Transaortic cryoablation of uncommon atrioventricular nodal reentrant tachycardia after Senning and Rastelli operations.

A 36-years-old woman with a congenital corrected transposition of the great arteries, who underwent Senning and Rastelli operations, was admitted with a symptomatic supraventricular tachycardia. During an electrophysiological study, uncommon atrioventricular (AV) nodal reentrant tachycardia was induced. The coronary veins and coronary sinus did not connect to the systemic venous atrium. The His bundle electrogram (HBE) was recorded at the anterior septum of the mitral valve via the aorta. The target of ablation was the site of the earliest atrial activation during the tachycardia, 5 mm posterior to the AV node, and a successful cryoablation was performed using a transaortic approach. Both the antegrade and retrograde conduction of the slow AV nodal pathway was eliminated.

Familial atrial rapid fibrillation associated with double mutations of SCN5A and KCNQ1.

Familial atrial fibrillation is inherited and sporadically occurs in the paediatric population. Generally, fibrillated wavelets are reported at a frequency of approximately 6 Hz. Herein, we report a familial case presenting rapidly fibrillated wavelets at frequencies of approximately 12 to 30 Hz associated with KCNQ1 and SCN5A mutations.

A novel procedure of puncture to access the pulmonary venous atrium in complex congenital heart disease with surgical correction.

BACKGROUND: In complex congenital heart disease, supraventricular arrhythmia develops long term after surgical repair. The arrhythmia could have pharmacological tolerance and sometimes be fatal. We report our experiences with puncturing tough or calcified surgical repair material to access the pulmonary venous atrium for the purpose of the management of arrhythmia in complex congenital heart disease with surgical correction. METHODS: From June 2016, subsequent 9 patients underwent the procedure. Their age at the procedure ranged from 11 to 43 years old (median 26.4 years old). Surgical procedures were Mustard procedure (XenomedicaⓇ) in 6, lateral tunnel total cavo-pulmonary connection with autologous pericardium in 2, and extra-cardiac total cavo-pulmonary connection with expanded polytetrafluoroethylene (ePTFE) tube in 1. RESULTS: Multi-planar reconstruction imaging by cardiac computed tomography was done for making plans before the procedures. Under intracardiac echocardiography guidance, an 8 French steerable sheath was perpendicularly adjusted to target objects. The sharpened edge of 0.014 inch guide wire penetrated with gentle forward force. Subsequently, the puncture site was dilated from a small balloon to a large one step by step. In all patients, penetration was successfully completed. Catheter ablation was achieved in 8 patients and a pacemaker was implanted through the re-canalized superior caval vein in 1 patient. No complications were recorded. CONCLUSION: The trans-catheter puncture of the synthetic or calcified material is safe and feasible, although careful planning is required with imaging. A steerable sheath could easily be controlled to the make appropriate angle to the target object for preventing slippage and conveying effective force.

Impact of preoperative electrophysiological intervention on occurrence of peri/postoperative supraventricular tachycardia following Fontan surgery.

BACKGROUND: Little is known about the effects of preoperative electrophysiological study (EPS) and catheter ablation (CA) in Fontan surgery candidates with supraventricular tachycardia (SVT). OBJECTIVE: The purpose of this study was to investigate the clinical impact of EPS-guided intervention in Fontan surgery candidates with preceding SVT events. METHODS: A total of 109 consecutive patients with a history of SVT before Fontan surgery were divided into 3 groups: 44 in whom EPS with CA was attempted (CA group); 21 in whom EPS without CA was attempted (EPS group); and 44 in whom EPS was not performed (N group). The incidence and diagnosis of SVT, acute success rate of CA, and risk factors of peri/postoperative SVT were retrospectively investigated. RESULTS: The total incidence of SVT within 1 year after Fontan surgery was 34% (n = 37), with 91% of cases occurring within 1 month. Among the 71 SVT incidences diagnosed with EPS, 31 were atrioventricular reentrant tachycardias (AVRTs) involving twin atrioventricular nodes, 12 were atrioventricular nodal reentrant tachycardias, 12 were atrial tachycardias, 7 were orthodromic AVRTs via the accessory pathway, 7 were atrial flutters, and 2 were junctional tachycardias. The acute success rate of CA was 91% (48/53). The rate of peri/postoperative atrioventricular reciprocating SVT was significantly lower in the CA group than in the N or EPS group (11% vs 43% or 43%; P <.05). No/unsuccessful CA significantly increased the risk of peri/postoperative SVT in multivariate analysis (odds ratio 4.43; 95% confidence interval 1.69-11.59). CONCLUSION: Preoperative CA reduces peri/postoperative SVT occurrence in Fontan surgery candidates at high risk for SVT.

Transvenous shock-only implantable cardioverter defibrillator after an atrio-pulmonary Fontan surgery.

A 42-year-old woman with tricuspid atresia who underwent a Fontan surgery (atrio-pulmonary connection) was admitted to our hospital due to symptomatic ventricular tachycardia (VT). A defibrillation lead was implanted in a distal site of a coronary vein since there was no usual entry to the ventricle. Ventricular pacing was impossible due to the high threshold, however, good sensing was obtained. Three years later, she felt palpitations and a subsequent shock therapy while climbing stairs. The cardioverter data showed that an appropriate cardioversion therapy successfully converted VT to normal rhythm.

Point ablation for macro-reentrant ventricular tachycardia associated with Ebstein's anomaly and pulmonary atresia: a case report.

We report a case with Ebstein's anomaly and pulmonary atresia with sustained monomorphic ventricular tachycardia in a patient without a ventriculotomy history. In the low voltage area between the atrialised right ventricle and hypoplastic right ventricle, there was a ventricular tachycardia substrate and slow conduction. The tachycardia circuit was eliminated by a point catheter ablation at the area with diastolic fractionated potentials.

Electrophysiological features and radiofrequency catheter ablation of accessory pathways associated with atrioventricular discordance.

INTRODUCTION: Although a high prevalence of the presence of an accessory pathway (AP) associated with atrioventricular (AV) discordance has been reported, a case series of its characteristics and the results of catheter ablation (CA) have not been sufficiently documented. METHODS AND RESULTS: We retrospectively examined 11 consecutive patients with atrioventricular discordance who underwent CA for atrioventricular reciprocating tachycardia (AVRT) via an AP and planned cardiac surgery after CA. Orthodromic AVRTs were induced in 10 patients via AP, but no antidromic/duodromic AVRT was induced in any of the cases. A total of 13 APs were identified, and all of them were located around the anatomical tricuspid valve (TV) annulus, including two Ebsteinoid valves. The APs were predominantly located posteriorly, posterolaterally, and posteroseptally on the TV in nine patients (82%). Two patients (18%) had multiple APs or a single broad AP. Four (36%) and three (27%) patients showed twin AVNs and other supraventricular tachycardias (SVTs) except AVRT via the AP. Ten patients (91%) had acute successful CA in the first session, except for one patient with multiple APs who required the third session to eliminate all APs before the planned Fontan surgery. There were no major complications associated with CA. Seven of eight patients who underwent cardiac surgery after CA did not experience peri-/postoperative SVT. CONCLUSION: APs in patients with AV discordance are usually associated with the anatomical TV annulus. CA of an AP in AV discordance is highly effective and recommended to reduce the risk of SVT. The coexistence of twin AVNs and other SVTs should be considered during CA of an AP in AV discordance.

Acute and Long-Term Outcomes of Transvenous Cardiac Pacing Device Implantation in Patients With Congenital Heart Disease.

Background: Little is known about the acute/long-term outcomes of implantation of cardiac implantable electronic devices (CIED) using a transvenous approach for patients with congenital heart disease (CHD). Methods and Results: We retrospectively investigated the acute/long-term results and complications associated with transvenous CIED implantation in 140 patients with CHD. We implanted 77 pacemakers, 51 implantable cardioverter defibrillators (ICD), and 12 cardiac resynchronization therapy (CRT) devices. Although we successfully implanted pacemakers and ICD in all patients, we could not place a coronary sinus (CS) lead in 25% of the patients requiring CRT devices due to coronary vein anomalies associated with corrected transposition of the great arteries (cTGA). Overall complication rate, lead failure rate, and incidence of device infection were 16%, 9%, and 0.7%, respectively. There was no significant difference in overall complication rates between the simple (n=22) and complex CHD (n=118) groups (14% vs. 16%). The 10-year lead survival for the ICD leads (77%) was significantly lower than for the pacemaker leads (91%, P=0.0065). Conclusions: The outcomes of transvenous CIED in patients with CHD seemed acceptable, although there was a relatively high incidence of complications. CS lead placement for cTGA may be hindered by coronary vein anomalies. Lead survival tended to be lower for ICD than for pacemakers in these patients.

Different responses to exercise between Andersen-Tawil syndrome and catecholaminergic polymorphic ventricular tachycardia.

Aims: Andersen-Tawil Syndrome (ATS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are both inherited arrhythmic disorders characterized by bidirectional ventricular tachycardia (VT). The aim of this study was to evaluate the diagnostic value of exercise stress tests for differentiating between ATS and CPVT. Methods and results: We included 26 ATS patients with KCNJ2 mutations from 22 families and 25 CPVT patients with RyR2 mutations from 22 families. We compared the clinical and electrocardiographic (ECG) characteristics, responses of ventricular arrhythmias (VAs) to exercise testing, and the morphology of VAs between ATS and CPVT patients. Ventricular arrhythmias were more frequently observed at baseline in ATS patients compared with CPVT patients [the ratio of ventricular premature beats (VPBs)/sinus: 0.83 ± 1.87 vs. 0.06 ± 0.30, P = 0.01]. At peak exercise, VAs were suppressed in ATS patients, whereas they were increased in CPVT patients (0.14 ± 0.40 vs. 1.94 ± 2.71, P < 0.001). Twelve-lead ECG showed that all 25 VPBs and 15 (94%) of 16 bidirectional VTs were right bundle branch block (RBBB) morphology in ATS patients, whereas 19 (86%) of 22 VPBs had left bundle branch block (LBBB), and 12 (71%) of 17 bidirectional VT had LBBB and RBBB morphologies in CPVT patients. Conclusion: In patients with ATS, VAs with RBBB morphology were frequently observed at baseline and suppressed at peak exercise. In contrast, exercise provoked VAs with mainly LBBB morphology in patients with CPVT. In adjunct to clinical and baseline ECG assessments, exercise testing might be useful for making the diagnosis of ATS vs. CPVT, both characterized by bidirectional VT.

Safety and Efficacy of Radiofrequency Catheter Ablation for Tachyarrhythmia in Children Weighing Less Than 10 kg.

An increasing number of children are undergoing radiofrequency catheter ablation (RFCA) for tachyarrhythmia. However, infants and toddlers undergoing RFCA are often resistant to medication or need to eliminate arrhythmia substrate, and the risks of RFCA complications are still high in infants and toddlers. From April 2008 and December 2016, 285 children who underwent radiofrequency catheter ablation (RFCA) were stratified according to body weight (group A, less than 10 kg, n = 22; group B, over 10 kg, n = 263) and the clinical features of RFCA were retrospectively reviewed in these groups. Indications for RFCA included drug-refractory tachyarrhythmia or symptomatic tachycardia and tachycardia-induced cardiomyopathy. The acute success rate in this group was 90.9%, with a relatively low recurrence rate (15.0%) after 7.0 ± 1.6 years follow-up. We performed RFCA using only 2-4 catheters in all cases. Major complications included complete right bundle branch block in one patient. No significant differences in rates of success, recurrence, or complications were noted between children weighing less and more than 10 kg. RFCA is safe and efficacious for tachyarrhythmia even in patients weighing less than 10 kg.

Long-Term Efficacy of Implantable Cardioverter Defibrillator in Repaired Tetralogy of Fallot　- Role of Anti-tachycardia Pacing.

BACKGROUND: Tetralogy of Fallot (TOF) is one of the common congenital heart diseases (CHD) in implantable cardioverter defibrillator (ICD) recipients, but few studies have reported the long-term outcomes of and the anti-tachycardia pacing (ATP) efficacy in repaired TOF.Methods and Results:Twenty-one repaired TOF patients with an ICD implanted between April 2003 and March 2015 were investigated retrospectively. ICD therapy and clinical outcome were analyzed. Mean patient age was 39±11 years; 62% were male; and mean age at repair surgery was 9.4±6.8 years. During a median follow-up of 5.6 years (range, 2.6-8.4 years), no patients died. Appropriate ATP were delivered in 11 patients (52%), with appropriate shocks in 5 patients (24%) and inappropriate shocks in 5 patients (24%). The success rate of ATP was 98% for fast ventricular tachycardia (VT; cycle length ≤320 ms) and 98% for slow VT (cycle length >320 ms). ATP effectiveness increased from 81.5% with the first ATP attempt to 93.7% with the second ATP attempt, to 97.5% with the third ATP attempt, and to 98.6% with the fourth or successive ATP attempt (P<0.0001, Cochran-Armitage trend test). CONCLUSIONS: ATP was highly effective in repaired TOF regardless of VT cycle length. Multiple ATP attempts could have an important role in VT termination, and the novel subcutaneous ICD without ATP capability should be used carefully.

Successful catheter ablation of ventricular tachycardia in a patient with congenitally corrected transposition of great arteries after double switch operation.

Ventricular tachycardia (VT) may cause sudden death late after repair of congenital heart disease. Radiofrequency catheter ablation (CA) of VT can be effective but may be hampered by hypertrophied myocardium or prosthetic material. A 33-year-old man with congenitally corrected transposition of the great arteries (ccTGA) had undergone a double switch operation (DSO) with the combined Mustard and Rastelli procedures when he was 10 years old. He developed sustained VT 16 years after the surgery. An electrophysiological study was performed using a 3D mapping system. During the VT, abnormal fragmented potentials were identified in the right ventricular side near the patch of ventricular septal defect. Radiofrequency energy was delivered at the site with changes in the QRS morphology. Electroanatomical mapping of the left ventricle was performed via a retrograde transaortic approach. Successful ablation of the fractionated potentials was likewise achieved on the left side. We report, to our knowledge, the first case of a successful radiofrequency CA of VT in a patient with ccTGA after a DSO. A slow conduction zone, which was proved to be part of the tachycardia substrate, existed around the patch of ventricular septal defect. Fragmented activities during VT were recorded from both ventricles. The tachycardia circuit was eliminated after ablating the right and left sides of the ventricular septal defect patch.

Ventricular Tachycardia Rotating a Scar of a Total Right Ventricular Exclusion.

We describe a 15-year-old postoperative girl who underwent surgical 3-dimensional mapping and ablation of hemodynamically unstable ventricular tachycardia (VT) with an on-pump beating heart surgical technique. She had previously received a tricuspid valve closure, entire right ventricular free wall resection, and finally Fontan operation with an extracardiac conduit to treat a severe Ebstein's anomaly. Activation mapping revealed a VT rotating around a large right ventricular free wall incisional scar with a narrow conduction channel between the scar and a tricuspid annulus (TA). A linear radiofrequency ablation connecting the scar and the TA terminated the VT.

Incidence, Clinical Course, and Risk Factors of Amiodarone-Induced Thyroid Dysfunction in Japanese Adults With Congenital Heart Disease.

BACKGROUND: Although amiodarone (AMD)-induced thyroid dysfunction (AITD) is an important complication of AMD therapy, little is known about AITD in adult Japanese patients with congenital heart disease (CHD). METHODS AND RESULTS: We retrospectively studied 131 adult patients with CHD who were on low-dose AMD (median, 150 mg/day). The median patient age was 28 years, and the median follow-up was 44 months. The incidence, clinical course, and risk factors of AITD, including AMD-induced thyrotoxicosis (AIT) and AMD-induced hypothyroidism (AIH), were evaluated. The total incidence of AITD was 30% (AIT: 18%, n=24; AIH: 12%, n=16). Approximately 67% of patients with AIT displayed deterioration of tachyarrhythmia, and 38% patients underwent steroid therapy. Although thyroid function and symptoms associated with AIT improved within 6 months after diagnosis in most patients with AIT (92%), 1 patient died suddenly during an acute phase of AIT. No patient with AIH exhibited deterioration of tachyarrhythmia, and 9 patients underwent thyroid hormone replacement therapy. Cox multivariate analysis identified no independent risk factor for AIT, whereas liver dysfunction (hazard ratio 2.573; 95% confidence interval 1.102-5.795) was an independent risk factor for AIH. CONCLUSIONS: AITD commonly occurred in adult Japanese patients with CHD even though they were on a low-dose AMD regimen. Risk factors for AITD may vary according to ethnicity and diet.

Electrophysiologic studies and radiofrequency catheter ablation of ectopic atrial tachycardia in children.

Ectopic atrial tachycardia (EAT) often resists medical therapy, making radiofrequency catheter ablation (RFCA) the preferred treatment. This study reviewed the records of 35 patients who underwent electrophysiologic studies (EPS) and 39 RFCA procedures for EAT during a 10-year period. Of the 35 patients, 10 (28%) presented with decreased ventricular function and tachycardia-induced cardiomyopathy (TIC). The EAT originated on the right atrial side in 19 patients (54%) and on the left atrial side in the remaining 16 patients (46%). The right atrial sites included the right atrial appendage (RAA) (n = 9, 25%), the tricuspid annulus (n = 7, 20%), and the crista terminalis (n = 3). The left atrial sites included the left atrial appendage (LAA) (n = 6, 17%), the pulmonary veins (n = 5, 14%), the mitral annulus (n = 3), and the posterior wall of the left atrium (n = 2). The mechanism of all EAT probably is automaticity. All EATs could be abolished using RFCA. Follow-up data were available for all patients 2 to 8 years after RFCA. All 35 patients remained recurrence free, and ventricular function improved for all 10 patients with TIC. The origin of EAT in children differed from its origin in adults. The authors conclude that RFCA is a safe and effective treatment option for children with refractory EAT and should be considered early in the course of their illness.

Successful catheter ablation of reentrant junctional tachycardia in a patient with asplenia syndrome before total cavo-pulmonary connection.

Asplenia syndrome is commonly associated with complex structural cardiac malformations, and junctional tachycardia (JT), which may compromise hemodynamic status, has been reported in association with asplenia syndrome.(1) We report successful radiofrequency catheter ablation of reentrant JT in a patient with asplenia syndrome.

Spontaneous closure of ventricular septal defects followed up from <3 months of age.

BACKGROUND: This study evaluates the incidence and timing of spontaneous closure (SC) of ventricular septal defect (VSD) using Doppler color flow mapping. METHODS: A total of 225 infants (mean age 30 days) were diagnosed with uncomplicated VSD: 31 (14%) subpulmonary VSD, 159 (70%) perimembranous, and 35 (16%) muscular. The patients were divided into two groups according to the presence or absence of congestive heart failure (CHF). SC was confirmed with color Doppler. RESULTS: Surgical closure was performed in 59 patients (26%). SC occurred in 107 patients (48%); three (10%) of 31 with subpulmonary VSD, 75 (47%) of 159 with perimembranous VSD, and 29 (83%) of 35 with a muscular VSD. Average age at SC was 19 months. In three SC patients with a subpulmonary VSD, there was no aortic valve prolapse and no aortic regurgitation. SC occurred in 96% of SC patients with a perimembranous VSD by the age of 6 years, and in 93% of those with a muscular VSD by the age of 3 years. In patients without CHF, the rate of SC was 72%; 23% in subpulmonary VSD, 74% in perimembranous, and 85% in muscular. SC occurred in only 23% of patients with a perimembranous VSD with CHF. Mean age at the final examination was 6.9 years in 59 patients with a VSD remaining open, and 63% of patients with a perimembranous VSD remaining open had an aneurysm of the ventricular membranous septum. CONCLUSIONS: The SC rate of VSD by mean age of 6.9 years was 48%, but it was 72% in patients without CHF. In patients with CHF, SC was seen only in patients with a perimembranous VSD. The rate of SC was 10% in subpulmonary VSD. The authors contend that SC probably occurred by growth of muscular septum surrounding VSD. Muscular VSD spontaneously closed earlier than perimembranous VSD.

Catheter ablation for a right anteroseptal accessory pathway in a patient with an endocardial cushion defect.

We report a radiofrequency catheter ablation for atrioventricular reentrant tachycardia in a patient with a right anteroseptal accessory pathway complicating an endocardial cushion defect. His bundle potential was recorded 20 mm posterior to the accessory pathway. In the presence of associated congenital heart disease, it is very important to understand the anatomy of the conduction system prior to radiofrequency catheter ablation.