[Catecholaminergic polymorphic ventricular tachycardia in adolescents: a clinical, electrocardiographic and genetic diagnosis]

Catecholaminergic polymorphic ventricular tachycardia is one of the most lethal channelopathies, characterized by ventricular arrhythmias triggered by stress or physical activity. We present the case of an adolescent who consulted for recurrent syncope precipitated by exercise. In the diagnostic approach, catecholaminergic polymorphic ventricular tachycardia was reached, with a mutation in the cardiac ryanodine receptor gene, Heterozygous c.14311G> A (p.v4771I exon 100), antiarrhythmic drugs and implantable cardioverter-defibrillator were necessary with satisfactory evolution. Clinical suspicion, stress test and genetic tests are essential for a timely diagnosis and management of this pathology.

Indirect pathological indicators for cardiac sarcoidosis on endomyocardial biopsy

BACKGROUND

The definitive pathologic diagnosis of cardiac sarcoidosis requires observation of a granuloma in the myocardial tissue. It is common, however, to receive a "negative" report for a clinically probable case. We would like to advise pathologists and clinicians on how to interpret "negative" biopsies.

METHODS

Our study samples were 27 endomyocardial biopsies from 25 patients, three cardiac transplantation and an autopsied heart with suspected cardiac sarcoidosis. Pathologic, radiologic, and clinical features were compared.

RESULTS

The presence of micro-granulomas or increased histiocytic infiltration was always (6/6 or 100%) associated with fatty infiltration and confluent fibrosis, and they showed radiological features of sarcoidosis. Three of five cases (60%) with fatty change and confluent fibrosis were probable for cardiac sarcoidosis on radiology. When either confluent fibrosis or fatty change was present, one-third (3/9) were radiologically probable for cardiac sarcoidosis. We interpreted cases with micro-granuloma as positive for cardiac sarcoidosis (five of 25, 20%). Cases with both confluent fibrosis and fatty change were interpreted as probable for cardiac sarcoidosis (seven of 25, 28%). Another 13 cases, including eight cases with either confluent fibrosis or fatty change, were interpreted as low probability based on endomyocardial biopsy.

CONCLUSIONS

The presence of micro-granuloma could be an evidence for positive diagnosis of cardiac sarcoidosis. Presence of both confluent fibrosis and fatty change is necessary for probable cardiac sarcoidosis in the absence of granuloma. Either of confluent fibrosis or fatty change may be an indirect pathological evidence but they are interpreted as nonspecific findings.

Intravenous lipid emulsion therapy for cardiac arrest and refractory ventricular tachycardia due to multiple herb intoxication

Herbal products have been used for therapeutic purposes for a long time. However, many herbs can be toxic and even life-threatening. If refractory ventricular tachycardia (VT) is caused by herbal products and shows no response to conventional therapy, intravenous lipid emulsion (ILE) therapy can be considered. We report a case of herbal intoxication leading to refractory VT, which was successfully treated with ILE therapy. A 36-year-old woman with aplastic anemia presented with mental changes. She had taken an unknown herbal decoction three days before visiting the hospital. Soon after coming to the hospital, she went into cardiac arrest. Cardiopulmonary resuscitation was performed, and return of spontaneous circulation with VT was achieved. Synchronized cardioversion was then performed and amiodarone was administered. However, VT with pulse continued, so ILE therapy was attempted, which led to the resolution of VT.

Resistant Ventricular Tachycardia due to Idiopathic Left Ventricular Aneurysm: Successful Treatment with Surgery

Left ventricular aneurysms (LVAs) are characterized by a wide connection to the left ventricle and paradoxical systolic motions. Although patients with LVAs are usually asymptomatic, some may present with arrhythmias, heart failure, and even cardiac arrest. In this case report, we describe a 62-year-old male patient who presented to our emergency service with complaints of palpitation and shortness of breath of 2 hours' duration. His blood pressure was 84/56 mm Hg, and he was in a confused state. An electrocardiogram revealed ventricular tachycardia (VT) with right bundle branch block and a ventricular rate of 188 bpm. The patient's hemodynamic instability necessitated a direct current cardioversion, which restored the sinus rhythm. During the in-hospital course, he had numerous recurrent VT episodes despite treatment with intravenous amiodarone and magnesium sulfate as well as radiofrequency ablation. Upon consensus with a cardiovascular surgeon's team, urgent surgery was performed due to the resistant VT episodes. The patient's clinical course was uneventful, and he was discharged on the 11th postoperative day. We have been following up the patient for almost 1 year, during which he has not experienced palpitations or associated symptoms. Our case indicates that surgery may be a preferable treatment option for patients with heart failure and resistant VT related to LVAs.

[Analysis of risk factors of ventricular arrhythmia in patients with Brugada syndrome]

Objective: To investigate the risk factors of ventricular arrhythmias in patients with Brugada syndrome. Methods: Clinical data of 60 Brugada syndrome patients admitted in the department of cardiology of the First Affiliated Hospital of Nanjing Medical University from March 2003 to December 2016 were collected and retrospectively analyzed. The age at diagnosis was (43.2±13.1) years (0.6-83.0 years), 98.3% were males (n=59), and the patients were followed up to (92±41) months (12-169 months). The 12-lead surface electrocardiogram (ECG) recorded at the time of diagnosis and showing the highest type 1 ST elevation, either spontaneously or after provocative drug test, was used for the analysis. Patients were divided into ventricular arrhythmia (VA, n=12) group and non-ventricular arrhythmia (non-VA, n=48) group depending on the presence or absence of clinical VA event. The demographic data and ECG data of the 2 groups were compared, and the independent risk factors of VA events were analyzed by stepwise logistic regression. Results: Incidence of family history of sudden death (7/12 vs. 22.9% (11/48)) and percentage of type 1 ST elevation in the peripheral ECG leads (6/12 vs. 16.67% (8/48)) were significantly higher in VA group than in non-VA group (both P<0.05). Max Tpeak-Tend (Max-Tpe) interval ((144±53)ms vs. (110±16)ms) and dispersion of Tpe ((74±50)ms vs. (43±17)ms) were significantly higher in VA group than in non-VA group (both P<0.05). The area under receiver operating characteristic (ROC) curves for the Max-Tpe interval was 0.693 and Max-Tpe interval ≥140 ms was determined as an optimized cutoff point with increased risk of VA event, which had a sensitivity of 50.0%, a specificity of 98.0%, a positive predictive value of 85.7%, and a negative predictive value of 88.7% for predicting VA event. The ROC curves for the dispersion of Tpe was 0.775 and dispersion of Tpe ≥45 ms was determined as an optimized cutoff point for predicting VA event, which had a sensitivity of 91.7%, a specificity of 64.6%, a positive predictive value of 39.3%, and a negative predictive value of 96.9% for predicting VA event. In multivariate analysis, Max-Tpe interval ≥140 ms (OR=27.53, 95%CI 1.07-706.77, P=0.045) and family history of sudden death (OR=24.63, 95%CI 2.05-295.38, P=0.011) were found to be the independent risk factors of arrhythmic events. Conclusions: Max-Tpe interval ≥140 ms and family history of sudden death are risk factors of VA event in included patients with Brugada syndrome.

[Electrocardiographic characteristics of idiopathic ventricular arrhythmias originating from the tricuspid annulus regions]

Object: To explore the electrocardiographic characteristics of ventricular arrhythmias (VAs) originating from tricuspid annulus region. Methods: Present study included 169 consecutive patients undergoing catheter ablation of VAs from tricuspid annulus origin in our department from August 2007 to September 2016. Based on the origin sites, the patients were divided into two subgroups, the free wall group (81 cases) and septal wall group (88 cases). Based on the location, patients in the free wall group were classified into anterolateral (22 cases), lateral (26 cases) and posterolateral (33 cases) subgroups. Patients in the septal group were classified into anteroseptal (10 cases), midseptal (71 cases) and posteroseptal (7 cases) subgroups. We analyzed the electrocardiographic features of these patients and in 87 patients with PVCs/VT originating from right ventricular outflow tract. Results: (1) A positive R wave inⅠ, aVL, V(5)-V(6) leads were found among most of patients, only few cases originating from tricuspid annulus anteroseptum group and tricuspid annulus anterolateral group demonstrated qr or qs pattern in aVL lead. 97.53% (79/81) patients demonstrated rS pattern in V(1)-V(3) leads with VAs originating from tricuspid annulus free wall, and 9/10 patients demonstrated rS pattern in V(1) lead with VAs originating from anteroseptum, and 97.44% (76/78) patients demonstrated QS pattern in V(1) lead with VAs originating from midseptum and posteroseptum. Precordial lead transition zone was on or behind V(3) for tricuspid annulus free wall group (96.3%, 78/81), but in front of V(3) for tricuspid annulus septum wall group (47.73%, 42/88) (P<0.01). The S wave's amplitude smaller than-1.81 mV in lead V(2) can be used as a cutoff value to identify if PVC/VT is originating from free wall or septum of TA. R wave in inferior wall leads was found among 98.85% (86/87) patients with PVCs/VT originating from right ventricular outflow tract. Conclusion: A positive R wave in Ⅰ, aVL, V(5)-V(6) leads was found among most of patients with idiopathic ventricular arrhythmias originating from the tricuspid annulus regions, but VAs originating from different portions of tricuspid annulus area have distinct electrocardiographic characteristics.

[One case of elderly patient with extremely severe burn complicated by ventricular tachycardia]

One elderly patient with extremely severe burn was admitted to our department on 4th August, 2017. The patient suffered multiple sustained ventricular tachycardia from post injury day 2 to 4 due to relatively high input volume during shock stage. Amiodarone could not be given through intravenous injection because of his low blood pressure. After consultation with cardiologist, ventricular tachycardia was corrected by electrical cardioversion of several times. According to this case, the first treatment is electrical cardioversion when elderly patient with extremely severe burn shows sustained ventricular tachycardia which can not be corrected with medicine.

In-hospital major arrhythmias, arrhythmic death and resuscitation after successful primary percutaneous intervention for acute transmural infarction: a retrospective single-centre cohort study

BACKGROUND

Transmural acute myocardial infarction (AMI) is associated with a high risk for ventricular arrhythmia before, during and after treatment. Consequently, it is recommended that patients diagnosed with transmural AMI be monitored in a cardiac care unit (CCU) so life-threatening arrhythmias can be treated promptly. We examined the incidence and timing of in-hospital malignant ventricular arrhythmias, sudden cardiac or arrhythmic death (SCD/AD) and resuscitation requirements in patients with transmural AMI recovering from percutaneous coronary intervention (PCI) undertaken within 12 h of symptom onset and without antecedent thrombolysis.

METHODS

This was a retrospective cohort study using the Duisburg Heart Center (Germany) cardiac patient registry. In total, 975 patients met the inclusion criteria. The composite endpoint was post-PCI ventricular fibrillation or tachycardia, SCD/AD or requirement for resuscitation. We compared the demographic and clinical characteristics of patients who met the composite endpoint with those who did not, recorded the timing of endpoint episodes, and used multivariable logistic regression analysis to identify factors associated with the endpoint criteria.

RESULTS

There was no significant difference in the length of CCU or hospital stay between the groups. In-hospital mortality was 6.5%, and the composite endpoint was met in 7.4% of cases. Malignant ventricular tachyarrhythmia occurred in 2.8% of the patients, and SCD/AD occurred in 0.3% of the cases. There was a biphasic temporal distribution of endpoint events; specifically, 76.7% occurred < 96 h after symptom onset, and 12.6% occurred 240-360 h after symptom onset. Multivariable regression analysis identified positive associations between an endpoint episode and the following: age (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.05] per year); left ventricular ejection fraction (LVEF) < 30% (OR 3.66, 95% CI 1.91-6.99); peak serum creatine phosphokinase concentration (OR 1.01, 95% CI 1.00-1.02 per 100 U/dl); leucocytosis (OR 1.86, 95% CI 1.04-3.32), and coronary thrombus (OR 1.85, 95% CI 1.04-3.27).

CONCLUSIONS

Most post-PCI malignant ventricular arrhythmias, SCD/AD and resuscitation episodes occurred within 96 h of transmural AMI (76.7%). A substantial minority (12.6%) of these events arose 240-360 h after symptom onset. Further study is needed to establish the influence of age, LVEF < 30%, peak serum creatine phosphokinase concentration, leucocytosis and coronary thrombus on post-PCI outcomes after transmural AMI.

[Initial experience of catheter ablation of ventricular tachycardia originate from endocardium via direct ventricle puncture access in patients underwent mechanical valve implantation]

Objective: To evaluate the results of catheter ablation of ventricular tachycardia (VT) via direct ventricle puncture access in patients without traditional approach. Methods: Two idiopathic left fasicular VT patients with mechanical aortic and mitrial valve repalcement and 1 patient with right ventricular originated VT post mechanical tricuspid valve repalcement from March 2010 to July 2012 in Fuwai hospital were enrolled in this study. For left fasicular VT patients, catheter ablation was performed using transapical left ventricular access via minithoracotomy. For the patient with right ventricular originated VT, catheter ablation was performed via percutaneous right ventricle puncture at xiphoid. Abaltion was guided under EnSite NavX mapping system. The feasibility of VT ablation via direct ventricle puncture access and long-term VT recurrence were investigated. Results: Catheter ablation was successful in all patients, and all clinical VTs were eliminated. The procedure time was 53, 62 and 74 minutes respectively with radiation time 11, 16 and 20 minutes. The ablation time was 130, 170 and 240 seconds individually. No procedure related complication occurred. After a follow-up time of 76, 55 and 82 months respectively, no VT recurrence was found in patients with left fasicular VT. New-onset VT with different morphology with previous VT was recorded in the patient with right ventricular originated VT, subcutaneous implantable defibrillator was implanted finally in this patient. Conclusions: For patients with endocardial origined ventricular arrhythmias which could not be ablated via traditional approaches, direct ventricle puncture access with hybrid techniques provides a new approach foreliminating VTs in these patients.

Unsolved Questions on the Anatomy of the Ventricular Conduction System

We reviewed the anatomical characteristics of the conduction system in the ventricles of human and ungulate hearts and then raised some questions to be answered by clinical and anatomical studies in the future. The ventricular conduction system is a 3-dimensional structure as compared to the 2-dimensional character of the atrial conduction system. The proximal part consisting of the atrioventricular node, the bundle of His and fascicles are groups of conducting cells surrounded by fibrous connective tissue so as to insulate from the underlying myocardium. Their location and morphological characters are well established. The bundle of His is a cord like structure but the left and right fascicles are broad at the proximal and branching at the distal part. The more distal part of fascicles and Purkinje system are linear networks of conducting cells at the immediate subendocardium but the intra-mural network is detected at the inner half of the ventricular wall. The papillary muscle also harbors Purkinje system not in the deeper part. It is hard to recognize histologically in human hearts but conducting cells as well as Purkinje cells are easily recognized in ungulate hearts. Further observation on human and ungulate hearts with myocardial infarct, we could find preserved Purkinje system at the subendocardium in contrast to the damaged system at the deeper myocardium. Further studies are necessary on the anatomical characteristics of this peripheral conduction system so as to correlate the clinical data on hearts with ventricular arrhythmias.

[Clinical challenges in the management of catecholaminergic polymorphic ventricular tachycardia in children]

Objective: Catecholaminergic polymorphic ventricular tachycardia (CPVT) accounts for up to 10%-15% sudden cardiac death (SCD) in the children and young population. This study aimed to assess the current situation and challenges in CPVT clinical diagnosis. Method: A retrospective review included 11 children (7 male patients) at the First Hospital of Tsinghua University clinically diagnosed with CPVT from June 2014 to July 2017. Each patient was evaluated with detailed history, physical examination, resting 12-lead electrocardiogram(ECG), 24-h Holter, exercise stress test, Doppler echocardiography and genetic test. Result: During physical activity and/or emotional stress, ten children presented with recurrent syncope and one child presented with palpitation and chest distress. The mean age of symptom onset was 8.4 (4.0-13.7) years with a delayed diagnosis of 2.4 (0.04-5.00) years. Two children had a familial history of syncope or sudden death. Nine children were initially misdiagnosed as complex arrhythmic conditions (n=4), syncope of unknown origin (n=3), and drug-resistant epilepsy (n=2) treated with antiepileptic medication for several years. Bidirectional VT and (or) polymorphic VT were detected using Holter recording or exercise test ECG in all patients. Genetic test revealed CPVT-associated pathologic or possible pathologic mutations in nine patients. All patients were treated with beta-blockers. Six patients were asymptomatic, four patients reported infrequent syncope, and one sudden death occurred during a mean follow-up of 0.97 years. Conclusion: CPVT mainly occurs in children and adolescents with recurrent syncope during physical activities and/or emotional stress. Early diagnosis of CPVT remains challenging due to delayed diagnosis or misdiagnosis. Detailed clinical history and exercise stress test improve the early diagnosis and intervention for CPVT patients.

[Ventricular arrhythmias : What has been confirmed in therapy?]

Ventricular arrhythmias include a wide range of potentially benign single ventricular premature contractions to ventricular tachycardia and ventricular fibrillation with a risk for sudden cardiac death. The diagnosis of ventricular arrhythmia is made by 12-lead electrocardiogram, 24 h Holter monitoring, an external or implantable loop recorder, or during in-hospital monitoring. Especially the diagnosis of wide complex tachycardias is challenging in terms of differentiating between ventricular tachycardia and supraventricular tachycardia with aberrant atrioventricular conduction. After documentation of ventricular arrhythmias, diagnostic work-up with respect to structural or electrical cardiomyopathy is mandatory followed by risk stratification for sudden cardiac death. Therapeutic options for treatment of ventricular arrhythmias range from pharmacological therapy and interventional procedures such as catheter ablation and implantable devices. The current article provides an overview of the diagnosis of ventricular tachycardia and underlying cardiomyopathies. Furthermore, medical and interventional therapies are described. In addition, the indications for implantable and wearable defibrillators are presented.

[Upper abdominal pain, nausea, and vomiting in a 63-year-old woman]

We present a case of myotonic dystrophy type I and its complications including cholangitis and cardiac arrhythmias. The therapy options focus on the consequences of the disease and result in an endoscopic retrograde cholangiography (ERC) and implantation of an implantable cardioverter-defibrillator (ICD). Myotonic dystrophy is a disease which results in a loss of smooth and skeletal muscle cells leading to multiple consequences such as gastrointestinal symptoms and cardiac manifestations.

The Role of Intravenous Dopamine on Hemodynamic Support during Radiofrequency Catheter Ablation of Poorly Tolerated Idiopathic Ventricular Tachycardia

Background and Objectives

Hemodynamically unstable idiopathic ventricular tachycardias (VTs) are a challenge for activation or entrainment mapping technique. Mechanical circulatory support is an option, but is not always readily available. In this study, we investigated the safety and efficacy of hemodynamic support using intravenous (IV) dopamine solely during radiofrequency catheter ablation (RFCA) of hemodynamically unstable VT.

Subjects and Methods

Seven out of 86 patients with hemodynamically unstable idiopathic VT underwent de novo RFCA using dopamine in our single center. They were included in the study and reviewed retrospectively to investigate the procedural characteristics and outcomes.

Results

All patients were male, and the mean age was 50.7±5.3 years. One patient had implantable cardioverter-defibrillator for the secondary prevention. No evidence of myocardial ischemia was found in all patients. During the procedure, the mean blood pressure during VT without dopamine was 52.3±4.1 mmHg and increased to 82.6±3.8 mmHg after administering dopamine (Δ28.8±3.2 mmHg; total average dopamine dosage was 1266.1±389.6 mcg/kg). In all patients, activation mapping was safely applied, and VTs were terminated during energy delivery. Non-inducibility of clinical VT was achieved in all cases. There was no evidence of deterioration due to hypoperfusion during the peri-procedural period. No recurrence of ventricular tachyarrhythmias was observed in any of the patients, during a median follow-up of 23.0±6.1 months.

Conclusion

Hemodynamic support using IV dopamine during RFCA of hemodynamically unstable idiopathic VT facilitated detailed mapping to guide successful ablation.

[Recurrent syncope related to catecholaminergic polymorphic ventricular tachycardia due to de novo RyR2-R2401H mutation]

Objective: To explore the clinical and molecular genetic features of a Chinese patient with catecholaminergic polymorphic ventricular tachycardia (CPVT). Methods: Clinical data including resting electrocardiography, echocardiography and treadmill exercise testing of a patient with CPVT admitted to our department in March 2013 were analyzed, and the peripheral venous blood samples of the patient and his family members and 400 ethnicity-matched healthy controls were obtained. All exons and exon-intron boundaries of the six CPVT-related genes including RYR2, CASQ2, TRDN, CALM1, KCNJ2 and ANKB were sequenced to detect the variants related to CPVT. The relationship between the genotypes and phenotypes was analyzed to direct the target therapy. Results: Recurrent syncope induced either by exercise or extreme frightened fear was observed in this patient. There was no positive family history of syncope or sudden death. The resting electrocardiography and echocardiography of the patient were normal, while the exercise testing revealed bidirectional and polymorphic ventricular tachycardia. A cardiac ryanodine receptor gene mutation (R2401H) was identified in this patient, while this mutation was absent in his parents and sister and 400 controls. No variant was detected in the remaining five candidate genes. Treatment with high dose of metoprolol succinate (118.75 mg/d) was effective and patient was free of syncopal attack during the 2 years follow-up. Conclusion: This is the first report on RyR2-R2401H mutation in Chinese patient with CPVT, and high dose of metoptolol is the effective therapy option for CPVT related to RyR2 mutation.

Sensing and detection in Medtronic implantable cardioverter defibrillators

Ensuring sensing and detection of ventricular tachycardia (VT) and ventricular fibrillation (VF) was a prerequisite for the clinical trials that established the survival benefit of implantable cardioverter defibrillators (ICDs). However, for decades, a high incidence of unnecessary shocks limited patients' and physicians' acceptance of ICD therapy. Oversensing, misclassification of supraventricular tachycardia (SVT) as VT, and self-terminating VT accounted for the vast majority of unnecessary shocks. Medtronic ICDs utilize sensitive baseline settings with minimal blanking periods to ensure accurate sensing of VF, VT, and SVT electrograms. Programmable algorithms reject oversensing caused by far-field R waves, T waves, and non-physiologic signals caused by lead failure. A robust hierarchy of SVT-VT discriminators minimize misclassification of SVT as VT. These features, combined with evidence-based programming, have reduced the 1‑year inappropriate shock rate to 1.5 % for dual-/triple-chamber ICDs and to 2.5 % for single-chamber ICDs.

[The wearable cardioverter/defibrillator : Temporary protection from sudden cardiac death]

In the majority of cases sudden cardiac death (SCD) is caused by ventricular tachyarrhythmia. Implantable cardioverter-defibrillators (ICD) represent an evidence-based and established method for prevention of SCD. For patients who do not fulfill the criteria for guideline-conform implantation of an ICD but still have an increased, e.g. transient risk for SCD, a wearable cardioverter-defibrillator (WCD) vest was developed to temporarily prevent SCD. Numerous studies have shown the safety and efficacy of the WCD, although there is still a gap in evidence concerning a reduction in overall mortality and improvement in prognosis. This article gives an overview on the currently available literature on WCD, the indications, potential risks and complications.

Ventricular Tachycardia Associated Syncope in a Patient of Variant Angina without Chest Pain

A 68-year-old man was admitted for a syncope workup. After routine evaluation, he was diagnosed with syncope of an unknown cause and was discharged from the hospital. He was readmitted due to dizziness. On repeated Holter monitoring, polymorphic ventricular tachycardia was detected during syncope. We performed intracoronary ergonovine provocation test; severe coronary spasm was induced at 70% stenosis of the proximal left anterior descending artery. The patient was treated with percutaneous coronary intervention. We present a rare case of syncope induced by ventricular arrhythmia in a patient with variant angina without chest pain.

Epileptic seizure in a patient with an implantable cardioverter-defibrillator: Quo vadis right ventricular lead?

The case of a 77-year-old man admitted for suspected epileptic seizure is reported. Patient history showed implantation of a single-chamber implantable cardioverter-defibrillator (ICD) after cardiac arrest in 2007 with replacement in 2012 due to battery depletion; the patient reported no previous syncope, unconsciousness or seizures. Interrogation records of the ICD showed five ventricular tachyarrhythmia episodes that corresponded to the "seizure". Further examination revealed incorrect position of the RV-lead. Diagnosis was a provoked epileptic seizure due to undersensing of ventricular tachycardia because of improper ICD lead implantation in the coronary sinus. Treatment consisted of implantation of a new device with an additional ICD lead into the right ventricle.

Intramural Reentrant Ventricular Tachycardia in a Patient with Severe Hypertensive Left Ventricular Hypertrophy

We describe the case of a patient with severe hypertensive left ventricular hypertrophy and sustained hemodynamically unstable ventricular tachycardia (VT). Entrainment was demonstrated in the electrophysiological study. Activation mapping and pacemapping identified the location of the intramural reentrant VT with the exit site close to the epicardium. However, VT persisted after ablation at the epicardial exit site. Successful ablation was performed endocardially at the corresponding position.

Catheter ablation of ventricular tachycardia in patients with post-infarction cardiomyopathy

Monomorphic ventricular tachycardia (VT) in patients with post-infarction cardiomyopathy (CMP) is caused by reentry through slowly conducting tissue with in areas of myocardial scar. The use of implantable cardioverter-defibrillators (ICDs) has helped to decrease the risk of arrhythmic death in patients with post-infarction CMP, but the symptomatic and psychological burden of ICD shocks remains significant. Experience with catheter ablation has progressed substantially in the past 20 years, and is now routinely used to treat patients with post-infarction CMP who experience VT or receive ICD therapy. Depending on the hemodynamic tolerance of VT, a variety of mapping techniques may be used to identify sites for catheter ablation, including activation and entrainment mapping for mappable VTs, or substrate mapping for unmappable VTs. In this review, we discuss the pathophysiology of VT in post-infarction CMP patients, and the contemporary practice of catheter ablation.

Repeated Aborted Sudden Cardiac Death with Long QT Syndrome in a Patient with Anomalous Origin of the Right Coronary Artery from the Left Coronary Cusp

A 15-year-old female with a prior history of aborted cardiac death and surgical correction of anomalous origin of the right coronary artery (RCA) presented with polymorphic ventricular tachycardia. Her electrocardiogram after defibrillation was suggestive of congenital long QT syndrome (LQTS). The patient was treated with a β-blocker and remained free from ventricular arrhythmia during the follow-up of more than 6 months. Here, we present the case of a young female with repeated aborted cardiac death accompanied by anomalous origin of the RCA and congenital LQTS for the first time.

Acquired Long QT Syndrome Manifesting with Torsades de Pointes in a Patient with Panhypopituitarism due to Radiotherapy

We describe a 64-year-old male patient with panhypopituitarism who experienced polymorphic ventricular tachycardia (VT) associated with long QT intervals. The panhypopituitarism developed as a sequelae of radiation therapy administered 20 years prior to his current presentation and was recently aggravated by urinary tract infection with sepsis. In this case, polymorphic VT was resistant to conventional therapy (including magnesium infusion), and QT prolongation and T wave inversion were normalized after the administration of steroid and thyroid hormones. Thyroid hormone is generally known to be associated with torsades de pointes (TdP), but steroid or other hormones may also provoke TdP. Hormonal disorders should be considered as a cause of polymorphic VT with long QT intervals. Some arrhythmias can be life-threatening, and they can be prevented with supplementation of the insufficient hormone.

Catecholaminergic polymorphic ventricular tachycardia in a patient with recurrent exertional syncope

A 16-year-old male with a prior history of recurrent syncope was referred to our hospital after being resuscitated from cardiac arrest developed while playing volleyball. His electrocardiogram (ECG) demonstrated ventricular fibrillation at a local emergency department. After referral, an ECG showed bidirectional ventricular tachycardia (VT) and nonsustained Torsade de Pointes. Two days later, his heart rate became regular, and no additional episodes of VT were observed. His ECG showed sinus rhythm with a corrected QT interval of 423 msec, and two-dimensional echocardiography was unremarkable. We made the diagnosis of a catecholaminergic polymorphic VT. However, only premature ventricular complex bigeminy was induced on exercise ECG and epinephrine infusion tests, and the patient showed no episodes of syncope. His father and mother had different missense mutations in the cardiac ryanodine receptor on genetic testing. The proband had both mutations in different alleles and was symptomatic. It was recommended that the patient avoid competitive physical activities, and a β-blocker was prescribed.

Childhood brugada syndrome in two korean families

Since the first descriptions of Brugada as a new clinical entity defined by sudden cardiac death in patients with typical electrocardiogram (ECG) patterns, Brugada syndrome (BS) has been increasingly diagnosed. This syndrome is known as a disease that is inherited via an autosomal dominant trait, and the SCN5A mutation has been found in 20-25% of BS patients. Because BS primarily manifests in adulthood, little information is available on BS during childhood. Although there have been several reports on adult BS in Korea, pediatric BS has not been reported. Herein, we report on childhood BS in two families. One infantile BS patient and his family had a novel SCN5A mutation (c.4035G>T, p.W1345C, heterozygote) in domain III of the sodium channel.