Preexcitation Research Articles

Feasibility, efficacy, and safety of intracardiac echocardiography guided transseptal puncture: a single-center retrospective study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transseptal puncture (TSP) is routinely performed to gain access into the left atrium for left-sided arrhythmias. Although fluoroscopy is mainly used for visualization of TSP, intracardiac echocardiography has been increasingly used to visualize the TSP. However, the available data to support routine use of ICE for visualization is scarce, particularly for pediatric patients and patients with cardiac implantable electronic devices (CIED). Purpose The purpose of this single-center retrospective study was to evaluate feasibility, efficacy, and safety of ICE guided TSP, also including pediatric patients and patients with CIED. Methods In this retrospective study, we analyzed consecutive patients who underwent ICE guided TSP from July 2014 to December 2021. When TSP was performed in patients with CIED, the device´s parameters were tested before and after the procedure. Adverse events (AE) were classified as those that were directly associated with the TSP and those who might be associated with the TSP. All AE either required an intervention, prolonged hospital stay, or had a negative impact on patient´s health. Results The study included 1360 consecutive patients (44.6% (607/1360) male; mean age 59.1 ± 15.6 years; mean BMI 28.1 ± 5.0 kg/m2), 4.3% (59/1360) of patients were pediatric (the youngest was 4 years old and weighed 17 kg) and 8.9% had a CIED (121/1360 – 56.2% (68/121) single chamber; 33.1% (40/121) dual chamber; 10.7% (13/121) resynchronization device). In majority, atrial fibrillation or atypical atrial flutter were the main indication for TSP (75.4%; 1062/1360), followed by ventricular tachycardia (9.4%; 128/1360), ventricular preexcitation (8.8%; 120/1360), and atrial tachycardia (3.5%; 47/1360). A total of 1839 punctures were performed (64.3% (875/1360) single TSP; 35.7% (485/1360) double TSP). Only in two patients (0.14%; 2/1360) the TSP was initially not possible. In one, it was later performed with radiofrequency needle. In total, there were 0.7% (13/1839) of AE. Two events (0.11%; 2/1839) were directly associated with the TSP. In one patient, a tamponade occurred immediately after a double TSP. In another patient with a dual chamber CIED, the ventricular lead was dislocated during the maneuvering of the TSP assembly. The other 11 events (0.6%; 11/1839 - 2 late tamponades and 9 pericardial effusions) could be associated with the TSP, however, they could also be associated with ablations or maneuvering of the catheters. In patients with CIED, there were 3 AE (2.1%; 3/144) – 1 AE was directly associated with the TSP (ventricular lead dislocation described above) and 2 AE which might be associated with the TSP (1 late tamponade and 1 pericardial effusion). There were no AE (0.0%; 0/60) in pediatric patients. Conclusion ICE guided TSP is an effective and safe method for obtaining left atrial access in adult and pediatric patients. Special care should be given to patients with CIED as lead dislocation is possible.

Ventricular pre-excitation in young patients: long term follow-up and natural history in a contemporary cohort

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular preexcitation (VPE) due to atrio-ventricular accessory pathways (AP) has been associated to a higher incidence of sudden cardiac death (1,2). The incidence of major arrhythmic events (MAE) may be higher in children (1,3), but most of the past studies recruited a high proportion of patients with congenital heart disease (CHD), treated with outdated pharmacological therapy (1). Transcatheter ablation (TCA) of the AP is a safe and effective therapy and it is nowadays the standard of care (1,2). However, it may be less effective and more dangerous in smaller and younger children (1,3). It is described that patients may spontaneously lose VPE during childhood (1), but the natural history of VPE is not well understood yet. Purpose To study the natural history of VPE. We focused especially on the likelihood of spontaneous resolution of VPE during growth, the possible associated factors, and the incidence of MAE during a long follow up in a contemporary paediatric cohort. Methods We retrospectively recruited patients diagnosed with VPE at age 0 to 12, referred from 1993 to 2021 to two tertiary care hospitals. Significant CHD and double AP were excluded. The primary outcome was the spontaneous resolution of VPE, defined by the loss of short PR and delta wave seen in at least two consecutive ECG and/or on 24-hour Holter monitoring. The follow up stopped when the patients reached 16 years of age, met the primary outcome or effective TCA was performed. Given the time-to-event dependency of the condition, the survival analysis of VPE considered the left truncation resulted from the recruitment of patients after the first days of life. Results We recruited 153 patients with a median age of diagnosis of 4.9 (0.2 – 8.4). The median follow-up time was 4.9 (1.6 – 8) years. During follow-up, 42 (28%) patients spontaneously loss VPE. The left truncated Kaplan-Meier survival curve of VPE is shown in Picture 1. It estimates that VPE would persist in 53% (40.1-70.2) and 33.8% (23.7-48.4) of patients at the age of 1 and 16, respectively. Symptoms and intermittent preexcitation were the only variables significantly associated with lower (OR 0.2) and higher probability (OR 3.45) of SR of VPE. The vast majority of patients with symptoms was treated with drug therapy before the age of 8, and TCA was safely delayed thereafter. None of the patients experienced a MAE during follow up. Conclusion According to our data, a large proportion of paediatric patients are likely to spontaneously lose VPE within the first year of life, and a spontaneous resolution may occur later during childhood in a non-negligible number of cases. The absence of symptoms and/or intermittent preexcitation are significant predictors of loss of VPE. The results of our study are of the utmost clinical relevance, since they support a wait-and-see strategy, especially in very young children with VPE.

Pre-excited atrial fibrillation revealed at a very delayed age: case report

BackgroundWolff-Parkinson-White (WPW) syndrome is a condition characterized by the persistence of an accessory pathway responsible for ventricular pre-excitation that can lead to symptomatic and potentially severe arrhythmias. Coexistence with atrial fibrillation is well known and not uncommon, exposing to potential degenerescence into ventricular fibrillation when atrial impulses are transmitted along the accessory pathway. WPW syndrome is most prevalent in younger patients and cases revealed after an advanced age have rarely been described in the literature.Case presentationHere, we report a case of atrial pre-excitation first diagnosed at the age of 72 years that required external electrical cardioversion with a favorable outcome. The diagnosis was based on clinical and electrographic findings.ConclusionsWPW syndrome is a relatively rare cardiac disorder that can be a cause of sudden death, especially when combined with atrial fibrillation. Therefore, cardiologists have to consider this diagnosis in patients presenting clinical signs of arrhythmia with an electrical pattern of WPW.

Successful catheter ablation of the accessory pathway in an unusual location in a 13-year-old girl with a coronary sinus diverticulum and Wolff-Parkinson-White syndrome.

Wolff-Parkinson-White syndrome is a congenital cardiac pre-excitation syndrome that is effectively treated by ablating the accessory pathway. However, accessory pathways located in the posteroseptal region can sometimes be challenging. In this paper, we present the successful ablation of the epicardial posteroseptal accessory pathway through the middle cardiac vein in a 13-year-old girl with a coronary sinus diverticulum and Wolff-Parkinson-White syndrome, after unsuccessful ablation attempts at different locations. If the ablation procedure fails, the possibility of the posteroseptal pathway should be kept in mind, and coronary sinus angiography should be performed. In cases with a coronary sinus diverticulum where ablation is not successful, other coronary sinus structures, for example, the middle cardiac vein should be considered as potential accessory pathways.

PO-03-125 VENTRICULAR PREEXCITATION AND PEDIATRIC HYPERTROPHIC CARDIOMYOPATHY: ETIOLOGY AND ACCESSORY PATHWAY CHARACTERISTICS

The etiology of pediatric hypertrophic cardiomyopathy (HCM) is varied. Ventricular preexcitation (VPe) is well recognized, yet little is known regarding the specific etiology, and accessory pathways (AP) characteristics. Define the etiology of HCM in patients with VPe and the characteristics of the responsible APs. Retrospective cohort study of patients <21 years of age with HCM/VPe from 2000-22. The etiology was defined as sarcomeric/non-sarcomeric (isolated HCM), storage disorder, metabolic disease, or genetic syndrome. AP were designated as atrioventricular (AV) or fasciculoventricular fibers (FVF) using standard invasive EP study criteria when available. AV APs were defined as high risk if any of the following were <250 ms: shortest preexcited RR interval in AF, shortest paced preexcited cycle length, or APERP. ECG characteristics were compared in patients with VPe exclusively secondary to an FVF to those with anteroseptal AP-mediated VPe. From a total of 345 patients with HCM, 28 (8%) had VPe and proportion with VPe varied significantly between etiologic groups: isolated HCM 10/220 (5%), storage 8/17 (47%), metabolic 5/19 (26%), genetic syndrome 5/89 (6%), p < 0.001. Six (21%) had clinical AF (1 with SPPRI <250 ms, 4 with storage disease). Invasive EP study was performed in 22, identifying 39 APs (23 AV AP, 16 FVF; fig 1). VPe resulted exclusively from an FVF in 8 (36%) patients. Multiple AV APs were seen in 8 (36%) and AV AP plus FVF in 10 (45%). Five (23%) patients had AV APs with high-risk conduction properties (≥1 in each etiologic group). Ablation was acutely successful in 13/14 patients with recurrence in 3. The only complication was a single case of heart block after ablation of a high-risk midseptal AP. Patients with storage disease had larger QRS amplitudes (median 42.3 v. 23.0 mm, p < 0.01). The delta wave amplitude did not discriminate between anteroseptal AP and FVF (median 4.3 v. 4.1 mm, p = 0.92). VPe and high risk or multiple AP may be associated with any etiology of childhood HCM. This is most common in storage disorders associated with high QRS amplitudes and clinical AF, with important implications for prognosis and management.

Automated classification of pediatric age from 12-lead ECG using deep residual convolutional neural networks

With increased interest in screening of young people for potential causes of sudden death, accurate automated detection of ventricular pre-excitation (VPE) or Wolff–Parkinson–White syndrome (WPW) in the pediatric resting ECG is important. Several recent studies have shown interobserver variability when reading screening ECGs and thus an accurate automated reading for this potential cause of sudden death is critical. We designed and tested an automated algorithm to detect pediatric VPE optimized for low prevalence.Digital ECGs with 12 leads or 15 leads (12-lead plus V3R, V4R and V7) were selected from multiple hospitals and separated into a testing and training database. Inclusion criterion was age less than 16 years. The reference for algorithm detection of VPE was cardiologist annotation of VPE for each ECG. The training database (n = 772) consisted of VPE ECGs (n = 37), normal ECGs (n = 492) and a high concentration of conduction defects, RBBB (n = 232) and LBBB (n = 11). The testing database was a random sample (n = 763). All ECGs were analyzed with the Philips DXL ECG Analysis algorithm for basic waveform measurements. Additional ECG features specific to VPE, mainly delta wave scoring, were calculated from the basic measurements and the average beat. A classifier based on decision tree bootstrap aggregation (tree bagger) was trained in multiple steps to select the number of decision trees and the 10 best features. The classifier accuracy was measured on the test database.The new algorithm detected pediatric VPE with a sensitivity of 78%, a specificity of 99.9%, a positive predictive value of 88% and negative predictive value of 99.7%.This new algorithm for detection of pediatric VPE performs well with a reasonable positive and negative predictive value despite the low prevalence in the general population.

PO-03-142 ABLATION OF EPICARDIAL POSTEROSEPTAL ACCESSORY PATHWAYS IN CHILDREN

Epicardial posteroseptal accessory pathways (Epi-PSAPs) within the coronary sinus (CS) are a rarely reported ablation target in children. They are often associated with abnormal CS anatomy as well as risk of coronary artery (CA) injury. To assess characteristics associated with successful outcome of Epi-PSAP ablation in children. Retrospective cohort study at a tertiary care institution including all patients aged ≤18 years who underwent ablation of Epi-PSAP from 2000-2022. Clinical/electrophysiological characteristics and outcomes were analyzed. Epi-PSAP was targeted in 19 patients. Mean age at procedure was 13.4 (12.1-14.7) years, mean weight was 62.5 (47-78) kg. Prior ablations had been attempted in 7/19 patients. Ventricular preexcitation was present in 12/19 (63%) patients, with steep negative delta wave in lead II in all cases, and 8/12 (67%) demonstrating high risk antegrade conduction. CS angiogram to define the anatomy was performed in all patients. In 5/5 (100%) of cases where CS diverticulum was identified by CS angiogram, it proved to be the ablation target. CA angiogram to define arterial proximity (5mm cutoff) was obtained in 17/19 (90%). CA system was right dominant in 10/17 (59%), and closest arteries were ≥5mm away from the target in 11/17 (65%). Primary energy was RF in 12/19 (63%, artery ≥5mm) and cryo in 7/19 (37%, artery <5mm). Ablation was acutely successful in 18/19 (95%) patients, chronically successful in 15/18 (83%) of patients, over 98.2 (57.8-138.7) months of follow up.There was no apparent difference in outcome between ablation sites in 1) coronary vein; 2) CS diverticulum; or 3) floor of CS (FIG1.A.). The presence of a sharp unipolar accessory pathway potential (FIG1.B.) at the target site was significantly associated with acute (p=0.003) and chronic (p=0.005) success. Choice of energy was not significantly associated with outcome. Performance of CS angiogram (FIG1.C) was significantly associated with acute (p=0.04) and chronic (p=0.03) success when all ablation attempts were analyzed. There was no incidence of major adverse events. Majority of Epi-PSAP in children are manifest with high risk antegrade conduction properties. They can be ablated with RF energy when the coronary arteries are ≥5mm from ablation target, or alternatively with cryoablation. Localizing a sharp unipolar AP potential, identification of CS anatomy by CS angiogram, and delineation of arterial proximity by CA angiogram are associated with successful ablation.

PE-454609-1 MYOCARDIAL WORK IN VENTRICULAR PREEXCITATION

Ventricular preexcitation alters the electromechanical activation sequence and may induce left ventricular (LV) contractile discoordination and pathologic remodelling in selected cases. To evaluate LV myocardial work before and after accessory pathway (AP) ablation in patients with WPW preexcitation and to compare them to normal controls. Mechanical activation mapping and myocardial work calculation was performed in 11 pediatric patients with the WPW syndrome/pattern and left sided or paraseptal APs undergoing catheter ablation (successful in 10/11) and 8 healthy age-matched controls using speckle tracking echocardiography and the GE ECHOPAC version 204.57.0.745 software with the integrated AFI module. An 18-segmental echocardiographic LV model was used. Global LV myocardial work efficiency (GWE) was calculated as the ratio of global constructive work to the sum of global constructive and global wasted work (GWW). The time from delta wave onset to R wave peak in lead V6 (delta to R) was used to quantify the degree of preexcitation. Before ablation GWW was higher (164 vs 102 mmHg%, P=0.015) and GWE lower (median 91 vs 94%, P=0.010) in patients vs controls. After successful ablation GWW decreased from 164 to 93 mmHg% (P=0.006) and GWE increased from 91.1 to 94.0 % (P=0.006). GWE tended to correlate negatively with the delta to R interval (R=0.59, P=0.056). Before ablation, segmental WE increased with distance from ventricular AP insertion from median 69.5 % at AP location to 98.0 % in distant segments (P<0.001). After ablation, WE was equally distributed among LV segments (Figure). Mechanical activation mapping localized APs with a median (IQR) segmental distance of 0 (0-1) segments from the EP mapped location. Ventricular preexcitation induces significant LV myocardial work inefficiency in segments adjacent to AP which correlates with the degree of preexcitation and is normalized after ablation. The amount of wasted work in asymptomatic preexcitation may be considered when assessing the potential for pathologic LV remodelling or discussing the indication for prophylactic ablation. Mechanical activation mapping may be used to localize manifest APs.

Forecasting patient instability: Current advances & future opportunities

The adverse effects of conventional right ventricular (RV) apical pacing prompted the search for more physiological pacing sites, such as selective and nonselective His bundle pacing (HBP), a variant of nonselective HBP (para-Hisian pacing), and mid-septal pacing. However, knowledge of their true benefit on the physiology of ventricular activation, lead stability, and pacing thresholds is limited.We included 152 consecutive patients (mean age 61 ± 24, 63% men) in this retrospective study. Of these, 137 patients with different bradyarrhythmias underwent active fixation lead implantation at the RV apex (n = 54), para-Hisian region (n = 66), or mid interventricular septum (n = 17). Fifteen patients with ventricular preexcitation due to an accessory pathway not undergoing pacing were included as controls. A 12‑lead ECG was recorded in all patients, and cardiac electrical synchrony was assessed using the Synchromax® cross-correlation cardiac synchrony index (CSI).QRS duration was prolonged in all pacing sites: from 114 ± 28 to 160 ± 29 (RV apex), from 110 ± 28 to 122 ± 29 (para-Hisian), and from 121 ± 24 to 154 ± 30 (mid interventricular septum). The CSI was significantly improved only in patients undergoing para-Hisian pacing, despite a slight widening of the QRS interval. There was no difference in pacing thresholds and sensed R-wave voltage between pacing sites. Only 1 lead, implanted at the para-Hisian region (1.5%), was dislodged towards the mid septum 48 h after implantation but did not require repositioning.QRS duration was not associated with changes in CSI, meaning that QRS width does not significantly affect electrical synchrony.

Ventricular pre-excitation in cats: 17 cases

ObjectivesAtrioventricular accessory pathways are abnormal electrical connections between the atria and ventricles that predispose to ventricular pre-excitation (VPE) and tachycardias. AnimalsSeventeen cats with VPE and 15 healthy matched-control cats. Material and methodsMulticenter case-control retrospective study. Clinical records were searched for cats with VPE, defined as preserved atrioventricular synchrony, reduced PQ interval, and increased QRS complex duration with a delta wave. Clinical, electrocardiography, echocardiographic, and outcome data were collated. ResultsMost cats with VPE were male (16/17 cats), non-pedigree cats (11/17 cats). Median age and mean body weight were 5.4 years (0.3–11.9 years) and 4.6 ± 0.8 kg, respectively. Clinical signs at presentation included lethargy (10/17 cats), tachypnea (6/17 cats), and/or syncope (3/17 cats). In two cats, VPE was an incidental finding. Congestive heart failure was uncommon (3/17 cats). Nine (9/17) cats had tachyarrhythmias: 7/9 cats had narrow QRS complex tachycardia and 2/9 cats had wide QRS complex tachycardia. Four cats had ventricular arrhythmias. Cats with VPE had larger left (P < 0.001) and right (P < 0.001) atria and thicker interventricular septum (P = 0.019) and left ventricular free wall (P = 0.028) than controls. Three cats had hypertrophic cardiomyopathy. Treatment included different combinations of sotalol (5/17 cats), diltiazem (5/17 cats), atenolol (4/17 cats), furosemide (4/17 cats), and platelet inhibitors (4/17 cats). Five cats died, all from cardiac death (median survival time 1882 days [2–1882 days]). ConclusionsCats with VPE had a relatively long survival, albeit showing larger atria and thicker left ventricular walls than healthy cats.

Accessory pathways in monozygotic twins with different clinical phenotypes: a case report

BackgroundThe atrioventricular reentrant tachycardia (AVRT) is the most common tachycardia associated with accessory pathways (APs). Although sporadic Wolff-Parkinson-White (WPW) syndrome has been well-described, AP occurrence in identical twins with WPW syndrome remains rarely reported.Case presentationWe report a case of 14-year-old monozygotic twin brothers referred for an electrophysiology (EP) study. Twin A presented with recurrent symptomatic narrow complex tachycardia after exercise, noted for 3 years. His 12-lead surface electrocardiogram (ECG) did not show ventricular pre-excitation. However, an orthodromic AVRT utilizing a concealed right posteroseptal AP was found and successfully ablated. AVRT did not recur 12 months after the procedure. Twin B was asymptomatic. During his medical examination for firefighter volunteerism, his 12-lead ECG showed a spontaneous ventricular pre-excitation. EP study revealed a short anterograde right midseptal AP, which was then successfully eliminated by catheter ablation. His 12-lead ECG showed no ventricular pre-excitation recurrence 12 months after the procedure.ConclusionsThese identical twin brothers had a right-side AP in almost the same place but showed completely different phenotypes. This case clearly illustrates the difficulty in understanding genetic contribution in the origin of atrioventricular APs. Environmental exposure could play a role in their clinical presentations and AP electrophysiological properties.

Radiofrequency catheter ablation for improving myocardial work in patients with ventricular pre-excitation.

Previous studies have not consistently found significant improvements in left ventricular ejection fraction or global longitudinal strain (GLS) after radiofrequency catheter ablation (RFCA) in patients with ventricular pre-excitation. The aim of this study was thus to explore the effects of RFCA on left ventricular function in patients with ventricular pre-excitation using a new noninvasive echocardiographic method of myocardial work. A total of 34 patients with ventricular pre-excitation who underwent RFCA and 18 healthy controls were prospectively included in this study. Before and after participants underwent RFCA, electrocardiographic and echocardiographic data of the patients were collected at resting and pacing heart rates (HRs) of 100 beats per minute (bpm) and 120 bpm (controlled by high right atrial pacing during the procedure). Clinical data of the healthy controls at resting HR were also collected. A self-controlled paired sample t test was used to compare the differences before and after participants underwent RFCA. After participants underwent RFCA, the global wasted work (GWW) of the included patients decreased (resting HR: 165.3±68.8 vs. 92.6±42.5 mmHg%, P<0.001; HR of 100 bpm: 276.3±121.2 vs. 187.9±96.0 mmHg%, P<0.001; HR of 120 bpm: 323.9±126.7 vs. 181.0%±74.3 mmHg%. P<0.001), while the global work efficiency (GWE) increased (resting HR: 91.5%±3.8% vs. 94.9%±1.6%; P<0.001; HR of 100 bpm: 87.0%±5.2% vs. 91.0%±3.3%, P<0.001; HR of 120 bpm: 85.0%±5.1% vs. 90.3%±3.7%, P<0.001). In patients with ventricular pre-excitation, impaired GWW and GWE can be improved with RFCA. In clinical practice, noninvasive myocardial work assessment can be used in patients with ventricular pre-excitation.

"Asymptomatic WPW" : Is treatment necessary?

The term "asymptomatic WPW" (Wolff-Parkinson-White) is often used as asynonym for ventricular pre-excitation of the WPW type due to an accessory pathway characterized by ashort PR interval and adelta wave on the electrocardiogram (ECG) without the clinical occurrence of paroxysmal tachycardia. Asymptomatic WPW is often diagnosed in young and otherwise healthy people. There is asmall associated risk of sudden cardiac death due to rapid antegrade conduction over the accessory pathway during atrial fibrillation. This paper highlights aspects of noninvasive and invasive risk stratification, therapy by catheter ablation, and the ongoing risk-benefit discussion in asymptomatic WPW.

WPW Syndrome type a in an Adult Male- A Unique Case Report: Fascinating three Decades Roller-Coaster Journey of WPW Syndrome type a and its Subsequent Resolution.

Wolff-Parkinson-White syndrome is the most common form of ventricular preexcitation and affects 1-3 per 1,000 persons worldwide. Many patients remain asymptomatic throughout their lives: however, approximately half of the patients with Wolff-Parkinson-White syndrome experience symptoms secondary to tachyarrhythmias, such as paroxysmal supraventricular tachycardia, atrial fibrillation, atrial flutter, and rarely, ventricular fibrillation and sudden death. Patients with Wolff-Parkinson-White syndrome may present with a multitude of symptoms such as unexplained anxiety, palpitations, fatigue, light-headedness or dizziness, loss of consciousness, and shortness of breath. We report a peculiar case of three decades of fascinating journey of an adult male suffering from WPW syndrome Type A and its spontaneous resolution eventually.&#x0D; Keywords: WPW Syndrome, spontaneous resolution of delta wave, three decades natural &#x0D; history of WPW.

Ablation of Ventricular Preexcitation to Cure Preexcitation-Induced Dilated Cardiomyopathy in Infants: Diagnosis and Outcome.

To investigate the clinical features of preexcitation-induced dilated cardiomyopathy in infants and evaluate safety and efficacy of radiofrequency ablation (RFCA) in these patients. This study included 10 infants (4 males and 6 females) with mean age of 6.78±3.14 months, mean weight of 8.11±1.71 kg, and mean left ventricular ejection fraction (LVEF) was 32.6±10.34%. Tachycardiomyopathy has been excluded and all patients were refractory to the drugs. All of these 10 patients underwent RFCA. All the accessory pathways in these patients were located on right free wall and the acute success rate was 100%. No complication associated with the procedure occurred. In one case preexcitation recurred and was ablated successfully during the second attempt. There were 3 patients with mild cardiac dysfunction (LVEF, 40≤LVEF<50%), 3 with moderate (30≤LVEF<40%), and 4 with severe cardiac dysfunction (LVEF<30%, the ages were 3, 6, 7, and 10 months, respectively). The time for LVEF normalization was 1 week, 1 to 3 months, and ≥3 months, respectively. In 3 of the 4 severe cardiac dysfunction patients, the LVEF normalized at 3, 6, and 12 months after ablation, the LVEF of the remaining case did not recover at 3 months and is still being followed. Ventricular preexcitation could lead to severe cardiac dysfunction during infancy. RFCA may be a safe and effective treatment option in right free wall accessory pathways, even in infants with cardiac dysfunction. Cases of more severe cardiac dysfunction might require a longer time for LVEF recovery after RFCA.

Unconventional results of the holter monitoring in a patient

Fragments of Holter monitoring of a 39-year-old patient with a combination of an electrocardiographic pattern of the ventricular preexcitation phenomenon and atrioventricular block are presented. The possibility of remote analysis of the patient’s monitoring electrocardiogram data in twelve leads is provided.

Electrocardiographic patterns of ventricular pre-excitation in dogs with right-sided accessory pathways.

The aim of the study was to describe the electrocardiographic features of ventricular pre-excitation (VPE) patterns characterized by the presence of delta (δ) wave, short P-δQRS interval, wide δQRS complexes in dogs with right-sided accessory pathways. Twenty-six dogs with a confirmed accessory pathways (AP) via electrophysiological mapping were included. All dogs underwent a complete physical examination, 12-lead ECG, thoracic radiography, echocardiographic examination and electrophysiologic mapping. The AP were located in the following regions: right anterior, right posteroseptal, right posterior. The following parameters were determined: P-δQRS interval, δQRS duration, δQRS axis, δQRS morphology, δ-wave polarity, Q-wave, R-wave, R'-wave, S-wave amplitude, and R/S ratio. In lead II, the median δQRS complex duration was 82.4 (IQR 7.2) and the median P-δQRS interval duration was 54.6 (IQR 4.2) msec. The median δQRS complex axis in the frontal plane was: + 68° (IQR 52.5) for right anterior APs, - 24 ° (IQR 24) for right postero-septal APs, - 43.5 ° (IQR 27.25) for right posterior APs (P = 0.007). In lead II, the polarity of the δ wave was positive in 5/5 right anterior APs and negative in 7/11 postero-septal APs and 8/10 in right posterior APs. In precordial leads of all dogs, R/S was ≤ 1 in V1 and > 1 in all leads from V2 to V6. Surface electrocardiogram can be used to distinguish right anterior APs from right posterior and right postero-septal ahead of an invasive electrophysiological study.

Feasibility and Diagnostic Value of Recording Smartwatch Electrocardiograms in Neonates and Children.

The objective of this study was to evaluate the agreement of smartwatch-derived single-lead electrocardiogram (ECG) recordings with 12-lead ECGs for diagnosing electrocardiographic abnormalities. A 12-lead ECG and an ECG using Apple Watch were obtained in 110 children (aged 1week to 16years) with normal (n=75) or abnormal (n=35) 12-lead ECGs (atrioventricular block [7], supraventricular tachycardia [SVT] {5}, bundle branch block [12], ventricular preexcitation [6], long QT [5]). In children aged <6years, the ECG recording was performed with the active participation of an adult who applied the neonate or child's finger to the crown of the watch. In older children, tracings were obtained after brief teaching without adult guidance. All 12-lead ECGs were independently evaluated by 2 blinded cardiologists. Apple Watch ECGs were independently evaluated by another blinded cardiologist. In 109 children (99.1%), the smartwatch tracing was of sufficient quality for evaluation. Smartwatch tracings were 84% sensitive and 100% specific for the detection of an abnormal ECG. All 75 normal tracings were correctly identified. Of the 35 children with abnormalities on 12-lead ECGs, 5 (14%) were missed, most often because of baseline wander and artifacts. Rhythm disorders (atrioventricular block or SVT) and bundle branch blocks were correctly detected in most cases (11 of 12 and 11 of 12, respectively); preexcitation and long QT was detected in 4 of 6 and 4 of 5, respectively. Smartwatch ECGs recorded with parental assistance in children aged up to 6years and independently in older children have the potential to detect clinically relevant conditions.

Wolff-Parkinson-White syndrome and dilated cardiomyopathy: Not only an electrical issue?

The present case describes a dilated cardiomyopathy associated with both antidromic and orthodromic atrio-ventricular reentrant tachycardias supported by multiple right accessory pathways. Both right accessory pathways were successfully eliminated by catheter ablation and the patient progressively recovered during the follow up. The following etiologies might be involved: 1) primitive dilated cardiomyopathy (or post-inflammatory); 2) septal dyssinchrony due to ventricular pre-excitation; 3) tachycardiomyopathy.

Clinical characteristics of Danon disease

Objective: To review the clinical data of 7 patients with Danon disease and analyze their clinical characteristics. Methods: The medical records of 7 patients with Danon disease, who were hospitalized in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from April 2008 to July 2021, were reviewed and summarized, of which 6 cases were diagnosed as Danon disease by lysosomal-associated membrane protein-2 (LAMP-2) gene mutation detection and 1 case was diagnosed by clinicopathological features. Clinical manifestations, biochemical indexes, electrocardiogram, echocardiography, skeletal muscle and myocardial biopsy and gene detection results were analyzed, and patients received clinical follow-up after discharge. Results: Six patients were male and average age was (15.4±3.5) years and the average follow-up time was (27.7±17.0) months. The main clinical manifestations were myocardial hypertrophy (6/7), decreased myodynamia (2/7) and poor academic performance (3/7). Electrocardiogram features included pre-excitation syndrome (6/7) and left ventricular hypertrophy (7/7). Echocardiography examination evidenced myocardial hypertrophy (6/7), and left ventricular dilatation and systolic dysfunction during the disease course (1/7). The results of skeletal muscle biopsy in 6 patients were consistent with autophagy vacuolar myopathy. Subendocardial myocardial biopsy was performed in 3 patients, and a large amount of glycogen deposition with autophagosome formation was found in cardiomyocytes. LAMP-2 gene was detected in 6 patients, and missense mutations were found in all these patients. During the follow-up period, implantable cardioverter defibrillator implantation was performed in 1 patient because of high atrioventricular block 4 years after diagnosis, and there was no death or hospitalization for cardiovascular events in the other patients. Conclusion: The main clinical manifestations of Danon disease are cardiomyopathy, myopathy and mental retardation. Pre-excitation syndrome is a common electrocardiographic manifestation. Autophagy vacuoles can be seen in skeletal muscle and myocardial pathological biopsies. LAMP-2 gene mutation analysis is helpful in the diagnose of this disease.