Preexcitation Research Articles

Abstract 4133324: Socioeconomic status, race, and ethnicity in management of pediatric SVT

Introduction: Electrophysiology study and ablation (EPS) is often the preferred approach to management of supraventricular tachycardia (SVT) and/or ventricular pre-excitation (WPW) in older children/adolescents. There are inequities in arrhythmia management in adults, and in other areas of pediatric cardiology, but little is known about disparities in management of SVT in children. Research question: Do racial/ethnic and socioeconomic inequities affect referral for EPS in patients with SVT and/or WPW? Methods: This retrospective observational study utilized the Pediatric Health Information System of 49 children’s hospitals’ administrative data from 2016-2022. We included patients with SVT or WPW seen in the emergency department, admitted for observation, or inpatient. We excluded patients with congenital heart disease. The outcome was having a procedure code for EPS. The childhood opportunity index (COI, scale 1-100) based on zip code was used to measure socioeconomic status (SES). Results: Among 37,818 patients with primary diagnosis of SVT (27620, 73%) or WPW (10198, 27%), 9840 (26%) underwent EPS (Table 1). COI was higher in patients who underwent EPS than those who did not (median 59 [IQR 34,82] vs 57 [IQR 30,81]). In addition, time from initial visit with diagnosis of SVT/WPW to EPS was longer in patients with lower COI (beta= -0.026, p=0.007). Black (21.2%), Hispanic (23.8%), and American Indian (19.8%) patients were less likely to undergo EPS than White (26.5%) and Asian (28.31%) patients and those with other (28.4%) or unknown/missing (35.7%) race (p<0.001, Figure 1). In both subgroups of patients with SVT and WPW, EPS differed by race and COI, and higher COI predicted shorter time to EPS. Conclusions: In this hospital database of pediatric patients, we found disparities in use of EPS for the management of SVT and/or WPW. Patients of minoritized race/ethnicity and lower SES were less likely to undergo EPS.

Morbidity Burden in Patients With Ebstein Anomaly: The Natural History.

The lifetime morbidity burden of patients with Ebstein anomaly (EA) has not been well described. Through an extensive 2-country register-based collaboration, patients diagnosed with EA who were born between 1930 and 2017 were identified in Danish and Swedish nationwide medical registries. Each patient was matched by age and sex with 10 control subjects from the general population. Cox proportional-hazards regression, Fine-Gray competing risk regression, and Kaplan-Meier failure function were used to estimate the morbidity burden. The study included 794 patients diagnosed with EA and 7940 controls, with a median follow-up period of 33 years. Among patients with EA, approximately half (n=442) had isolated EA, and 28% (n=218) had concomitant atrial septal defect. Patients with complex anatomy demonstrated the highest cardiovascular morbidity burden, followed by those with concomitant atrial septal defect and isolated EA. The lifetime cumulative incidence of supraventricular arrhythmia and ventricular preexcitation in patients with EA, with or without atrial septal defect, was approximately 70% and 19%, respectively. Supraventricular arrhythmia substantially increased the risk of ischemic stroke (hazard ratio [HR] 22.6 [95% CI, 11.1-45.9]). Presence of atrial septal defect significantly affected arrhythmia and heart failure burden compared with isolated EA. In the total cohort of patients with EA, supraventricular arrhythmia onset led to an immediate high incidence of heart failure, with a 10-year cumulative incidence of 18%. The natural history of EA, whether isolated or not, involves a substantial burden of cardiovascular morbidity and thus a highly vulnerable long-term prognosis.

Catheter ablation in a monochorionic diamniotic twin pregnancy: A case report and literature review.

Preexcitation syndrome is an uncommon congenital cardiac disorder that impairs the normal cardiac conduction system. Radiofrequency ablation is one of the most effective treatments for this condition. Nevertheless, radiofrequency ablation is rare in women with preexcitation syndrome during pregnancy. A 33-year-old woman with monochorionic diamniotic twin pregnancy complicated by sinus arrhythmia with ventricular preexcitation at 14 weeks and 5 days of gestation, with paroxysmal palpitations and shortness of breath at 16 weeks with paroxysmal supraventricular tachycardia with preexcitation syndrome and a heart rate ranging from 180 to 225 beats per minute. The pregnant occurred sudden palpitations and shortness of breath in the shower. Electrocardiography revealed paroxysmal supraventricular tachycardia, and electrophysiological study revealed preexcitation syndrome (dominant accessory route of the left free wall) with atrioventricular reentrant tachycardia. Radiofrequency catheter ablation was performed at 20 weeks. Symptoms of preexcitation syndrome resolved after the radiofrequency catheter ablation, and 2 healthy infants were delivered at 36 weeks and 2 days of gestation by cesarean section. Preexcitation syndrome may result in life-threatening arrhythmias such as supraventricular tachycardia during pregnancy and delivery. It might be efficiently controlled through optimal treatment by a multidisciplinary team, which would effectively minimize arrhythmia risk events during pregnancy and improve maternal-fetal outcomes. Based on the patient's individual situation, radiofrequency ablation may be a procedure in pregnant women with preexcitation syndrome.

Electrocardiographic Clues for Early Diagnosis of Ventricular Pre-Excitation and Non-Invasive Risk Stratification in Athletes: A Practical Guide for Sports Cardiologists.

Ventricular pre-excitation (VP) is a cardiac disorder characterized by the presence of an accessory pathway (AP) that bypasses the atrioventricular node (AVN), which, although often asymptomatic, exposes individuals to an increased risk of re-entrant supraventricular tachycardias and sudden cardiac death (SCD) due to rapid atrial fibrillation (AF) conduction. This condition is particularly significant in sports cardiology, where preparticipation ECG screening is routinely performed on athletes. Professional athletes, given their elevated risk of developing malignant arrhythmias, require careful assessment. Early identification of VP and proper risk stratification are crucial for determining the most appropriate management strategy and ensuring the safety of these individuals during competitive sports. Non-invasive tools, such as resting electrocardiograms (ECGs), ambulatory ECG monitoring, and exercise stress tests, are commonly employed, although their interpretation can sometimes be challenging. This review aims to provide practical tips and electrocardiographic clues for detecting VP beyond the classical triad (short PR interval, delta wave, and prolonged QRS interval) and offers guidance on non-invasive risk stratification. Although the diagnostic gold standard remains invasive electrophysiological study, appropriate interpretation of the ECG can help limit unnecessary referrals for young, often asymptomatic, athletes.

A change in QT interval and ST-segment after radiofrequency catheter ablation in pediatric patients with Wolff–Parkinson–White syndrome

BackgroundFew studies have examined QT, JT interval, and ST-segment changes due to radiofrequency catheter ablation (RFA) in manifest Wolff–Parkinson–White (WPW) syndrome in pediatric patients. MethodsThe study involved 27 patients (male-to-female, 13:14; age, 12 (5–16) years) who were diagnosed with WPW syndrome and underwent RFA in our hospital between 2009 and 2022. Electrocardiographic (ECG) changes were compared between the group with ventricular preexcitation due to an accessory pathway (manifest group, n = 16) and those without it (concealed group, n = 11). ResultsThe QT interval before RFA was significantly longer in the manifest group than in the concealed group (402 [362–482] vs. 344 [323–427]; p = 0.001). The QT interval was significantly shortened in the manifest group before and after RFA (402 [362–482] vs. 360 [298–422] msec; p = 0.01). At 1 month, the QT interval difference between the manifest and concealed groups disappeared (366 [305–437] vs. 335 [301–436] msec; p = 0.001). ST-segment changes were found after RFA in 56 % (9/16) of the patients in the manifest group but not in the concealed group. ECG changes presenting the Brugada-pattern was found in one patient. One month later, ECG abnormalities persisted in only one patient. ConclusionsIn pediatric patients, the QT interval was prolonged in manifest WPW syndrome but shortened after RFA. In the manifest group, transient ST-segment change and T-wave abnormalities were often observed after RFA; however, the ECG normalized in approximately 1 month.

Clinical and genetic profile of Chinese children with Danon disease: A single-center retrospective cohort study

BackgroundDanon disease (DD) is a rare X-linked dominant lysosomal storage disorder. Studies on DD pediatric patients are limited due to the small number of cases and challenges in early detection. MethodsWe retrospectively analyzed clinical and genetic data of 29 pediatric patients who visited our hospital for treatment or genetic counseling of DD from July 2014 to December 2023. ResultsThe mean age at diagnosis was 7.2±5.9 years for males (n=21) and 9.4±5.0 years for females (n=8). Asymptomatic elevated liver aminotransferase and/or creatine kinase (CK) levels were initial manifestations detected in 10 (48%) male patients and absent in female patients. Hypertrophic cardiomyopathy (HCM) was observed in 20 (95%) male and 7 (88%) female patients, while dilated cardiomyopathy (DCM) was not detected. Ventricular preexcitation (VP) was observed initially in 10 (36%) patients and in 15 (54%) at latest evaluation. Patients with VP had higher left ventricular posterior wall thickness in diastole z-scores than those without VP (5.6±2.2 vs. 3.5±2.1, p=0.029). During a median 2.7-years follow-up, two males received heart transplants. One boy and one girl died of heart failure and sudden cardiac arrest, respectively. Twenty-three pathogenic LAMP2 variants were identified, including seven novel variants. ConclusionsA retrospective review of 29 DD cases suggests an underrecognized asymptomatic period in male DD patients, characterized by elevations in serum CK and transaminases. HCM appears to be the only cardiac manifestation in pediatric female patients, unlike a high incidence of DCM in adult female patients. The incidence of VP may increase with disease progression.

Clinical, electrocardiographic, and diagnostic imaging features and outcomes in cats with electrocardiographic diagnosis of ventricular pre-excitation: a retrospective study of 23 cases (2010–2022)

Introduction/ObjectivesVentricular pre-excitation (VPE) occurs when atrial electrical impulses prematurely excite the ventricles through an aberrant muscle bundle known as an accessory pathway (AP). Orthodromic atrioventricular reciprocating tachycardia is a re-entrant, narrow complex supraventricular tachycardia (SVT), maintained through retrograde conduction over an AP. The study aimed to describe patient signalments, clinical signs, electrocardiographic (ECG) and diagnostic imaging features, treatments, prognostic variables, and outcomes in cats with ECG diagnosis of VPE. AnimalsTwenty-three cats diagnosed with VPE between January 2010 and August 2022 were included in this study. Materials and MethodsThis was a multicenter, retrospective study with twenty-three cats diagnosed with VPE between January 2010 and August 2022. Ventricular pre-excitation diagnosis was based on ECG evidence of shortened PR interval, delta wave, and prolonged QRS duration. The median survival time (MST) was estimated by the Kaplan-Meier curve. Log-rank tests were performed to assess for an association between clinical signs or presence of structural heart disease on the MST. ResultsFourteen (60.8%) cats with VPE also had SVT documented on ECG, with 7 of 14 with ECG confirmation of orthodromic atrioventricular reciprocating tachycardia. Four (17.4%) cats had suspected AP-mediated tachyarrhythmia based on associated clinical signs. Common presenting signs included collapse (15/23; 65.2%) and respiratory distress (14/23; 60.8%). Five (21.7%) cats were asymptomatic. Heart rate during SVT ranged from 310 to 420 bpm (median: 375 bpm). Initial treatment included atenolol (10/18), sotalol (5/18), diltiazem (2/18), and amiodarone (1/18). From the date of diagnosis, MST was 1872 days (5.1 years). ConclusionsThe majority of cats with VPE also had symptomatic SVT. The prognosis for cats with VPE is considered good with an MST of greater than five years.

What an anesthesiologist should know about pediatric arrhythmias.

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.

Ventricular preexcitation of every other beat or ventricular bigeminy or both?

Bigeminy is a cardiac arrhythmia in which there is a single ectopic beat, or irregular heartbeat, following each regular heartbeat. This case demonstrates the diagnostic challenges that can be encountered while interpreting ECGs of patients with “apparent ventricular bigeminy’.

Scorpion Bite Mimicking Acute Coronary Syndrome/Myocarditis Later Detected to Have Preexcitation Syndrome—A Case Report and Review of Literature

Abstract Introduction: Scorpion sting-induced myocarditis is a strange and potentially life-threatening problem that merits careful clinical consideration and management. Case Details: Our case, a young male presented with history of scorpion bite over left foot sole associated with local burning an itching with subsequent development of systemic symptoms. The patient received supportive care, including pain management, fluid resuscitation, and close cardiac monitoring. Given the severity of the myocardial involvement, specific interventions targeting the venom’s impact on the heart were initiated. The patient showed significant improvement in symptoms and cardiac function with the implemented management strategies. We present a case report of a patient who suffered myocarditis following a scorpion sting, emphasizing the distinctive clinical features, diagnostic dilemma, and successful management. This case highlights the importance of heightened awareness among healthcare providers when faced with scorpion envenomation, particularly in regions where such encounters are prevalent. Conclusion: This case report contributes to the limited literature on scorpion bite-induced myocarditis, shedding light on the diagnostic intricacies and successful management.

Ventricular pre-excitation in an elderly cat

An 18-year-old female neutered Domestic Shorthair cat was referred for investigation of seizure-like episodes. Physical and neurological examination were unremarkable, as were systemic arterial blood pressure, cardiac troponin I, complete blood count and biochemistry profile. Diagnostic tests included transthoracic echocardiography which ruled out any structural cardiomyopathy, and electrocardiography which showed an underlying regular wide QRS-complex rhythm with pronounced shortening of the PR interval. Considering the findings, a diagnosis of suspected ventricular pre-excitation secondary to an accessory pathway was made. Further investigations were declined and, as no periods of tachycardia were seen on the five-minute electrocardiogram, no antiarrhythmic treatment was started.

Modern management of acute atrial fibrillation and atrial flutter.

This clinical review is intended to assist emergency physicians manage patients who present to the emergency department (ED) with acute/recent-onset atrial fibrillation (AF) or flutter (AFL). This article is based primarily on the 2021 Canadian Association of Emergency Physicians (CAEP) Acute Atrial Fibrillation/Flutter Best Practices Checklist. We encourage readers to download the open access CAEP Checklist article (https://link.springer.com/article/10.1007/s43678-021-00167-y) and the free smartphone app (CAEP Atrial Fibrillation Guide). We focus on four key elements of ED care: assessment and risk stratification, rate and rhythm control, short-term and long-term stroke prevention, and disposition and follow-up. It is important to determine if AF/AFL with rapid ventricular response is a primary arrhythmia or secondary to medical causes. While it is unusual for patients with primary AF to be unstable, urgent cardioversion is occasionally required. The criteria for when cardioversion is safe have recently changed and it is essential that physicians are well versed in them. When rhythm control is not safe, provide effective and safe IV rate control. When rhythm control is safe, either pharmacological or electrical cardioversion acceptable, per patient and physician preference. Rapid ventricular pre-excitation (Wolff-Parkinson-White Syndrome) usually, but not always, requires urgent electrical cardioversion. ED physicians should prescribe oral anticoagulants at discharge if indicated. No specific direct oral anticoagulant is preferred, and references should be freely consulted for optimal dosing. Hospital admission is rarely required for acute AF/AFL patients, who should be given good discharge instructions.

Effects of accessory pathway catheter ablation on left ventricular function in patients with dyssynchrony-induced cardiomyopathy associated with pre-excitation syndrome

Aim. To evaluate the effect of radiofrequency ablation (RFA) of accessory pathways on left ventricle (LV) function in patients with Wolff-Parkinson-White (WPW) syndrome and preexitation-induced dyssynchrony cardiomyopathy.Methods. The study included 22 patients with registered preexitation on the ECG and signs of dyssynchronous cardiomyopathy according to echocardiography (Echo): asynchronous movement of interventricular septum, ejection fraction (EF) decrease and/or global longitudinal strain of the left ventricle (GLS LV), heart chamber increase. The average age of patients at the time of RFA of the accessory pathways - 11 years [8;14].Results. A regular normalization of the QRS complex width was observed after RFA (p = 0.0002). To assess reverse LV remodeling, all patients underwent Echo on day 3 after RFA. In patients with an initially reduced LVEF, its increase was noted. In patients with initial dilatation and an increase in LV volume, normalization of these indicators was noted. However, dynamics of LVEF and its volume was not statistically significant in the early postoperative period. According to Speckle-tracking Echo during medical check-up, complete normalization of longitudinal deformation was observed in 13 patients (59%), this indicator improvement - in 7 patients (31.8%). The average GLS LV before RFA was -17.25 [-16.4; -19], after RFA - -21.5 [-19; -24] (p = 0.0001).Conclusion. Reverse remodeling and restoration of LV function after RFA of accessory pathways indicates a cause- and-effect relationship between the accessory pathways functioning and dyssynchronous cardiomyopathy development. Therefore, patients with signs of preexitation-induced dyssynchronous cardiomyopathy are indicated for RFA of accessory pathways, regardless of age and tachycardia paroxysms.

Reversible acute heart failure induced by thyrotoxic cardiomyopathy: A case report.

Thyrotoxic cardiomyopathy is a rare but severe complication of thyrotoxicosis, leading to episodes of acute heart failure. This case report highlights a rare presentation of thyrotoxic cardiomyopathy with low-output heart failure, emphasizing the importance of early diagnosis and comprehensive management. The report aims to increase awareness among clinicians about the potential reversibility of this condition and the effective strategies for managing such complex cases. This patient presented with dyspnea and chest constriction, without any antecedent predisposing factors. Subsequently, the patient abruptly manifested symptoms indicative of acute heart failure during outpatient consultation. Electrocardiography revealed rapid atrial fibrillation with type A preexcitation syndrome, whereas cardiac ultrasonography demonstrated global cardiac enlargement with a diminished ejection fraction (EF). After a comprehensive evaluation, the patient was diagnosed with thyrotoxic cardiomyopathy, acute heart failure, and atrial fibrillation with preexcitation syndrome. Immediate interventions comprised diuretic administration, oxygen therapy, and antiarrhythmic agents, addressing acute heart failure concomitant with preexcitation syndrome. Following a fortnight of comprehensive therapeutic measures, the patient was discharged with a prescription for oral medications, notably methimazole. Following the intervention, the patient showed significant improvement with the resolution of heart failure symptoms and dyspnea, restoration of sinus rhythm, improved left ventricular ejection fraction (LVEF improved from 36% to 45%), and normalization of thyroid function. These outcomes underscore the efficacy of the intervention strategy and offer a hopeful prognosis for similar cases. Thyrotoxicosis may cause cardiomyopathy in patients with heart failure that manifests as dilated cardiac chambers. Clinicians should carefully screen patients for this reversible condition. Diagnosis requires a comprehensive assessment of various tests, and the therapeutic goal is to restore normal thyroid function.

Ablation of anomalous mitral annular pathways via transradial access: early hospital discharge due to the covid-19 pandemic

Abstract Introduction Wolff-Parkinson-White (WPW) syndrome arises from the conduction through accessory pathways (AP) connecting the atria and ventricles, bypassing the atrioventricular node. Radiofrequency catheter ablation of AP is the recommended treatment, often performed via transradial access. This approach is widely utilized in percutaneous coronary intervention due to its safety, effectiveness, patient preference, cost-effectiveness, and simplicity. Our study aims to present the results of AP ablation in the mitral annulus through transradial access amid the Covid-19 pandemic, marked by hospital bed scarcity and the need for early discharge. Materials and Methods Between May 2020 and December 2021, eight cases of transradial AP ablation in the mitral annulus were conducted. The service had previously achieved success in 16 transradial ablation cases. Among the eight cases during the pandemic, 62.5% were male, aged 24 to 56 years, all experiencing tachycardic palpitations and pre-syncope with a history of hospitalization. In 25% of cases, syncope episodes occurred. Patients were on propafenone, with no structural heart disease. Covid-19 tests were negative. Radial and ulnar artery perfusion integrity was assessed using the Allen maneuver and arterial Doppler. The right radial artery was used in 100% of cases. Sixty-two point five percent of accessory pathways were in anterolateral positions, and 37.5% were left posteroseptal. The approach was through the right radial artery, under local anesthesia, with venous sedation, using a 7Fr introducer sheath and positioning of the explorer catheter. Mapping was conducted during sinus rhythm, and adenosine IV tests followed ablation. The catheter was removed, and a pneumatic local dressing was applied for 2 hours, followed by a conventional dressing change for 24 hours. Results Ablation was successful in all eight patients. The procedure time ranged from 40 to 80 minutes, with an average of 55 minutes. Two to four radiofrequency applications were applied for a total of 2 minutes, using 55 W energy and a temperature of 55 to 60°C. No complications occurred during or after the procedure. Patients were discharged three hours post-intervention. Follow-up included reviews every four months, ECGs without ventricular pre-excitation, asymptomatic patients without antiarrhythmic medication, and no complications at the puncture site one year post-procedure. Conclusion Although based on a small sample of eight cases, and acknowledging the need for a larger sample to establish the procedure as an alternative, considering possible operator experience influence, we conclude that radial access proved effective and safe in this patient group. Its usage was exceptional, specifically in the context of a pandemic with crowded hospitals. Selection criteria and comparisons with other alternatives should be adopted for analyzing its potential future use.Transradial approachAblation catheter in the mitral plane

TRANSOESOPHAGEAL ELECTROPHYSIOLOGICAL STUDY IN PEDIATRIC PATIENTS WITH VENTRICULAR PRE–EXCITATION

Abstract Introduction The transoesophageal electrophysiological study (SETE) is a simple, semi–invasive and highly reliable test for risk stratification in patients with ventricular pre–excitation. In paediatric subjects, symptoms may be nonspecific or poorly reported; hence the usefulness of the study in guiding the therapeutic strategy. The guidelines also suggest performing it in all asymptomatic patients with ventricular preexcitation above 8 years of age.Purpose of the study: to evaluate the inducibility of re–entry tachycardia at SETE in paediatric patients with ventricular pre–excitation. Materials and Methods We observed 21 patients aged between a few days of life and 12 years (average age 11 years); 14 of them had constant and 7 intermittent pre–excitations. The latter were subjected to the study as they reported dubious symptoms either due to sports activities or due to a previous diagnosis of neonatal TPS. The study was performed by carrying out the protocols of continuous atrial stimulation at increasing frequencies, programmed atrial stimulation with single, double, and triple extra stimulus and atrial stimulation with burst. Results Of the 21 patients, 8 (38.1%) were inducible. Of the 14 patients with constant ventricular pre–excitation, 5 had tachycardia upon return to the study (35.7%), 4 of which were symptomatic due to previous TPS. Therefore, only one patient with constant and asymptomatic ventricular pre–excitation was inducible. Of the 7 patients with intermittent ventricular preexcitation (documented by Holter or exercise test), 3 developed TPS at SETE (42.8%): all these patients complained of heart palpitations but did not have a documented arrhythmia. On the contrary, all patients with intermittent ventricular preexcitation and asymptomatic were found to be non–inducible. In patients in whom it was possible to calculate the effective antegrade refractory period of the anomalous pathway, shorter refractory period showed greater inducibility. Non–sustained atrial fibrillation was induced in only two patients. Conclusions SETE demonstrates a good correlation between symptoms and inducibility especially in patients with intermittent ventricular pre–excitation. In fact, if the manifest pre–excitation disappears with growth in about a third of patients, the retrograde conduction capacity of the pathway often persists. The study also allows us to identify patients with constant pre–excitation but pathway at low risk.

ST SEGMENT DEPRESSION: MUCH ADO ABOUT NOTHING

Abstract Introduction ST depression in ECG trace is classically used to assess the cardiac ischaemia. Several other causes of ST depression, like hypokalaemia, digoxin therapy, left ventricular hypertrophy, left bundle branch block can be easily excluded. Sometimes the ST segment depression during tachycardia is observed in young healthy people where ischemic background is rare. Case Report We present the case of an asymptomatic and without cardiovascular risk factors 29–years–old man who performed, during occasional sport visit, an ECG showing sinus tachycardia with diffuse ST segment depression. The ECG obtained at the presentation in Emergency Department of our hospital confirmed sinus tachycardia at 140 beats per minute and diffuse ST segment depression. This finding persisted during the following six hours and slowly regressed with normalization of the heart rate. The same ECG alteration was founded during an exercise test when the heart rate rised up to 90 bpm. A coronary angiography showed anatomically normal and angiographically free of stenosis coronaries; the functional study, using Fractional Flow Reserve (FFR), Coronary Flow Reserve (CFR) and Index of Microcirculatory Resistance (IMR), currently gold standard for the functional study of microcirculation, was normal. No alterations were founded at the cardiac magnetic resonance. Due to a previous resting ECG suspected of ventricular preexcitation, an electrophysiological study was performed and showed neither accessory pathways nor inducibility arrhythmias. The asymptomatic and hemodynamically stable patient was discharged and an ambulatorial follow–up was planned. Conclusion This case emphasizes the ever–present difficulty of attributing unequivocal etiological meanings to electrocardiographic alterations.

Flecainide sebagai Antiaritmia untuk Fibrilasi Atrium dan Aritmia Lainnya

Atrial fibrillation (AF) is one of the most common arrhythmias globally, and its prevalence is projected to increase, including in Indonesia. AF progression is related to lower quality of life and less responsive to therapy or even becomes irreversible. The progression of AF is significantly slower with the rhythm control strategy than with the rate control strategy alone. The options for therapy in Indonesia are limited to amiodarone and propafenone. Amiodarone is one of the most common drugs prescribed for AF rhythm control, but associated with multiple organ toxicities, thus increasing the risk of multiple side effects, especially on long-term usage, potentially leading to drug discontinuation. Flecainide is an antiarrhythmia with a favourable effectiveness and safety profile, especially for AF management, used for acute cardioversion, long-term rhythm control, and as a therapeutic modality for AF with preexcitation syndrome. Flecainide is a potential drug to address the unmet needs of amiodarone as a long-term management for AF.

Pre-Excited Atrial Fibrillation in Wolff-Parkinson-White (WPW) Syndrome: A Case Report and a Review of the Literature.

Wolff-Parkinson-White (WPW) syndrome is defined by specific electrocardiogram (ECG) changes resulting in ventricular pre-excitation (the so-called WPW pattern), related to the presence of an accessory pathway (AP), combined with recurrent tachyarrhythmias. WPW syndrome is characterized by different supraventricular tachyarrhythmias (SVT), including atrioventricular re-entry tachycardia (AVRT) and atrial fibrillation (AF) with rapid ventricular response, with AVRT being the most common arrhythmia associated with WPW, and AF occurring in up to 50% of patients with WPW. Several mechanisms might be responsible for AF development in the WPW syndrome, and a proper electrocardiographic interpretation is of pivotal importance since misdiagnosing pre-excited AF could lead to the administration of incorrect treatment, potentially inducing ventricular fibrillation (VF). Great awareness of pre-excited AF's common ECG characteristics as well as associated causes and its treatment is needed to increase diagnostic performance and improve patients' outcomes. In the present review, starting from a paradigmatic case, we discuss the characteristics of pre-excited AF in the emergency department and its management, focusing on the most common ECG abnormalities, pharmacological and invasive treatment of this rhythm disorder.

Diagnosis and treatment of arrhythmogenic cardiomyopathy in children

Objective: To summarize the clinical manifestations, experiences in diagnosis and treatment of arrhythmogenic cardiomyopathy (ACM) in children. Methods: A retrospective analysis of the clinical manifestations, laboratory tests, radiological features, treatment and follow-up results was conducted in 11 children diagnosed with ACM at the center of congenital heart disease, Beijing anzhen hospital from May 2010 to March 2022. Results: A total of 11 patients aged 2 to 16 years, including 5 males and 6 females were diagnosed with ACM. The clinical manifestations included decreased activity tolerance (7 patients), heart failure (4 patients), syncope or sudden death (3 patients), palpitation (3 patients), and chest tightness and pain (3 patients). Electrocardiogram showed right bundle branch block in 9 cases, paroxysmal ventricular tachycardia in 4 cases, frequent premature ventricular contraction in 4 cases, ventricular pre-excitation in 1 case, left bundle branch block in 1 case, and first degree atrioventricular block in 2 cases. Echocardiography showed enlargement of the right heart, widening of the right ventricular outflow tract, and thinning and bulging of the local wall of the right ventricle with reduced pulsation. Ventricular thrombosis was found in 2 cases. Six children underwent cardiac magnetic resonance imaging, which mainly showed severe enlargement of the right heart, thin free wall of the right ventricle, decreased right heart function, enhanced right ventricular myocardium, and formation of right ventricular aneurysm. Two children underwent myocardial biopsy examination and presented with typical pathological changes of ACM. Genetic tests in five patients revealed DSG2 gene mutation in 2 cases, PKP2 gene mutation in 2 cases, and MYH6 gene mutation in 1 case. All patients received anti heart failure treatment and antiarrhythmic drugs. Two children received anticoagulant treatment due to ventricular thrombosis. Radiofrequency ablation was performed in 2 patients. Glenn procedure was performed in 4 patients, and heart transplantation was performed in 1 patient due to progressive heart failure. The follow-up period ranged from 6 months to 12 years. Two cases died of right heart failure, 6 cases had different degrees of heart failure, 1 case had intermittent chest tightness and pain, and 2 cases were stable. Conclusions: ACM is a progressive genetic cardiomyopathy characterized by decreased activity tolerance, cardiac failure and arrhythmia in pediatric patients. The diagnosis is mainly based on clinical manifestations, electrocardiogram, cardiac imaging changes, and genetic testing. Early detection, diagnosis, and personalized treatment can improve the prognosis.