Ventricular Tachycardia In Children Research Articles

Idiopathic fascicular ventricular tachycardia in children: a challenging arrythmia worth recognizing.

Idiopathic fascicular ventricular tachycardia in children: a challenging arrythmia worth recognizing.

Idiopathic left fascicular ventricular tachycardia in children and adolescents.

Idiopathic ventricular tachycardia (VT) in children with structurally normal hearts is generally unrelated to the risk of sudden arrhythmic death. Still, it may be associated with deterioration in the quality of life. VT involving the fascicular conduction system is the most typical form of idiopathic left VT. In this retrospective study, we describe the experience of the clinical presentation, catheter ablation, and long-term follow-up of left fascicular VT in children. An electrophysiological study was performed on consecutive children at a single tertiary center. Clinical fascicular left VT was induced by programmed stimulation, and catheter ablation was guided searching for Purkinje potentials. We included 18 patients (0.8 patients/year): 14 (77.8%) males and four females. The mean age of the first VT episode was 8.5 ± 5 years. Intravenous verapamil administration was effective for paroxysmal fascicular VT but not for prevention of recurrences. The mean age at the time of catheter ablation was 11.1 ± 3.8 years (8 months-16 years). The mean weight was 36.8 ± 16.4 kg (8.7-58 kg). A 100% success rate was observed with catheter ablation after repeated procedures without major complications. Mean follow-up was 2.0 ± 1.2 years (1.0-4.0 years, median 1.5), with permanent success in all patients and no antiarrhythmic drug administration. Fascicular VT has an adverse clinical course in children. In most cases, this condition is drug refractory. Catheter ablation is successful and safe treatment and should represent the first-line approach in symptomatic children.

The Efficacy of Anti-Arrhythmic Drugs in Children With Idiopathic Frequent Symptomatic or Asymptomatic Premature Ventricular Complexes With or Without Asymptomatic Ventricular Tachycardia: a Retrospective Multi-Center Study

The aim of the study is to compare the efficacy of flecainide, beta-blockers, sotalol, and verapamil in children with frequent PVCs, with or without asymptomatic VT. Frequent premature ventricular complexes (PVCs) and asymptomatic ventricular tachycardia (VT) in children with structurally normal hearts require anti-arrhythmic drug (AAD) therapy depending on the severity of symptoms or ventricular dysfunction; however, data on efficacy in children are scarce. Both symptomatic and asymptomatic children (≥ 1 year and < 18 years of age) with a PVC burden of 5% or more, with or without asymptomatic runs of VT, who had consecutive Holter recordings, were included in this retrospective multi-center study. The groups of patients receiving AAD therapy were compared to an untreated control group. A medication episode was defined as a timeframe in which the highest dosage at a fixed level of a single drug was used in a patient. A total of 35 children and 46 medication episodes were included, with an overall change in PVC burden on Holter of -4.4 percentage points, compared to -4.2 in the control group of 14 patients. The mean reduction in PVC burden was only significant in patients receiving flecainide (− 13.8 percentage points; N = 10; p = 0.032), compared to the control group and other groups receiving beta-blockers (− 1.7 percentage points; N = 18), sotalol (+ 1.0 percentage points; N = 7), or verapamil (− 3.9 percentage points; N = 11). The efficacy of anti-arrhythmic drug therapy on frequent PVCs or asymptomatic VTs in children is very limited. Only flecainide appears to be effective in lowering the PVC burden.

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

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

Catheter ablation of ventricular tachycardia in the pediatric patients: A single-center experience.

Ventricular tachycardia (VT) with or without structural heart disease is uncommon but well-recognized clinically in children. With this retrospective study, we collected the data from the in-hospital pediatric patients of VT with catheter ablation therapy. The purpose of this study is to assess the acute results and the long-term outcome of catheter ablation in pediatric patients of VT in our single pediatric center. This study included 53 consecutive children (male/female=33/20, mean age=8.2±3.4 years, mean bodyweight=32.6±13.7kg). All patients underwent electrophysiological study with an attempt of catheter ablation for clinical monomorphic VT. Acute and long-term success rate of catheter ablation for the treatment of VT were compared between right and left VT as well as fascicular VT (FVT) and nonfascicular VT. There were 53 idiopathic VT forms found in the children, including FVT (n=32), outflow tract VT (n=15), papillary muscle VT (n=5), and bundle branch reentry VT (n=1). Acute success of catheter ablations for VT was achieved in 57 of all the 59 ablation procedures (97%) with VT recurrence occurred in six of 53 patients (11%). During a mean follow-up period of 29.2±21.7 months (range 1-76 months) after hospital discharge, ablations in nonfascicular VT were as successful as FVT. There was no significant difference in the success rate between the right and left VT. Catheter ablation is an effective treatment for idiopathic VT in children. The acute and long-term success rates of catheter ablation for idiopathic VT in pediatric patients with normal heart structure are satisfying.

Sudden Death by Catecholaminergic Polymorphic Ventricular Tachycardia in Children

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a severe cardiac arrhythmogenic hereditary illness, which affects children and young adults with a structurally healthy heart. Its prevalence is of one case in 10 thousand inhabitants. It is a potentially fatal illness, part of the differential diagnosis of syncope in children. The present study has the purpose of relating the case of a child that, during the investigation of convulsive syncope, presented sudden death aborted due to CPVT and to describe the diagnosis difficulties of the case, comparing with data from the literature

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

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. 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. 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. 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.

Ventricular tachycardia in children with diphtheritic myocarditis

Nine children with diphtheritic ventricular tachycardia ranging in age from 2 to 11 years (mean 6.5 years) were observed and followed up until their terminal state. The ventricular tachycardia showed a left bundle branch block contour in 5 of 9 patients, right bundle branch block in four, multifocal pacemaker in three and unifocal in six patients. Fusion and captured beats were present in two and 4 patients respectively, including one patient who had both. Four cases were without obvious atrio-ventricular dissociation. All patients were treated with standard therapy for diphtheria, and prednison was given to patients with myocarditis. Because of its controversial results, antiarrhythmic agent was not given. The prognosis is very poor; all patients died one to 8 days after ventricular tachycardia appearance.

A pharmacokinetic model for amiodarone in infants developed from an opportunistic sampling trial and published literature data.

Amiodarone is a first-line antiarrhythmic for life-threatening ventricular fibrillation or ventricular tachycardia in children, yet little is known about its pharmacokinetics (PK) in this population. We developed a population PK (PopPK) model using samples collected via an opportunistic study design of children receiving amiodarone per standard of care supplemented by amiodarone PK data from the literature. Both study data and literature data were predominantly from infants<2years old, so our analysis was restricted to this group. The final combined dataset consisted of 266 plasma drug concentrations in 45 subjects with a median (interquartile range) postnatal age of 40.1 (11.0-120.4) days and weight of 3.9 (3.1-5.1) kg. Since the median sampling time after the first dose was short (study: 95h; literature: 72h) relative to the terminal half-life estimated in adult PopPK studies, values of the deep compartment volume and flow were fixed to literature values. A 3-compartment model best described the data and was validated by visual predictive checks and non-parametric bootstrap analysis. The final model included body weight as a covariate on all volumes and on both inter-compartmental and elimination clearances. The empiric Bayesian estimates for clearance (CL), volume of distribution at steady state, and terminal half-life were 0.25 (90% CL 0.14-0.36) L/kg/h, 93 (68-174) L/kg, and 266 (197-477) h, respectively. These studies will provide useful information for future PopPK studies of amiodarone in infants and children that could improve dosage regimens.

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.

Left ventricular dysfunction is associated with frequent premature ventricular complexes and asymptomatic ventricular tachycardia in children.

To assess the risk factors for left ventricular (LV) dysfunction in a paediatric population with idiopathic frequent premature ventricular contractions (PVCs) and asymptomatic ventricular tachycardias (VTs). Paediatric patients with the diagnosis of idiopathic frequent PVCs and asymptomatic VTs were retrospectively evaluated. Frequent PVCs were defined as ≥5% on 24 h Holter recording. Left ventricular dysfunction was defined as a shortening fraction of ≤28%. Seventy-two children were identified. Six patients showed LV dysfunction at diagnosis [age 10 ± 7 years, 2 (33%) had symptoms such as syncope, palpitations, fatigue, and dizziness], and 66 showed normal LV function [age 8 ± 6 years, 22 (33%) with symptoms]. Patients with LV dysfunction had a higher percentage of PVCs on Holter recordings (47 ± 16 vs. 16 ± 11%, P = 0.006), higher prevalence of VT [5 (83%) vs. 27 (41%), P = 0.045] and sustained ventricular tachycardia (sVT) [3 (50%) vs. 4 (6%), P = 0.001], and a higher number of couplets [6 (100%) vs. 34 (52%), P = 0.030]. In patients with LV dysfunction, two responded to medication (Classes Ic and II) and five underwent ablation, of which one was unsuccessful. During follow-up, LV function normalized in five of six patients. In patients with a normal function, none developed LV dysfunction during the follow-up. In children with idiopathic PVCs and asymptomatic VTs, development of LV dysfunction is associated with a higher burden of PVCs, the presence of sVTs, and couplets. Left ventricular dysfunction appears to be reversible if the burden of PVCs is decreased by medication or ablation.

Association of Late Gadolinium Enhancement and Degree of Left Ventricular Hypertrophy Assessed on Cardiac Magnetic Resonance Imaging With Ventricular Tachycardia in Children With Hypertrophic Cardiomyopathy

There are limited data on the clinical significance of left ventricular (LV) mass and late gadolinium enhancement (LGE) in pediatric hypertrophic cardiomyopathy (HC). We reviewed cardiovascular magnetic resonance (CMR) studies of children with HC to investigate the associations between the extent and distribution of LGE and LV mass with ventricular tachycardia (VT) in children with HC. A blinded observer reviewed CMR studies for the presence and distribution of LV hypertrophy and LGE using a 17-segment model. The primary outcome was VT. LGE was present 17 of 33 subjects (52%). VT was present on outpatient Holter monitor or exercise stress test in 7 patients, of which 5 patients (71%) had LGE. Each additional segment of LGE was associated with an increase in the odds of VT (odds ratio [OR] 1.4, 95% CI 1.1 to 1.9) and fewer than 5 segments with LGE had 93% specificity for the presence or absence of VT (OR 0.06, 95% CI 0.01 to 0.5). VT was more common in patients with LGE in the apical septal (p= 0.03), basal inferoseptal (p<0.01), and basal inferior (p= 0.04) segments, whereas LGE in more commonly involved segments (midanteroseptal and midinferoseptal) was not associated with VT (p= 0.13, 0.26). Patients with VT had greater LV mass index (76.4 ± 40.4g/m(2.7) vs 50.9 ± 24.3g/m(2.7); p= 0.03). Each centimeter of increased maximum LV thickness was associated with increased likelihood of VT (OR 2.9, 95% CI 1.2 to 6.8). In conclusion, in pediatric HC, CMR to evaluate the extent and pattern of LGE, LV mass index, and maximum LV thickness may help to identify children with HC at risk of VT.

Premature ventricular contraction-induced cardiomyopathy in children.

Adults with high premature ventricular contraction burden can develop left ventricular dilation, dysfunction, and strain, consistent with a cardiomyopathy, which is reversible with radiofrequency ablation of the premature ventricular contractions. Evidence in children with similar ectopy burden is limited. We performed a single-centre retrospective review to examine the prevalence of premature ventricular contraction-induced cardiomyopathy, natural history of ventricular ectopy, and progression to ventricular tachycardia in children with frequent premature ventricular contractions. Children aged between 6 months and 18 years, with premature ventricular contractions comprising at least 20% of rhythm on 24-hour Holter monitor, were included in our study. Those with significant structural heart disease, ventricular tachycardia greater than 1% of rhythm at the time of premature ventricular contraction diagnosis, or family history of cardiomyopathy - except tachycardia-induced - were excluded. Cardiomyopathy was defined by echocardiographic assessment. A total of 36 children met the study criteria; seven patients (19.4%, 95% CI 6.2-32.6%) met the criteria for cardiomyopathy, mostly at initial presentation. Ectopy decreased to <10% of beats without intervention in 16.7% (95% CI 4.3-29.1%) of the patients. No patient progressed to having ventricular tachycardia as more than 1% of beats on follow-up Holter. Radiofrequency ablation was performed in three patients without cardiomyopathy. Our study demonstrates a higher prevalence of cardiomyopathy among children with high premature ventricular contraction burden than that previously shown. Ectopy tended to persist throughout follow-up. These trends suggest the need for a multi-centre study on frequent premature ventricular contractions in children. In the interim, regular follow-up with imaging to evaluate for cardiomyopathy is warranted.

Catheter ablation of idiopathic ventricular tachycardia in children using the EnSite NavX system with/without fluoroscopy

Curative therapy of idiopathic ventricular tachycardia remains a challenge in interventional electrophysiology. The aim of this study was to demonstrate the utility of an EnSite NavX system in the catheter ablation of idiopathic ventricular tachycardia in children. In all, 17 children with idiopathic ventricular tachycardia underwent electrophysiological studies using the EnSite NavX system guidance. The mean patient age was 13 ± 2.4 years (range: 7.8-17.9) and the mean patient weight was 52.3 ± 11.9 kg (range: 32-75). The origin of ventricular tachycardia was in the right ventricular outflow tract in nine patients, in the left ventricle in six, near the bundle of His/right bundle branch in one, and in the left aortic cusp in one. The mean procedure and fluoroscopy times were 169.3 ± 43.2 minutes and 8 ± 10.8 minutes, respectively. No fluoroscopy was used in six patients. The mean radiation exposure was 33.1 ± 56.4 mGy. Acute success was achieved in 14 patients (82%). The focus of ventricular tachycardia was epicardial in two failed procedures. During a mean follow-up of 8.5 ± 7.6 months, ventricular tachycardia recurred in three patients, two of whom underwent a second procedure. Except for one patient who developed transient right bundle branch block, no complications were seen. Catheter ablation of idiopathic ventricular tachycardia in children can be performed safely and effectively with low fluoroscopy exposure using the EnSite NavX system.

Antitachycardia pacing reduces appropriate and inappropriate shocks in children and congenital heart disease patients

Antitachycardia pacing (ATP) can reduce implantable cardioverter-defibrillator shocks, but its use in children and patients with congenital heart disease (CHD) is not well described. To review the efficacy of ATP in children and patients with CHD. We reviewed implantable cardioverter-defibrillator therapies in children and patients with CHD (aged 2-52 years) at our institution. Appropriate therapies were defined as those delivered for true ventricular tachycardia (VT) or ventricular fibrillation; other therapies were defined as inappropriate. During a median follow-up of 4 years (range 0.5-15 years), 17 of 79 patients (23%) received appropriate therapy and 14 received ATP for 100 episodes of VT. ATP was highly successful (88%) in terminating VT, and only 10 of 100 episodes required a shock. Shocks were effective in terminating VT/ventricular fibrillation in 21 of 24 episodes (87%). The outcomes of appropriate therapy were similar for ATP and shocks (success 88% vs 87%, failure 9% vs 8%, acceleration 3% vs 4% for ATP and shocks, respectively). Thirty-one patients (39%) received inappropriate therapy. Inappropriate ATP (without subsequent shocks) was delivered to 11 patients for the following: sinus tachycardia (19 episodes in 7 patients) with slowing of the rate after ATP, T-wave oversensing (2 episodes in 2 patients) with loss of oversensing after ATP, and reentrant supraventricular tachycardia (14 episodes in 2 patients) terminated with ventricular ATP. ATP is highly efficacious for VT in children and patients with CHD. In addition to reducing appropriate shocks, inappropriate shocks due to sinus or supraventricular tachycardia can be significantly reduced with ATP.

Clinical and Electrophysiological Characteristics of Idiopathic Ventricular Tachycardia in Children

Purpose: We performed this study to know the mechanism, the outcome of RF ablation and prognosis of the pediatric patients with VT. Methods and Results: The 50 children (mean 11.5±3.5 years) with monomorphic VT without any structural heart disease were enrolled in this study. The VT originated from the right ventricle (RV) in 30 patients (pts), and left ventricle (LV) in 20 pts. The VTs were induced by exercise in 19 pts (63%) of the RVVT, and 9 pts (45%) of the LVVT, and by programmed ventricular stimulation in 14 pts (47%) of the RVVT, 7 pts (35%) of the LVVT. The mechanism of the VT was suspected to be triggered activity in 12 pts (40%), automaticity in 13 pts (43%), and re-entry in 5 pts (17%) of the RVVT, whereas it was 2 pts (10%), 8 pts (40%), and 10 pts (50%) of the LVVT, respectively. In 3 pts with VT, a non-verapamil sensitive re-entry was documented. Radiofrequency ablation was performed in 43 pts, and 31 pts (72%) were successfully ablated. Conclusions: Mechanism of the idiopathic VT in children was various, but triggered activity in LVVT was very few. In some pts with idiopathic VT, a non-verapamil sensitive re-entry was documented, which was more common in pts with ischemic heart disease or cardiomyopathy.

Diagnosis-specific characteristics of ventricular tachycardia in children with structurally normal hearts

Improved mechanistic insights and clinical tools provide increasing diagnostic refinement for ventricular tachycardia in young patients with structurally normal hearts, yielding potentially important prognostic and management implications. The purpose of this study was to survey the clinical characteristics and outcomes of otherwise healthy children with ventricular tachycardia (VT) who were classified according to contemporary diagnostic criteria. A single-center retrospective review of patients younger than 18 years of age with VT diagnosed between January 1980 and December 2005 was undertaken. Patients with significant systemic illness or with underlying structural or functional heart disease were excluded. A total of 77 patients met inclusion criteria and were grouped as follows: accelerated idioventricular rhythm (AIVR; n = 19), right ventricular tachycardia (RVT; n = 30), left ventricular tachycardia (LVT; n = 23), and catecholamine sensitive polymorphic VT (CPVT; n = 5). AIVR patients were youngest at diagnosis and had the most benign natural history, while the opposite was true of CPVT patients. Ablation was attempted in 2/30 RVT (50% success) and 10/23 LVT (80% success) patients. Severe cardiac events occurred in 3/23 LVT (no deaths) and 2/5 CPVT (one death) patients. The natural history and appropriate management of VT in young patients with structurally normal hearts are highly dependent on the specific diagnosis. LVT and CPVT are associated with significantly greater morbidity and mortality than AIVR and RVT.

Identification and emergency treatment of ventricular tachycardia in children

儿童室性心动过速起病急、进展快、病死率高,其主要危害是引起血流动力学障碍而出现不同的临床症状,有的患儿甚至可转变为心室颤动致心源性猝死.所以室性心动过速的出现则无论发病年龄,还是有无基础性疾病的存在,往往需要急诊有效处理~([1]).但在紧急情况下,由于室性心动过速鉴别困难,医生在处理时表现得进退两难。

Sympathetic tone and ventricular tachycardia

The pathogenesis of idiopathic monomorphic ventricular tachycardia is not clear. We suppose that a lack of balance of the sympathetic system could be involved. Frequency domain analyses of the heart rate can be useful to understand autonomic system balance. Therefore we performed this evaluation on a sample of seven children affected by idiopathic monomorphic ventricular tachycardia. We performed a Holter recording for palpitations on all the children, with an average age of 12 (range: 7-18 years). In all the patients many episodes of repeated sustained or nonsustained ventricular tachycardia were demonstrated, with an average heart rate of 170 bpm. We excluded any structural heart defect through echocardiography and magnetic resonance imaging studies in all the children. A negative tridimensional electroanatomic mapping was performed on five of them. Holter analysis of ventricular rate variability was performed in the frequency domain. Two main components were distinguished in a spectrum calculated on the basis of 24 h-long recordings. We studied low frequency and high frequency components. We compared the values obtained with those of a control group of 10 healthy children, admitted to our cardiology division, day-care system. Affected patients showed a reduction of average high frequency as a sign of a reduction of vagal activity and an average increase of the low frequency/high frequency ratio. The data may confirm our hypothesis of the involvement of the sympathetic nervous system in idiopathic monomorphic ventricular tachycardia in children.

Frequency of Spontaneous Ventricular Tachycardia in a Pediatric Population

Few data exist on the incidence of spontaneously occurring ventricular tachycardia (VT) in an unselected pediatric population. The aim of this study was to define the incidence and outcomes of VT in a general pediatric population. A retrospective analysis was performed of all documented episodes of VT in children referred to a single center during a 10-year study period ending in December 2005. The study center drains a stable referral area with 252,000 children aged <16 years, with no other pediatric cardiologic or pediatric intensive care services available. Twenty-seven patients with spontaneously occurring episodes of VT were observed, accounting for a VT incidence of 1.1 episodes/100,000 childhood years. Thirteen patients had VT in the absence of structural heart disease, and 14 had VT in the presence of a wide range of underlying cardiac disease. Overall mortality was 5 of 27 patients (19%), but mortality was seen exclusively in patients with underlying heart disease; for this subgroup of patients, mortality was 36%. Idiopathic VT in children with structurally normal hearts carried a good prognosis, and treatment was required in a minority (20%) of these patients. In conclusion, this study highlights that VT in childhood is rare, and outcomes are highly dependent on the underlying pathologic substrate.