Unmasking the uncommon: bidirectional ventricular tachycardia in two rare paediatric cardiomyopathies.

We present two exceptional cases of 14-year-old girls diagnosed with rare cardiomyopathies (left ventricular non-compaction, and arrhythmogenic right ventricular cardiomyopathy), both presenting with the unusual finding of bidirectional ventricular tachycardia.

Coronary sinus ablations in pediatric patients with supraventricular arrhythmias.

BACKGROUND: Intracoronary sinus ablations have been performed for various arrhythmical substrates. The aim of this study is to report our experience on pediatric patients of the safety and efficacy of ablations in the coronary sinus. METHODS: This is a retrospective study of all patients who underwent ablations in the coronary sinus from October 2013 to October 2021 at a single center. Clinical presentation, type of arrhythmia causing tachycardia, ablation procedure, and outcome were recorded. RESULTS: A total of 27 patients were included in the study. Nineteen (69%) of those followed up received a diagnosis of Wolff-Parkinson-White syndrome (WPW), 4 (15%) were cases of supraventricular tachycardia with concealed accessory pathway (AP), 2 (8%) were cases of focal atrial tachycardia, and 2 (8%) were cases of permanent junctional reciprocating tachycardia. Negative delta wave was noteworthy especially in lead II in 11/19 (58%) cases and coronary sinus diverticulum was detected in the WPW cases. Of those with manifest AP (19 cases), 15 (79%) had a high-risk AP and the AP in all WPW cases was adenosine unresponsive. Radiofrequency (RF) catheter ablation was performed in 25/27 (93%) cases during the procedure, and 16/25 (64%) of these were irrigated RF catheters. No complications were observed in the follow-up, including coronary artery injury. CONCLUSIONS: Catheter ablation of supraventricular tachyarrhythmias can be accomplished effectively and potentially safely within the coronary sinus. Coronary sinus diverticula should be suspected in patients with manifest posteroseptal APs who have a previous failed ablation and typical electrocardiographic signs.

Effects of Systolic Dysfunction on Clinical and Diagnostic Parameters in Pediatric Patients with Isolated Left Ventricular Non-compaction.

OBJECTIVE: Left ventricular non-compaction is a rare cardiomyopathy following an early arrest in endomyocardial morphogenesis. This study aimed to present the clinical and electrocardiographic characteristics, diagnostic features, treatment strategies, effects of systolic dysfunction on clinical and diagnostic parameters, and follow-up of pediatric patients diagnosed with left ventricular non-compaction. METHODS: We retrospectively reviewed children with isolated left ventricular non-compaction at Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital from January 2010 to June 2020. RESULTS: Fifty-five children were diagnosed with left ventricular non-compaction. Thirty-two patients (58.2%) were male, and the median age of presentation was 8.5 years (1 month-17.9 years). The median follow-up of the study was 19 months (1-121 months). Fourteen (25.5%) presented with systolic dysfunction (ejection fraction < 45%), and 2 presented with resuscitated/aborted cardiac arrest. Electrocardiographic abnormalities were present in 78.2%. Fragmented QRS was observed in 6 patients, and QTc duration was 450 milliseconds and above in 17 patients (30.9%). Electrocardiographic abnormalities, low QRS voltage, fragmented QRS, and thrombus were common in patients with ejection fraction < 45% group. Atrial and ventricular arrhythmias (including ventricular fibrillation-VF) were found with similar frequency in both ejection fraction < 45% and ≥45% groups. One patient with a complete atrioventricular block and 1 with long QT syndrome and severe bradycardia underwent permanent pacemaker implantation. Five (9.1%) patients died. CONCLUSIONS: Left ventricular non-compaction has heterogeneous clinical findings in childhood. It is essential to follow-up with the patients closely for the development of ventricular dysfunction or arrhythmias due to the progressive course of the disease. Further studies are needed since life-threatening ventricular arrhythmias can be seen, even in patients with preserved ejection fraction.

Predictors of prolonged pleural effusion after Fontan operation.

Prolonged pleural effusion is a fairly common condition which has considerable impact on complicated and longer hospital stays after Fontan surgery. Identifying the patient population prone to have pleural effusions is still seeking for an answer. This study is to determine the variables that may predict prolonged pleural effusion according to the data of 69 patients who underwent Fontan operation between June 2018 and December 2020 and survived to date. Prolonged pleural effusion was defined as the need for a chest tube for more than 7 days. Two patient groups, with and without prolonged effusion, were compared in terms of pre-, peri-, and post-operative variables. The patients were subdivided into "high-risk" and "low-risk" groups based on the pre-operative catheterisation data. The most frequent main diagnosis was tricuspid atresia (n: 13, 19%). Among 69 patients, 28 (40%) had prolonged pleural effusion whereas 11 (16%) had effusions that lasted longer than 14 days. Ten patients among prolonged effusion group (35%) had pulmonary atresia coexistent with the main diagnosis. Fontan operation was performed in 6 patients (8.7%) over the age of 10, and 4 of these patients (67%) had prolonged pleural effusion. Among numerous variables, statistical significance between the two groups was achieved in pre-operative mean pulmonary artery pressure, post-operative albumin, C-reactive protein levels, length of hospital stay, duration of chest tube drainage, and amount of effusion per day. Early recognition and treatment strategies with routine medical protocol use remain to be the cornerstone for the management of post-operative prolonged pleural effusions after Fontan surgery.

Electrocardiographic and electrophysiological characteristics of fasciculoventricular fibers in children.

OBJECTIVES: Fasciculoventricular fiber (FVF) that does not cause tachyarrhythmia is a rare form of ventricular preexcitation, which is important to distinguish from Kent fibers. Although, adenosine and some electrocardiographic features are important in the differentiation of Wolff Parkinson White (WPW) than FVF, a clear distinction may not always be possible without an electrophysiological study (EPS). In this study, we aimed to present the clinical and electrophysiological features of our pediatric patients with fasciculoventricular fiber. PATIENTS AND METHOD: Between October 2013 and September 2021, 565 patients who underwent electrophysiological studies due to ventricular preexcitation in our clinic were screened in the study, and 27 (4.7%) patients with fasciculoventricular fiber were included. The data of the patients were obtained from the file records using the electronic internet database system Filemaker® . Electrophysiological study age, weight, gender, symptom, and presence of congenital heart disease of the patients were obtained from the file records. Accessory pathway localization was evaluated according to the modified Arruda algorithm in pre-procedural electrocardiography. In addition, delta wave amplitudes were measured in the first 40 ms from the surface ECG. PR interval, QRS interval, and delta wave amplitude were recorded before and after ablation in patients with additional accessory pathways. Post-procedure values were included in the FVF group. RESULTS: The mean age of the patients was 11.47 ± 4.25 years. All 70.4% of the reasons for admission were symptoms such as palpitations and syncope. Two patients had hypertrophic cardiomyopathy and 1 patient had ccTGA. In the electrophysiological study, additional manifest WPW was found in 9 (33%) patients (3 patients with high risk, 6 patients with orthodromic supraventricular tachycardia), focal atrial tachycardia in a patient, and atrioventricular nodal reentry tachycardia in a patient. While the delta wave amplitude was found to be 2.56 ± 1.38(1-5.5) mm in the first 40 ms in surface electrocardiography in 9 patients with additional accessory pathway, it was found to be 1.64 ± 0.67(0.5-3) mm in the FVF group. There was no statistically significant difference between the 2 groups (p = .398). Delta wave amplitude > 3.5 mm was not detected in any patient with isolated FVF. Interestingly, delta wave amplitude was < 3.5 mm in 7 (78%) of 9 patients who were identified and ablated with an additional accessory pathway. Total 19 of the patients (59.3%) were adenosine-responsive (18 isolated FVF, 1 manifest AP+FVF adenosine-responsive. 8 patients with other manifest AP + FVF had no pre-procedural adenosine-asystole response, and all of them QRS were expanded). CONCLUSION: Although, the fasciculoventricular fibers themselves are not the cause of tachyarrhythmia, the accessory pathway and other tachyarrhythmia substrate frequency accompanying these cases are quite high (approximately 40%) in EPS. The delta wave characteristics of ablated patients are very similar to FVF patients. While all patients with isolated FVF were adenosine responsive, most of those with additional manifest WPW were unresponsive. Therefore, performing EPS in patients with suspected FVF based on surface ECG features seems to be important for the detection of additional tachyarrhythmias and risky accessory pathways.

A very rare cause of sudden cardiac arrest in children: triadin knockout syndrome.

Triadin knockout syndrome has been defined as a disease with transient long QT, T wave abnormalities, and extremely severe fatal cardiac arrhythmias in young children. In this report, we wanted to share the characteristics of our two cases who presented with sudden cardiac arrest and were diagnosed with triadin knockout syndrome. CASE 1: A 7.5-year-old male patient was referred to our clinic with a history of recurrent syncope and aborted cardiac arrest. There was no family history of sudden death, syncope, or arrhythmia. Physical examination, electrocardiography, echocardiography, and 24-hour rhythm Holter monitoring were normal, and bidirectional ventricular tachycardiaT was detected during the exercise stress test. Genetic analysis revealed a homozygous mutation of c.531_533delinsGG, p.(Lys179Asnfs * 44) frameshift variant in TRDN(NM_006073) gene. CASE 2: A 4.5-year-old male was admitted due to syncope during exertion and underwent cardiopulmonary resuscitation due to sudden cardiac arrest. He had family history about sudden cardiac death. Physical examination was normal, and there was borderline QTc prolongation. Bidirectional non-sustained polymorphic ventricular tachycardia was observed at adrenaline provocation test. In genetic analysis, c.568dupA, pII190Asnfs * 2 frameshift variant homozygous mutation was detected in TRDN(NM_006073) gene. Intracardiac defibrillator implantation were performed for both cases. There has not been any event under propranolol and flecainide combination treatment. CONCLUSION: Triadin knockout syndrome (TCOS) is a rare overlap syndrome characterized by highly malignant arrhythmias, and it is a deadly combination of long QT syndrome and catecholaminergic polymorphic ventricular tachycardia that affects primarily young children. Since lethal arrhythmias are frequently described, genetic testing is very important in these patients. Because, identification of a genetic mutation may be a guide in treatment.

Early postoperative arrhythmias in patients undergoing congenital heart surgery.

BACKGROUND: This study aims to evaluate early postoperative arrhythmias in children undergoing congenital cardiac surgery. METHODS: A total of 670 pediatric patients (355 males, 315 females; median age: 4 months; range, 1 day to 18 years) who underwent cardiac surgery due to congenital heart defects between December 2018 and November 2019 were included. The rate of postoperative arrhythmias, diagnosis, potential risk factors, and management strategies were evaluated. Multivariate regression analysis was used to identify significant factors of development of postoperative arrhythmias. RESULTS: Tachyarrhythmia was detected in 54 patients (8.1%), and the most common tachyarrhythmia was junctional ectopic tachycardia. Medical treatment was required in 25/38 (66%) of junctional ectopic tachycardia patients. Amiodarone was initiated in 18, dexmedetomidine in five, and flecainide + amiodarone in two of the patients. Different degrees of atrioventricular block were observed in 30 patients (4.5%). In 12 patients, permanent pacemakers were implanted during hospitalization. Age at the time of surgery under one-year-old, high inotropic scores, prolonged operation time, and high Aristotele"s scores were independent risk factors associated with early postoperative arrhythmia (p<0.05). The most common operations associated with early postoperative arrhythmia were left ventricular outflow tract, (6/20, 30%), complete atrioventricular septal defect (13/53, 24%), and tetralogy of Fallot (20/134, 14%) surgeries. CONCLUSION: Cardiac arrhythmias are common in the early period after congenital heart surgery in children. The diagnosis and frequency of arrhythmias may vary according to different surgical procedures.

Radiation Dose Reduction in Congenital Heart Disease Patients During Cardiac Catheterization by a Novel Protocol.

OBJECTIVE: Cardiac catheterization remains a major source of radiation exposure for patients with congenital heart disease. This study reports the magnitude of radiation with a 3.75 frame per second (fps) pulse fluoroscopy rate and compares the reduction with the previous 15 fps protocol during cardiac catheterization for pediatric and adult congenital heart disease. MATERIAL AND METHODS: All diagnostic and interventional cardiac catheterization procedures from a single tertiary center were analyzed from January 1, 2014 to December 31, 2015, one year before and after implementing lower starting pulse fluoroscopy rates. The radiation dose was quantified as air kerma dose (mGy) and dose-area product (DAP; µGy/m2). Radiation exposure was analyzed for diagnostic and interventional procedures; the diagnostic group was subdivided into cyanotic and acyanotic patients, whereas the interventional group was subdivided according to the most common indications. RESULTS: A total of 786 procedures were analyzed. The median fluoroscopy times and contrast amounts did not show a statistically significant difference between both periods (487 vs. 456 seconds and 42.5 vs. 45.3 cm3). The median air kerma for all procedures showed an 88% reduction after implementing lower pulse fluoroscopy rates (340-41 mGy). The doses were reduced significantly for diagnostic and interventional angiograms from 470 mGy and 162 mGy to 40 mGy and154 mGy. Among all patient groups, the most striking decrease was observed in the diagnostic procedures we use, of which fluoroscopy is more prominent than cine angiography. CONCLUSION: We claim that novel radiation dose reduction protocols could be easily applied without increasing fluoroscopy time or losing image quality.

Catheter ablation of focal atrial tachycardia in children using three-dimensional electroanatomic mapping system: a 6-year single-centre experience.

OBJECTIVE: This study demonstrates the clinical and electrophysiological details of catheter ablation conducted in children with focal atrial tachycardia using three-dimensional electroanatomic mapping systems. PATIENTS AND METHODS: Electrophysiological procedures were performed using the EnSite™ system. RESULTS: Between 2014 and 2020, 60 children (median age 12.01 years [16 days-18 years]; median weight 41.5 kg [3-98 kg]) with focal atrial tachycardia and treated with catheter ablation were evaluated retrospectively. Tachycardia-induced cardiomyopathy was developed in 15 patients (25%). Most of the focal atrial tachycardia foci were right-sided (75%), and more than one focus was found in four patients. Radiofrequency ablation was performed in 47 patients (irrigated radiofrequency ablation in seven cases), cryoablation in 9, and radiofrequency ablation and cryoablation in the same session in 4 patients. The median procedural time was 163.5 minutes (82-473 minutes). Fluoroscopy was used in 29 of (48.3%) patients (especially for left-side substrate) with a mean time of 8.6 ± 6.2 minutes. The acute success rate was 95%. The procedure failed in three patients, and recurrence was observed in 3.5% of patients (2/57) during a median follow-up of 17 months (2-69 months). The second ablation was performed in four cases, of which three were successful. Overall success rate was 96.6% with no major complications observed, except in one patient with minimal pericardial effusion. CONCLUSION: Catheter ablation seems to be an effective and safe treatment in focal atrial tachycardia. Electroanatomic mapping system can facilitate the ablation procedure and minimise radiation exposure.

Cryoablation with an 8-mm tip catheter for typical AVNRT in children: a single center 5-year experience.

BACKGROUND: In children with typical atrioventricular nodal reentrant tachycardia (tAVNRT), cryoablation is preferred over radiofrequency ablation (RFA) because of its safety profile and acceptable long-term success rates. In this study, we have assessed the utility of 8-mm tip cryocatheters for tAVNRT ablation in our center. METHODS: All pediatric AVNRT patients who underwent cryoablation with an 8-mm tip cryocatheter in our center between 2013 and 2018 were included. EnSite™ (St. Jude Medical Inc., St. Paul, MN, USA) was used in all patients. RESULTS: A total of 120 patients (64 females, 53%) were included in this study, and the mean age was 13.9 years with a standard deviation of 2.5 years. Eleven patients (9.1%) had structural heart disease, and 12 patients (10%) had additional arrhythmia substrate. The mean number of effective cryolesions was 8 with a standard deviation of 2.3. Fluoroscopy was used in three patients (2.5%). There were minor complications in only four patients (3.3%)-transient first-degree atrioventricular block or transient incomplete right bundle branch block. Acute success rate of cryoablation was 108/120 (90%). In twelve patients, cryoablation was suboptimal, or it failed. The procedure was completed successfully with RFA in the same session in ten patients. Overall acute success rate of ablation (Cryo ± RFA) was 98.5%. During a mean follow-up period of 24.6 months with a standard deviation of 11.3 months, three patients had recurrence (2.5%). Time between the beginning of the effective cryolesion and termination of AVNRT was found associated with acute success of cryoablation (p = 0.013). CONCLUSIONS: Cryoablation of AVNRT with an 8-mm tip catheter in children appears to be safe, with an acceptable acute success rate and a low recurrence rate. A faster termination of AVNRT during the cryolesion, slowing down before ending with atrioventricular block, is a good indicator for acute success.

Clinical characteristics of hypertrophic cardiomyopathy in children: An 8-year single center experience.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the second most common pediatric cardiomyopathy. Although there is a large body of literature about HCM in adults, there is limited information on HCM in childhood. We evaluated various aspects of pediatric HCM patients treated at our center. METHODS: We identified 152 pediatric patients with HCM between October 2011 and October 2019. Clinical history, invasive (ICD, pacemaker, electrophysiologic study, catheter ablation therapy) and non-invasive (ECG, holter moniterization, echocardiography, cardiac MR, genetic study, medicam treatment) data were collected and evaluated. RESULTS: The mean ± standard deviation age of patients was 8.9 ± 5.7 years (1 month-18 years) and 67.8% were male. The most frequent clinical symptoms were murmur and palpitations. Three cases (2%) had aborted sudden death as the first manifestation of HCM. Of these patients, 120 (78.9%) had non-syndromic HCM and 32 (27.2%) had syndromic HCM. Asymmetric septal hypertrophy was common (48.3%) in the non-syndromic group, whereas concentric hypertrophy was common (56.2%) in syndromic group. Left ventricular outflow tract obstruction (LVOTO) occurred in 39 (25.6%) patients. Nine (5.9%) patients underwent electrophysiologic study and/or ablation and 16 patients underwent surgical intervention. Implantable cardioverter defibrillator (ICD) insertion was performed in 38 patients (26 transvenous, 12 epicardial). ICDs were inserted in three (7.9%) patients for secondary prevention; in the remaining patients (92.1%) the devices were placed for primary prevention. Mean SD follow-up time was 27.1 ± 22 months. Five (3.3%) patients died during the follow-up. No patient had heart transplantation or a long-term assistive device. CONCLUSION: The etiology of HCM is heterogeneous and present at any age. It is important to determine the timing of surgery and potential risks for sudden cardiac arrest. As most cases of HCM are familial, evaluation of family members at risk should be a routine component of clinical management.

Aortic cusp ablation for premature ventricular contractions and ventricular tachycardia in children: a 5-year single-center experience.

PURPOSE: Aortic cusps might be the source of supraventricular or ventricular arrhythmias. For many years, aortic cusp ablation has been widely used to treat premature ventricular contractions (PVCs) and ventricular tachycardia (VT). However, the data on the outcomes of this procedure in children are limited. The study aimed to convey or describe our own aortic cusp ablation experiences in children and, thus, contribute to the literature. METHODS: The focus was pediatric cases of ventricular arrhythmia in which the origin of the PVCs was ablated above the Valsalva. The sample comprised patients who underwent aortic cusp ablation between 2013 and 2018. The demographic characteristics, noninvasive test results, procedure details, and follow-up results for the patients were noted. RESULTS: The 3D EnSite Precision cardiac mapping system and limited fluoroscopy were used. A total of 26 procedures were performed on 22 patients. The mean age was 14.4 ± 3.0 (9-19) years, and the mean weight was 57.3 ± 17.5 (27-99) kg. The mean follow-up period after the first presentation was 38.6 ± 22.9 (3-72) months. There were significant differences in the values of the transition index, V2S/V3R, IIR/IIIR, aVRS/aVLS ratio, and QRS polarity in I at various locations. The most common ablation site was the left coronary cusp (LCC). Radio frequency (RF) ablation, cryoablation, and irrigated RF ablation were found to be effective energy sources in 15, 4, and 3 patients, respectively. Patients who underwent ablation at the LCC-right coronary cusp (RCC) commissure were more likely to present with only VT and to experience worsening symptoms. Twelve patients had previously undergone ablation of the right ventricular outflow tract (RVOT). Ablation in the RVOT had been previously performed in all the patients who eventually underwent ablation at the RCC and the LCC-RCC commissure. CONCLUSION: Aortic cusp ablation can be safely performed in children. The careful evaluation of previous noninvasive tests provides important data for determining the location. There might be significant differences in the signs and requirements on the basis of the locations during mapping and ablation.

Evaluation of different lead types and implantation techniques in pediatric populations with permanent pacemakers: Single-center with 10 years' experience.

BACKGROUND: Permanent pacemaker (PM) implantation is performed for various indications and by different techniques in children; however, many problems with lead performance are encountered during follow-up. This study aims to evaluate the possible effects of different lead types and implantation techniques on pacing at early and midterm in children with a permanent PM. PATIENTS AND METHODS: Pediatric patients who underwent permanent PM system implantation at our tertiary cardiac surgery center between January 1, 2010 and January 1, 2020 were evaluated retrospectively. Patients were categorized in the epicardial pacing lead (EP), transvenous pacing lead (TP), and transvenous bipolar lumenless (Select Secure [SS]) lead groups according to the lead implantation technique and lead type with the same manufacturer. Groups were evaluated statistically for demographic features, pacing type and indication for implantation, lead electrical performance, lead failure, complications, and outcome. RESULTS: Over 10 years, 323 lead implantations were performed on 167 patients (96 males, median age 68 months [5 days-18 years]). Of 323 leads, 213 (66%) were EP, 64 (20%) were TP, and 46 (14%) were SS. Of the total, 136 of the leads were implanted in atria, and 187 were implanted in ventricles. Primary pacing indications were postoperative complete atrioventricular (AV) block (n = 95), congenital AV block (n = 71), sinus node dysfunction (n = 13), and acquired complete AV block (n = 1). Additional cardiac diseases were present in 115 patients (69%). No statistically significant difference was observed in gender, syndrome, or pacing indication (P > .05). Atrial and ventricular capture, threshold, sensing, and lead impedance measurements were not significantly different at the initial and follow-up periods (P > .05). The median follow-up duration was 3.3 years (6 months-10 years). Twenty lead failures were determined in 15 patients (EP: 14 lead failures in 10 patients; TP: two lead failures in two patients; and SS: four lead failures in three patients) during follow-up, and no statistically significant difference was found between groups (P = .466). The 5-year lead survival was 98% for TP, 95% for EP, and 90% for SS; the 10-year lead survival was 90% for TP, 70% for EP, and 70% for SS. There was no mortality related to chronic pacing or due to the procedure of implantation. CONCLUSIONS: Despite improvements in technology, lead failure is still one of the most critical problems during these patients' follow-up. Early to midterm lead survival rates of all three lead types were satisfactory.

The assessment of patients with situs inversus and corrected transposition of the great arteries.

INTRODUCTION: Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart defect. There are different subgroups according to the location of the heart in the thorax, apical position and situs. OBJECTIVES: The purpose of this study was to assess pediatric patients with situs inversus (SI) ccTGA (SI-ccTGA), a rare subgroup of this condition, in detail. METHODS: The records of patients with SI-ccTGA followed between January 1, 2010 and January 1, 2019 in our clinic were analyzed retrospectively. Demographic features, associated cardiac defects, arrhythmias and follow-up data were recorded. RESULTS: Twenty-one out of 120 ccTGA patients had SI. The median age was 30 months (4 days-18 years). There were hemodynamically significant associated lesions in 85.7% (n=18) of the patients. A large ventricular septal defect was found in 16 patients (76.2%), severe pulmonary stenosis in 11 (52.4%), pulmonary atresia in six (28.5%), and severe tricuspid regurgitation in two (9.5%). Eleven out of 21 patients had biventricular physiology and eight had single-ventricle physiology. Bidirectional cavopulmonary anastomosis followed by a hemi-Mustard-Rastelli operation were planned for the remaining two patients. Twelve out of 18 patients with associated defects (66.6%) were operated and surgery was planned for three more patients (16.6%). The remaining three patients were scheduled for clinical follow-up. Arrhythmias developed in two (9.5%) patients on follow-up; ablation was performed in one of them and pacemaker implantation followed by cardiac resynchronization therapy was performed in the other. Two patients died during follow-up, one after a central shunt operation and the other preoperatively due to pneumonia and sepsis. CONCLUSION: SI-ccTGA is not a mirror image of situs solitus ccTGA (SS-ccTGA) due to important anatomic and physiologic differences between them. SI-ccTGA patients have a lower risk of tricuspid valve regurgitation than SS-ccTGA patients. The timing of clinical presentation of these patients mainly depends on the type and severity of the associated lesions, as in all subtypes of ccTGA.

Successful left coronary cusp cryoablation in an adolescent with premature ventricular extrasystoles-associated cardiomyopathy.

Ventricular arrhythmias arising from coronary cusps are not uncommon. However, the mapping and ablation of outflow tract ventricular arrhythmias originating from aortic cusps can be challenging. Radiofrequency ablation of this area can cause rare but serious complications. This was a report of a 17-year-old male patient with very frequent, nonsustained ventricular tachycardia attacks and premature ventricular contraction-induced cardiomyopathy. The origin of the ventricular arrhythmia was determined to be the left coronary cusp, and the patient was treated successfully with cryoablation. In high-risk areas, cryoablation is an effective and safe alternative method.

Accelerated idioventricular rhythm resulting in torsades de pointes and cardiac arrest in a child: successfully cryoablated in left'coronary cusp.

Known as a benign arrhythmia and normally requiring no specific treatment, accelerated idioventricular rhythm can rarely degenerate to a life-threatening arrhythmia. Here, we present a child with left coronary cusp-originating accelerated idioventricular rhythm, degenerating into torsades de pointes and resulting in cardiac arrest, which was ablated with a cryocatheter. An 11-year-old boy, followed due to asymptomatic accelerated idioventricular rhythm before, was referred to our department because he had experienced an aborted cardiac arrest during sleep. He had been resuscitated for 5 minutes. Twenty-four-hour Holter-ECG revealed incessant accelerated idioventricular rhythm, consisting up to 90% of the whole record and two torsades de pointes attacks, triggered by accelerated idioventricular rhythm-induced "R on T" phenomenon, and resulting in syncope and cardiac arrest. Transthoracic echocardiography revealed no structural cardiac defect but mild left ventricular systolic dysfunction with an ejection fraction of 45% and shortening fraction 23%. An electrophysiologic study was conducted, and accelerated idioventricular rhythm focus was mapped to left aortic coronary cusp. A cryocatheter with an 8-mm tip was preferred for successful ablation of the accelerated idioventricular rhythm focus, due to close neighbourhood to coronary ostium. The patient was discharged in 3 days without any premature ventricular contractions or accelerated idioventricular rhythm and with normalised cardiac functions. After 9 months on follow-up, he was still asymptomatic, without any premature ventricular contractions or accelerated idioventricular rhythm and with normal cardiac functions. Although the clinical course of accelerated idioventricular rhythm is known as benign, accelerated idioventricular rhythm can rarely degenerate to a life-threatening arrhythmia. In such cases, electrophysiologic study and catheter ablation are a good option in such cases with accelerated idioventricular rhythm for an ultimate cure.

Clinical features and arrhythmic complications of patients with pediatric-onset arrhythmogenic right ventricular dysplasia.

OBJECTIVE: Arrhythmogenic right ventricular dysplasia (ARVD) is a myocardial genetic disease that occurs primarily in the right ventricle. Patients with ARVD may present with severe ventricular arrhythmias, syncope, and cardiac arrest. The purpose of this study is to evaluate the clinical features and arrhythmic complications of patients with pediatric-onset ARVD. METHODS: Patients diagnosed with ARVD between January 2010 and January 2019 were included in this study. RESULTS: A total of 19 patients with ARVD were evaluated. Of them, 15 patients were male, and their mean age was 12±4 years. The most common symptoms were palpitations (n=6), syncope (n=4), and heart failure symptoms (n=2). Five patients were asymptomatic. Thirteen patients had an epsilon wave; all patients ≥14 years had a T wave inversion in V1-3. Premature ventricular contractions (PVCs) were observed in 15 patients, and ventricular tachycardia (VT) was observed in 9 patients. All patients underwent cardiac magnetic resonance imaging (MRI). Echocardiography and cardiac MRI of two patients were normal at the time of admission; patients were in the concealed phase, and the diagnosis was made by ECG, Holter monitoring, and genetic findings. We administered a beta-blocker in all patients. Two patients underwent an electrophysiological study and ablation because of PVC/VT. An implantable cardiac defibrillator was implanted in 8 patients. The mean follow-up period was 21.5±11 months. Two patients were deceased with incessant VT and heart failure, and one patient was deceased with multiorgan dysfunction after biventricular assist device implantation (n=3). CONCLUSION: Diagnosis of pediatric-onset ARVD might be much more difficult in children. Sudden cardiac death might be prevented in the early period by raising the awareness of physicians about the disorder. Prevention of sudden death with implantable cardiac defibrillators is crucial in the management of these patients. It should be kept in mind that children with structurally normal hearts may present with an earlier concealed phase and can be diagnosed with ARVD.

Successful cryoablation of incessant fast-slow atypical atrioventricular nodal reentrant tachycardia in a child with tachycardia-induced cardiomyopathy.

A 15-year-old female patient presented at the clinic with heart failure (HF). A 12-lead electrocardiogram showed a heart rate of 170 bpm; negative P waves in leads DII, DIII, aVF; and long RP tachycardia (LRPT). Echocardiography demonstrated a shortening fraction (SF) of 20%. An electrophysiology study during tachycardia revealed an atrial-His time of 52 milliseconds and a His-atrial interval of 295 milliseconds. During ventricular entrainment, the postpacing interval-tachycardia cycle length was measured at 225 milliseconds. There was a pseudo V-A-A-V response. These findings confirmed the diagnosis of atypical atrioventricular nodal re-entrant tachycardia (aAVNRT). Successful slow pathway cryoablation was performed with an 8-mm-tip cryocatheter. After 2 weeks, the SF was measured as 34%. During a 2-year follow-up period, no recurrence was observed. In conclusion, fast-slow aAVNRT should be a part of the differential diagnosis of incessant LRPT leading to HF. Cryoablation can be used successfully in cases of aAVNRT.