Regular supraventricular tachycardia (SVT) is frequently encountered in clinical practice. Guidelines are available from the National Service Framework (NSF) for the treatment of patients attending emergency departments (ED) with SVT. These recommend a thyroid-function test (TFT) and arrhythmia electrocardiography (ECG), and referral to a heart-rhythm specialist on discharge. Hospital admission is rarely required. In our multicentre study, we examined the implementation of these guidelines among patients attending the ED with SVT. Only 34% of patients had specialist referrals, with an average wait of 50.3 days (the majority of delays resulted from referral requests from general practitioners). A history of previous SVT, the mode of tachycardia termination, patient age and/or comorbidities were similar for the 27 (23.5%) patients who were admitted overnight. Of these, 15 (13%) of the total 115 patients who attended ED with regular SVT were referred for Holter monitoring despite having ECGs demonstrating arrhythmia. Low referral rates, unnecessary investigations and admissions indicate a need for improvement for better patient care and to minimise healthcare costs. We have formulated a standard operating procedure, which will be available via the College of Emergency Medicine website.

AIMS:

The aim of this study was to report the 10-year experience of our Institution in cryoablation of supraventricular tachycardia due to a right accessory pathway (AP).

METHODS AND RESULTS:

Seventy-one cryoablations of right AP were performed between July 2002 and October 2011 in our Institution in 66 patients (mean age 12 + 3 years, 56% males). Acute procedural success rate was 97%: 80% in patients with concealed AP and 100% in those with manifest AP (P < 0.05). Acute procedural success rate was not related to institutional experience. No permanent complication occurred. Sixteen patients had recurrences during the follow-up (18.6 ± 6.6 months; range 3-111), 13 within the first month of follow-up, 2 within the 6 months of follow-up, and 1 within 12 months of follow-up. Cox regression showed that sex, patient age, number of delivered cryo-bonus, and presence of manifest or concealed AP are not independent predictors of procedural success. Among the 16 patients with recurrences, in 10 a cryoablation redo was successful and with no further AP recurrences. The mean fluoroscopy time was 28.4 min (range 19.7-44.6) with a significant decrease (P = 0.033) in relation to the increase of the institutional experience. There were no permanent ablation-related complications.

CONCLUSION:

Cryoablation of right-sided AP is effective and very safe in children. Better results are achieved in manifest AP. The learning curve has a real impact in the attempt to reduce the fluoroscopy time.

Ablation of ventricular tachycardia in patients with ischemic cardiomyopathy is more complicated and more difficult than ablation of most supraventricular tachycardias. Arrhythmogenic substrate is complex and its localisation is often unclear. Because of the tachycardia characteristics, more precise mapping methods often can't be utilised. Also, patients are usually seriously ill with decreased systolic function, heart failure, ischemia and various comorbidities where tachycardia induction and ablation procedure may facilitate abrupt hemodynamic disturbance. Uninducibility of the clinical tachycardia can be achieved in 65-95% of patients, but tachycardia recurs in 20-44% of patients. Serious complications were noted in 8% of patients with lethal outcome in 2.7% of patients. Decision about therapeutic strategy should be made individually according to potential risk and procedure benefit. This paper presents the first case of the successful ablation of ventricular tachycardia in a patient with ischemic cardiomyopathy in our country.

BACKGROUND AND PURPOSE:

Anoctamin 5 (ANO5) is a putative intracellular calcium-activated chloride channel. Recessive mutations in ANO5 cause primary skeletal muscle disorders (limb-girdle muscular dystrophy 2L and distal muscular dystrophy), which are phenotypically similar to dysferlinopathy, a muscular dystrophy due to dysferlin-encoding gene (DYSF) mutations.

METHODS:

This study reports the phenotype and genotype of seven unrelated patients with ANO5-muscular dystrophy.

RESULTS:

Three patients had amyloid deposition in muscle and two had cardiac involvement. An additional patient without skeletal muscle amyloidosis had cardiac involvement with septal hypokinesis and supraventricular tachycardia requiring ablation. Amyloid subtyping using laser capture microdissection and mass spectrometry-based proteomic analysis did not identify ANO5 or any fragment of ANO5 in the amyloid deposits, but detected other known amyloidogenic proteins. Three patients had myotonic discharges without clinical myotonia. Four ANO5 mutations are novel, including a heterozygous 0.4 Mb deletion involving the entire ANO5 gene.

CONCLUSIONS:

The results of the present study suggest that ANO5 mutations can be associated with amyloid deposition in muscle, but the nature of the amyloid deposits remains indeterminate, as does their relationship with cardiac involvement. ANO5 analysis should be considered in cases of muscle amyloid deposition of indeterminate etiology. Electrical myotonia can accompany ANO5-muscular dystrophy.

The common atrioventricular nodal re-entry tachycardia is the most common form of paroxysmal supraventricular tachycardia. It starts frequently with a supraventricular ectopic beat that, on finding the fast pathway in refractory period, travels in the slow pathway as to appear as a prolongation of the PR interval on the ECG. In this study, we show a singular case of a common atrioventricular nodal re-entry tachycardia triggered by the spontaneous interruption of an atrial tachycardia.

We sought to describe the evaluation, treatment, and follow-up of adolescents who presented to a single institution with chest pain and an elevated troponin I value in the absence of typical symptoms of pericarditis or myocarditis. Materials and methods We performed a retrospective review of patients in the age group of 10-18 years of age with no history of significant heart disease admitted to our institution from 2000 to 2010 after presenting with chest pain and an elevated troponin I value.A total of 16 patients were identified with a median age of 16.5 years (range 11.2-17.8 years). Of these 13 (81%) were male and 10 (63%) showed evidence of localised ST elevations on electrocardiogram. The median peak troponin I level was 17.8 nanograms per millilitre (range 0.89-227, normal less than 0.4). There were eight patients (50%) with a diagnosis of coronary vasospasm, three patients (20%) with atypical myopericarditis, one patient with coronary anomaly, one patient with hypercoagulable disorder, and one patient with prolonged supraventricular tachycardia. In two patients, no definitive diagnosis was made. There was one patient who needed catheter-based intervention, which involved stenting of a coronary artery after a procedure-related complication.In our cohort of adolescents without history of significant cardiac disease, chest pain and elevated troponin I levels were attributed to a variety of causes. Although coronary vasospasm and atypical myopericarditis were seen most commonly, coronary anomaly was identified in one case. Magnetic resonance imaging proved a useful diagnostic tool to assess coronary artery anatomy and myocardial changes suggestive of myocarditis. On the basis of these results and a review of the literature, a general evaluation algorithm is presented.

Propranolol and digoxin have been used as first line drugs for treatment of supraventricular tachycardia (SVT) in infants. Flecainide and other drugs have been effective as a second line treatment for controlling refractory SVT.This is a prospective study without randomization and control. The inclusion criteria were: infants (≤12 months) with tachyarrhythmia who failed to respond to first line drugs. Patients having post-surgical arrhythmias were excluded from the study.A total of 8 infants were treated with flecainide for refractory tachyarrhythmia's. Diagnosis on electrocardiogram (ECG) was atrioventricular reentry tachycardia (AVRT) in 5, atrial ectopic tachycardia (AET) in 2, a combination of AVRT and atrioventricular nodal reentry tachycardia (AVNRT) in 1. All patients had failed trial of antiarrhythmic drugs prior to presentation: digoxin and propranolol in 7, amiodarone in 3, cardioversion in 1. Flecainide (80-130 mg/m(2) orally) resulted in termination of the tachycardia in all 8 patients. Acute pharmacological termination of arrhythmia occurred with oral flecainide loading in 1 and temporarily with intravenous esmolol loading in 1 patient. Adjuvant therapy in form of propranolol was used in 5 and digoxin in 2. There were no side effects noted. Four episodes of recurrence were noted in 3 patients over 2 years, all of which responded to dose increase. Mean follow up time is 24.75 months.This small case series indicates that flecainide is an effective antiarrhythmic agent, free of side effects and when used orally is capable of terminating and controlling relatively resistant supraventricular tachycardia in children.

Abstract

Objectives:

Data regarding efficacy and safety of three-dimensional localisation systems (3D) are limited. We performed a meta-analysis of randomized trials comparing combined fluoroscopy and 3D guided to fluoroscopically-only guided procedures.

Design:

A systematic search was performed using multiple databases between 1990- 2010. Outcomes were acute and long-term success, ablation, procedure and fluoroscopic times, radiation dose (RD), and complications.

Results:

Thirteen studies involving 1292 patients were identified. 3D were tested against fluoroscopic guidance in 666 patients for supraventricular tachycardia (SVT), atrial flutter (AFL), atrial fibrillation (AF) and ventricular tachycardia (VT). Acute and long-term freedom from arrhythmia were not significantly different between 3D and control for AFL (acute success 97% vs. 93%, p=0.57; chronic success 93% vs. 96%, p=0.90) or SVT (acute success 94% vs. 100%, p=0.36; chronic success 88% vs. 88%, p=0.80). A shorter fluoroscopic time was achieved with 3D in AFL (p<0.001) and SVT (p=0.002). RD was significantly less for both AFL (p=0.002) and SVT (p=0.01). Ablation & procedure time and complications were not statistically different.

Conclusions:

Success, procedure time, and complications were similar between fluoroscopic and 3D-guided ablations. Fluoroscopic time and RD were significantly reduced for ablation of AFL and SVT with 3D.

BACKGROUND AND PURPOSE:

It is unknown whether supraventricular arrhythmias other than atrial fibrillation or flutter are associated with stroke.

METHODS:

To examine the association between paroxysmal supraventricular tachycardia (PSVT) and stroke, we performed a retrospective cohort study using administrative claims data from all emergency department encounters and hospitalizations at California's nonfederal acute care hospitals in 2009. Our cohort comprised all adult patients with ≥1 emergency department visit or hospitalization from which they were discharged alive and without a diagnosis of stroke. Our primary exposure was a diagnosis of PSVT recorded at an encounter before stroke or documented as present-on-admission at the time of stroke. To reduce confounding, we excluded patients with diagnoses of atrial fibrillation. We defined PSVT, stroke, and atrial fibrillation using International Classification of Diseases, Ninth Revision, Clinical Modification codes previously validated by detailed chart review.

RESULTS:

Of 4806830 eligible patients, 14121 (0.29%) were diagnosed with PSVT and 14402 (0.30%) experienced a stroke. The cumulative rate of stroke after PSVT diagnosis (0.94%; 95% confidence interval, 0.76%-1.16%) significantly exceeded the rate among patients without a diagnosis of PSVT (0.21%; 95% confidence interval, 0.21%-0.22%). In Cox proportional hazards analysis controlling for demographic characteristics and potential confounders, PSVT was independently associated with a higher risk of subsequent stroke (hazard ratio, 2.10; 95% confidence interval, 1.69-2.62).

CONCLUSIONS:

In a large and demographically diverse sample of patients, we found an independent association between PSVT and ischemic stroke. PSVT seems to be a novel risk factor that may account for some proportion of strokes that are currently classified as cryptogenic.