Using 2D speckle-tracking echocardiography to localize the accessory pathway and evaluate cardiac function and dyssynchrony in pediatric patients with Wolf-Parkinson-White syndrome.

Wolf-Parkinson-White (WPW) accessory pathway (AP) may be associated with reentry supraventricular tachycardia (SVT) in addition to ventricular dyssynchrony and cardiac dysfunction. Electrophysiological studies (EPS) are the gold standard for the localization of the AP; however, 2D speckle-tracking echocardiography (2D-STE) may help in the localization of the AP noninvasively. Our study aims to evaluate the capability of 2D-STE for AP localization and the identification of AP-related contractile abnormalities and dyssynchrony in pediatric patients with WPW syndrome. This prospective multicenter cohort study involved 18 pediatric patients with ventricular preexcitation from January 2021 to January 2023. Tissue Doppler imaging (TDI), conventional echocardiography, and 2D-STE were done. Myocardial velocities, myocardial performance index (MPI), the global and segmental longitudinal strain of the left ventricle (LV), and time-to-peak longitudinal strain (TPLS) were measured before and after ablation. The longitudinal strain of the LV segments supplied by the AP, or the nearby segments close to the AP, was significantly impaired and improved after ablation (P = 0.0001). The abnormal strain pattern in the affected segments could predict the location of the AP. The TPLS of the affected segments significantly increased after ablation (P = 0.0001), denoting improved dyssynchrony. The ejection time and the LV MPI measured at the basal septum improved significantly after ablation. CONCLUSIONS: 2D STE may be used for noninvasive localization of the AP and to evaluate cardiac function and dyssynchrony in patients with WPW. Further research on more patients is necessary to validate this method for AP localization. WHAT IS KNOWN: • Accessory pathways (AP) associated with the Wolf-Parkinson-White (WPW) syndrome have been linked to supraventricular tachycardia (SVT). Even without SVT, WPW can cause left ventricular dyssynchrony, contractile dysfunction, and cardiomyopathy. • Electrophysiology study is the gold standard for the localization of the AP in WPW syndrome. WHAT IS NEW: • The combination of 2D-speckle-tracking echocardiography (2D-STE) and the modified Arruda algorithm can precisely localize the AP associated with WPW syndrome. • 2D-STE can potentially assess cardiac function and dyssynchrony related to WPW syndrome. Additionally, 2D-STE can be utilized to evaluate the effectiveness of ablation in restoring cardiac function and dyssynchrony.

Anatomy for ablation of atrioventricular nodal reentry tachycardia and accessory pathways.

The atrioventricular (AV) valve plane and the central septum are of particular importance for electrophysiological diagnosis and interventional therapy of supraventricular tachycardias because accessory electrical connections of various types may be present in addition to the specific conduction system. Although modern 3D electroanatomic reconstruction systems including high-density mapping can be of great assistance, detailed knowledge of the anatomic structures involved, their complex three-dimensional arrangement, and their electrical properties in conjunction with electrophysiological features of supraventricular arrhythmias is essential for safe and efficient electrophysiological treatment. The aim of this article is to present current anatomical, topographical, and electrophysiological findings against the background of historical, seminal, and still indispensable literature.

Right-sided Mahaim-mediated tachycardia combined with atypical atrioventricular nodal reentrant tachycardia and left free wall accessory pathway: A case report.

A 37-year-old man was admitted to our hospital with paroxysmal palpitation for half year. A previous electrogram showed a narrow complex tachycardia. Electrophysiologic study (EPS) found a concealed left-sided free wall pathway accessory. In addition, a transseptal approach was used for radiofrequency ablation. After successful ablation, EPS induced a wide complex tachycardia and a narrow complex tachycardia. The wide complex tachycardia was diagnosed as a right-sided Mahaim fiber atriofascicular accessory pathway, and the narrow complex tachycardia was diagnosed as atypical atrioventricular nodal reentrant tachycardia (AVNRT). Then, the right-sided Mahaim fiber atriofascicular accessory pathway and atypical AVNRT were successfully ablated. Herein, we report a rare case of a concealed left-sided accessory pathway combined with a right atriofascicular Mahaim fiber and atypical AVNRT.

Atrioventricular accessory pathway unmasked by heart valve replacement.

A 50-year-old male patient with a history of severe valvular regurgitation underwent mitral and aortic valve replacement surgery 3 months ago. Preoperative 12-lead electrocardiogram presented atrial flutter (AFL) and atrial fibrillation. AFL complicated with ventricular pre-excitation was observed on current admission. The potential mechanisms underlying these changes were considered multifaceted, and valve replacement procedure may be a rare incentive factor.

A Frequent Observation of Wolff-Parkinson-White Syndrome and Fasciculoventricular Pathways in Patients With Danon Disease.

BACKGROUND: Danon disease is typically associated with cardiomyopathy and ventricular pre-excitation. The study aimed to characterize the clinical profile of Danon disease, analyze electrocardiographic (ECG) and electrophysiologic features, and investigate their association with Wolff-Parkinson-White (WPW) syndrome and fasciculoventricular pathways (FVPs).Methods and Results:Clinical course, family history, ECG and electrophysiological data were collected from 16 patients with Danon disease. Over 0.4-8 years of follow up, 1 female patient died suddenly, and 5 male patients died of progressive heart failure by age 13-20 years. Family history analysis revealed that 3 mothers experienced hospitalization or death for heart failure at age 28-41 years. There was 100% penetrance for ECG abnormalities in 13 patients with original ECGs. Short PR intervals and delta waves were present in 9 and 8 patients, respectively. There were significant age-associated increases in the QRS complex width (r=0.556, P=0.048) and the number of leads with notched QRS (r=0.575, P=0.04). Four patients who underwent electrophysiological studies all had FVPs, and 2 of them still had left-side atrioventricular pathways. CONCLUSIONS: Danon disease causes a malignant clinical course characterized by early death caused by heart failure in both genders and progressive ECG changes as patients age. The pre-excited ECG pattern is related to FVPs and WPW, which is suggestive of extensive cardiac involvement.

Accessory pathway ablation during atrial fibrillation in Ebstein anomaly.

An 84-year-old woman with type B Wolff-Parkinson-White (WPW) with Ebstein anomaly was admitted with heart failure. She had rapid wide QRS tachycardia due to accessory pathway (AP) conduction associated with atrial fibrillation (AF). Since transesophageal echocardiography before catheter ablation showed a left atrial thrombus, ablation was performed using a 3D mapping system under AF. After marking the functional tricuspid anulus with intra-cardiac echocardiography, 3D intra-cardiac electrogram visualization (ripple map) during AF enabled clear identification of location of the AP. After ablation, there was no complication of cerebral infarction, and the heart failure improved.

Fasciculoventricular and atrioventricular accessory pathways in patients with Danon disease and preexcitation: A multicenter experience.

BACKGROUND: Studies have suggested that a fasciculoventricular pathway (FVP) may be the cause of preexcitation in patients with Danon disease, a rare X-linked dominant genetic disorder of hypertrophic cardiomyopathy. OBJECTIVE: The purpose of this study was to describe the prevalence of ventricular preexcitation on resting 12-lead electrocardiogram (ECG) in patients with Danon disease and the electrophysiological study (EPS) results of those with preexcitation. METHODS: Patients with confirmed Danon disease diagnosed with preexcitation (PR ≤120 ms, delta wave, QRS >110 ms) on ECG were included from a multicenter registry. The incidence of arrhythmias, implantable cardioverter-defibrillator (ICD) procedures, ICD shocks, and EPS results were collected. RESULTS: Thirteen of 40 patients (32.5%) with Danon disease were found to have preexcitation (mean age 17.3 years; 38% women). EPS performed in 9 of 13 patients (69%) demonstrated FVP only in 2 (22.2%), extranodal pathway without exclusion of FVP in 2 (22.2%), and both FVP and extranodal pathway in 5 (55.6%). Two patients had malignant accessory pathway (AP) properties. Over median follow-up of 842 days (interquartile range 138-1678), 11 patients (85%) had ICD placement, and 6 (46.1%) underwent heart transplantation. No patients required therapy for ventricular tachycardia, and 2 patients (15%) had paroxysmal atrial fibrillation. CONCLUSION: In a large multicenter cohort of patients with Danon disease, there was a high prevalence of FVP and extranodal pathways diagnosed on EPS in those with preexcitation. These findings suggest patients with preexcitation and Danon disease should undergo EPS to assess for FVP and potentially malignant extranodal AP.

Fast pathway ablation unmasks nodoventricular fibers in a 15-year-old patient with supraventricular tachycardia.

We described a 15-year-old boy who underwent the catheter ablation for the nodoventricular (NV) tachycardia that had difficulty in differentiation from atrioventricular nodal reentrant tachycardia with upper common pathway. The modification of the fast pathway revealed an anterograde conduction of the NV fiber. We successfully performed the catheter ablation targeting for the right ventricular insertion site of the NV fiber.

Arrhythmias with Bystander Accessory Pathways.

An accessory pathway (AP) could manifest its presence exclusively during an orthodromic supraventricular tachycardia or with preexcitation during sinus rhythm (SR). The manifestations of the presence of an AP depend on its ability to conduct antegradely from atrium (A) to ventricle (V), retrogradely (V to A), or both. AP retrograde conduction is necessary to establish an atrioventricular reentrant tachycardia circuit. If an AP can only conduct antegradely, it will function as a bystander AV connection during independent arrhythmias. The correct diagnosis of this condition is very important, as it will determine the immediate and long-term management.

Catheter ablation of a latent accessory pathway under continuous infusion of adenosine: A case report.

RATIONALE: In absence of conduction over the accessory pathway (AP) during the electrophysiological study, mapping and ablation is impossible. Various techniques can be used to activate absent conduction. In this presentation we describe the first case of latent AP ablation performed under continuous infusion of adenosine. PATIENT CONCERNS: A 65-year-old man, presented to emergency department with atrial fibrillation and antegrade conduction through a left lateral AP. He had palpitations and lightheadedness that occurred every 2 to 3 weeks. DIAGNOSIS: The electrophysiological study confirmed a latent left-side AP. INTERVENTIONS: Catheter ablation could not be performed because of absent conduction through AP. Therefore, a continuous infusion of adenosine was used to activate AP. Ablation was performed at the left lateral mitral ring. OUTCOMES: After catheter ablation and a new adenosine bolus there was no conduction through AP. LESSONS: In case of a latent AP when ablation is difficult to perform because of absent conduction at the time of electrophysiological study, adenosine can be used in doses of 1.5 mg/kg over 5 minutes continuous infusion.

Novel Assessment of Accessory Pathway Function in Patients with Wolff-Parkinson-White Syndrome.

Surrogates for the shortest pre-excited R-R interval in atrial fibrillation (SPERRI) such as the accessory pathway effective refractory period (APERP) and shortest pre-excited paced cycle length (SPPCL) are flawed assessments of accessory pathway function in patients with WPW. Multi-extrastimulus pacing may have the theoretical advantage of more accurately mimicking the clinical reality of atrial fibrillation and thus may serve to better assess accessory pathway function. This cross-sectional study included 25 consecutive patients, aged ≤ 18 years, undergoing electrophysiology study for WPW. The longest S1S2, S2S3, S3S4 coupling intervals at which the antegrade AP refractoriness occurred, SPERRI, and SPPCL were recorded. Induction of atrial fibrillation was attempted in all patients and induced in 8 (32%, 4 SPERRIbaseline (265 ms ± 61 ms), 4 SPERRIIsuprel (258 ms ± 41 ms)). At baseline, the lower value of the S3ERP or S4ERP (274 ms ± 52 ms) was lower than the SPPCL (296 ms ± 54 ms, p < 0.0001) and APERP (296 ms ± 41 ms, p < 0.0001). More patients had S3ERP or S4ERP ≤ 250 ms (12/25, 48%) compared to those with APERP ≤ 250 ms (2/25 8%), p = 0.0016), SPPCL 5/24, 20%), p = 0.008 or either (6/25, 24%), p = 0.0143). With Isuprel, the lower value of the S3ERP or S4ERP (221 ms ± 36 ms) trended to be lower than the APERP (252 ms ± 36 ms, p = 0.0001) and the SPPCL (266 ms ± 57 ms, p = 0.001). With Isuprel, there was no statistical difference in the proportion of patients with S3ERP or S4ERP < 250 ms (12/16, 75%) compared to those with APERP ≤ 250 ms ((9/16, 56%), p = 0.08), SPPCL ≤ 250 ms ((9/16, 56%), p = 0.08), or either ((10/16, 63%), p = 0.16). Multi-extrastimulus pacing protocols demonstrate that accessory pathways are less refractory than as defined by single extrastimulus pacing and straight decremental pacing.

Improvement in Dyssynchrony with Pharmacological Ablation of Right-Sided Accessory Pathway-Induced Cardiomyopathy in Infants.

Right-sided accessary pathways in patients with Wolff-Parkinson-White (WPW) syndrome may cause cardiac dyssynchrony and dilated cardiomyopathy, with a characteristic septal shape, irrespective of any supraventricular tachycardia episodes. We report on two infants (13 and 5 months), whose right-sided accessary pathway-induced dilated cardiomyopathy was successfully treated by flecainide for the first time. After the flecainide administration, an abnormal aneurysmal dilation of the basal interventricular septum was almost restored to normal, and the decreased ejection fraction recovered. Flecainide use may be an important therapeutic option for this entity to avoid catheter ablation during infancy.

Efficacy of Nifekalant in Patients With Wolff-Parkinson-White Syndrome and Atrial Fibrillation: Electrophysiological and Clinical Findings.

Background The efficacy of nifekalant in preexcited atrial fibrillation ( AF ) has not been assessed. Methods and Results The study populations consisted of patients with sustained preexcited AF (n=51), paroxysmal supraventricular tachycardia (n=201), and persistent AF (n=87). Effects of intravenous infusion of nifekalant were assessed on electrophysiological and clinical parameters. Nifekalant prolonged the shortest preexcited R-R, the average preexcited R-R, and the average R-R intervals from 290±35 to 333±44 ms, 353±49 to 443±64 ms, and 356±53 to 467±75 ms, respectively, in patients with preexcited AF (all P<0.001). Nifekalant also decreased the percentage of preexcited QRS complexes, heart rate, and increased systolic pressure (all P<0.001). Nifekalant terminated AF in 33 of 51 patients (65%). Similar effects were also observed in a subgroup of 12 patients with preexcited AF and impaired left ventricular function. In patients with paroxysmal supraventricular tachycardia, nifekalant significantly prolonged the effective refractory period, the block cycle length of the antegrade accessory pathway, and the atrial effective refractory period (all P<0.001). Nifekalant had no effect on the effective refractory period of the antegrade atrioventricular node. Finally, in patients with persistent AF without an accessory pathway, nifekalant did not significantly decrease the ventricular rate of AF . One patient developed Torsades de Pointes. No other adverse effects were observed. Conclusions Nifekalant prolongs the effective refractory period of the antegrade accessory pathway and atrium without blocking antegrade conduction through the atrioventricular node, leading to slowing and/or to termination of preexcited AF . Thus, nifekalant might be an effective and a relatively safe drug in patients with preexcited AF .

Mahaim fibers coexisting with coarctation of aorta and bicuspid aortic valve.

We found a coexistence of Mahaim fibers, coarctation of aorta and bicuspid valve in a young patient presenting with palpitations and subraventricular tachycardia. This rare combination of these three congenital cardiac abnormalities occurring in the same patient has not been reported previously. Detailed cardiac studies unmasked the patient's cardiac abnormalities. Furthermore, successful percutaneous intervention in treating coarctation and catheter-based ablation of Mahaim fibers were performed with resolution of symptoms. This case is discussed here in detail, alongside a review of the literature.

Coexistence of atrioventricular accessory pathways and drug-induced type 1 Brugada pattern.

BACKGROUND: Atrial arrhythmias, particularly atrioventricular nodal reentrant tachycardia, can coexist with drug-induced type 1 Brugada electrocardiogram (ECG) pattern (DI-Type1-BrP). The present study was designed to determine the prevalence of DI-Type1-BrP in patients with atrioventricular accessory pathways (AV-APs) and to investigate the clinical, electrocardiographic, electrophysiologic, and genetic characteristics of these patients. METHODS: One-hundred twenty-four consecutive cases of AV-APs and 84 controls underwent an ajmaline challenge test to unmask DI-Type1-BrP. Genetic screening and analysis was performed in 55 of the cases (19 with and 36 without DI-Type1-BrP). RESULTS: Patients with AV-APs were significantly more likely than controls to have a Type1-BrP unmasked (16.1 vs 4.8%, P = 0.012). At baseline, patients with DI-Type1-BrP had higher prevalence of chest pain, QR/rSr' pattern in V1 and QRS notching/slurring in V2 and aVL during preexcitation, rSr' pattern in V1 -V2 , and QRS notching/slurring in aVL during orthodromic atrioventricular reentrant tachycardia (AVRT) compared to patients without DI-Type1-BrP. Abnormal QRS configuration (QRS notching/slurring and/or fragmentation) in V2 during preexcitation was present in all patients with DI-Type1 BrP. The prevalence of spontaneous preexcited atrial fibrillation (AF) and history of AF were similar (15% vs 18.3%, P = 0.726) in patients with and without DI-Type1-BrP, respectively. The prevalence of mutations in Brugada-susceptibility genes was higher (36.8% vs 8.3%, P = 0.02) in patients with DI-Type1-BrP compared to patients without DI-Type1-BrP. CONCLUSIONS: DI-Type1-BrP is relatively common in patients with AV-APs. We identify 12-lead ECG characteristics during preexcitation and orthodromic AVRT that point to an underlying type1-BrP, portending an increased probability for development of malignant arrhythmias.

Sinus Node Dysfunction and Atrial Fibrillation: A Reversible Phenomenon?

BACKGROUND: Symptomatic sinus node dysfunction (SND) consists of a variety of manifestations, including tachycardia-bradycardia syndrome. Atrial fibrillation (AF) is commonly associated with SND, which complicates the management of both conditions. This paper reviews the epidemiology, pathophysiology, and clinical trial data investigating therapeutic approaches for treatment of patients with both SND and AF. METHODS: The authors reviewed articles published in English describing the epidemiology, pathophysiology, and therapeutic approaches for patients with SND and AF. The search was conducted using PubMed. Keywords included: sick sinus syndrome, sinus node dysfunction, atrial fibrillation, pacing, and pulmonary vein isolation. RESULTS: SND affects up to one in five patients with AF. AF can lead to anatomical and electrophysiological remodeling in both atria, including the region of sinoatrial node. Changes including atrial fibrosis, altered calcium channel metabolism, and transformed gene expression have been demonstrated in patients with AF and SND. Nonrandomized clinical trial data have failed to demonstrate whether any pacing strategy can reduce the risk of AF. Pulmonary vein isolation appears to decrease episodes of tachybrady syndrome and sinus pauses. CONCLUSIONS: SND affects up to one in five patients with AF. The pathophysiological derangements in gene expression, ion channel metabolism, and alterations in myocardial architecture associated with AF may lead to anatomic and electrical changes in the region of the sinoatrial node. Ablation may improve symptoms associated with SND in patients with AF. Future randomized trials are needed to clarify the epidemiology and optimal management of patients with SND and AF.

Concealed Accessory Pathways with a Single Ventricular and Two Discrete Atrial Insertion Sites.

BACKGROUND: Atrioventricular reciprocating tachycardia (AVRT) utilizing a concealed accessory pathway is common. It is well appreciated that some patients may have multiple accessory pathways with separate atrial and ventricular insertion sites. METHODS: We present three cases of AVRT utilizing concealed pathways with evidence that each utilizing a single ventricular insertion and two discrete atrial insertion sites. RESULTS: In case one, two discrete atrial insertion sites were mapped in two separate procedures, and only during the second ablation was the Kent potential identified. Ablation of the Kent potential at this site remote from the two atrial insertion sites resulted in the termination of the retrograde conduction in both pathways. Case two presented with supraventricular tachycardia (SVT) with alternating eccentric atrial activation patterns without alteration in the tachycardia cycle length. The two distinct atrial insertion sites during orthodromic AVRT and ventricular pacing were targeted and each of the two atrial insertion sites were successfully mapped and ablated. In case three, retrograde decremental conduction utilizing both atrial insertion sites was identified prior to ablation. After mapping and ablation of the first discrete atrial insertion site, tachycardia persisted utilizing the second atrial insertion site. Only after ablation of the second atrial insertion site was SVT noninducible, and VA conduction was no longer present. CONCLUSIONS: Concealed retrograde accessory pathways with discrete atrial insertion sites may have a common ventricular insertion site. Identification and ablation of the ventricular insertion site or the separate discrete atrial insertion sites result in successful treatment.