Purkinje-Related Ventricular Tachycardia and Ventricular Fibrillation: Solved and Unsolved Questions.

Of the monomorphic ventricular tachycardias, there are 4 specific tachycardias related to the Purkinje system: 1) idiopathic verapamil-sensitive fascicular ventricular tachycardia (FVT); 2) non-re-entrant FVT; 3) bundle branch re-entry and interfascicular re-entry; and 4) Purkinje-mediated VT in structural heart disease. Verapamil-sensitive FVT is classified into 4 types according to the location of the circuit: 1) left posterior type; 2) left anterior type; 3) left upper septal type;and 4) reverse type. And, in the left anterior and posterior types, there are septal and papillary muscle subtypes.

Catheter Ablation for Brugada Syndrome.

Brugada syndrome (BrS) is an arrhythmogenic disease associated with an increased risk of ventricular fibrillation (VF) and sudden cardiac death (SCD). To date, the standard therapy for the prevention of SCD in BrS is the use of an implantable cardioverter-defibrillator (ICD) especially in patients who have experienced a prior cardiac arrest or syncopal events secondary to VF. However, ICDs do not prevent the occurrence of VF but react to defibrillate the VF episode, thereby preventing SCD.

Mapping and Ablation of Fascicular Tachycardias (Reentrant and Nonreentrant).

Fascicular ventricular tachycardia (FVT) usually involves the left fascicular system; namely the left posterior fascicle, anterior fascicle, and rarely the upper septal fascicle. It may also involve the right Purkinje arborization. This tachycardia can be seen in normal heart or in the setting of structural heart diseases.

Efficacy of Endocardial Ablation of Drug-Resistant Ventricular Fibrillation in Brugada Syndrome: Long-Term Outcome.

Background Both endocardial trigger elimination and epicardial substrate modification are effective in treating ventricular fibrillation (VF) in Brugada syndrome. However, the primary approach and the characteristics of patients who respond to endocardial ablation remain unknown. Methods Among 123 symptomatic Brugada syndrome patients (VF, 63%; syncope, 37%), ablation was performed in 21 VF/electrical storm patients, the majority of whom were resistant to antiarrhythmic drugs.

Radiofrequency Catheter Ablation of Ventricular Tachycardia in Patients With Hypertrophic Cardiomyopathy and Apical Aneurysm.

Objectives: This study evaluated the characteristics and results of radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in patients with hypertrophic cardiomyopathy (HCM) and left ventricular apical aneurysm (AA).

Background: Monomorphic VT in patients with HCM and left ventricular AA has been reported. However, outcome data of RFCA are insufficient.

Fascicular Ventricular Tachycardia Originating From Papillary Muscles: Purkinje Network Involvement in the Reentrant Circuit.

Background: Verapamil-sensitive fascicular ventricular tachycardia (FVT) has been demonstrated to be a reentrant mechanism using the Purkinje network as a part of its reentrant circuit. Although the papillary muscles (PMs) are implicated in arrhythmogenic structure, reentrant FVT originating from the PMs has not been well defined.

Methods And Results: We studied 13 patients in whom FVT was successfully eliminated by ablation at the posterior PMs (n=8; PPM-FVT) and anterior PMs (n=5; APM-FVT).

Non-Reentrant Fascicular Tachycardia: Clinical and Electrophysiological Characteristics of a Distinct Type of Idiopathic Ventricular Tachycardia.

Background: The most common form of idiopathic Purkinje-related ventricular tachycardia (VT) is the reentrant type. We describe the clinical and electrophysiological characteristics of focal non-reentrant fascicular tachycardia.

Methods And Results: Among 530 idiopathic VT patients who were referred for ablation, we identified 15 (2.

Alternative approach for management of an electrical storm in Brugada syndrome:Importance of primary ablation within a narrow time window.

Placement of an implantable cardioverter-defibrillator (ICD) is the only powerful treatment modality for Brugada syndrome in patients presenting with ventricular fibrillation (VF). For those whose first presentation is an electrical storm, pharmacologic therapy is typically used to control VF followed by ICD implantation. We report an alternative approach whereby, before ICD implantation, emergency catheter ablation of the VF-triggering premature ventricular contraction (PVC) resulted in long-term VF-free survival.

Insight into specific pro-arrhythmic triggers in Brugada and early repolarization syndromes: results of long-term follow-up.

The pro-arrhythmic triggers in Brugada and early repolarization syndromes (BrS, ERS) have not been analyzed systematically except for case reports. We clinically investigated the circumstances which precede/predispose to arrhythmic events in these syndromes during long-term follow-up. A detailed history from the patients/witnesses was taken to investigate the antecedent events in the last few hours that preceded syncope/ventricular fibrillation (VF); medical records, ECG and blood test from the emergency room (ER) were reviewed.

Anatomical Ablation Strategy for Noninducible Fascicular Tachycardia.

The presence of structural heart disease does not exclude fascicular ventricular tachycardia (VT), especially if the VT is verapamil sensitive. An empirical anatomic approach is effective when fascicular VT is noninducible or if diastolic Purkinje potential (P1) cannot be recorded during VT mapping. Pace mapping at the successful ablation site is usually not effective because selective pacing of P1 is difficult and there is an antidromic activation of the proximal P1 potential.

Verapamil-Sensitive Upper Septal Idiopathic Left Ventricular Tachycardia: Prevalence, Mechanism, and Electrophysiological Characteristics.

Objectives: This study sought to demonstrate the prevalence, mechanism, and electrocardiographic and electrophysiological characteristics of upper septal idiopathic left fascicular ventricular tachycardia (US-ILVT).

Background: ILVT is classified into left anterior and posterior types with no clear data about US-ILVT.

Methods: Among 193 ILVT patients, we identified 12 patients (6.

Late Gadolinium Enhancement on Cardiac MRI Correlates with QT Dynamicity Represented by QT/RR Relationship in Patients with Ventricular Arrhythmias.

Background: The distribution of late gadolinium enhancement (LGE) on the cardiac MRI (CMR) indicates myocardial fibrosis and provides information of possible reentry substrates. QT dynamicity reflecting repolarization abnormalities has gained attention as a potential prognostic predictive factor.

Objective: To clarify the correlation between the LGE distribution on CMR and QT dynamicity represented by the QT/RR relationship.

The relationship between repolarization parameters and serum electrolyte levels in patients with J wave syndromes.

Background: Intravenous administration of magnesium (Mg(2+)) is effective for polymorphic ventricular tachycardia via homogenization of transmural ventricular repolarization. Mg(2+) likely plays some role in the heterogeneity of repolarization in J wave syndromes.

Objective: To investigate the relationship between the repolarization parameters and serum Mg(2+), potassium (K(+)), and calcium (Ca(2+)) levels in J wave syndromes.

Late gadolinium enhancement of cardiac magnetic resonance imaging indicates abnormalities of time-domain T-wave alternans in hypertrophic cardiomyopathy with ventricular tachycardia.

Background: The presence of myocardial scar detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging has been described as a good independent predictor of mortality in patients with hypertrophic cardiomyopathy (HCM). Time-domain T-wave alternans (TWA) is also a potential predictor of cardiac mortality in patients with left ventricular dysfunction.

Objective: The purpose of this study was to elucidate the relationship between LGE distribution and TWA in patients with HCM.

The QRS morphology pattern in V5R is a novel and simple parameter for differentiating the origin of idiopathic outflow tract ventricular arrhythmias.

Aims: There are many reports on the ECG characteristics of idiopathic outflow tract ventricular arrhythmias (OT-VAs) to predict their origin. However, differentiating near regions using 12-lead ECGs is still complicated. The synthesized 18-lead ECG derived from the 12-lead ECG can provide virtual waveforms of the right-sided chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9).

Repolarization characteristics in early repolarization and brugada syndromes: insight into an overlapping mechanism of lethal arrhythmias.

Introduction: We reported impaired QT-rate dependence in early repolarization syndrome (ERS); however, contemporary data have shown peak incidence of sudden cardiac death (SCD) in ERS and Brugada syndrome (BrS) at mid-night and early morning. Taken together, we analyzed the nocturnal QT-rate dependence in both syndromes.

Methods And Results: A total of 172 subjects were enrolled: 11 ERS, 11 BrS patients, 50 subjects with an uneventful ER pattern (ERP), and 100 non-J-wave control subjects.

Three cases of corticosteroid therapy triggering ventricular fibrillation in J-wave syndromes.

We describe three cases of J-wave syndrome in which ventricular fibrillation (VF) was probably induced by corticosteroid therapy. The patients involved were being treated with prednisolone for concomitant bronchial asthma. One of the three patients had only one episode of VF during her long follow-up period (14 years).

Impaired ventricular repolarization dynamics in patients with early repolarization syndrome.

Introduction: Almost all current investigations on early repolarization syndrome (ERS) have focused on the J-wave characteristics and ST-segment configuration; however, few have reported on ventricular repolarization indexes in ERS.

Methods And Results: A total of 145 subjects were enrolled: 10 ERS patients, 45 uneventful ER pattern (ERP) subjects, and 90 healthy controls without J waves or ST-segment elevation. Ambulatory ECG-derived parameters (QT, QTc(B), QTc(F), T peak-Tend(Tpe), and QT/RR slope) were measured and statistically compared.

Acute myocardial infarction with a left main trunk lesion and documented lambda-like J waves.

We herein describe a case of a myocardial infarction, in which Lambda-like J waves were documented. The patient was referred to our hospital due to ventricular fibrillation. The twelve-lead electrocardiogram (ECG) on admission showed prominent J waves in the lateral and precordial leads.

Enhanced transmural dispersion of repolarization in patients with J wave syndromes.

Introduction: Recently, great attention has been paid to the risk stratification of asymptomatic patients with an electrocardiographic early repolarization (ER) pattern. We investigated several repolarization parameters including the Tpeak-Tend interval and Tpeak-Tend/QT ratio in healthy individuals and patients with J wave syndrome who were aborted from sudden cardiac death.

Methods And Results: Ninety-two subjects were enrolled: 12 patients with ventricular fibrillation associated with J waves, 40 healthy subjects with an uneventful ER pattern and 40 healthy control subjects (C) without any evident J waves.

Recovery of advanced atrioventricular block by cilostazol.

We describe a case of advanced atrioventricular (AV) block, in which treatment with cilostazol was effective in recovering the AV conduction. The patient was referred to our hospital for close examination of the advanced AV block and permanent pacemaker implantation. Although the patient had experienced third-degree AV block with occasional AV synchrony for more than two days, the AV conduction completely recovered after treatment with oral cilostazol at 200 mg/day.

Brugada syndrome case: difficult differentiation between a concealed form and tricyclic antidepressant-induced Brugada sign.

We describe a case of Brugada syndrome, in which recurrent syncope with convulsive seizures was induced after antidepressant treatment. The patient had been treated with five kinds of psychotropic drugs. The twelve-lead ECG after the syncope exhibited an RSR'-pattern in the precordial leads, however, a coved type ST-segment elevation was induced by a pilsicainide test.