Type Of Ventricular Tachycardia Research Articles

Design of a low-area hardware architecture to predict early signs of sudden cardiac arrests

Sudden cardiac arrest (SCA) results in an unexpected and untimely death within minutes, and its early prediction can alert cardiac patients to a timely medical diagnosis. To detect early symptoms of an SCA, the detection and classification of ventricular tachycardias (VT) are of utmost importance. In this work, a low-area yet highly accurate hardware architecture for VT classification is proposed based on the detection of premature ventricular contraction (PVC) beats. After pre-processing of the ECG signals using a wavelet-based pre-processing unit, a characteristics-matching algorithm is used to detect the PVC beats, and a low-complexity adaptive decision-based logic classifier is used to classify them into four types of VTs, namely monomorphic, polymorphic, non-sustained VT (NSVT), and sustained VT (SVT). FPGA verification of the hardware architecture for the VT classifier using the Nexys 4 DDR Artix-7 board utilizes 10.4 % of the total available resources and displays the type of VT and the number of PVCs detected to help in determining the severity of SCA and the need for medical attention. The ASIC implementation of the proposed PVC-based VT classification using the SCL 180 nm CMOS technology results in an area overhead of 0.02 mm2 and a power consumption of 3.47 μW for a high accuracy rate of 98.2 %. When compared to the existing CA detection systems for wearable devices, the proposed one consumes the least area while achieving high detection rates.

Frequency of Arrhythmias and Postural Orthostatic Tachycardia Syndrome in Patients With Marfan Syndrome: A Nationwide Inpatient Study.

BackgroundMarfan syndrome (MFS) is an autosomal dominant connective tissue disorder affecting multiple systems, particularly the cardiovascular system. The leading causes of death in MFS are aortopathies and valvular disease. We wanted to identify the frequency of arrhythmia and postural orthostatic tachycardia syndrome, length of hospital stay, health care–associated costs (HAC), and in‐hospital mortality in patients with MFS.Methods and ResultsThe National Inpatient Sample database from 2005 to 2014 was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD‐9‐CM) codes for MFS and arrhythmias. Patients were classified into subgroups: supraventricular tachycardia, ventricular tachycardia (VT), atrial fibrillation, atrial flutter, and without any type of arrhythmia. Data about length of stay, HAC, and in‐hospital mortality were also abstracted from National Inpatient Sample database. Adjusted HAC was calculated as multiplying HAC and cost‐to‐charge ratio; 12 079 MFS hospitalizations were identified; 1893 patients (15.7%) had an arrhythmia; and 4.9% of the patients had postural orthostatic tachycardia syndrome. Median values of length of stay and adjusted HAC in VT group were the highest among the groups (VT: 6 days, $18 975.8; supraventricular tachycardia: 4 days, $11 906.6; atrial flutter: 4 days, $11 274.5; atrial fibrillation: 5 days, $10431.4; without any type of arrhythmia: 4 days, $8336.6; both P=0.0001). VT group had highest in‐patient mortality (VT: 5.3%, atrial fibrillation: 4.1%, without any type of arrhythmia: 2.1%, atrial flutter: 1.7%, supraventricular tachycardia: 0%; P<0.0001) even after adjustment for potential confounders (without any type of arrhythmia versus VT; odds ratio [95% CI]: 3.18 [1.62–6.24], P=0.001).ConclusionsArrhythmias and postural orthostatic tachycardia syndrome in MFS were high and associated with increased length of stay, HAC, and in‐hospital mortality especially in patients with VT.

Genome-Wide Association Study for Idiopathic Ventricular Tachyarrhythmias Identifies Key Role of CCR7 and PKN2 in Calcium Homeostasis and Cardiac Rhythm Maintenance.

Idiopathic ventricular tachycardia (VT) occurs in structurally normal hearts and accounts for a significant number of all types of VT. The genome-wide association study is the most effective strategy for identifying novel genetic variants for common diseases. However, no genome-wide association study has been reported for idiopathic VT. We conducted the first genome-wide association study for idiopathic VT in the Chinese Han population using a discovery population with 246 cases and 648 controls and a replication population with 222 cases and >4072 controls. Candidate VT genes were functionally characterized in zebrafish. Real-time RT-PCR analysis was used to determine the effects of candidate genes on expression of ion channels and regulators. Patch-clamping was used to record L-type calcium current from neonatal rat cardiomyocytes with overexpression of candidate genes. We identified 4 significant loci represented by rs78960694 (minor allele frequency [MAF]=5.02% in cases and 1.84% in controls; P=4.30×10-12, odds ratio [OR]=3.91) and rs2229095 (MAF=3.25% in cases and 1.63% in controls; P=1.02×10-7, OR=3.44) near and in CCR7, respectively, rs68126098 in NELL1 (MAF=40.98% in cases and 32.07% in controls; P=2.40×10-8, OR=1.53), rs2390325 between PKN2 and LMO4 (MAF=21.19% in cases and 15.12% in controls; P=1.92×10-7, OR=1.62), and rs270065 in CSMD1 (MAF=33.63% in cases and 40.25% in controls; P=9.51×10-7, OR=0.69). Note that the associations of idiopathic VT for CCR7 variant rs78960694 and NELL1 variant rs68126098 reach genome-wide significance (P<5.00×10-8). Overexpression of either PKN2 or CCR7 increased the heart rate in zebrafish, and enhanced expression of CACNA1C, RYR2, or NOS1AP in zebrafish embryos, HEK293, and AC16 cardiomyocytes. Overexpression of either PKN2 or CCR7 significantly increased L-type Ca2+ current density. The first genome-wide association study identifies 4 novel loci and 2 risk genes (PKN2 and CCR7) for idiopathic VT. These findings identify new molecular determinants for cardiac calcium homeostasis and rhythm maintenance and provide novel targets for diagnosis and treatment for idiopathic VT.

The prevalence of left and right bundle branch block morphology ventricular tachycardia amongst patients with arrhythmogenic cardiomyopathy and sustained ventricular tachycardia: insights from the European Survey on Arrhythmogenic Cardiomyopathy.

In arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) typically displays a left bundle branch block (LBBB) morphology while a right bundle branch block (RBBB) morphology is rare. The present study assesses the VT morphology in ACM patients with sustained VT and their clinical and genetic characteristics. Twenty-six centres from 11 European countries provided information on 954 ACM patients who had ≥1 episode of sustained VT spontaneously documented during patients' clinical course. Arrhythmogenic cardiomyopathy was defined according to the 2010 Task Force Criteria, and VT morphology according to the QRS pattern in V1. Overall, 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Male sex prevalence was 79.3%, 88.1%, and 56.7% in the LBBB-VT, RBBB-VT, and LBBB + RBBB-VT groups, respectively (P = 0.007). First RBBB-VT occurred 5 years after the first LBBB-VT (46.5 ± 14.4 vs 41.1 ± 15.8 years, P = 0.011). An implanted cardioverter-defibrillator was more frequently implanted in the RBBB-VT (92.9%) and the LBBB + RBBB-VT groups (90%) than in the LBBB-VT group (68.1%) (P < 0.001). Mutations in PKP2 predominated in the LBBB-VT (65.2%) and the LBBB + RBBB-VT (41.7%) groups while DSP mutations predominated in the RBBB-VT group (45.5%). By multivariable analysis, female sex was associated with LBBB + RBBB-VT (P = 0.011) while DSP mutations were associated with RBBB-VT (P < 0.001). After a median follow-up of 103 (51-185) months, death occurred in 106 (11.1%) patients with no intergroup difference (P = 0.176). RBBB-VT accounts for a significant proportion of sustained VTs in ACM. Sex and type of pathogenic mutations were associated with VT type, female sex with LBBB + RBBB-VT, and DSP mutation with RBBB-VT.

Sustained ventricular tachycardia of left, right or both bundle branch block morphology in patients with Arrhythmogenic Cardiomyopathy

Abstract Aims In arrhythmogenic cardiomyopathy (ACM) sustained monomorphic ventricular tachycardia (VT) typically displays left bundle branch block (LBBB) morphology. Sustained VT with right bundle branch block (RBBB) morphology is very rare despite the frequent left ventricular involvement. The present study sought to assess the prevalence of spontaneous sustained LBBB-VT, RBBB-VT or both as well as clinical and genetic differences associated with these VT types. Methods and results Twenty-six centers from 11 European countries provided information on 952 patients with ACM and &amp;gt;1 episode of sustained VT observed during the patients' clinical course. VT was classified as: LBBB-VT; RBBB-VT or LBBB+RBBB-VT. Among 952 patients, 881 (92.5%) had LBBB-VT alone, 71 (7.5%) had RBBB-VT [alone in 42 (4.4%) patients or with LBBB-VT in 29 (3.0%) patients]. Male prevalence was 90.5%, 79.2% and 55.9% in the RBBB-VT, LBBB-VT and LBBB+RBBB-VT groups, respectively (P=0.001). Patients' age at first VT did not differ amongst the 3 VT groups. ICD implantation was more frequent for the RBBB-VT and the LBBB+RBBB groups (≈90% each) vs. 67.9% for the LBBB-VT group (P=0.001). Death incidence (9.5%–17.2%) was not significantly different between the 3 groups (P=0.425). Plakophylin-2 mutations predominated in the LBBB-VT and LBBB-VT+RBBB-VT groups (47.2% and 27.3%, respectively) and Desmoplakin mutations in the RBBB-VT group (36.7%). Conclusion This large European survey demonstrates: 1) Sustained RBBB-VT is documented in 7.5% patients with ACM; 2) Males markedly predominate in the RBBB-VT and LBBB-VT groups but not in the LBBB+RBBB VT group; 3) Distribution of desmosomal mutations appears to be different in the 3 VT groups. Funding Acknowledgement Type of funding source: None

Ventricular tachycardia in the absence of structural heart disease

### Learning objectives The earliest recorded description of ventricular tachycardia (VT) is credited to Sir Thomas Lewis in 19 091. VT is defined as a rhythm originating in the ventricles...

Atrial Fibrillation, Ventricular Arrhythmia, and Left Ventricular Remodeling in the ICU – First Results of the Single- Center RHYTHM-ACC Registry

Abstract The aim of this study was to investigate the association between left ventricular remodeling, atrial fibrillation (AF), and the severity of ventricular tachycardia (VT) in patients with ventricular rhythm disturbances admitted in a level 3 facility of acute cardiac care. Material and Methods: The RHYTHM-ACC registry was a single-center observational study, including 150 consecutive patients with sustained or non-sustained ventricular tachycardia (sVT and nsVT, respectively) admitted in an intensive cardiac care unit (ICCU), separated in: group 1 - 29 patients (21.01%) with dilated cardiomyopathy (DCM), and group 2 - 109 patients (78.99%) with normal ventricular performance. We investigated the difference between clinical characteristics of patients with sVT versus those with nsVT in each study group, and the association between AF and different forms of ventricular arrhythmia in 38 (25.33%) patients with AF and 112 (74.66%) patients in sinus rhythm. Results: There were no significant differences between the study groups with respect to type of ventricular arrhythmia: sVT (46.87% vs. 36.44%, p = 0.2), nsVT (43.75% vs. 55.93%, p = 0.2), or ventricular fibrillation (VF) (9.37% vs. 7.62%, p = 0.7). However, patients with DCM presented a significantly higher incidence of AF (43.75% vs. 20.33%, p = 0.01) and bundle branch block (37.5% vs. 11.86%, p = 0.0007). VF occurred more frequently in patients with AF compared to those in sinus rhythm (18.42% vs. 4.46%, p = 0.006). Multivariate analysis identified the co-existence of AF (OR = 4.8, p = 0.01) and the presence of a bundle branch block (BBB) (OR = 3.9, p = 0.03) as the most powerful predictors for the degeneration of VT into VF in patients admitted with sVT or nsVT in an ICCU unit. Conclusions: In patients with any type of VT admitted in an ICCU, the presence of ventricular remodeling is associated with a higher incidence of AF and conduction abnormalities, but not with a more severe pattern of ventricular arrhythmia. At the same time, AF and BBB seem to represent the most powerful predictors for degeneration of VT into VF, independent of the type of VT.

Role of (epi)genetic mechanisms in enhancing fear inhibitory function

Pediatric ventricular tachycardia (VT) occurs in both structurally normal and abnormal hearts. Spontaneous, sustained VT has an incidence of 1/100,000 among children. However, short episodes of VT can occur in up to 3% of healthy teenagers and up to 16% in hypertrophic cardiomyopathy. Prevalence of VT after tetralogy of Fallot repair has been estimated to be between 3% and 14% in several large clinical series, with a 2% incidence of cardiac death over 32 years. Because VT-related fatality is more prevalent in adults, it was previously believed that VT in children/adolescents had the same characteristics, etiologies, and outcomes despite not having evidence-based data. So, our systematic literature review was designed to identify evidence-based characteristics, etiologies, and risk stratification of the benign and malignant types of VT.We performed a systematic review of the literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.“PubMed,” “Science Direct,” “Web of Science”, “CINAHL” and “Cochrane” databases were searched for relevant studies using the search terms “ventricular tachycardia,” “pediatric,” “children,” “management,” “risk,” and “treatment”. Inclusion criteria included neonatal/pediatric/adolescent subjects; retrospective or prospective case series, case-control studies that described natural history of idiopathic VT in structural normal hearts, and sudden cardiac death risk factors in secondary VT in structurally normal or abnormal hearts. Studies were excluded if they were performed using animal models, exclusively described adult patients, or were review articles. We found 64 studies focused on three types of pediatric VT. These can be subdivided as follows: Idiopathic VT in structurally normal heart (24 studies), secondary VT in structurally normal hearts (22 studies), and VT in structurally normal hearts (18 studies). We propose an algorithm to differentiate benign from malignant VT using EKG morphologies, Holter criteria, and echocardiography. Also we risk stratify SCD in secondary pediatric VT in patients with structurally normal as well as structurally abnormal hearts in evidence-based methodology. Pediatric VT can be benign or malignant according to underlying etiologies. We propose an evidence-based algorithm to make this differentiation, followed by risk stratification of SCD in malignant and secondary VT in structurally normal or abnormal hearts.

Ventricular rate stabilization for treatment of recurrent VT.

Apatient with ischaemic cardiomyopathy received asecondary prevention VVI implantable cardioverter-defibrillator (ICD) after an episode of sustained ventricular tachycardia (VT). Because of recurrent VTs transmitted via CareLink, medical therapy was optimized and VT ablation was performed. Subsequently, afast VT with atypical short-long-short initiation developed. In addition, there was an increasing need for ventricular pacing due to sinus bradycardia. This new type of VT could be successfully dealt with by upgrading to DDD ICD and activating the Ventricular Rate Stabilization algorithm.

The clinical analysis of 212 cases of transesophageal atrial pacing(TEAP)

Objective To discuss the clinical application value of transesophageal atrial pacing(TEAP)in basic general hospitals. Methods A total of 212 subjects were selected,with dizziness,syncope,paroxysmal palpitations and other clinical symptoms and electrocardiogram showed sinus slow,atrioventricular block,short PR interval period,or with the first urgent symptom of tachycardia.The author doubted these symptoms were due to decreased function of the sinoatrial and atrioventricular node or Paroxysmal Supraventricular Tachycardia(PSVT),and treated them with TEAP with xd-5a. Results 121 cases(57.1%) were positive,83 cases(68.6%) of sinoatrial node dysfunction,38 cases(31.4%) of PSVT,then sinoatrial node dysfunction were given atropine load experiment and double checked TEAP.The authors detected 57 cases of non-increased vagus nerve tension in 83 positive cases,29 cases(20.1%)of sinoatrial node hypofunction,8 cases of atrioventricular node hypofunction,14 cases of double node hypofunction,6 cases of tachycardia-bradycardia syndrome;38 cases(31.4%) of PSVT,20 cases of dual atrioventricular nodal pathways(DAVNP),12 cases of atrioventricular bypass,4 cases of atrial tachycardia(AT),2 cases of ventricular tachycardia(VT);12 cases from 38 cases of positive results manifested as the first urgent symptom of achycardia,included 5 cases of DAVNP,5 cases of atrioventricular bypass,overdrive pacing terminated tachycardia successfully,2 cases of male VT,1 case terminated tachycardia through giving intravenous amiodarone successfully,1 case was taken electrical cardioversion uccessfully. Conclusion The common causes of slow sinus and atrioventricular block and the common cardiac electrophysiological types of PSVT and VT were detected through TEAP examination with the best diagnostic and differential diagnostic value.According to diagnosis guide,clinicians adopted correct and effective treatment strategies with good clinical application value.The author suggest this methods should be used in clinical,especially in basic general hospitals. Key words: Cardiac Pacing,Artificial; Esophagus; Sinoatrial node; Atrioventricular node; Arrhythmia

What is Ventricular Tachycardia for an Automated External Defibrillator?

Aim: Assessment and comparison of different algorithms that Automated External Defibrillators (AEDs) use to recognize as shockable monomorphic and polymorphic Ventricular Tachycardia (VT). Method: Engineering bench tests for a descriptive systematic evaluation in commercially available AEDs. AEDs were tested through an ECG simulator that is capable to generate different kind of monomorphic and polymorphic VT. All tests were performed at the engineering facility of the Lombardia Regional Emergency Service (AREU). Results: The tests showed marked differences among the AEDs when a Monomorphic Ventricular Tachycardia was simulated. The AED recognized the Monomorphic Ventricular Tachycardia (MVT) as shockable rhythm above a value ranging from 140 to 230 BPM. For Polymorphic Ventricular Tachycardia (PVT) not all AEDs delivered a shock when pre determined types of VT were selected.

Successful control of life-threatening polymorphic ventricular tachycardia by radiofrequency catheter ablation in an infant

We present a case of a 9-month-old girl in whom malignant polymorphic ventricular tachycardia (VT) was successfully controlled by radiofrequency catheter ablation under guidance with a three-dimensional mapping system. The VTs originated from the left ventricular lateral wall, left ventricular anterior wall, and left ventricular apex. At least six types of VTs were documented during the electrophysiology study. All VTs were successfully controlled after two sessions of radiofrequency catheter ablation, and she was discharged from our hospital on propranolol, mexiletine, flecainide, and aprindine.

Long-term results of catheter ablation for ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy/dysplasia

AimsThis study analyzed the arrhythmogenic substrates and mechanisms of ventricular tachycardia (VT), and long-term outcomes of catheter ablation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). MethodsNine patients (1 female, 40±17 years) with ARVC/D and sustained monomorphic VT (SMVT) exhibiting left bundle branch block morphology of the QRS complex were studied. The diagnosis of ARVC/D was confirmed by means of echocardiography, magnetic resonance imaging, and electroanatomic mapping in all patients. ResultsThe patients underwent 10 ablation procedures. At the initial ablation, the mean VT rate was 196±21 (170–240)bpm. In total, 17 VT types were observed. One VT type with left axis (+I, aVL), or right axis (+II,III,aVF) of the QRS complex was present in 3 and 1 patient, respectively. Two VT types of left and intermediate (+I, II, aVL) axis or of left and right axis of the QRS complex were observed in 3 and 2 patients, respectively. Multiple VT types with left axis QRS complex recurred in 1 patient. One VT displayed characteristics of focal arrhythmia, the mechanism of remaining VTs was clearly macroreentrant. The critical slow-conducting isthmus of the reentry circuit was located at the infero-lateral aspect of tricuspid annulus and was bounded by the annulus and baso-lateral wall scar in 7 VTs; the isthmus was located within the scars in the remaining VTs. During 52±31 (12–93) month follow-up since the last ablation, 8 (89%) patients remained free from any VT recurrence without antiarhythmic drug. ConclusionsPatients with ARVC/D frequently presented ≥1 SMVT type. The critical isthmus of reentry circuit was dominantly located close to the tricuspid annulus. Long-term outcome of extensive endocardial ablation was favorable with isolated VT recurrences in one patient.

Clinical and Electrophysiological Characteristics of Ventricular Tachycardia of Epicardialorigin Associated with Cardiac Sarcoidosis

Background: Cardiac sarcoidosis is generally recognized as a cause of ventricular tachycardia (VT) and sudden death. Before, we described the characteristics and outcome of VT due to cardiac sarcoidosis. This time, we make a study of sarcoid VT coursed from epicardium. Method and Result: In the 9 consecutive patients (57±11 years, 2 male) who admitted to our hospital with the diagnosis of VT associated with cardiac sarcoidosis and underwent radiofrequency catheter ablation, we were able to confirm 2 VTs (2 patients) coursed from epicardium. (31 VTs were appeared in 9 patients. 6.4%). The LVEF were 47% in the patient who have endcardium VT. (The meam LVEF of cardiac sarcoidosis patient 41±10%). VTs coursed from epicardium cannot induced from program stimulations. Both VTs coursed from posterior wall of left ventricle and cannot disappear catheter ablation from endocardium. Epicardium VTs have not purkinje-fiber potentials before or after the potential, and terminated naturally without sustain over 30 second. During 26 month follow-up, fatal VT episodes were not occur. Conclusion: Cardiac sarcoidosis provoke different types of VTs. In our study, VTs course from epicarium were fewer than that course from endocardium.

Recent Advancement of Treatment in Catecholaminergic Polymorphic Ventricular Tachycardia

Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is malignant arrhythmia characterized physical induced bidirectional or polymorphic ventricular tachycardia (VT). Methods and Results: From the Japanese registry of CPVT, 69 patients (M:F=25:44, age=11.7±7.8 years) were enrolled in this study. These patients were divided into 35 patients who were diagnosed during 1900s and 34 patients after 2000s. The incidence of sustained VT, nonsustained VT, and VF (10:22:3 vs 7:24:0, ns), the type of VT, and the rate of VT (194±29 vs 196±58, ns) were not different in these 2 groups. However, there was no sudden death in 2000s group, but 8 patients were died in 1900s group (p=0.003). Although statistically insignificant, there was no sudden death in 7 patients who was diagnosed over 20 year-old, however 8 of 62 patients were died who was diagnosed before 20 year-old. Conclusion: The prognosis of CPVT was markedly improved in the last 2 decade. This may be the result of propagation of the necessity of the restriction of exercise in the patients with CPVT, and also from the recent advancement of the use of antiarrhythmic medication, such as flecainide. The patients who were first diagnosed in adulthood may have better prognosis than the patients who were diagnosed in childhood.

Clinical Spectrum and Prognostic Factors of Pediatric Ventricular Tachycardia

There have been no studies on the clinical characteristics and prognostic factors of pediatric ventricular tachycardia (VT). Eighty-one patients with pediatric VT were studied retrospectively at a single center. The median follow-up period was 6.0 years (0.7-23.5 years). Patients were categorized into 6 groups: idiopathic VT (IVT, n=37), catecholaminergic polymorphic VT (CPVT, n=10), congenital heart disease-associated VT (n=15), myocarditis-associated VT (n=8), cardiomyopathy-associated VT (CMP-VT, n=5) and miscellaneous. The age distribution of VT had 2 peaks (infant and teenager). VT with left bundle branch block configuration was more frequently nonsustained than VT with right bundle branch block configuration (61% vs 8%). Although 22% were asymptomatic, 38% experienced syncope or seizure and 16% had cardiac arrest. The overall mortality rate was 7.4%. The expected life span without cardiac arrest was <4 years in the CMP-VT group and the 10-year survival rate in CPVT patients was approximately 55%. Onset at infancy, monomorphic type and transcatheter/surgical ablation were related to the successful resolution of VT. Logistic regression analysis revealed that CPVT, CMP-VT, polymorphic VT and sustained VT were significantly correlated with death or cardiac arrest. The clinical features and prognosis of pediatric VT differed with the VT type, clinical categories and onset age. Accurate diagnosis and proper treatment according to the clinical categories may improve the outcome.

The Relationship between Pacing Site and Induction or Termination of Sustained Monomorphic Ventricular Tachycardia by Antitachycardia Pacing

With the development of left ventricular pacing for cardiac resynchronization, there is an interest in the possibility of improving ventricular antitachycardia pacing (ATP) efficacy by pacing from the LV electrode(s). This study assessed the efficacy of pacing delivered from the left coronary vein (LCV) compared to that delivered from the right ventricular apex (RVA) upon ventricular tachycardia (VT) induction and termination. Sixty patients undergoing provocative ventricular electrophysiology (EP) studies in three centers were enrolled. Multipolar EP catheters were placed in the atrium, the RVA, and LCV. VT induction was attempted from the RVA and LCV in random order. Upon detection of monomorphic VT, burst ATP for up to 10 pulses at 88% VT cycle length was delivered from the RVA or LCV, in a random order, and crossed over when possible. Identical VT morphologies were reinduced to allow paired comparison of RVA versus LCV ATP. Data from 55 patients were analyzed. Thirty-four morphologically distinct monomorphic VT types were induced in 22 patients. ATP succeeded in 18 (55%) and VTs in 13 patients. RVA ATP terminated 15 of 23 (65%) VTs, and LCV ATP terminated 10 of 23 (43%) VTs (P = 0.14). ATP delivered ipsilateral to the earliest activation site required 5.0 + or - 2.6 pulses to terminate compared to 4.8 + or - 1.7 pulses when delivered from the contralateral site (P = 0.90). Paired comparison was possible for 13 VT morphologies in 11 patients. Paired RVA and LCV ATP efficacy was identical (54%vs 54%, P = 1.0). ATP delivered from a LCV lead offers no efficacy advantage over pacing from the RVA.

Role of radiofrequency catheter ablation of ventricular tachycardia in cardiac sarcoidosis: Report from a multicenter registry

Management of ventricular tachycardia (VT) is challenging in patients with cardiac sarcoidosis. The purpose of this study was to assess the response of VT in patients with cardiac sarcoidosis to medical therapy and radiofrequency ablation. Forty-two patients with a diagnosis of cardiac sarcoidosis based on the Japanese Health Ministry criteria were followed. When VT occurred, a stepwise approach was used: implantable cardioverter-defibrillator placement, immunosuppressive agents, antiarrhythmic medications, then radiofrequency ablation. In nine patients (age 46.7 +/- 8.6 years; ejection fraction 42 +/- 14%), VT was not controlled by medical therapy, and radiofrequency ablation was performed. A total of 44 VTs (mean cycle length 348 +/- 78 ms) were induced. Endocardial radiofrequency ablation was performed in eight patients (right ventricular in 5, left ventricular in 3) and epicardial radiofrequency ablation in one patient. In 4 of 5 patients with right ventricular VTs, a peritricuspid circuit was identified. Critical areas were identified for 21 (48%) of 44 VTs, resulting in elimination of 31 (70%) of 44 VTs. The most frequent VT circuit was reentry in the peritricuspid area. This type of VT was eliminated in all patients. Arrhythmic events decreased from 271 +/- 363 episodes preablation to 4.0 +/- 9.7 postablation. All patients had either a decrease (n = 4) or complete elimination (n = 5) of VT during mean follow-up of 19.8 +/- 19.6 months. Catheter ablation of VT in patients with cardiac sarcoidosis refractory to medical therapy is effective in eliminating VT or markedly reducing the VT burden. The disease process in cardiac sarcoidosis often involves a specific area in the basal right ventricle predisposing to peritricuspid reentry.

Bidirectional Ventricular Tachycardia Caused by a Reentrant Mechanism With Left Bundle Branch Block Configuration on Electrocardiography

Reentrant bidirectional ventricular tachycardia (VT) with left bundle branch block (LBBB) configuration was diagnosed in a 54-year-old woman who showed 2 types of VT: QRS morphologies of LBBB with inferior axis and LBBB with superior axis. The development of VT with a superior axis was preceded by VT with inferior axis and/or both configurations of VT in alternate beats exhibiting bidirectional VT. The electrophysiological study demonstrated reproducible induction of both types of VT by programmed ventricular stimulation and both types of VT were entrained. Using conventional pace mapping and electro-anatomical mapping methods, radiofrequency energy applications at the 2 exit sites of the reentry path successfully terminated both types of VT and the patient was free from VT attacks for more than 15 months.

Reentrant Ventricular Tachycardia Originating in the Right Ventricular Outflow Tract Slow Conduction Identified by Right Coronary Artery Ostium Pacing

A case of reentrant ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) is described. An electrophysiological study revealed that programmed stimulation from the right ventricle apex induced 2 types of VT with similar left bundle branch block configuration and inferior axis. Yet, VT cycle length (CL) was different; one was stable, sustained VT with a CL of 360 ms and the other was hemodynamically intolerable VT with a CL of 330 ms. Similarly for both VTs, perfect pace mapping was obtained at the anterior septum beneath the pulmonary valve in the RVOT, and exits of both VTs were very close. Entrainment mapping during stable VT was performed and the anterior septum RVOT was designated as the exit for the stable VT. Intriguingly, entrainment pacing from the ostium of the right coronary artery showed that the post-pacing interval was identical to VTCL. The stimulus to QRS interval was very long (340 ms) during entrainment with concealed fusion, and the right coronary artery ostium was therefore consistent with the VT reentry circuit inner loop or the upper portion of the VT reentry circuit exit. These findings suggest that the stable VT reentry circuit had a slow conduction zone from the ostium of the right coronary artery to the exit in the anterior septum RVOT. When radiofrequency catheter ablation was performed at the 2 exits of the anterior septum RVOT, both VTs then could not be induced.