to experience symptomatic atrial fibrillation and face higher procedural complications during catheter ablation. Conclusions: Our findings underscore the necessity for sex‐specific approaches in sports cardiology. Recognizing and addressing these differences could enhance performance and reduce adverse cardiac events in athletes. Future research should focus on developing tailored screening, prevention, and treatment strategies to bridge the knowledge gap and promote cardiovascular health in both male and female athletes. [ABSTRACT FROM AUTHOR]

Fetal autoimmune atrioventricular block (AVB) is a rare but potentially lifethreatening condition. It results from the passage of maternal anti-SSA/Ro or Anti SSB/La auto-antibodies into the fetal circulation, leading to inflammation and fibrosis of the AV node and often to irreversible damage. Besides AVB, these antibodies can also cause cardiomyopathies, but there is no evidence linking them to tachyarrhythmias. We present the case of a patient with significant risk factors for fetal AVB: a prior history of hydrops fetalis, high anti-SSA/Ro antibody levels and hypothyroidism. In this case, the use of dexamethasone and intravenous immunoglobulin may have contributed to reversing the first degree atrioventricular block detected at 19 weeks of gestation. Additionally, at 21 weeks, the fetus developed a tachyarrhythmia that needed treatment with flecainide. Soon after the birth, the newborn underwent ECG Holter and Wolff-Parkinson-White Syndrome (WPWS) was diagnosed. To our knowledge, the coexistence of fetal AVB and WPWS has never been described. [ABSTRACT FROM AUTHOR]

Background: Atrioventricular node (AVN) ablation is an effective treatment for atrial fibrillation (AF) with uncontrolled ventricular rates despite maximal pharmacological treatment. Intracardiac echocardiography (ICE) can help with visualizing structures, positioning catheters, and guiding the ablation procedure. We compared only fluoroscopy-guided and ICE-guided AVN ablation regarding patients with permanent AF. Methods: Sixty-two consecutive patients underwent AVN ablation were enrolled in our retrospective single-center study (ICE group: 28 patients, Standard group: 34 patients). Procedural data, acute and long-term success rate, and complications were analyzed. Results: ICE guidance for AVN ablation significantly reduced fluoroscopy time (0.30 [0.06; 0.85] min vs. 7.95 [3.23; 6.59] min, p < 0.01), first-to-last ablation time (4 [2; 16.3] min vs. 26.5 [2.3; 72.5] min, p = 0.02), and in-procedure time (40 [34; 55] min vs. 60 [45; 110], p = 0.02). There was no difference in either the total ablation time (199 [91; 436] s vs. 294 [110; 659] s, p = 0.22) or in total ablation energy (8272 [4004; 14,651] J vs. 6065 [2708; 16,406] J, p = 0.28). The acute success rate was similar (ICE: 100% vs. Standard: 94%, p = 0.49) between the groups. Conclusions: In our retrospective trial, ICE-guided AVN ablation reduced fluoroscopy time, procedure time, and first-to-last ablation time. There was no difference in ablation time, total ablation energy, acute and long-term success, and complication rate. [ABSTRACT FROM AUTHOR]

The article presents a case study of a patient with ventricular tachycardia originating from the para-Hisian region, where detailed electrophysiological mapping and pacing maneuvers were used to identify the reentrant mechanism. It also discusses the effectiveness of entrainment pacing in determining the optimal ablation site, challenges associated with ablation in this anatomical region, and the role of detailed electroanatomical mapping in avoiding damage to the AV conduction system.

Objective: The management of women presenting with with complete heart block during pregnancy remains very challenging.Untill now, there is not an established consensus for the most appropriate anaesthetic technique for caesarean section in women with complete atrioventricular block. Case(s): On our case, the atrioventricular complete heart block was diagnosed on the preoperative routine test for Caesarian Section due to cephalo-pelvic disproportion. The patient had no regular antenatal check ups at a local hospital. Her parents reported rare episodes of syncope during childhood and adolescence and one more episode two year before. During pregnancy she did not report any sincope episode except from being tired . For obstetric reasons caesarean section was performed successfully under spinal anaesthesia with continuous monitorization during intraoperative time without a pacemaker .Even though the patient reacted well during administration of atropine a temporary pacemaker was found to be in case we would need it. A healthy baby boy of 3350 gram was delivered. During postpartum period the patient did not have any complains or syncope episodes. It was strongly recommended to her a regular follow up to cardiology department. Conclusion: As suggested by our case, asymptomatic atrioventricular complete heart block in pregnancy can be managed successfully without pacemaker. However, careful monitoring, is necessity by the pregnancy heart team with a cardiologist, anaesthetist and obstetrician, with experience in the management of high risk pregnancies. Management of the risk for cardiovascular and obstetrical complications is difficult in pregnant women with complete heart block. Asymptomatic complete heart block in late pregnancy should be managed without pacemaker by the pregnancy heart team with a cardiologist, anaesthetist and obstetrician, with experience in the management of high risk pregnancies. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Venous spasm is an important reason for complicated or failed implantations of cardiac implantable electronic devices. Prevention or risk reduction of venous spasm during cardiac implantable electronic device implantation may be achieved by ultrasound or fluoroscopic imaging prior to puncture, cephalic vein cut‐down, sufficient pre‐ and perioperative hydration, nitroglycerin injection and effective sedation, and analgesia. This case report with literature review focuses on venous spasm as a potential cause for complicated implantations of cardiac implantable electronic devices. The case report is clinically relevant as it describes a progressive spasm affecting the axillary and the subclavian vein. A 66‐year‐old female complained of symptomatic atrial fibrillation (AF) and atypical atrial flutter despite interventional and medical treatment. As an ultimate treatment, she was scheduled for pacemaker implantation and atrioventricular node ablation. Several puncture attempts of the axillary vein failed. Despite venous blood aspiration, no guidewires could be advanced into the axillary vein. We performed a first venogram revealing significant spasm of the axillary vein. Another failed venous puncture occurred after change of access site to the subclavian vein. A second venogram displayed progression of the spasm, now affecting both the axillary and the subclavian veins. Normal saline perfusion was administered as well as intravenous isosorbide. Unfortunately, a repeated venogram after 15 min waiting time showed persistence of the spasm, still affecting both veins. The procedure was discontinued as the patient became uncomfortable. Venous spasm is an important reason for complicated or failed implantations of cardiac implantable electronic devices. Commonly used medical prevention and treatment are intravenous fluids and nitroglycerin. Prevention or risk reduction of venous spasm during cardiac implantable electronic device implantation may be achieved by ultrasound or fluoroscopic imaging prior to puncture, cephalic vein cut‐down, sufficient pre‐ and perioperative hydration, nitroglycerin injection and effective sedation and analgesia. [ABSTRACT FROM AUTHOR]

Background: There is limited research on the intra‐individual efficacy of ventricular pacing minimization algorithms developed by Biotronik—the Ventricular Pace Suppression algorithm (VpS) and the Intrinsic Rhythm Support plus algorithm (IRSplus) (BIOTRONIK SE & Co. KG, Berlin, Germany). We performed a randomized pilot trial that evaluated the efficacy of two algorithms in patients with symptomatic sinus node dysfunction (SND) who received a dual‐chamber pacemaker. Methods: The trial was conducted in 11 tertiary hospitals in South Korea. The patients were randomized to either the VpS or IRSplus algorithm group after a 3‐month period of fixed atrioventricular (AV) delay. The primary outcome was the ventricular pacing percentage (Vp%) at each follow‐up visit. The secondary outcomes were the occurrence of heart failure (HF) and atrial fibrillation (AF) during the study period. Results: Data from 131 patients were analyzed. Initially, their average Vp% over 3 months with a fixed AV interval was 14.1 ± 19.4%. Patients were randomly assigned to VpS and IRSplus groups, with 66 and 65 in each. Algorithms reduced average Vp% to 4.0 ± 11.3% at 9 months and 6.7 ± 14.9% at 15 months. These algorithms were more effective for patients with paced AV delay (PAVD) ≤300 ms compared to those with PAVD >300 ms. Both algorithms were equally effective in reducing Vp%. Clinical AF or HF hospitalization was not observed during the study period. Conclusion: The VpS and IRSplus algorithms are effective and safe in minimizing unnecessary ventricular pacing in patients with SND. [ABSTRACT FROM AUTHOR]

In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled "SVT Quest" is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V‐A‐V or V‐A‐A‐V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His‐ventricular pathway‐related tachycardia based on observations such as V‐V‐A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure! [ABSTRACT FROM AUTHOR]

The cardiac conduction system (CCS) is a network of specialized cardiomyocytes that coordinates electrical impulse generation and propagation for synchronized heart contractions. Although the components of the CCS, including the sinoatrial node, atrioventricular node, His bundle, bundle branches, and Purkinje fibers, were anatomically discovered more than 100 years ago, their molecular constituents and regulatory mechanisms remain incompletely understood. Here, we demonstrate the transcriptomic landscape of the postnatal mouse CCS at a single-cell resolution with spatial information. Integration of single-cell and spatial transcriptomics uncover region-specific markers and zonation patterns of expression. Network inference shows heterogeneous gene regulatory networks across the CCS. Notably, region-specific gene regulation is recapitulated in vitro using neonatal mouse atrial and ventricular myocytes overexpressing CCS-specific transcription factors, Tbx3 and/or Irx3. This finding is supported by ATAC-seq of different CCS regions, Tbx3 ChIP-seq, and Irx motifs. Overall, this study provides comprehensive molecular profiles of the postnatal CCS and elucidates gene regulatory mechanisms contributing to its heterogeneity. The cardiac conduction system consists of specialized cardiomyocytes that synchronize heart contractions. Here, Oh et al. provide comprehensive molecular profiles of the postnatal cardiac conduction system and elucidate gene regulatory mechanisms contributing to its heterogeneity. [ABSTRACT FROM AUTHOR]

Background: Dexmedetomidine and propofol are common sedatives in intensive care units and for interventional procedures. Both may compromise sinus node function and atrioventricular conduction. The objective of this prospective, randomized study is to compare the effect of dexmedetomidine with propofol on sinus node function and atrioventricular conduction. Methods: In a tertiary care center in Switzerland we included from September 2019 to October 2020 160 patients (65 ± 11 years old; 32% female) undergoing first ablation for atrial fibrillation by cryoballoon ablation or by radiofrequency ablation. Patients were randomly assigned to deep sedation with dexmedetomidine (DEX group) versus propofol (PRO group). A standard electrophysiological study was performed after pulmonary vein isolation with the patients still deeply sedated and hemodynamically stable. Results: Eighty patients each were randomized to the DEX and PRO group. DEX group patients had higher baseline sinus cycle length (1022 vs. 1138 ms; p = 0.003) and longer sinus node recovery time (SNRT400; 1597 vs. 1412 ms; p = 0.042). However, both corrected SNRT and normalized SNRT did not differ. DEX group patients had longer PR interval (207 vs. 186 ms; p = 0.002) and AH interval (111 vs. 95 ms, p = 0.008), longer Wenckebach cycle length of the atrioventricular node (512 vs. 456 ms; p = 0.005), and longer atrioventricular node effective refractory period (390 vs. 344 ms; p = 0.009). QRS width and HV interval were not different. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients during the electrophysiological study, without differences among groups (20% vs. 15%, p = 0.533). Conclusions: Dexmedetomidine has a more pronounced slowing effect on sinus rate and suprahissian AV conduction than propofol, but not on infrahissian AV conduction and ventricular repolarization. These differences need to be taken into account when using these sedatives. Trial registration: ClinicalTrials.gov number NCT03844841, 19/02/2019 [ABSTRACT FROM AUTHOR]

This article discusses a case of narrow complex tachycardia with alternating atrial activation. The patient had previously undergone an ablation procedure for pre-excited atrial fibrillation but experienced recurrent episodes of palpitations. The article explores the mechanism behind the alternating atrial activation and suggests that it may be due to conduction block across the mitral isthmus. The left lateral pathway was successfully ablated, resulting in the resolution of the tachycardia. Further research and mapping techniques are recommended to improve the accuracy of ablation procedures. [Extracted from the article]

The article presents a case study of a 21-year-old woman undergoing electrophysiological study for long RP (Refractory Period) tachycardia. It initially suspected atrial tachycardia or atypical atrioventricular nodal reentrant tachycardia (aAVNRT), later confirming slow-slow AVNRT. It is reported that Radiofrequency ablation targeted the AV (atrioventricular) node's right inferior extension, successfully resolving the tachycardia.

The article presents a case study of a 69-year-old female who underwent an electrophysiological study due to recurrent supraventricular tachycardia (SVT). It highlighted the occurrence of a wide complex tachycardia (WCT) and explored the mechanism behind its transformation following a premature ventricular complex (PVC). Treatment discussed involved radiofrequency ablation targeting the base of the triangle of Koch, which successfully eliminated SVT inducibility and potentially the NFV pathway.

Background: Severe first‐degree atrioventricular (AV) block may produce symptoms similar to heart failure due to AV dyssynchrony, a syndrome termed AV dromotropathy. According to guidelines, it should be considered for permanent pacemaker implantation, yet evidence supporting this treatment is scarce. Objectives: This study aimed to determine the impact of AV‐optimized conduction system pacing (CSP) in patients with symptomatic severe first‐degree AV block and echocardiographic signs of AV dyssynchrony. Methods: Patients with symptomatic first‐degree AV block (PR > 250 ms), preserved left ventricular ejection fraction, narrow QRS, and AV dyssynchrony were included in the study. In a single‐blind cross‐over design, patients were randomized to AV sequential CSP or backup VVI pacing with a base rate of 40 bpm. We compared exercise capacity, echocardiographic parameters, and symptom occurrence at the end of 3 months of each period. Results: Fourteen patients completed the study. During the AV‐optimized CSP compared to the backup pacing period, patients achieved a higher workload on exercise test (147.2 ± 50.9 vs. 140.7 ± 55.8 W; p =.032), with a trend towards higher peak VO2 (23.3 ± 7.1 vs. 22.8 ± 7.1 mL/min/kg; p =.224), and higher left ventricular stroke volume (LVSV 74.5 ± 13.8 vs. 66.4 ± 12.5 mL; p <.001). Symptomatic improvement was recorded, with fewer patients reporting general tiredness and 71% of patients preferring the AV‐optimized CSP (p =.008). Conclusions: AV‐optimized CSP could improve symptoms, exercise capacity and LVSV in patients with severe first‐degree AV block. [ABSTRACT FROM AUTHOR]

Introduction: Concomitant left bundle branch area pacing (LBBAP) with atrioventricular (AV) nodal ablation is emerging as a viable management option in atrial fibrillation refractory to medical management. Its viability in patients with pulmonary disease and atrial fibrillation is unknown. Methods and results: This is a retrospective, observational cohort study in consecutive patients who underwent concomitant LBBAP with AV nodal ablation with advanced pulmonary disease at the Cleveland Clinic Fairview Hospital between January 2019 and January 2023. Patient characteristics, comorbidities, and medication use were extracted via chart review. Rates of hospitalizations, medication use, and structural disease seen on echocardiography were compared before and after the procedure. There were 27 patients with group 3 pulmonary hypertension who underwent the procedure. In the 24 months preprocedure, there were 114 admissions for heart failure or atrial fibrillation compared to 9 admissions postprocedure (p <.001). Mean follow up was 17.3 ± 12.1 months. There were no significant complications or lead dislodgements. Echocardiographic characteristics were similar prior to and after pacemaker implantation. Use of medications for rate and rhythm control was common preprocedure, and was reduced dramatically postprocedure. Conclusion: This small, retrospective cohort study suggests concomitant LBBAP with AV nodal ablation may be safe and efficacious for management of atrial fibrillation in patients with advanced pulmonary disease. [ABSTRACT FROM AUTHOR]

This article, titled "PVC or Not PVC? That Is the Question," discusses a case study of a 32-year-old man who was referred for evaluation of potential premature ventricular contraction (PVC)-induced cardiomyopathy. The patient had a sinus rhythm with numerous wide QRS complex ectopic beats and severe left ventricular dysfunction. The article explores the correct diagnosis based on the electrocardiogram (ECG) results and discusses the treatment and outcome of the patient. It also highlights the importance of careful examination of QRS morphology to differentiate between supraventricular beats with aberrancy and ventricular beats. [Extracted from the article]

Background: The lead of left bundle branch area pacing (LBBAP) inserted into the muscular septum will make the transvenous lead extraction (TLE) of LBBAP more challenging and because in LBBAP ventricular lead (V lead) should be inserted into the part of the septum, damage to the vessel near the lead could occur. The case reports introduced the complications of LBBAP previously introduced, but not being considered in detail. Case presentation: The two patients (76-year-old man, 90-year-old man) with a complete atrioventricular block (CAVB) undergoing the LBBAP procedure experienced complications related to the procedure. The complications were abrupt dysfunction of V lead and damage to the septal vein in the process of the procedure, respectively. Fortunately, they were discharged without any other complications. Conclusions: A deliberate approach for the procedure would be needed as well as successful insertion appropriate for the protocol of LBBAP. And long-term follow-up of complications should be needed. [ABSTRACT FROM AUTHOR]

The feasibility of the conduction system pacing combined with atrioventricular node ablation was demonstrated in patients with atrial fibrillation in whom rate control can't be achieved with medication and heart failure. We present a case of an 82-year-old man with a personal history of permanent atrial fibrillation, admitted with symptoms of heart failure. The resting electrocardiogram showed a very fast ventricular response, and the echocardiography showed a depressed left ventricular function, raising the suspicion of a tachycardia-mediated cardiomyopathy. Since the patient was on maximum doses of atrioventricular nodal-blocking drugs, we opted for a physiological pacing and atrioventricular node ablation strategy. First, the His bundle capture was achieved at low pacing thresholds, and ablation of the atrioventricular node was attempted. Unfortunately, after several failed attempts, an acute increase in the His bundle capture threshold was noted, suggesting inadvertent tissue ablation beneath the pacing lead. In this scenario, we removed the lead from the His bundle area and achieved optimal left bundle branch area pacing. With the lead in this position, atrioventricular node ablation was performed during the first attempt. At the six-month follow-up, there was no recovery of atrioventricular node conduction. Device interrogation revealed stable pacing and sensing parameters, and there was a significant improvement in clinical status and left ventricular function. Mastering both His bundle pacing and left bundle branch area pacing offers the potential to overcome intraprocedural challenges, giving alternative strategies to achieve physiological pacing. These approaches can be used interchangeably based on the evolving dynamics of the procedure and the patient's specific needs. [ABSTRACT FROM AUTHOR]

Significance: Damage to the cardiac conduction system remains one of the most significant risks associated with surgical interventions to correct congenital heart disease. This work demonstrates how light-scattering spectroscopy (LSS) can be used to non-destructively characterize cardiac tissue regions. Aim: To present an approach for associating tissue composition information with location-specific LSS data and further evaluate an LSS and machine learning system as a method for non-destructive tissue characterization. Approach: A custom LSS probe was used to gather spectral data from locations across 14 excised human pediatric nodal tissue samples (8 sinus nodes, 6 atrioventricular nodes). The LSS spectra were used to train linear and neural-network-based regressor models to predict tissue composition characteristics derived from the 3D models. Results: Nodal tissue region nuclear densities were reported. A linear model trained to regress nuclear density from spectra achieved a prediction r-squared of 0.64 and a concordance correlation coefficient of 0.78. Conclusions: These methods build on previous studies suggesting that LSS measurements combined with machine learning signal processing can provide clinically relevant cardiac tissue composition. [ABSTRACT FROM AUTHOR]

Introduction: Postoperative atrial fibrillation (POAF) is common following open heart surgery, and is associated with significant morbidity. Medications used for ventricular rate control of POAF may not be effective in controlling rapid ventricular rates during the postoperative period because of increased sympathetic tone. The purpose of this study was to develop nonpharmacologic rate control of POAF by atrioventricular node (AVN) fat pad stimulation using clinically available temporary pacing wires in the canine sterile pericarditis model. Methods: We studied 10 sterile pericarditis dogs in the closed‐chest state on postoperative days 1−3. The AVN fat pad stimulation (amplitude 2–15 mA; frequency 20 Hz; pulse width 0.03–0.2 ms) was performed during sustained POAF (>5 min). We measured ventricular rate and inefficient ventricular contractions during sustained POAF and compared it with and without AVN fat pad stimulation. Also, the parameters of AVN fat pad stimulation to achieve a rate control of POAF were measured over the postoperative days. Results: Eleven episodes of sustained POAF were induced in 5/10 sterile pericarditis dogs in the closed‐chest state on postoperative days 1−2. During POAF, the AVN fat pad stimulation decreased the ventricular rate from 178 ± 52 bpm to 100 ± 8 bpm in nine episodes. Nonpharmacologic rate control therapy successfully controlled the ventricular rate and eliminated inefficient ventricular contractions during POAF for the duration of the AVN fat pad stimulation. The AVN fat pad stimulation output remained relatively stable over the postoperative days. Conclusion: During sustained POAF, nonpharmacologic rate control by AVN fat pad stimulation effectively and safely controlled rapid ventricular rates throughout the postoperative period. [ABSTRACT FROM AUTHOR]

The article focuses on exploring the mechanism behind narrow QRS tachycardia recurrence in a patient years after undergoing "rightward inferior extension" ablation for atrioventricular nodal reentrant tachycardia (AVNRT). Topics include the identification of the tachycardia's origin near the His bundle, unsuccessful ventricular entrainment pacing, and the diagnostic challenges posed by variations in atrio-His intervals during electrophysiological study and ablation procedures.

Background: Patients who have recurrent atrial fibrillation (AF) following redo catheter ablation may eventually be managed with a pace-and-ablate approach, involving pacemaker implant followed by atrioventricular nodal ablation (AVNA). We sought to determine which factors would predict subsequent AVNA in patients undergoing redo AF ablation. Methods: We analyzed patients undergoing redo AF ablations between 2013 and 2019 at our institution. Follow-up was censored on December 31, 2021. Patients with no available follow- up data were excluded. Time-to-event analysis with Cox proportional hazard regression was used to compare those who underwent AVNA to those who did not. Results: A total of 467 patients were included, of whom 39 (8.4%) underwent AVNA. After multivariable adjustment, female sex (aHR 4.68 [95% CI 2.30-9.50]; p < 0.001), ischemic heart disease (aHR 2.99 [95% CI 1.25-7.16]; p = 0.014), presence of a preexisting pacemaker (aHR 3.25 [95% CI 1.10-9.60]; p = 0.033), and persistent AF (aHR 2.22 [95% CI 1.07-4.59]; p = 0.032) were associated with increased risk of subsequent AVNA requirement. Conclusion: Female sex, ischemic heart disease, and persistent AF may be useful clinical predictors of the requirement for subsequent AVNA and may be considered as part of shared clinical decision making. [ABSTRACT FROM AUTHOR]

Background: Atrioventricular nodal reentrant tachycardia (AVNRT) sometimes recurs even after anatomical slow pathway (SP) ablation targeting the rightward inferior extension (RIE). This multicenter study aimed to determine the reasons for AVNRT recurrence. Methods and Results: Forty-six patients were treated successfully for recurrent AVNRT. Initial treatment was for 38 slow-fast AVNRTs, 3 fast-slow AVNRTs, 2 slow-slow AVNRTs, 2 slow-fast and fast-slow AVNRTs, and 1 noninducible AVNRT. All initial treatments were of RF application to the RIE; SP elimination was achieved in 11, dual AVN physiology was seen in 29, and AVNRT remained inducible in 5. The recurrent AVNRTs included 34 slow-fast AVNRTs, 6 fast-slow AVNRTs, 3 slow-slow AVNRTs, 2 slow-fast and fast-slow AVNRTs, and 1 slow-fast and slow-slow AVNRTs. Successful ablation site was within the RIE in 39 and left inferior extension in 7. In 30 of 39, the successful RIE site was in the same area or higher than that of the initial procedure. Conclusion: For a high majority (around 85%) of patients in whom AVNRT recurs after initial ablation success, the site of a second successful procedure will be within the RIE even though the RIE was originally targeted. Furthermore, a high majority (around 86%) of sites of successful ablation will be higher than those originally targeted. [ABSTRACT FROM AUTHOR]

Assess pre and postinterventional anxiety levels in radiofrequency catheter ablation recipients (RFCA) for atrioventricular nodal reentry tachycardia (AVNRT) and investigate whether changes are associated with demographic and clinical characteristics and AVNRT subtypes. This was a single-centre prospective study conducted from September 2019 to March 2020. A total of 51 patients who were to undergo RFCA due to newly diagnosed symptomatic AVNRT were included. Electrophysiological studies were performed on all patients, the AVNRT subtype was determined, and the RFCA procedure was applied. The severity of anxiety before RFCA and 3 months after the procedure was determined by the state-trait anxiety inventory. The mean age was 50.1±17.3 years and 70.6% (n=36) were women. The median STAI-State score after ablation (37 [33–42]) was significantly lower than before (63 [52–72]) (p<0.001). Similarly, median STAI-Trait scores after ablation (45 [39–49]) were found to be significantly lower than before the procedure (59 [46–69]) (p<0.001). There were no significant relationships between the decrease in STAI-State or STAI-Trait scores and analyzed parameters such as age, sex, AVNRT type and other laboratory values. Administration of RFCA in AVNRT can improve AVNRT-induced anxiety and could eliminate the potential need for antiarrhythmic or anxiolytic therapy. Therefore, RFCA may also positively impact quality of life, and reduce unnecessary treatments, and healthcare costs associated with AVNRT. [ABSTRACT FROM AUTHOR]

Background Double-wave macrore-entry is a rare mechanism of atrial tachycardia with limited documentation in the literature. We present a three-dimensional documentation of a double-wave 'typical' atrial flutter in a patient with extensive atrial cardiomyopathy. Case summary A 78-year-old female with a history of atrial cardiomyopathy and dual-chamber pacemaker for sinus node disease presented with palpitations and incessant atrial flutter. Electrophysiological study revealed a regular tachycardia with a cycle length (TCL) of 230 ms, with proximal to distal coronary sinus (CS) activation. Three-dimensional mapping identified two independent wavefronts circulating the cavotricuspid isthmus (CTI), each with a TCL of 460 ms. Cavotricuspid isthmus ablation resulted in conversion into a distinct tachycardia with left atrial roof origin. Linear ablation in this location slowed the TCL to 435 ms with concentric CS activation and another CTI dependent atrial flutter was mapped, this time with only one wavefront of activation. Further ablation with a second, more lateral, line in the CTI led to tachycardia interruption. Given the extensive atrial scarring and high arrhythmic recurrence risk, atrioventricular node ablation was performed. Discussion Double-wave re-entrant tachycardias were primarily observed in experimental models, precipitating acceleration of ventricular and supraventricular tachycardias via extrastimulation. In our case, there is documentation of a spontaneous double-wave of activation around the CTI, representing the first documented double-wave 'typical' atrial flutter. Unlike other cases in the literature, the two wavefronts were equidistant, which resulted in a regular tachycardia with TCL that was half of the single-wave cycle length. Three-dimensional propagation mapping was essential to visualize the two distinct wavefronts. [ABSTRACT FROM AUTHOR]

The article discusses a case study of a 43-year-old woman with drug-refractory palpitations who underwent electrophysiologic study and ablation. The patient exhibited a spontaneous conversion of a long RP to short RP tachycardia during supraventricular tachycardia. The mechanism behind this phenomenon was attributed to longitudinal dissociation of a bypass tract with decremental properties. The study highlights the unique features of this case and the successful ablation of the bypass tract to eliminate the tachycardia. [Extracted from the article]

This article discusses the mechanism of a narrow QRS tachycardia in a patient with type-A Wolff-Parkinson-White (WPW) syndrome. The patient, a 52-year-old woman, was referred for catheter ablation of the tachycardia. The article presents the case presentation, differential diagnoses, and the final diagnosis of orthodromic reciprocating tachycardia (ORT) via a posteroseptal accessory pathway (AP) with a bystander left lateral AP. The article also explores the clinical insights gained from the case and discusses the challenges in distinguishing between an atrioventricular AP and a nodoventricular pathway. [Extracted from the article]

Tricuspid valve disease is an often underrecognized clinical problem that is associated with significant morbidity and mortality. Unfortunately, patients will often present late in their disease course with severe right-sided heart failure, pulmonary hypertension, and life-limiting symptoms that have few durable treatment options. Traditionally, the only treatment for tricuspid valve disease has been medical therapy or surgery; however, there have been increasing interest and success with the use of transcatheter tricuspid valve therapies over the past several years to treat patients with previously limited therapeutic options. The tricuspid valve is complex anatomically, lying adjacent to important anatomic structures such as the right coronary artery and the atrioventricular node, and is the passageway for permanent pacemaker leads into the right ventricle. In addition, the mechanism of tricuspid pathology varies widely between patients, which can be due to primary, secondary, or a combination of causes, meaning that it is not possible for 1 type of device to be suitable for treatment of all cases of tricuspid valve disease. To best visualize the pathology, several modalities of advanced cardiac imaging are often required, including transthoracic echocardiography, transesophageal echocardiography, cardiac computed tomography, and cardiac magnetic resonance imaging, to best visualize the pathology. This detailed imaging provides important information for choosing the ideal transcatheter treatment options for patients with tricuspid valve disease, taking into account the need for the lifetime management of the patient. This review highlights the important background, anatomic considerations, therapeutic options, and future directions with regard to treatment of tricuspid valve disease. [ABSTRACT FROM AUTHOR]

Introduction: Information about autonomic nervous system (ANS) activity may offer insights about atrial fibrillation (AF) progression and support personalized AF treatment but is not easily accessible from the ECG. In this study, we propose a new approach for ECG-based assessment of respiratory modulation in atrioventricular (AV) nodal refractory period and conduction delay. Methods: A 1-dimensional convolutional neural network (1D-CNN) was trained to estimate respiratory modulation of AV nodal conduction properties from 1- minute segments of RR series, respiration signals, and atrial fibrillatory rates (AFR) using synthetic data that replicates clinical ECG-derived data. The synthetic data were generated using a network model of the AV node and 4 million unique model parameter sets. The 1D-CNN was then used to analyze respiratory modulation in clinical deep breathing test data of 28 patients in AF, where an ECG-derived respiration signal was extracted using a novel approach based on periodic component analysis. Results: We demonstrated using synthetic data that the 1D-CNN can estimate the respiratory modulation from RR series alone with a Pearson sample correlation of r = 0.805 and that the addition of either respiration signal (r = 0.830), AFR (r = 0.837), or both (r = 0.855) improves the estimation. Discussion: Initial results from analysis of ECG data suggest that our proposed estimate of respiration-induced autonomic modulation, aresp, is reproducible and sufficiently sensitive to monitor changes and detect individual differences. However, further studies are needed to verify the reproducibility, sensitivity, and clinical significance of aresp. [ABSTRACT FROM AUTHOR]

A 16-year-old man presented with short VA supraventricular tachycardia and 2:1 atrioventricular ratio. The correct maneuvers allowed us to guide not only the mechanism but also the probable location of the atrioventricular block. [ABSTRACT FROM AUTHOR]

Introduction: Mapping system is useful in ablation of atrioventricular nodal reentry tachycardia (AVNRT) and localization of anatomic variances. Voltage mapping identifies a low voltage area in the Koch triangle called low‐voltage‐bridge (LVB); propagation mapping identifies the collision point (CP) of atrial wavefront convergence. We conducted a prospective study to evaluate the relationship between LVB and CP with successful site of ablation and identify standard value for LVB. Materials and Methods: Three‐dimensional (3D) maps of the right atria were constructed from intracardiac recordings using the ablation catheter. Cut‐off values on voltage map were adjusted until LVB was observed. On propagation map, atrial wavefronts during sinus rhythm collide in the site representing CP, indicating the area of slow pathway conduction. Ablation site was selected targeting LVB and CP site, confirmed by anatomic position on fluoroscopy and atrioventricular ratio. Results: Twenty‐seven consecutive patients were included. LVB and CP were present in all patients. Postprocedural evaluation identified standard cut‐off of 0.3−1 mV useful for LVB identification. An overlap between LVB and CP was observed in 23 (85%) patients. Procedure success was achieved in all patient with effective site at first application in 22 (81%) patients. There was a significant correlation between LVB, CP, and the site of effective ablation (p = .001). Conclusion: We found correlation between LVB and CP with the site of effective ablation, identifying a voltage range useful for standardized LVB identification. These techniques could be useful to identify ablation site and minimize radiation exposure. [ABSTRACT FROM AUTHOR]

To investigate the short- and long-term risks of atrioventricular block and other cardiac conduction disorders associated with being tested for Borrelia burgdorferi (Bb) antibodies or Bb seropositivity as measures of confounding by indication and Bb infection, respectively. We performed a nationwide population-based matched cohort study (Denmark, 1993–2021). We included 52 200 Bb-seropositive individuals (stratified as only Bb- IgM-seropositive [ n = 26 103], only Bb- IgG-seropositive [ n = 18 698], and Bb- IgM-and-IgG-seropositive [ n = 7399]) and two age- and sex-matched comparison cohorts: 104 400 Bb-seronegative individuals and 261 000 population controls. We investigated the risk associated with being tested for serum Bb antibodies and being Bb seropositive. Outcomes were atrioventricular block and other conduction disorders. We calculated short-term odds ratios (aOR) (within 1 month), and long-term hazard ratios (aHR) (after 1 month) adjusted for age, sex, diabetes, chronic heart failure, and kidney disease with 95% CI. Compared with population controls, individuals tested for Bb antibodies had increased short- and long-term risks of atrioventricular block (aOR 47.9, 95% CI: 30.0–76.7, aHR 1.3, 95% CI:1.2–1.3), and other conduction disorders (aOR 18.2, 95% CI: 10.1–32.8, aHR 1.2, 95% CI: 1.1–1.4). Compared with Bb -seronegative individuals, only Bb- IgM-and-IgG-seropositive individuals had increased short-term risk of atrioventricular block (aOR: 2.1, 95% CI: 1.5–3.1). The results suggest that Bb antibody testing is included in the diagnostic work-up of conduction disorders. Finally, that Bb seropositivity is not associated with other conduction disorders than atrioventricular block or with increased long-term risk of conduction disorders. [ABSTRACT FROM AUTHOR]

Smartwatches represent one of the most widely adopted technological innovations among wearable devices. Their evolution has equipped them with an increasing array of features, including the capability to record an electrocardiogram. This functionality allows users to detect potential arrhythmias, enabling prompt intervention or monitoring of existing arrhythmias, such as atrial fibrillation. In our research, we aimed to compile case reports, case series, and cohort studies from the Web of Science, PubMed, Scopus, and Embase databases published until 1 August 2023. The search employed keywords such as "Smart Watch", "Apple Watch", "Samsung Gear", "Samsung Galaxy Watch", "Google Pixel Watch", "Fitbit", "Huawei Watch", "Withings", "Garmin", "Atrial Fibrillation", "Supraventricular Tachycardia", "Cardiac Arrhythmia", "Ventricular Tachycardia", "Atrioventricular Nodal Reentrant Tachycardia", "Atrioventricular Reentrant Tachycardia", "Heart Block", "Atrial Flutter", "Ectopic Atrial Tachycardia", and "Bradyarrhythmia." We obtained a total of 758 results, from which we selected 57 articles, including 33 case reports and case series, as well as 24 cohort studies. Most of the scientific works focused on atrial fibrillation, which is often detected using Apple Watches. Nevertheless, we also included articles investigating arrhythmias with the potential for circulatory collapse without immediate intervention. This systematic literature review provides a comprehensive overview of the current state of research on arrhythmia detection using smartwatches. Through further research, it may be possible to develop a care protocol that integrates arrhythmias recorded by smartwatches, allowing for timely access to appropriate medical care for patients. Additionally, continuous monitoring of existing arrhythmias using smartwatches could facilitate the assessment of the effectiveness of prescribed therapies. [ABSTRACT FROM AUTHOR]

An 80-year-old female was referred to our institution due to transient right upper limb weakness. Transthoracic and transesophageal echocardiography revealed a tumor in the left atrium. The tumor was attached to the posterior wall of the left atrium near the atrioventricular node. Intraoperative pathological examination revealed that the tumor was a myxoma, and complete resection was successfully performed. However, she experienced persistent complete atrioventricular block postoperatively and required pacemaker implantation. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 54-year-old man undergoing radiofrequency ablation for atrial fibrillation, encountering an irregular tachycardia during the procedure. Topics discussed include the mechanism of irregular tachycardia, interpretation challenges due to its irregularity, and the diagnosis of orthodromic reciprocating tachycardia.

This study aimed to elucidate the similarities and differences between amyloid-forming corpora amylacea (CA) in the prostate and lung, examine the nature of CAs in cystic tumors of the atrioventricular node (CTAVN), and clarify the distinctions between amyloid-forming CA and spheroid-type amyloid deposition. We conducted proteomics analyses using liquid chromatography–tandem mass spectrometry with laser microdissection and immunohistochemistry to validate the characteristics of CAs in the lung and prostate. Our findings revealed that the CAs in these organs primarily consisted of common proteins (β2-microglobulin and lysozyme) and locally produced proteins. Moreover, we observed a discrepancy between the histopathological and proteomic analysis results in CTAVN-associated CAs. In addition, while the histopathological appearance of the amyloid-forming CAs and spheroid-type amyloid deposits were nearly identical, the latter deposition lacked β2-microglobulin and lysozyme and exhibited evident destruction of the surrounding tissue. A literature review further supported these findings. These results suggest that amyloid-forming CAs in the lung and prostate are formed through a shared mechanism, serving as waste containers (wasteosomes) and/or storage for excess proteins (functional amyloids). In contrast, we hypothesize that while amyloid-forming CA and spheroid-type amyloid deposits are formed, in part, through common mechanisms, the latter are pathological. [ABSTRACT FROM AUTHOR]

Introduction: The optimal slow pathway (SP) ablation site in cases with an inferiorly located His bundle (HIS) remains unclear. Methods and Results: In 45 patients with atrioventricular nodal reentrant tachycardia, the relationship between the HIS location and successful SP ablation site was assessed in electroanatomical maps. We assessed the location of the SP ablation site relative to the bottom of the coronary sinus ostium in the superior‐to‐inferior (SPSI), anterior‐to‐posterior (SPAP), and right‐to‐left (SPRL) directions. The HIS location was assessed in the same manner. The HIS location in the superior‐to‐inferior direction (HISSI), SPSI, SPAP, and SPRL were 17.7 ± 6.4, 1.7 ± 6.4, 13.6 ± 12.3, and −1.0 ± 13.0 mm, respectively. The HISSI was positively correlated with SPSI (R2 = 0.62; P <.01) and SPAP (R2 = 0.22; P <.01), whereas it was not correlated with SPRL (R2 = 0.01; P =.65). The distance between the HIS and SP ablation site was 17.7 ± 6.4 mm and was not affected by the location of HIS. The ratio of the amplitudes of atrial and ventricular potential recorded at the SP ablation site did not differ between the high HIS group (HISSI ≥ 13 mm) and low HIS group (HISSI < 13 mm) (0.10 ± 0.06 vs. 0.10 ± 0.06; P =.38). Conclusion: In cases with an inferiorly located HIS, SP ablation should be performed at a lower and more posterior site than in typical cases. [ABSTRACT FROM AUTHOR]

Background: Atrioventricular block (AVB) secondary to transient causes can recover with its correction. However, studies assessing predictors of recovery and long‐term recurrence are lacking. Methods: Patients with advanced or complete AVB who had a reversible cause admitted in a single expert center were retrospectively studied. Patients with AVB secondary to acute coronary syndromes were excluded from analysis. Results: In a population of 162 patients, the main factors associated with recovery of rhythm without a permanent pacemaker (PPM) implantation were the presence of chronic kidney disease (CKD) on dialysis (OR 7.6; CI 95% 1.2–47.5 (p =.03)); greater serum potassium levels (OR 2.3; CI 95% 1.28–4.0 (p <.01)), higher dosage of bradycardic drugs (OR 2.2; CI 95% 1.13–4.4 (p =.02)), the association between different bradycardic drugs (OR 9.0; CI 95% 2.02–40.3 (p <.01)) and between drug therapy and hyperkaliemia (OR 5.2; CI 95% 1.8–15.1 (p <.01)). There was an overall high burden of conductions abnormalities which did not correlate with recovery of rhythm (OR 0.5; CI 95% 0.19–1.5 (p =.23)). In 29 patients (17.9%) there was a correction of the AVB. During a maximum follow‐up of 130 months, 24 patients (82.8%) had a recurrence which warranted a PPM. In the overall cohort only five patients (3%) had sustained recovery of rhythm. Conclusions: Recovery of AVB was mainly observed with higher doses of drug therapy, higher serum potassium levels or a combination of factors and regardless of baseline conduction abnormalities. The high rate of recurrence during follow‐up warrants a close follow‐up or PPM implantation at index admission. [ABSTRACT FROM AUTHOR]

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