Functional evaluation of the tachycardia patient-derived iPSC cardiomyocytes carrying a novel pathogenic SCN5A variant.

Tachycardia is characterized by high beating rates that can lead to life-threatening fibrillations. Mutations in several ion-channel genes were implicated with tachycardia; however, the complex genetic contributors and their modes of action are still unclear. Here, we investigated the influence of an SCN5A gene variant on tachycardia phenotype by deriving patient-specific iPSCs and cardiomyocytes (iPSC-CM). Two tachycardia patients were genetically analyzed and revealed to inherit a heterozygous p.F1465L variant in the SCN5A gene. Gene expression and immunocytochemical analysis in iPSC-CMs generated from patients did not show any significant changes in mRNA levels of SCN5A or gross NaV1.5 cellular mislocalization, compared to healthy-derived iPSC-CMs. Electrophysiological and contraction imaging analysis in patient iPSC-CMs revealed intermittent fibrillation-like states, occasional arrhythmic events, and sustained high-paced contractions that could be selectively reduced by flecainide treatment. The patch-clamp analysis demonstrated a negative shift in the voltage-dependent activation at the patient-derived iPSC-CMs compared to the healthy control line, suggestive of a gain-of-function activity associated with the SCN5A+/p.F1465L variant. Our patient-derived iPSC-CM model recapitulated the clinically relevant characteristics of tachycardia associated with a novel pathogenic SCN5A+/p.F1465L variant leading to altered Na+ channel kinetics as the likely mechanism underlying high excitability and tachycardia phenotype.

Human macrophages directly modulate iPSC-derived cardiomyocytes at healthy state and congenital arrhythmia model in vitro.

The electrophysiological regulation of cardiomyocytes (CMs) by the cardiac macrophages (MΦs) has been recently described as an unconventional role of MΦs in the murine heart. Investigating the molecular and physiological modulation of CM by MΦ is critical to understand the novel mechanisms behind cardiac disorders from the systems perspective and to develop new therapeutic approaches. Here, we developed an in vitro direct coculture system to investigate the cellular and functional interaction between human-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) and monocyte-derived MΦs both in healthy-state and congenital arrhythmia disease model associated with SCN5A ion channel mutations. Congenital arrhythmia patient-derived (P) and healthy individual-derived control (C) monocytes and derived MΦs exhibited distinct M1- and M2-like polarization-related gene expression pattern. The iPSC-CMs and MΦs formed direct membrane contacts in cocultures demonstrated by time-lapse imaging, scanning electron microscopy, and immunolabeling. The intracellular Ca2+ transients were observed in iPSC-CMs and MΦs when in contact with each other. Interestingly, the C-MΦs in direct contact with C-CMs significantly accelerated the contraction rates, demonstrating the positive chronotropic effect of MΦs on healthy cardiac cultures. Furthermore, the MΦs carrying the SCN5A gene mutation significantly enhanced the arrhythmic events in both C-CMs and P-CMs, implying that the sodium channel mutation in the MΦ is important for the CM function. Importantly, when C-MΦs were coupled to tachycardic P-CMs, the contraction frequency drastically decreased, and rhythmicity enhanced implicating the amelioration of the disease phenotype in vitro. Consequently, our results indicated the functional regulatory role of MΦs on human iPSC-CM contractility by membrane contacts in a physiologically relevant in vitro coculture model of both steady-state and arrhythmia. Our findings could serve as a valuable source for the development of effective immunoregulatory therapies for cardiac arrhythmia in the future.

Current Strategies for the Management of Anomalous Origin of Coronary Arteries from the Pulmonary Artery.

INTRODUCTION: The coronary arteries, which have to originate from the aorta, may sometimes rise from the pulmonary artery. This study evaluated clinical and diagnostic findings, treatment methods, and follow up of cases with anomalous coronary arteries arising from the pulmonary artery. PATIENTS AND METHODS: Eight patients with the diagnosis of anomalous left coronary artery from the pulmonary artery (ALCAPA) (N = 6) and anomalous right coronary artery from the pulmonary artery (ARCAPA) (N = 2), between January 2014 and January 2020 from a single center university hospital, were included in the study. Data from patients' demographic characteristics, electrocardiography, echocardiography, angiographic findings, operation, hospitalization, and follow up were evaluated. RESULTS: The study included eight patients (six females and two males) - six patients with ALCAPA and two with ARCAPA. The ages of the patients ranged between 3-135 (average: 53.25) months. The median body weight was calculated as 17.4 kg. Severe mitral valve insufficiency was detected in two patients and two other patients had a moderate degree of mitral insufficiency on echocardiography. Ejection fractions ranged between 16-74%. One patient had perimembranous malalignment large ventricular septal defect with pulmonary stenosis. Operative techniques were Takeuchi procedure (three patients), direct implantation (four patients), and left internal thoracic artery to left main coronary artery bypass (one patient). Mechanical cardiac support was not required in the postoperative period. Mortality did not occur. Mitral insufficiency and ejection fractions improved following correction of the coronary anatomy. CONCLUSION: It is important to diagnose the ALCAPA or ARCAPA, where the coronary artery originates from the pulmonary artery. Patients should be treated before congestive heart failure and fatal complications occur. Surgical correction should be planned regardless of symptom status, even though some of patients reach adulthood with an increased number of collaterals.

Congenital cardiac interventions during the peak phase of COVID-19 pandemics in the country in a pandemics hospital in Istanbul.

INTRODUCTION: In this report, we aim to present our algorithm and results of patients with congenital cardiac disorders who underwent surgical or interventional procedures during the peak phase of the pandemics in our country. PATIENTS AND METHODS: The first COVID-19 case was diagnosed in Turkey on 11 March, 2020, and the peak phase seemed to end by the end of April. All the patients whom were referred, treated, or previously operated but still at the hospital during the peak phase of COVID-19 pandemics in the country were included into this retrospective study. Patient's diagnosis, interventions, adverse events, and early post-procedural courses were studied. RESULTS: Thirty-one patients with various diagnoses of congenital cardiovascular disorders were retrospectively reviewed. Ages of the patients ranged between 2 days and 16 years. Seventeen cases were males and 14 cases were females. Elective cases were postponed. Priority was given to interventional procedures, and five cases were treated percutaneously. Palliative procedures were preferred in patients whom presumably would require long hospital stay. Corrective procedures were not hesitated in prioritised stable patients. Mortality occurred in one patient. Eight patients out of 151 ICU admissions were diagnosed with COVID-19, and they were transferred to COVID-19 ICU immediately. Three nurses whom also took care of the paediatric cases became infected with SARS-CoV-2; however, the children did not catch the disease. CONCLUSION: Mandatory and emergent congenital cardiac percutaneous and surgical procedures may be performed with similar postoperative risks as there are no pandemics with meticulous care and preventive measures.

Electroanatomic mapping-guided catheter ablation of atrial tachycardia in children with limited/zero fluoroscopy.

INTRODUCTION: Atrial tachycardia (AT) is an uncommon cause of supraventricular tachycardia in children and it is often resistant to medical therapy. Catheter ablation can be curative in children with AT. However, experience of ablation of pediatric AT is still very limited. The aim of this study, which is the largest series from a single center, was to assess the efficacy and safety of ablation of AT using an electroanatomical-mapping system. METHODS: It was a retrospective review of 39 children with AT who underwent catheter ablation procedure using the EnSite Velocity system (St. Jude Medical, St. Paul, MN, USA) between July 2012 and April 2017. RESULTS: The mean patient age was 13.32 ± 6.82 years. The location of AT was right sided in 25 and left sided in 13, and both sides in one patient. The mean procedure time was 184.23 ± 60.19 min. Fluoroscopy was not used in 25 of 39 patients. The mean fluoroscopy time in the remaining patients was 5.53 ± 5.22 min. Radiofrequency (RF) ablation was used in 22, cryoablation was used in 10, and both RF and cryoablation were used in seven. Acute success was achieved in 34 patients (87.2%). During a mean follow-up of 51.35 ± 12.62 months, AT recurred in five patients. These patients underwent second ablation procedures and four of them were successful. Final success was achieved in 33 out of 39 patients (84.6%). There were no complications except for one patient who had an uneventful pericardial needle injury during transseptal puncture without effusion. CONCLUSIONS: Catheter ablation of AT in children can be performed safely and effectively with a limited fluoroscopy using electroanatomical mapping systems.

Transseptal Puncture for Catheter Ablation in Children.

Transseptal puncture (TP) is used in pediatric patients to access the left atrium in left-sided arrhythmia catheter ablation. Performing this procedure can be difficult and risky, especially in small children. In this study, we aimed to evaluate the safety and feasibility of TPs in children ≤ 30 kg. Between April 2012 and April 2018, a retrospective evaluation was conducted of the clinical features, procedural outcomes, and follow-ups of ≤ 30 kg pediatric patients who required TPs for left-sided ablations at a pediatric electrophysiology center in which a three-dimensional mapping system was routinely used. A total of 45 pediatric patients who were ≤ 30 kg, underwent TPs: 10 patients ≤ 20 kg (Group 1) and 35 patients > 20 kg and ≤ 30 kg (Group 2). The TP success rate was 97.8%. The median procedure and fluoroscopy times were 120 min and 5.43 min, respectively. One patient developed self-limited pericardial effusion during the procedure; however, there were no incidences of cardiac tamponade. There was no significant difference between the two groups in terms of the procedure time and fluoroscopy time, and pericardial effusion was only observed in Group 2. TPs are safe and feasible in small children. These procedures can be performed with low complication rates in children weighing ≤ 30 kg.

Catheter ablation of left posterior fascicular ventricular tachycardia in children with limited fluoroscopy exposure.

INTRODUCTION: Catheter ablation of left posterior fascicular ventricular tachycardia in the pediatric population remains challenging, and most studies about this topic have been conducted on adult patients. This study aimed to assess the clinical presentation features and outcomes of catheter ablations performed using limited fluoroscopy with three-dimensional electroanatomic mapping system guidance in a pediatric left posterior fascicular ventricular tachycardia patient group. METHODS: A total of 20 consecutive patients undergoing left posterior fascicular ventricular tachycardia ablation at a single tertiary centre were enrolled. All children with left posterior fascicular ventricular tachycardia underwent electrophysiological studies using the EnSite NavX system guidance. Ablations were performed during the sinus rhythm based on the Purkinje potentials in all patients. RESULTS: The mean patient age was 12.7 years (range 2-16), and the mean patient weight was 51 kg (range 11-84). The mean procedure and median fluoroscopy times were 143.1 minutes and 3.4 minutes, respectively. No fluoroscopy was used in three patients. Acute success was achieved in 19 patients (95%). During a mean follow-up of 38.6 ± 19.35 months, left posterior fascicular ventricular tachycardia recurred in four patients (20%). Repeat ablations were performed successfully in those patients who developed recurrences. No complications were seen. CONCLUSIONS: Catheter ablation of left posterior fascicular ventricular tachycardia in children can be performed safely and effectively with low fluoroscopy exposure using a three-dimensional electroanatomic mapping system.

Long-term outcomes following cryoablation of atrioventricular nodal reentrant tachycardia in children.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is a common tachyarrhythmia substrate in children, which is successfully treated by catheter ablation using radiofrequency or cryothermal energy. In recent years, cryoablation (Cryo) using electroanatomical system guidance is more commonly preferred for use in children in order to decrease the risk of an atrioventricular block. However, there are concerns regarding the long-term efficacy of Cryo in treating AVNRT. We aimed to evaluate the feasibility, safety, and long-term efficacy of Cryo for AVNRT in children. METHODS AND RESULTS: A total of 275 consecutive children above 4 years of age diagnosed with AVNRT were included in our study. The EnSite system (St. Jude Medical, Inc., St. Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The study included 275 patients (148 females, age: 11.9 ± 3.6 years) undergoing catheter ablation for AVNRT from July 2012 to September 2016. Acute success was obtained in all (100%) patients with a mean procedure time of 140 ± 44 minutes. Fluoroscopy was used in only 12 (4.4%) patients. During a follow-up time of 25.6 ± 13.5 months (median: 23 months), AVNRT recurred in 12 of 279 (4.4%) of the patients. Age, sex, number of Cryo lesions, and catheter tip size (6-mm vs 8-mm) were not predictive for recurrence. In nine patients, a repeat ablation was successfully performed with cryoenergy. CONCLUSIONS: Cryo for AVNRT is a safe and effective procedure with excellent long-term outcomes. The use of electroanatomical systems during ablation significantly decreases exposure to fluoroscopy without compromising success.

Electroanatomic Mapping-Guided Catheter Ablation of Supraventricular Tachycardia in Children with Ebstein's Anomaly.

In Ebstein's anomaly (EA), tachycardia substrates are complex, and accessory pathway (AP) ablations are often challenging. This study demonstrates the utility of the EnSite Velocity system (St. Jude Medical, St Paul, MN) in the catheter ablation of supraventricular tachycardia in children with EA. Twenty patients [Female/Male = 8/12, median age 11.5 years (2.6-18)] with EA who underwent catheter ablation guided by the EnSite Velocity system between December 2011 and December 2016 were retrospectively evaluated. Five patients had severe EA, and two of them were at Fontan palliation pathway. The most common indications for ablations were palpitations/syncope and treatment-resistant arrhythmias. Thirty-one tachycardia substrate foci (21 manifest AP, 2 concealed AP, 4 Mahaim AP, 3 focal atrial tachycardias, and 1 typical atrioventricular nodal reentrant tachycardia) were detected in 20 patients. There were multiple tachycardia substrates in 11 patients (55%). The patient-based acute procedure success rate was 19/20 (95%), and the tachycardia-based success rate was 30/31 (97%). The mean procedure time was 170 ± 43 min (90-265). Fluoroscopy was not used in 15 (75%) patients. The mean fluoroscopy time in the remaining five patients was 3.6 ± 2.9 min (0.7-7.8). During a mean follow-up of 35.1 ± 20.3 months (6-60), tachycardia recurred in four patients (4/19, 21%). No complications were seen. Catheter ablation of arrhythmias can be performed effectively and safely in pediatric EA patients by using a limited fluoroscopic approach with the help of electroanatomical mapping systems. However, the rate of tachycardia recurrence at follow-up remains high.

Comparison of 6-mm Versus 8-mm-Tip Cryoablation Catheter for the Treatment of Atrioventricular Nodal Reentrant Tachycardia in Children: A Prospective Study.

Due to its safety profile, cryoablation (Cryo) for atrioventricular nodal reentrant tachycardia (AVNRT) is more commonly preferred over radiofrequency (RF) ablation in children in recent years. Recent studies demonstrated high long-term success rates comparable to radiofrequency ablation. The aim of this prospective study was to compare the efficacy and safety of an 8-mm-tip versus 6-mm-tip Cryo catheter in the treatment of AVNRT in children. A total of 125 consecutive patients over 10 years of age with AVNRT were included. EnSite system (St. JudeMedical, St Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The acute procedural success was 100% in both groups. The prodecure duration for the 8-mm-tip group was shorter (151.6 ± 63.2 vs. 126.6 ± 36.7 min, p < 0.01, respectively). Fluoroscopy was used in only 7 patients. The mean follow-up duration was 14.6 ± 8.4 months (median 13.5 months, min. 3 months and max. 27 months). The recurrence rate for AVNRT was also comparable between the two groups (6-mm tip: 9.6 vs. 8-mm tip: 8%). Cryo of AVNRT is a safe and effective procedure with comparable acute and mid-term follow-up success rates using 6-mm and 8-mm-tip catheters in children. In addition, procedure duration is shorter with an 8-mm-tip Cryo catheter.

Cryoablation with an 8-mm-Tip Catheter for Right-Sided Accessory Pathways in Children.

BACKGROUND: Cryoablation is increasingly utilized in children because of its safety profile. Recently, larger catheter tips have been more widely used to improve long-term success rates. The aim of this study was to assess the safety and efficacy of 8-mm-tip catheters for cryoablation of right-sided accessory pathways (APs) in children. METHODS: Electrophysiological procedures were performed using the EnSite™ system (St. Jude Medical Inc., St. Paul, MN, USA). RESULTS: Between July 2010 and July 2014, 54 patients (mean age: 13.1 ± 3.7 years) underwent cryoablation using an 8-mm-tip catheter. In 18 of 54 (33%) patients where an 8-mm-tip catheter was the first-choice catheter, the success rate was 18 of 18 (100%). There was a history of previous failed attempts or recurrence with radiofrequency ablation and/or 6-mm-tip cryoablation in 36 of 54 (67%) patients. The success rate in these patients was 24 of 36 (67%). No fluoroscopy was used in 34 of 54 procedures. The recurrence rate was six of 42 (14%) during a mean follow-up period of 32 ± 15 months. In one patient, transient atrioventricular block occurred. CONCLUSIONS: Cryoablation with an 8-mm-tip catheter for right-sided APs in children who weigh over 40 kg appears to be safe and acutely effective in cases where conventional ablation methods fail and also as a first choice for ablation procedure. However, the recurrence rate still seems to be high.

Using a Cardiac Event Recorder in Children with Potentially Arrhythmia-Related Symptoms.

BACKGROUND: In this study, we reported our experience with the use of cardiac event recorders in pediatric patients. METHODS: We evaluated 583 patients fitted with an event recorder (15-30 days) between March 2010 and November 2014 at our clinic. Excluded from the study were 117 patients with no recorded events and six with records contaminated by electrocardiogram artifacts. All of the patients received electrocardiograms, Holter monitoring, and echocardiography before the cardiac event recording. RESULTS: The patient sample consisted of 460 patients (64% female). The mean age was 12.8 ± 4.1 years. The median number of recorded events was 7. The indications included palpitations in 336 (73%) patients, syncope in 27 (6%) patients, and chest pain and palpitations in 97 (21%) patients. Whereas 64 patients (14%) had structural heart disease according to echocardiographic examination, the remaining patients had normal echocardiographic examination results. The most frequent cardiac comorbidities were mitral valve prolapse (6%), operated tetralogy of Fallot (1.5%), and complicated congenital heart diseases with single ventricle physiology (1%). The recorded events were sinus tachycardia in 113 (25%) patients, supraventricular tachycardia in 35 (8%) patients, ventricular extrasystole in 20 (4%) patients, supraventricular extrasystole in nine (2%) patients, and ventricular tachycardia in two (0.4%) patients. Based on the event recorder and follow-up electrocardiogram findings, 46 patients received an electrophysiology study/ablation. The symptom-rhythm correlation was 39%. CONCLUSION: In the presence of possible arrhythmia-related symptoms in children, a cardiac event recorder can be considered a useful primary diagnostic method. More research on this topic is needed.

Electroanatomic mapping guided cryoablation of Mahaim pathways in children with limited fluoroscopy exposure.

BACKGROUND: The presence of Mahaim accessory pathways (MAP) with anterograde decremental conduction is a disorder that leads to antidromic atrioventricular reentrant tachycardia. There are rare reports of cryoablation use in MAP. This study aims at sharing our experience with using cryoablation to treat MAP in children. METHODS: Electrophysiology study and catheter ablation were performed in 14 patients diagnosed with Mahaim tachycardia between January 2010 and December 2013. Cryoablation was used in nine of the cases. A three-dimensional navigation system with surface electrode patches (EnSite System, St. Jude Medical Inc., St. Paul, MN, USA) was used for all procedures. RESULTS: The patients (two girls and seven boys) had a median age of 11.5 years (8-18 years) and a median weight of 67 kg (31-80 kg). Mahaim conduction was localized in the right posterolateral (n = 4), right lateral region (n = 2), right posteroseptal (n = 1), right anterolateral (n = 1), and right anterior (n = 1). A pathway potential was noted in six of nine cases at the tricuspid annulus. Catheter choices and acute success rates were as follows: cryoablation in four (three of four successful), radiofrequency catheter ablation (RFA) and cryoablation in five (successful in four of five). No fluoroscopy was used in six of nine patients. The mean procedure duration was 249 ± 90 minutes. No major complications were observed. The final long-term success rate for cryoablation was seven of nine (78%). CONCLUSIONS: Cryoablation can be used as a reliable and effective alternative to RFA in the treatment of Mahaim accessory conduction pathways in children. Prospective comparative studies are necessary in order to further evaluate the long-term efficacy of this method.

Evaluation rhythm problems in unexplained syncope etiology with implantable loop recorder.

BACKGROUND: Syncope is a frequent complaint in children and adolescents and may be a significant sign of serious pathology. Although patient history, family history, and physical examination are sufficient to reach a diagnosis in most cases of syncope, the cause of syncope still cannot be determined after initial investigation in one-third to half of all patients. The aim of this study was to evaluate the diagnostic yield of implantable loop recorder (ILR) in children with unexplained syncope. METHODS: A retrospective review was carried out of clinical data, indications, findings, and a final management strategy in patients who underwent ILR implantation. RESULTS: A total of 12 patients with a mean age of 9.4 ± 4.5 years underwent ILR (Reveal Plus; Medtronic) implantation. ILR implantation indication was syncope in all of the patients. Family history, routine cardiac assessment, including resting 12-lead electrocardiogram, transthoracic echocardiography, 24 h Holter recording, and event recorder findings, were normal with the exception of one patient with (previously corrected) tetralogy of Fallot. After an average of 20 months (range, 1-36 months), six patients developed symptoms. ILR memory showed torsades de pointes-ventricular fibrillation (n = 3), catecholaminergic polymorphic ventricular tachycardia (n = 1), asystole and ventricular tachycardia (n = 1), and normal sinus rhythm (n = 1). At the time of writing six patients were still in follow up with no symptoms after an average of 25.2 months. CONCLUSION: Implantable loop recorder plays an important role in the diagnosis of life-threatening arrhythmias in which syncope is otherwise unexplained. ILR implantation should be remembered in children whose symptoms are strongly correlated with rhythm disturbances.

Effects of atomoxetine on heart rhythm in children and adolescents.

BACKGROUND: The aim of this study was to examine the effects of atomoxetine on heart rhythm using 12-lead electrocardiography (ECG) and 24 h Holter monitoring. METHODS: Children and adolescents who were diagnosed with attention deficit-hyperactivity disorder according to DSM-IV-TR were referred to a pediatric cardiology clinic for cardiologic examination before and after 4 or 5 weeks of atomoxetine treatment. Cardiac examination, complete blood count, biochemistry, thyroid function tests, 12-lead ECG and 24 h Holter monitoring were performed routinely in all patients. Each subject underwent 24 h Holter ECG monitoring before atomoxetine was started and after 4 or 5 weeks of effective dose atomoxetine treatment. RESULTS: Forty-one patients were included in this prospective study. No statistically significant change was found in QT, QTc or QT interval dispersion or blood pressure before and after 4 or 5 weeks of atomoxetine treatment. There was a statistically significant increase in heart rate (both during the day and at night) and QRS duration, and a statistically significant decrease in P wave dispersion. Three patients had rhythm disturbances. All of these three patients were asymptomatic and none of these arrhythmias reached clinical significance. CONCLUSION: Atomoxetine did not cause significant changes in ECG or Holter variables. In two patients, who had undiagnosed subclinical extrasystoles, extra beats were increased after 4th week of treatment, but still remained clinically insignificant. Before and after atomoxetine treatment, listening to the heart sounds for a longer time, may help clinicians to notice an extra beat. If an extra beat is identified then 24 Holter monitoring is recommended.

Implantation of looped epicardial cardioverter defibrillator coil on the surface of the right ventricular outflow tract.

BACKGROUND: We present the early results of looped epicardial cardioverter defibrillator coil implantation on the anterior surface of right ventricular outflow tract in infants and children. METHODS: Patients with a surgical history of an epicardial implantable cardioverter defibrillator system between 2013 and 2014 were included in the study. Patient age, gender, body weight, indications for a cardioverter defibrillator system implantation, defibrillation threshold values, and defibrillation therapies were retrospectively evaluated. RESULTS: There were eight patients with a mean age of 4.4 ± 2.9 years and a mean body weight of 19.5 ± 11.7 kg. Five of the patients had been diagnosed with long QT syndrome, one patient had been diagnosed with genetic channelopathy and noncompaction of the left ventricle, and two patients had been diagnosed with univentricle physiology. The implantable cardioverter defibrillator system was composed of pace-sense leads, an abdominal active can, and a defibrillation coil placed below the pulmonary valve annulus on the anterior surface of the heart. The mean defibrillation threshold was 6.6 ± 2.3 joules. There were four appropriate therapies in two patients in a mean follow-up of 9 ± 6.5 months. CONCLUSION: The significantly low defibrillation thresholds with the defibrillation coils located below the pulmonary valve annulus are encouraging. However, a larger patient series will be necessary to evaluate the safety and reliability of this technique.

Cardiac Interventions in Pregnant Patients without Fluoroscopy.

INTRODUCTION: Cardiac interventions with fluoroscopy during pregnancy carry significant risks for the fetus. This report reviews three pregnant patients: two of them requiring pacemaker implantation and one underwent diagnostic cardiac catheterization without fluoroscopy. METHODS: The cases were performed using EnSite system (St. Jude Medical Inc., MN, USA) guidance. The necessary cardiac structure geometries were reconstructed with a deflectable quadripolar electrophysiology catheter without fluoroscopy. In two cases, pacemaker leads were connected to the EnSite system for navigation and fixation of leads. In the third case, long sheaths and electrophysiology catheters were used to access the right ventricle and pulmonary artery. Transthoracic echocardiography was also used in all three cases. RESULTS: A 31-year-old woman at 8-week pregnancy was admitted with ventricular septal defect and significant pulmonary hypertension. The patient underwent catheterization to assess for the risk of continuation of pregnancy. There was partial reactivity, it was decided not to terminate the pregnancy, and an uneventful delivery was succeeded at 35 weeks of gestation without complications. The rest of the two pregnant patients were a 28-year-old pregnant woman at 14 weeks of gestation and a 40-year-old woman at 12-week gestation. Both of them presented with symptomatic complete AV block. A single-chamber pacemaker was implanted in the first one, and a dual-chamber pacemaker was implanted in the latter. Pregnancy continued in both without complications. CONCLUSION: Successful cardiac catheterization and pacemaker implantation can be performed safely in selected pregnant patients using an electroanatomic mapping system guidance without fluoroscopy.

Catecholaminergic Polymorphic Ventricular Tachycardia: A Rare Cause of Cardiac Arrest Following Blunt Chest Trauma.

UNLABELLED: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an electrophysiological disorder of a physically normal heart that occurs in children when the body is subjected to intense emotional or physical stress that causes adrenergic discharge. This troubling disease can be sporadic (spontaneous) or familial (genetic/inherited). Unfortunately, its associated ventricular tachycardia may cause sudden death, so early diagnosis of CPVT is very important. Treatment modalities include medical treatment, implantation of a cardioverter defibrillator, or surgical sympatectomy; but the implantable cardioverter defibrillator (ICD) should be the first choice in patients with a history of cardiac arrest. We herein present the case of a patient diagnosed with CPVT after a successful cardiopulmonary resuscitation triggered by blunt chest trauma. We implanted an implantable cardioverter defibrillator and started oral B-blocker treatment. During the course of follow-up, flecainide was added to his treatment depending on the patient's status regarding recurrent ICD shock. The patient has now continued follow-up without recurrent ICD shock since flecainide treatment was initiated. In conclusion, in patients with syncope and sudden cardiac arrest secondary to physical stress or blunt chest trauma, CPVT should be considered and an implantable cardioverter defibrillator must be implanted. Additionally, flecainide theraphy should be considered to decrease recurrent ICD shock. KEY WORDS: Blunt chest trauma; Cardiac arrest; CPVT.

The use of flecainide in critical neonates and infants with incessant supraventricular tachycardias.

OBJECTIVE: This study aimed to evaluate the efficacy of flecainide therapy in neonates and infants with drug resistant incessant supraventricular tachycardia. METHODS: The study included 11 neonates and infants who received medical and/or ablation therapy between January 2010 and December 2013. Mean patient age and weight were 101.6 ± 96 days and 5.3 ± 1.9 kg respectively. Of the 12 patients, 5 underwent ablation between January 2010 and December 2011, and 6 were treated medically between January 2012 and December 2013. Mean follow-up time was 18 months (6 months-4 years). RESULTS: The antiarrhythmic agent flecainide only became available in Turkey in 2012, and the most noteworthy point was its addition to the therapy administered prior to ablation (adenosine, esmolol-propranolol, propafenone, amiodarone and cardioversion). In all 6 patients admitted between January 2012 and December 2013, refractory SVT was successfully treated with the administration of a triple therapy regimen of esmolol-propranolol, amiodarone and flecainide. One patient with myocarditis developed an atrial flutter complicated by a concealed accessory pathway and was put on extracorporeal membrane oxygenation (ECMO) support due to cardiopulmonary failure. The SVT was terminated, but the patient died on the fifteenth day of ECMO support. One patient with recurrent tachycardia, who had previously undergone ablation for a complex cardiac anomaly and Wolf-Parkinson-White syndrome, was treated with ablation again. No recurrence of tachycardia was observed in any of the other 9 patients. CONCLUSION: It appears that the use of propranolol-esmolol and amiodarone combined with flecainide in the medical treatment of drug-resistant SVT may reduce the need for ablation in critical neonates and infants.

Percutaneous closure of large VSD using a home-made fenestrated atrial septal occluder in 18-year-old with pulmonary hypertension.

BACKGROUND: Hemodynamically significant muscular ventricular septal defects in children after the infantile period are a rare occurrence and ideal for transcatheter closure. In cases of severe concomitant pulmonary hypertension, it may be necessary to fenestrate the device. In this report, we present an 18-year old patient with a large mid-trabecular ventricular septal defect and severe pulmonary hypertension that underwent percutaneous closure of the defect with a home-made fenestrated atrial septal occluder. CASE PRESENTATION: An 18-year-old female patient referred to us with complaints of dyspnea (NYHA score of 2-3). Physical examination revealed an apical rumble and a harsh second heart sound. Echocardiographic examination revealed a large mid-trabecular ventricular septal defect with bidirectional shunt and the widest diameter measuring 22 mm on 2D echocardiography. Left and right heart cavities were enlarged. Before and after the vasoreactivity test performed during cardiac catheterization, average aortic pressure was 65 → 86 mmHg, average pulmonary artery pressure: 58 → 73 mmHg, Qp/Qs: 1.6 → 3.2, PVR: 4.6 → 4.3 Wood/U/m2 and PVR/SVR: 0.5 → 0.2. On left-ventricular angiocardiogram, the largest end-diastolic defect diameter was 21 mm. The closure procedure was performed with transthoracic echocardiographic guidance, using a 24 mm Cera septal occluder and a 14 F sheath dilator to make a 4.5-5 mm opening. Measured immediately after the procedure and during cardiac catheterization one month later, average aortic pressure was 75 → 75 mmHg, average pulmonary artery pressure: 66 → 30 mmHg, Qp/Qs 1.5 → 1.4, PVR: 4.4 → 2.9 Wood/U/m2 and PVR/SVR: 0.4 → 0.2. Transthoracic echocardiographic examination performed 24 hours after the procedure showed a max 35-40 mmHg gradient between the left and right ventricles through the fenestration. After the procedure, we observed sporadic early ventricular systoles and a nodal rhythm disorder that started after approximately 12 hours and spontaneously reverted to normal 9 days later. CONCLUSION: In patients with large ventricular septal defects, large atrial septal occluders may be used. In cases with risk of pulmonary vascular disease, a safer option would be to close the defect using a manually fenestrated device.