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The case was a 15‐year‐old male with a history of paroxysmal supraventricular tachycardia refractory to medical therapy and prior catheter. A repeat electrophysiology study and catheter ablation were applied. Baseline AH and HV intervals were 100 and 55 ms during normal sinus rhythm (NSR), respectively. Programmed atrial stimulation induced a short RP narrow complex tachycardia (HV interval 22 ms) with an incomplete right bundle branch block configuration and right axis deviation. Tachycardia was terminated with ATP 5 mg injection. An atrial premature beat within the His refractory period advanced and reset tachycardia. Entrainment performed from the coronary sinus and left ventricle both showed a post‐pacing interval minus tachycardia cycle length (TCL) of 90 ms. After confirming the diagnosis, left atrial mapping along mitral annulus was performed using trans‐septal access and accessory pathway potentials were recorded during NSR and tachycardia at the superior mitral annulus. An irrigated ablation catheter guided by 3‐D mapping was used to perform ablation during tachycardia. Tachycardia terminated immediately during the first RF application with ensuing automaticity exhibiting a warm‐up during radiofrequency delivery and a cooling down upon the suspension of ablation. Therefore, all phenomena of Mahaim‐fiber associated tachycardia were observed. In this case, we describe an antidromic atrio‐ventricular reentry tachycardia using a left atrio‐fascicular fiber inserting into the proximal left anterior fascicle. [ABSTRACT FROM AUTHOR]

Introduction: Supraventricular tachycardia (SVT) is a common pediatric arrhythmia. Beta blockers (BBs) and calcium channel blockers (CCBs) are used for treatment despite little data examining their use. We describe the prescriptive tendencies, efficacy, and tolerability of BBs and CCBs used in the treatment of pediatric SVT. Methods and Results: This is a multicenter retrospective cohort study from three academic children's hospitals. Individuals aged 1–21 years at time of SVT diagnosis initiated on a BB or a CCB between 01/01/2010 and 12/31/2020 were included. Exclusion criteria were pre‐excitation, ectopic atrial tachycardia, and hemodynamically significant heart disease. Demographic, comorbidity, symptomatology, and medication data were collected. Treatment success was defined using a composite data abstraction tool. Of 164 patients, 151 received a BB and 13 received a CCB. The success rate on the initial dosage was 46% for both BB and CCB; the success rate following dosage adjustments was also comparable for BBs (98/151, 65%) and CCBs (9/13, 69%). While 27 (18%) BB patients experienced intolerable side effects, no CCB patient did. Conclusion: Treatment with a BB or CCB was successful in half of patients. BBs were prescribed more frequently than CCBs but were associated with more side effects. [ABSTRACT FROM AUTHOR]

Introduction: The decremental properties of the nodoventricular pathway (NVP) are uncertain. Methods and Results: During short RP supraventricular tachycardia, a His‐refractory premature ventricular contraction (PVC) consistently terminated the tachycardia without atrial capture immediately after the PVC. Whereas a slightly earlier PVC failed to reset the subsequent His but terminated the tachycardia without atrial capture one cycle later. Conclusion: These observations are diagnostic of slow‐fast atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed‐NVP and can be explained by decremental properties in the NVP itself; greater prematurity of the PVC resulted in more decremental conduction over the NVP, causing the AVNRT termination one cycle later. [ABSTRACT FROM AUTHOR]

Background and aims: Methods for femoral venous haemostasis following electrophysiology (EP) procedures include manual compression (MC) and suture‐based techniques such as a figure‐of‐eight suture secured with a hand‐tied knot (Fo8HT) or a modified figure‐of‐eight suture secured with a 3‐way stopcock (Fo8MOD). We hypothesised that short‐term bleeding outcomes using the Fo8MOD approach would be superior to MC. We additionally compared outcomes between Fo8MOD and Fo8HT approaches. Methods: We studied consecutive patients undergoing EP procedures at our institution between March and December 2023. Patients were categorised into three haemostasis groups: MC, Fo8HT and Fo8MOD. Access site complications were classified as major (requiring intervention or blood transfusion, delaying discharge or resulting in death) or minor (bleeding/haematoma requiring additional compression). Results: 1089 patients were included: MC 718 (65.9%); Fo8HT 105 (9.6%); Fo8MOD 266 (24.4%). Procedures were most commonly for atrial fibrillation (52.4%), atrial flutter (10.9%), and atrioventricular nodal re‐entrant tachycardia (10.1%). In patients receiving periprocedural anticoagulation (865, 79.4%), Fo8MOD associated with fewer complications than MC or Fo8HT (major: MC 2.2%, Fo8HT 6.0%, Fo8MOD 0.8%, p =.01; minor: MC 16.5%, Fo8HT 12.0%, Fo8MOD 7.4%, p =.002). In patients not receiving periprocedural anticoagulation, complications did not differ between haemostasis methods (total major and minor complications 5.8%, p =.729 for between groups rates). On multivariable logistic regression, Fo8MOD was associated with a significantly lower risk of access site complications (OR 0.29 [95% CI 0.17–0.48], p <.001), whilst intraprocedural heparinisation (OR 5.25 [2.88–9.69], p <.001) and larger maximal sheath size (OR 1.06 [1.00–1.11], p =.04) were associated with a higher risk of complications. Conclusion: Femoral haemostasis with Fo8MOD associates with fewer access site complications than MC and Fo8HT following EP procedures that need periprocedural anticoagulation. [ABSTRACT FROM AUTHOR]

The article present case study of a 63‐year‐old woman with a history of palpitations and documented long-RP supraventricular tachycardia (SVT). Topics include evaluating SVT mechanisms through VOP responses; distinguishing between atypical atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT); and challenges posed by inadvertent capture of the Purkinje conduction system during pacing.

The article present case study of a 40-year-old female with catheter ablation of narrow QRS regular tachycardia. Topics include the mechanism behind narrow QRS regular tachycardia with ventriculoatrial (VA) dissociation; the differential diagnosis of Atrioventricular nodal reentrant tachycardia (AVNRT); nodoventricular or nodofascicular pathway-mediated orthodromic reciprocating tachycardia and the challenges in differentiating these from junctional tachycardia or AVNRT with bystander pathways.

Introduction: The reduction of fluoroscopic exposure during catheter ablation of supraventricular arrhythmias is widely adopted by experienced electrophysiology physicians with a relatively short learning curve and is becoming the standard of care in many parts of the world. While observational studies in the United States and some parts of Western Europe have evaluated the minimal fluoroscopic approach, there are scarce real‐world data for this technique and the generalizability of outcomes in other economic regions. Method: The AALARA study is a prospective, observational, multicenter, and multinational open‐label study. Patients were recruited from 13 countries across Central Eastern Europe, North and South Africa, the Middle East, and the CIS (Commonwealth of Independent States), with different levels of operator expertise using minimal fluoroscopic exposure techniques. Data on radiation exposure, procedural success, complications, recurrence, and quality of life changes were collected and analyzed. Result: A total of 680 patients were enrolled and followed for 6 months. The majority were ablation naïve with the commonest arrhythmia ablated being typical AVNRT (58%) followed by Atrial Flutter (23%). Zero fluoroscopy exposure was observed in almost 90% of the cases. Fluoroscopy was most commonly used during the ablation phase of the procedure. We observed a high acute success rate (99%), a low complication rate (0.4%), and a 6‐month recurrence rate of 3.8%. There was a significant improvement in the patient's symptoms and quality of life as measured by patient global assessment. Conclusion: The routine use of a 3D mapping system during right‐sided ablation was associated with low radiation exposure and associated with high acute success rate, low complications, and recurrence rate along with significant improvement in quality of life. The data confirm the reproducibility of this approach in real‐world settings across different healthcare systems, and operator experience supporting this approach to minimize radiation exposure without compromising efficacy and safety. Trial Registration: NCT04716270 [ABSTRACT FROM AUTHOR]

Catheter ablation for tachyarrhythmia via superior approach has been used in patients without possible inferior vena cava access such as in cases of venous occlusion or complex anomaly. Difficulty in catheter manipulation, instability, number of required vascular access, and radiation exposure of operator had been described in the procedure. Application of three‐dimensional (3‐D) mapping system in catheter ablation via superior approach could navigate the guiding catheter and provide more precise ablation. We reported four cases receiving catheter ablation due to atrioventricular nodal reentry tachycardia, atrial fibrillation, and right ventricular arrhythmia via superior approach facilitated by 3‐D mapping system with fewer vascular access and catheters. [ABSTRACT FROM AUTHOR]

We report a case of a 44‐year‐old male who underwent an electrophysiological study for symptomatic supraventricular tachycardia (SVT) with wide QRS complex. The SVT was diagnosed as an antidromic atrioventricular reentrant tachycardia (AVRT) via antegrade conduction of left‐sided accessory pathway (AP). However, the QRS morphology changed during the SVT, and then the SVT was terminated spontaneously. The mapping of AP was performed during sinus rhythm, and the radiofrequency application successfully eliminated the AP, which rendered tachycardias non‐inducible. This was a rare case of antidromic AVRT during which the QRS morphology changed. [ABSTRACT FROM AUTHOR]

Aim: There is no consensus on the best prophylaxis for supraventricular tachycardia (SVT) in infancy. We studied the efficacy and safety of sotalol. Method: This retrospective study comprised infants diagnosed with SVT before 1 year of age and treated with sotalol during 2002–2018 in Stockholm, Sweden. The patients' characteristics, comorbidities, sotalol dosages, QT intervals and outcomes were extracted from their medical records. Results: We studied 85 infants (65% boys) with a median age of eight (range 0–288) days at the time of diagnosis, including 78 with re‐entry tachycardia. Sotalol was completely or partially successful in the 67/75 patients who completed the treatment, as well as in four of the seven patients with other tachycardia mechanisms. The 48 infants with postnatal debut had significantly higher success rates than the 27 with foetal debut (96% vs. 78%, p = 0.04). Prolongation of corrected QT (QTc) intervals of ≥450 ms occurred in 16% of the total cohort and two patients with QTc intervals of ≥500 ms had their treatment changed. There were no cases of proarrhythmia after sotalol treatment. Conclusion: Sotalol provided effective and safe prophylaxis for SVT during infancy. QTc prolongation rarely caused treatment discontinuation and there were no cases of proarrhythmia. [ABSTRACT FROM AUTHOR]

Supraventricular tachycardia (SVT) is commonly evaluated in the emergency department (ED). While troponin has been shown to be elevated in SVT, its usefulness for predicting coronary artery disease and future adverse cardiovascular outcomes has not been shown. We aimed to evaluate the prognostic utility of troponin measurement as part of SVT management in the ED. We performed a literature search in the PubMed and Scopus databases from inception to August 30, 2023, including all studies reporting troponin measurements in adult patients (age > 18 years) presenting to the ED with supraventricular tachycardia. The primary outcome of interest for this study was the prevalence of elevated troponin in patients with SVT. Secondary outcomes included the prevalence of major adverse cardiac events (MACE) and additional cardiac testing with significant findings. We included 7 studies (500 patients) in our analysis. Six studies reported the number of patients with SVT and elevated troponin, with a pooled prevalence of 46% (95% CI 27–66%, I2 93%). The pooled prevalence of all MACE in our study was 6% (95% CI 1–25%), while the prevalence for MACE among patients with elevated serum troponin levels was 11% (95% CI 4–27%). Troponin levels are frequently ordered for ED patients with SVT and are often elevated. However, this review suggests that they have low prognostic value in predicting MACE. [ABSTRACT FROM AUTHOR]

To evaluate the rate of supraventricular tachycardia (SVT) termination between 6 mg and 12 mg initial adenosine doses. This multi-center, retrospective cohort study evaluated patients presenting to the emergency department (ED) from January 1, 2020 to June 30, 2022 in SVT and received adenosine. The primary objective of the study is to compare the rate of SVT termination between adenosine 6 mg and 12 mg as documented on a formal electrocardiogram. Secondary endpoints include termination of SVT with subsequent adenosine dose, time to ED disposition, adverse effects, and subgroup analyses of patients with a body mass index greater than or equal to 40 kg/m2 and a history of SVT. Of 213 patients included, a 6 mg initial adenosine dose was administered to 117 patients (54.9 %) and a 12 mg initial adenosine dose was administered to 96 patients (45.1 %). SVT termination following the initial dose of 6 mg or 12 mg was 56.4 % and 79.1 %, respectively (p < 0.001). Among the 46 patients who failed to terminate SVT with an initial 6 mg dose, 33 converted to sinus rhythm with a subsequent adenosine dose in comparison to 1 of the 7 patients receiving an initial dose of 12 mg (71.7 % vs 14.3 %, p = 0.007). Median time to ED disposition, either inpatient admission or discharge, was 209 and 161 min, respectively (p = 0.104). There was no statistical difference in either subgroup analyses. A higher rate of SVT termination was observed with an initial adenosine dose of 12 mg in the ED in comparison to the guideline recommended dose of 6 mg. There were no significant differences in adverse effects observed. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Objectives Methods Results Conclusion Event monitors are being increasingly used in pediatric and adult congenital heart disease (ACHD) patients for arrhythmia evaluation. Data on their diagnostic yield are limited.To evaluate the diagnostic yield of event monitors, patient characteristics associated with critical events, and clinical response to events.We retrospectively assessed event monitors prescribed to patients at our institution's Heart Center from 2017 to 2020. Thirty‐day event monitor tracings were reviewed by an electrophysiologist (EP) to identify critical events defined as supraventricular tachycardia (SVT, re‐entrant, atrial tachycardia, atrial flutter, and atrial fibrillation), ventricular tachycardia (VT), atrioventricular block, and pauses greater than 3 s. Patient characteristics and treatment data were collected. Characteristics associated with events were assessed using multivariable logistic regression. Trends in monitor prescription over time, diagnostic yield, and clinical response to events were analyzed.204/2330 (8.8%) event monitors had EP‐confirmed critical events. Critical events included SVT (51.5%), VT (38.5%), atrioventricular block (4%), and pauses (6%). 129/198 (65%) patients with critical events underwent treatment. Event monitoring usage increased by 52% between 2017 and 2020 (p < 0.0001). Complex CHD (OR 2.1, 95% CI 1.3–3.4, p = 0.004), cardiomyopathy (OR 2.9, 95% CI 1.5–4.8, p < 0.001), and EP‐ordered monitors (OR 1.6, 95% CI 1.2–2.1, p = 0.001) were more highly associated with critical events.Event monitor use is common, and critical events were captured in 8.8% of patients. The majority of patients with critical events underwent treatment. Factors associated with critical events include EPs as ordering providers, complex CHD, and cardiomyopathy. [ABSTRACT FROM AUTHOR]

5β-Cardenolides are pharmaceutically important metabolites from the specialized metabolism of Digitalis lanata. They were used over decades to treat cardiac insufficiency and supraventricular tachycardia. Since the 1960s, plant scientists have known that progesterone is an essential precursor of cardenolide formation. Therefore, biosynthesis of plant progesterone was mainly analyzed in species of the cardenolide-containing genus Digitalis during the following decades. Today, Digitalis enzymes catalyzing the main steps of progesterone biosynthesis are known. Most of them are found in a broad range of organisms. This review will summarize the findings of 60 years of research on plant progesterone metabolism with particular focus on the recent results in Digitalis lanata and other plants. [ABSTRACT FROM AUTHOR]

Objective Decreased survival and higher cardiovascular morbidity have been recently reported in a UK cohort of 61 RTHβ patients, but there is no evidence from other countries. Design Retrospective cohort study from an historical group of 284 Italian RTHβ patients, diagnosed between 1984 and 2023. Methods We collected data on diagnosis of 284 cases and longitudinal data of 249 RTHβ who carried heterozygous pathogenic variants in the THRB gene. We studied how thyroid function and recognized risk factors for cardiovascular disease, such as hypertension and diabetes, affected overall mortality and major cardiovascular events. Results The cumulative prevalence of sinus/supraventricular tachycardia and atrial fibrillation was 40% and 18%, respectively. FT4 values 57% higher than the upper limit of normal were associated with premature cardiovascular manifestations. Major cardiovascular events (MACEs) occurred in RTHβ patients at a median age (IQR) of 59.4 years (50.4-66.4) and early mortality resulted in a mean of 11 years of life lost. While at univariable analysis hypertension, dyslipidemia, high fasting glucose/diabetes were also associated with MACEs, at multivariable analysis only age at diagnosis, increased fT4 levels, and male gender remained significantly associated with MACEs and age at diagnosis and higher fT4 levels with mortality. Previous thyroidectomy or radioiodine therapy had no statistically significant effect in the prevention of major cardiovascular events or all-cause mortality. Conclusions These data should raise the general awareness on the cardiovascular risk and prompt a proactive cardiovascular monitoring in RTHβ, especially in men and those with fT4 levels above 30 pmol/L. [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]

Pediatric cardiac symptoms such as palpitations, syncope, or seizure-like episodes pose diagnostic challenges for general pediatricians. These symptoms, though often benign, may reveal underlying arrhythmias or inherited cardiac conditions (ICCs), affecting the quality of life and limiting activity participation. The purpose of this study is to determine the effectiveness and safety of implantable loop recorders (ILRs) in diagnosing and managing arrhythmias in pediatric patients. A retrospective cohort study conducted over an 8-year period from January 2016 to December 2023 in a single pediatric cardiology center. A cohort of 155 pediatric patients (median age 11.4 years) who underwent ILR implantation were selected based on symptoms such as palpitations, chest pain, or syncope, and those with previously recorded arrhythmias or high-risk ICCs. The primary outcomes were the diagnostic yield of ILRs for arrhythmias and subsequent changes in patient management. Diagnostic yield was defined as the detection of relevant arrhythmias, such as pauses of 3 s or longer, high-degree AV block, sinus node dysfunction, supraventricular tachycardia, ventricular tachycardia, or inappropriate sinus tachycardia. The median follow-up period was 2.3 years (845 days). Diagnostic arrhythmias were recorded in 60% of patients with symptom-activated transmissions and 80% of device-activated transmissions. Sinus pauses (37.5%) and VT (30%) were the most common arrhythmias detected. In patients with syncope (n = 76), 30% had relevant arrhythmias. In the palpitations group (n = 20), 35% had relevant arrhythmias. Approximately 80% of patients with ILR-diagnosed arrhythmias underwent targeted management, including medication changes and additional procedures. No significant complications were observed; minor complications occurred in 2.5% of patients. Conclusions: New generation ILRs are effective and safe for diagnosing and managing pediatric arrhythmias, providing significant reassurance to patients and families. Further studies are needed to evaluate the impact of ILRs on quality of life and sports participation in high-risk young patients. What is Known: • Pediatric Cardiac Symptoms: Symptoms like palpitations, syncope, and seizure-like episodes in pediatric patients pose significant diagnostic challenges. • Diagnostic Tools: Traditional diagnostic tools such as ECG, Holter monitors, and external loop recorders often have low diagnostic yields due to the sporadic nature of symptoms. • Implantable Loop Recorders (ILRs): ILRs have been shown to improve the diagnostic yield for arrhythmias in adults and provide long-term rhythm monitoring. What is New: • Effectiveness in Pediatrics: This study demonstrates that new generation ILRs significantly enhance the diagnostic yield for arrhythmias in pediatric patients with undiagnosed cardiac symptoms. • Safety and Efficacy: The study confirms that ILRs are both safe and effective in the pediatric population, with minimal complications and high diagnostic accuracy. • Targeted Management: Findings show that ILR-diagnosed arrhythmias lead to targeted management changes in approximately 80% of cases, including medication adjustments and additional procedures. • Long-term Monitoring: ILRs provide continuous long-term monitoring, offering reassurance to patients and families, and potentially improving quality of life and participation in activities for high-risk young patients. [ABSTRACT FROM AUTHOR]

Single-lead electrocardiogram (ECG) devices may allow detection and diagnosis of cardiac rhythms. However, data on their accuracy for detecting cardiac arrhythmias beyond atrial fibrillation are limited. We aimed to determine the accuracy of the AliveCor KardiaMobile (AC) (AliveCor Inc, Mountain View, CA, USA) for the diagnosis of arrhythmias against gold standard cardiac electrophysiology study (EPS). Patients undergoing clinically indicated EPS underwent simultaneous rhythm recording with an AC, standard 12-lead ECG, and EP catheters for intracardiac electrograms. Rhythms recorded during EPS were classified based on electrogram, 12-lead ECG, and clinical findings. Blinded reviewers provided differential diagnoses for the single-lead AC tracings; a separate reviewer compared diagnoses made between the AC tracings and EPS findings. In 49 patients, 843 cardiac rhythms were captured during 502 AC recordings. Analysis of tracings containing sinus rhythm (n=273) returned an overall accuracy of 92%, with sensitivity and specificity values of 93% and 92%, respectively. Accuracy for tracings per rhythm was atrial fibrillation 91% (n=51); supraventricular tachycardia accuracy was 89% (n=191), ventricular tachycardia 91% (n=198), ventricular fibrillation 98% (n=11), and asystole 100% (n=5). Accuracy for supraventricular ectopy was 93% (n=28) and for premature ventricular complexes was 91% (n=86). Overall accuracy was 94% for solitary rhythms and 93% in tracings from patients with baseline bundle branch block. When compared against the gold standard EPS diagnosis, the interpretation of arrhythmias recorded by an AliveCor single-lead ECG device had reasonable diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Background: The R wave in lead aVR, during the wide QRS complex tachycardia, is commonly observed in a ventricular tachycardia (VT) arising from certain locations in the ventricles. Objectives: This was a retrospective and a proof of concept study to correlate the sites of origin of VT and premature ventricular contractions (PVCs) with the occurrence of R wave in lead aVR. Methods: Patients with VT or high density of PVCs were included. Surface and intracardiac electrograms were recorded during the arrhythmia. VTs and PVCs arising from the inferior, inferolateral, or apical region of the ventricles were grouped into Zone 2. Those arising from the other areas of the ventricles were grouped into Zone 1. Results: Sixty‐four patients were included in the study. The mean age was 57 years. There were 47 males. Among 64 patients with VT or PVCs, 28 patients had an R wave in aVR (43.7%), In 26 of 28 patients with an R wave in aVR, the site of origin of the arrhythmia was in Zone 2. The R wave in aVR was absent in 36 patients, 34 of whom had the origin of arrhythmia focus in Zone 1. The presence of an R wave in aVR correctly identified Zone 2 as a site of origin of the arrhythmia with high sensitivity (93%) and specificity (94%). Conclusions: The presence of an R wave in aVR during wide QRS complex tachycardia or PVC is a valuable observation for identifying the site of origin of the arrhythmia and hence in distinguishing supraventricular tachycardia with aberrancy from VT. [ABSTRACT FROM AUTHOR]

Background and Objectives: Cardiovascular implantable electronic devices can detect atrial high‐rate episodes (AHREs). However, the predictors of clinically relevant AHREs have not been well identified. Methods: This prospective study included 145 patients (median age 64.5 ± 16.4 years, 53.1% females) without atrial fibrillation (AF) from December 2020 to January 2022. AHREs were defined as a programmed atrial detection rate >190 beats per minute. Cox regression analysis was used to identify the risk factors of AHREs. Results: During 6 months of follow‐up, AHREs occurred in 30.3% of patients. Multivariable Cox regression analysis showed factors related to development of AHREs including using anti‐arrhythmic drugs (AAD) before implantation (Hazard ratio (HR) 7.71; 95% confidence interval [95% CI], 2.58–23.02, p <.001), history of paroxysmal supraventricular tachycardia (PSVT; HR 2.45; [95% CI], 1.18–5.09, p =.016), the percentage of premature atrial contraction (PAC) on 24‐h Holter electrocardiogram (ECG) monitoring (HR 1.008; [95% CI], 1.003–1.014, p =.003), and left ventricular global longitudinal strain (GLS‐LV; HR 0.92;[95% CI], 0.84–0.99, p =.049). Conclusions: This study showed that a history of PSVT and using AAD, the percentage of PAC on 24‐h Holter ECG monitoring, and GLS‐LV were the independent predictors of new‐onset AHREs. [ABSTRACT FROM AUTHOR]

Background Sarcoidosis is a rare disease, and cardiac involvement is seen in the minority of patients. The clinical symptoms depend on the location of the noncaseating granulomas in the heart and vary from asymptomatic to atrioventricular (AV) conduction block, ventricular arrhythmia, heart failure, and sudden cardiac death. Clinically manifest cardiac sarcoidosis seldomly presents with supraventricular tachycardia. Case summary We present a case where a female patient presented with AV nodal re-entrant tachycardia as an uncommon initial presentation of cardiac sarcoidosis. Her resting electrocardiogram showed a complete left bundle branch block and first-degree AV conduction block. During hospitalization, there was continuous switching between sinus rhythm with first-degree AV block, 2:1 AV block, and AV nodal re-entrant tachycardia. Discussion It is important to be aware that cardiac sarcoidosis can rarely present with supraventricular tachycardia as initial symptom. Given the elevated risk of sudden cardiac death, early detection is crucial and all patients who require permanent pacing should be considered for implantable cardioverter-defibrillator implantation. [ABSTRACT FROM AUTHOR]

Background. Left ventricular hypertrabeculation (LVHT) is a myocardial disorder with different clinical manifestations, from total absence of symptoms to heart failure, arrhythmias, sudden cardiac death (SCD), and thromboembolic events. It is challenging to distinguish between the benign and pathological forms of LVHT. The aim of this study was to describe the arrhythmic manifestations of LVHT in a large group of pediatric patients and to correlate them with genetic results or other clinical markers. Methods. We retrospectively enrolled 140 pediatric patients with diagnosis of LVHT followed at our Institution from 2013 to 2023. Data regarding family history, instrumental exams, cardiac magnetic resonance, genetic testing and outcomes were collected. Most of them had isolated LVHT (80.7%); in other patients, mixed phenotypes (hypertrophic or dilated cardiomyopathy or congenital heart disease) were present. Results. Arrhythmias were found in 33 children (23.6%): 13 (9.3%) supraventricular tachyarrhythmias; 14 (10%) ventricular arrhythmias (five frequent PVCs (premature ventricular contractions), eight patients with ventricular tachycardia (VT), one ventricular fibrillation (VF)); two (1.4%) sinus node disfunctions; two (1.4%) complete atrio-ventricular blocks (AVB), three (2.1%) paroxysmal complete AVB, one (0.7%) severe I degree AVB. Three patients received an ICD (implantable cardioverter defibrillator). Comparison between LVHT patients with (33 pts) and without (107 pts) arrhythmias as regards genetic testing showed a statistical significance for the presence of class 4 or 5 genetic variants and arrhythmic manifestation (p = 0.037). Conclusions. In our pediatric cohort with LVHT, good outcomes were observed, but arrhythmias were not so rare (23.6%); no SCD occurred. [ABSTRACT FROM AUTHOR]

Background: Catheter-based slow pathway modification (SPM) for atrioventricular nodal reentrant tachycardia (AVNRT) is traditionally performed at empiric sites using anatomical landmarks and test ablation feedback within the triangle of Koch (TK). While studies have described more tailored techniques such as bipolar low voltage bridge (LVB) and wavefront collision identification, few have systematically compared the diagnostic yields of each and none have investigated whether omnipolar mapping technology provides incremental benefit. The objective of this study was to compare the utility of omnipolar and bipolar-derived qualitative and quantitative measurements in identifying and localizing dual AVN substrate in patients with versus without AVNRT. Methods: A retrospective case-control study of consecutive patients with paroxysmal supraventricular tachycardia undergoing electrophysiology study with both omnipolar and bipolar mapping from 2022-2023. Results: Thirteen AVNRT cases (median age 16.1 years, 512 TK points) were compared to nine non-AVNRT controls (median age 15.7 years, 332 TK points). Among qualitative variables, an omnipolar activation vector pivot, defined as a ≥45 degree change in activation direction within the TK, had the highest positive (81%) and negative predictive values (100%) for identifying AVNRT cases and had a median distance of 1 mm from SPM sites. Among quantitative variables, the optimal discriminatory performance for successful SPM sites was observed using bipolar voltage restricted to a peak frequency >340 Hz (c statistic 0.75). Conclusions: Omnipolar vector pivot analysis represents an automated, annotation-independent qualitative technique that is sensitive and specific for AVNRT substrate and co-localizes with successful SPM sites. Bipolar voltage quantitatively describes SP anisotropy better than omnipolar voltage, and the addition of peak frequency signal analysis further optimizes the selection of SPM sites. [ABSTRACT FROM AUTHOR]

Purpose: We report a case of a patient experiencing paroxysmal supraventricular tachycardia after infusing doxophylline. Methods: Clinical evaluations and the electrocardiogram were performed by specialists. Findings: Our patient felt palpitations and chest distress after intravenous Doxophylline. The electrocardiogram showed paroxysmal supraventricular tachycardia. There was no evidence to prove that there was any problem with his heart, liver, and kidney. According to the Naranjo Adverse Drug Reaction probability scale, paroxysmal supraventricular tachycardia has a probable relationship with Doxophylline. Implications: The paroxysmal supraventricular tachycardia is a rare but reasonable adverse reaction of Doxophylline, which should be paid more attention. [ABSTRACT FROM AUTHOR]

Introduction: We utilized data from the Third China National Stroke Registry to investigate the prevalence of atrial cardiopathy markers in patients with embolic stroke of undetermined source (ESUS) and to assess their association with death and stroke recurrence. Methods: In China, patients experiencing transient ischemic attack or ischemic stroke were recruited consecutively by the Third China National Stroke Registry. We compared atrial cardiopathy markers, such as left atrial (LA) enlargement, increased P-wave terminal force in lead V1 (PTFV1), premature atrial contractions, paroxysmal supraventricular tachycardia, advanced interatrial block, prolonged PR interval, prolonged P-wave dispersion, and prolonged P-wave duration between ESUS patients and those with small vessel disease and large artery atherosclerosis strokes. The association between these markers and the recurrence of stroke as well as mortality risk in ESUS patients was evaluated using Cox regression analysis. Results: Of 8,528 ischemic stroke patients who underwent a standard diagnostic workup, 2,415 were identified as having ESUS. Multivariable analysis revealed a significant association between elevated PTFV1 and an increased risk of stroke recurrence (HR: 2.50; 95% CI: 1.53–4.09; p < 0.01) as well as mortality (HR: 3.76; 95% CI: 1.58–8.91; p < 0.01) at 1 year in patients with ESUS. Furthermore, we observed that moderate-severe LA enlargement slightly increased the risk of stroke recurrence in patients with ESUS (HR: 1.95; 95% CI: 0.90–4.26; p = 0.09). Both LA diameter (HR: 1.03; 95% CI: 1.00–1.06; p = 0.03) and the top quartile of the LA diameter index (HR: 1.56; 95% CI: 1.03–2.40; p = 0.04) were associated with stroke recurrence in patients with ESUS. Conclusions: PTFV1 was independently associated with an elevated risk of stroke recurrence and mortality in ESUS patients. Additionally, a trend toward a correlation between LA enlargement and high stroke recurrence risk after ESUS was observed. [ABSTRACT FROM AUTHOR]

Etripamil is a calcium channel blocker currently in Phase 3 trials for the treatment of paroxysmal supraventricular tachycardia (PSVT). Systemic and local toxicity following once-weekly intranasal administration of etripamil was evaluated in cynomolgus macaques to support clinical development. Groups of animals (N = 8, 4 males and 4 females) were administered etripamil into the left nostril weekly at dose levels of 0 (vehicle), 1.9, 3.8, or 5.7 mg/kg/dose for 26 doses. Persistence, reversibility, and progression of findings were examined following a 28-day recovery period. Clinical signs were transient and were related to the intranasal administration (e.g., nasal discharge, sneezing, etc.) of etripamil. There were no macroscopic or systemic microscopic findings at any dose. Etripamil-related adaptive and reactive local changes affecting the nasal cavity, larynx, and nasopharynx were observed at ≥1.9 mg/kg/dose. Minimal to severe dose-dependent nasal epithelial damage was observed, mainly affecting respiratory and transitional epithelium. Following the 28-day recovery period, microscopic changes were confined to the left nasal cavity and nasopharynx. These changes were significantly lower in incidence and severity, with noticeable reversal of the adaptive and reactive changes, indicating partial to complete recovery of the epithelial lining. Based on the lack of systemic toxicity and the minimal and transient nasal changes, the systemic, no observable adverse effect level (NOAEL) of etripamil in monkeys was the high dose, 5.7 mg/kg/dose. The NOAEL for local toxicity was 1.9 mg/kg/dose. Collectively, these data support further study of etripamil in human trials as a potential treatment for PSVT. [ABSTRACT FROM AUTHOR]

Purpose of Review: In this article, we underscore the importance of identifying risk factors and monitoring pulmonary hypertension patients for signs of arrhythmias, as this proactive approach can reduce morbidity and mortality. Recent Findings: Atrial fibrillation is the most prevalent among cardiac arrhythmias and is associated with an increased risk of stroke, morbidity, and mortality. Smoking, obesity, hypertension, a sedentary lifestyle, and diabetes mellitus are some of the modifiable risk factors for atrial fibrillation. Recent studies show that the risk of atrial fibrillation is rising in patients with parenchymal and vascular lung disease. Stretching in the atria and pulmonary veins may lead to the onset of atrial fibrillation in cardiac conditions like hypertension, heart failure, and valvular disease. Atrial fibrillation in patients with pulmonary hypertension (PH) denotes a more advanced disease. Summary: Patients with PH are more susceptible to hemodynamic stress caused by tachycardia and an uncoordinated atrioventricular contraction. Therefore, atrial arrhythmias need to be treated because inadequate control of cardiac arrhythmias may result in poor clinical outcomes and lead to disease progression in PH patients. Aside from being a sign of severe disease, AF can also speed up and exacerbate the condition. [ABSTRACT FROM AUTHOR]

Abstract Background The R wave in lead aVR, during the wide QRS complex tachycardia, is commonly observed in a ventricular tachycardia (VT) arising from certain locations in the ventricles. Objectives This was a retrospective and a proof of concept study to correlate the sites of origin of VT and premature ventricular contractions (PVCs) with the occurrence of R wave in lead aVR. Methods Patients with VT or high density of PVCs were included. Surface and intracardiac electrograms were recorded during the arrhythmia. VTs and PVCs arising from the inferior, inferolateral, or apical region of the ventricles were grouped into Zone 2. Those arising from the other areas of the ventricles were grouped into Zone 1. Results Sixty‐four patients were included in the study. The mean age was 57 years. There were 47 males. Among 64 patients with VT or PVCs, 28 patients had an R wave in aVR (43.7%), In 26 of 28 patients with an R wave in aVR, the site of origin of the arrhythmia was in Zone 2. The R wave in aVR was absent in 36 patients, 34 of whom had the origin of arrhythmia focus in Zone 1. The presence of an R wave in aVR correctly identified Zone 2 as a site of origin of the arrhythmia with high sensitivity (93%) and specificity (94%). Conclusions The presence of an R wave in aVR during wide QRS complex tachycardia or PVC is a valuable observation for identifying the site of origin of the arrhythmia and hence in distinguishing supraventricular tachycardia with aberrancy from VT.

Background: Electrocardiographic diagnosis of causes of supraventricular tachycardia (SVT) is sometimes difficult and application of routine algorithms can lead to misdiagnosis in as many as 37 % of patients. ST segment depression may be useful in diagnosing the nature of SVT. Methods: We reviewed surface electrocardiogram (ECG) characteristics of 300 patients having SVT with 1:1 AV relationship and correlated findings with electrophysiology study (EPS) findings. Final diagnosis of AVNRT (Atrioventricular nodal reentrant tachycardia), Orthodromic AVRT (atrioventricular reentrant tachycardia) and atrial tachycardia (AT) was correlated with ECG parameters like heart rate, ST segment depressions and QRS morphology. Results: Out of 300 patients, majority patients included in study, were having AVNRT or AVRT. ST depression predicted AVRT if the ST depression was ≥ 2 mm (overall sensitivity of 38.3 % and specificity of 93.8 % to predict AVRT) and was downsloping in morphology (sensitivity of 36.9 % and specificity of 94.7 % to predict AVRT). At heart rates ≥214 beats per minute (bpm) as measured by 7 small squares of ECG at 25 mm/s, downsloping ST depression ≥2 mm had a sensitivity 37.9 % of and specificity of 89.2 % to predict AVRT. At heart rate

Background: Catheter ablation is a first-line treatment for symptomatic, recurrent supraventricular tachycardia (SVT). This study aims to demonstrate if 3D-electroanatomic mapping (EAM) during SVT ablation reduces fluoroscopy time (FT) and determine if further reductions in FT are observed longitudinally. Methods: All cases of SVT ablation between May 2011–May 2022 at a single tertiary centre were prospectively recruited. FT between the cohorts with and without EAM were compared. Within the EAM subset, the trend of FT across the years was analysed. Results: There were 1758 cases included, 563 without EAM, 1195 with EAM. EAM was associated with a longer procedure time (mean + 8.8 min, p = 0.001), but with mean reductions in FT and dose area product (DAP) by 19.6 min and 18 621 mGy*cm2 respectively (p

Identifying and treating pediatric arrhythmias is essential for pediatric anesthesiologists. Pediatric patients can present with narrow or wide complex tachycardias, though the former is more common. Patients with inherited channelopathies or cardiomyopathies are at increased risk. Since most pediatric patients present for anesthesia without a baseline electrocardiogram, the first identification of an arrhythmia may occur under general anesthesia. Supraventricular tachycardia, the most common pediatric tachyarrhythmia, represents a broad category of predominately narrow complex tachycardias. Stimulating events including intubation, vascular guidewire manipulation, and surgical stimulation can trigger episodes. Valsalva maneuvers are unreliable as treatment, making adenosine or other intravenous antiarrhythmics the preferred acute therapy. Reentrant tachycardias are the most common supraventricular tachycardia in pediatric patients, including atrioventricular reciprocating tachycardia (due to a distinct accessory pathway) and atrioventricular nodal reentrant tachycardia (due to an accessory pathway within the atrioventricular node). Patients with ventricular preexcitation, often referred to as Wolff‐Parkinson‐White syndrome, have a wide QRS with short PR interval, indicating antegrade conduction through the accessory pathway. These patients are at risk for sudden death if atrial fibrillation degenerates into ventricular fibrillation over a high‐risk accessory pathway. Automatic tachycardias, such as atrial tachycardia and junctional ectopic tachycardia, are causes of supraventricular tachycardia in pediatric patients, the latter most typically noted after cardiac surgery. Patients with inherited arrhythmia syndromes, such as congenital long QT syndrome, are at risk of developing ventricular arrhythmias such as polymorphic ventricular tachycardia (Torsades de Pointes) which can be exacerbated by QT prolonging medications. Patients with catecholaminergic polymorphic ventricular tachycardia are at particular risk for developing bidirectional ventricular tachycardia or ventricular fibrillation during exogenous or endogenous catecholamine surges. Non‐selective beta blockers are first line for most forms of long QT syndrome as well as catecholaminergic polymorphic ventricular tachycardia. Anesthesiologists should review the impact of medications on the QT interval and transmural dispersion of repolarization, to limit increasing the risk of Torsades de Pointes in patients with long QT syndrome. This review explores the key anesthetic considerations for these arrhythmias. [ABSTRACT FROM AUTHOR]

Most infants presenting with supraventricular tachycardia (SVT) are treated with an antiarrhythmic, primarily to prevent unrecognized future episodes that could lead to tachycardia-induced cardiomyopathy. A common practice at our institution is to not treat after the first presentation of infant SVT and instead educate parents on heart rate monitoring and reasons to present to care. The goal of this study was to evaluate the outcomes of non-pharmacologic treatment of infant SVT at first presentation and compare to outcomes of infants treated with an antiarrhythmic. This was a retrospective single center study of all infants presenting with a first episode of SVT from 2014 to 2021. Excluded were patients with a non-reentry type tachyarrhythmia, atrial flutter, long-RP tachycardia, congenital heart disease, or abnormal ventricular function. Sixty-four infants were included in the study. Thirty-six were managed without an antiarrhythmic. SVT recurred in 28% of the non-treatment group vs 50% in those treated with antiarrhythmics, p = 0.12. Of the patients admitted to the hospital, those in the non-treatment group had a shorter length of stay, 1(IQR 1–1) vs 3(IQR 2–4) days, p < 0.01. Non-treated patients were less likely to present to the emergency department for recurrent SVT, 6% vs 32%, p < 0.01. Neither group had a patient develop tachycardia-induced cardiomyopathy. For infants with structurally and functionally normal hearts, non-treatment combined with parental education after the first episode of SVT does not lead to worse outcomes. This approach avoids the burden of medication administration in an infant and may have the added benefit of empowering parents to feel comfortable managing clinically insignificant tachycardia at home. [ABSTRACT FROM AUTHOR]

Abstract Background Supraventricular tachycardia is the most common dysrhythmia in children. Initial vagal maneuvers are successful less than half of the time. Adenosine, a potent AV nodal blocker with a short half-life, is recommended as first line pharmacotherapy. Minor side effects from adenosine are common, but report of serious side effects such as sustained ventricular tachycardia, torsades de pointes, syncope or hypotension are confined to small case series or studies greater than 20 years old. We aimed to specifically identify the incidence of serious side effects of adenosine in children in the emergency department. Methods Between 2002 and 2022, all children less than 18 years old who received adenosine for tachyarrhythmia treatment in two emergency departments were included. The electronic record was reviewed for demographic information, patient history, treatments given, and side effects or complications were observed. Electrocardiograms before, during and after adenosine administration were reviewed. Results 77 patients met inclusion criteria. There were 74 patients with an initial rhythm of typical SVT. The other three patients included one with a junctional rhythm, one with atrial fibrillation, and one with an undetermined narrow complex tachycardia. 49 patients had cardiac rhythm monitoring during adenosine administration. 17 of these patients had three or more consecutive ventricular beats following adenosine, however no patients required treatment. No patients had syncope. One patient had brief hypotension after adenosine that normalized without intervention. Four patients were electrically cardioverted after adenosine, all for persistent dysrhythmias: two for persistent SVT with hypotension, one for atrial fibrillation and one for an undetermined rhythm. Twelve patients were placed on continuous antiarrhythmic medication for persistent SVT. Age, gender, prior SVT history, initial adenosine dose, and need for additional doses were not significant risk factors for a prolonged sinus pause or greater than two ventricular beats. Conclusions Adenosine treatment in typical supraventricular tachycardia in pediatric patients is safe.

Abstract 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!

The COVID-19 pandemic has posed significant risks to pregnant women and those recently pregnant, leading to heightened mortality and morbidity rates. Vaccination has emerged as a pivotal strategy in reducing COVID-19-related deaths and illnesses worldwide. However, the initial exclusion of pregnant individuals from most clinical trials raised concerns about vaccine safety in this population, contributing to vaccine hesitancy. This review aims to consolidate the existing literature to assess the safety and efficacy of COVID-19 vaccination in pregnant populations and neonatal outcomes. Diverse studies were included evaluating various aspects of safety for women and their newborns, encompassing mild to severe symptoms across different vaccines. The findings indicate the overall safety and efficacy of COVID-19 vaccination, with minimal adverse outcomes observed, including mild side effects like pain and fever. Although most studies reported the absence of severe adverse outcomes, isolated case reports have raised concerns about potential associations between maternal COVID-19 vaccination and conditions such as fetal supraventricular tachycardia and immune-mediated diseases. Our review underscores the importance of ongoing surveillance and monitoring to ensure vaccine safety in pregnant women. Overall, COVID-19 vaccination during pregnancy remains a safe and effective strategy, emphasizing the need for continued research and vigilance to safeguard maternal and fetal health. [ABSTRACT FROM AUTHOR]

Introduction: Supraventricular tachyarrhythmias (ST) are themost common cardiac arrhythmias. Little is known about the potential impact of demoralization, which is considered as partially distinct from depression, on the course of ST. A correct assessment of both depressive symptoms and demoralization appears relevant for the treatment of these cardiac diseases, potentially influencing their course. Methods: The sample consisted of 110 subjects affected by different ST, such as atrial fibrillation (AF), atrial flutter (AFL) and paroxysmal supraventricular tachycardia (PSVT). They all underwent a psychiatric evaluation; the Italian version of 9-item Patient Health Questionnaire (PHQ-9) and the Italian version of Demoralization Scale (DS) were administered. Descriptive statistics, pairwise comparisons, and correlational analysis have been implemented. Results: 26 individuals (23.6%) presented high levels of demoralization. Of these, 20 (76.9%) had a diagnosis of AF and six patients (23.1%) received a diagnosis of other ST. No differences in demoralization levels resulted in regard of sex, cardiac diagnoses and anticoagulant therapies. Amongst people with high levels of demoralization, 13 (50%) received no formal psychiatric diagnosis, and 12 (46.2%) showed moderate/severe depressive symptoms. Demoralization levels and PHQ-9 scores showed a significant positive correlation in the whole sample (r=0.550, p<0.001). Discussion: The present study found that in a sample of patients suffering from ST, high levels of demoralization were more frequent than clinically relevant depressive symptoms. We propose that demoralization and depression show partially distinguished psychopathological features, potentially associated with different therapeutic trajectories. [ABSTRACT FROM AUTHOR]

Background: Arrhythmias are the most common cardiac complications occurring in pregnancy. Although atrial or ventricular premature complexes may explain the majority of palpitations in pregnancy, the full spectrum of arrhythmias can occur. Main body: This article summarizes the evaluation and management of arrhythmias in pregnancy. Hemodynamically unstable arrhythmias need urgent cardioversion. For mild cases of benign arrhythmia, treatment is usually not required. Symptomatic but hemodynamically stable arrhythmic patients should first undergo an evaluation to establish the type of arrhythmia and the presence of structural heart disease. Given the potential risks of antiarrhythmic pharmacotherapy in pregnancy, this will ultimately determine the necessity for treatment. We will discuss the main antiarrhythmic medications, which have some established evidence of safety in pregnancy. Conclusions: In hemodynamically stable pregnant patients with A.F. or AFL with rapid ventricular rates (RVR), I.V. beta-blockers are recommended as the first-line option, and digoxin or verapamil, alone or in combination are recommended as second-line options for initial rate control in the absence of preexcitation. [ABSTRACT FROM AUTHOR]

Introduction: Pregnant women with pre-excitation syndrome are more likely to develop supraventricular tachycardia (SVT) during pregnancy and delivery, leading to an increased risk of adverse events. Method: This was a retrospective study of 309 pregnancies in 280 women (29 women had two pregnancies in this series) with pre-excitation syndrome who delivered at West China Second University Hospital from June 2011 to October 2021. All the 309 pregnant women with pre-excitation syndrome were divided into SVT and non-SVT groups to analyze the cardiac and obstetric complications. Results: Among the included pregnant women in the past 10 years, the prevalence of pre-excitation syndrome was 0.24% (309/127725). There were 309 cases with pre-excitation syndrome in all hospitalized pregnant women. Among them, 62 (20.1%, 62/309) had a history of SVT. In the 62 cases with SVT during pregnancy, 22 (35.5%) cases had a history of SVT. Gestational diabetes mellitus was associated with SVT during pregnancy. The cesarean section rate was 88.7% in the SVT group, which was significantly higher than that in the non-SVT group (64.8%) (P < 0.001). Cases with SVT during pregnancy had more cardiac and obstetric complications. Four fetal deaths were recorded in the SVT group. Additionally, 29 women experienced two pregnancies during the study period, among whom, five received radiofrequency ablation after the first delivery and obtained better outcomes in the second pregnancy. Conclusion: The adverse outcomes such as cardiac complications, maternal and fetal complications (PROM, prematurity, SGA, fetal distress, etc.) in pregnant women with pre-excitation syndrome were closely related to SVT, with possible risk factors including history of SVT before pregnancy, cardiac function, heart organic abnormalities, and gestational diabetes mellitus. [ABSTRACT FROM AUTHOR]

Supraventricular tachycardia (SVT) is the most common arrhythmia in infants. Once diagnosed, infants are admitted for antiarrhythmic therapy and discharged after observation. There are limited data on risk factors for readmission and readmission rates, while on medication. The objective of this study was to investigate risk factors for readmission and outcomes in infants diagnosed with SVT. This is a single-center retrospective study over a 10-year period of infants under 6 months of age with documented SVT. Infants with congenital heart disease requiring surgical or catheter intervention, gestational age less than 32 weeks or diagnosis of atrial flutter or fibrillation were excluded. The primary outcome was readmission within 31 days of hospital discharge. Long term need for ablation and eventual discontinuation of medications were assessed. Ninety patients were included. Beta blockers were the initial therapy in 66 and 28 required a medication change. Nineteen were readmitted within 31 days of discharge. The only clinical factor associated with early readmission was presence of ventricular pre-excitation (6/19 vs. 8/71, p = 0.03). Patients who were readmitted within 31 days had a longer length of treatment (12 [11.5, 22.0] vs. 10 [7.5, 12.0] months, p = 0.007) and were more likely to undergo ablation (4/19 vs. 2/71, p = 0.017). In this cohort of infants with SVT, readmission was common and ventricular pre-excitation was identified as a risk factor for readmission. Infants who were readmitted within 31 days of discharge had longer length of antiarrhythmic therapy and were more likely to undergo catheter ablation. [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]

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