Treatment Of Supraventricular Tachyarrhythmias Research Articles

Repurposing Verapamil to Enhance Killing of T-ALL Cells by the mTOR Inhibitor Everolimus.

New therapies are needed for patients with T-cell lymphoblastic leukemia (T-ALL) who do not respond to standard chemotherapy. Our previous studies showed that the mTORC1 inhibitor everolimus increases reactive oxygen species (ROS) levels, decreases the levels of NADPH and glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway (PPP), and induces apoptosis in T-ALL cells. Studies in T-ALL-xenografted NOD/SCID mice demonstrated that everolimus improved their response to the glucocorticoid (GC) dexamethasone. Here we show that verapamil, a calcium antagonist used in the treatment of supraventricular tachyarrhythmias, enhanced the effects of everolimus on ROS and cell death in T-ALL cell lines. The death-enhancing effect was synergistic and was confirmed in assays on a panel of therapy-resistant patient-derived xenografts (PDX) and primary samples from T-ALL patients. The verapamil-everolimus combination produced a dramatic reduction in the levels of G6PD and induction of p38 MAPK phosphorylation. Studies of NOD/SCID mice inoculated with refractory T-ALL PDX cells demonstrated that the addition of verapamil to everolimus plus dexamethasone significantly reduced tumor growth in vivo. Taken together, our results provide a rationale for repurposing verapamil in association with mTORC inhibitors and GC to treat refractory T-ALL.

Supraventricular tachyarrhythmias in patients with a persistent left superior vena cava.

A persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly. This venous anomaly can impact the evaluation and treatment of supraventricular tachyarrhythmia (SVA). The aim of this study was to assess the proportion and characteristics of PLSVC in adult SVA patients. From July 2002 to July 2012, clinical and procedural data from databases of 10 cardiac electrophysiology laboratories in the Yeungnam region of the Republic of Korea were reviewed. Of 6662 adult SVA patients who underwent an EP study or catheter ablation of SVA during the 10-year study period, 18 patients had PLSVC (mean age 47.6 ± 14.8 years, 10 men). The proportion of PLSVC in adult SVA patients was 0.27% (18/6662). SVA type and procedural outcomes of radiofrequency (RF) catheter ablation in these patients were investigated and the results were as follows: successful slow pathway modification in six of seven patients with atrioventricular nodal reentrant tachycardia (AVNRT), successful ablation of accessory pathway in three of four patients with atrioventricular reentrant tachycardia, and successful ablation of atrial tachycardia (cavotricuspid isthmus-dependent in two, septal macroreentry in one, focal from the PLSVC in one) in three of four patients. In one patient with junctional tachycardia, catheter ablation failed. In two patients with atrial fibrillation, catheter ablation was successful. Among adult SVA patients who underwent an EP study or RF catheter ablation during the 10-year study period, 0.27% had PLSVC. The most common type of SVA was AVNRT. The success rate of catheter ablation was 82% in SVA patients with PLSVC. There were no procedure-related complications.

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: a Review Article

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: a Review Article

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: A Review Article

Supraventricular tachyarrhythmia (SVT) is the most common tachyarrhythmia in pediatric patients and accounts for more than 90% of pediatric arrhythmias.

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: A Review Article

Supraventricular tachyarrhythmia (SVT) is the most common tachyarrhythmia in pediatric patients and accounts for more than 90% of pediatric arrhythmias. As many as 16 different mechanisms of pediatric SVT exist; we focused in this review article on the three most common groups of SVT mechanisms in pediatrics: atrioventricular re-entry tachyarrhythmia (AVRT), atrioventricular nodal re-entry tachyarrhythmia (AVNRT), and atrial tachyarrhythmia (AT).

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: A Review Article

Diagnosis and Treatment of Supraventricular Tachyarrhythmia in Pediatric Population: A Review Article

Dexmedetomidine use in patients undergoing electrophysiological study for supraventricular tachyarrhythmias.

Dexmedetomidine is a selective alpha-2 adrenergic agonist with sedative, analgesic, and anxiolytic properties. Dexmedetomidine has not been approved for use in pediatrics. Dexmedetomidine has been reported to depress sinus node and atrioventricular nodal function in pediatric patients; it has been suggested that the use of dexmedetomidine may not be desirable during electrophysiological studies. We hypothesize that the use of dexmedetomidine does not inhibit the induction of supraventricular tachyarrhythmias (SVT) during electrophysiological studies and does not inhibit the ablation of such arrhythmias. In this retrospective, observational cohort study, we reviewed all cases presenting to the cardiac catheterization laboratory for diagnosis or treatment of SVT since 2007. All cases were performed by the same electrophysiologist. The anesthesia was provided by one of the three cardiac anesthesiologists. One cardiac anesthesiologist did not use dexmedetomidine during electrophysiological studies. A second used dexmedetomidine, but only with an infusion. The third used dexmedetomidine with a primary bolus and an infusion. Thus, the patients were stratified into three different groups: Group 1 patients did not receive any dexmedetomidine. Group 2 patients received a dexmedetomidine infusion of 0.5-1 μg·kg-1 ·h-1 . Group 3 patients received a dexmedetomidine infusion of 0.5-1 μg·kg-1 ·h-1 and a dexmedetomidine bolus prior to the infusion of 0.5-1 μg·kg-1 . We then compared those patients for the following variables: demographic data including age, sex, height, weight; anesthetic data such as, mask vs intravenous induction, identity of induction agent, amount of sevoflurane and propofol used; amount of dexmedetomidine used; presence of congenital heart disease and other comorbidities; the need for isoproterenol and dose, the need for adenosine and dose, and the need for any other medications to affect rhythm both before and after radiofrequency ablation; the ability to induce the arrhythmia, the type of arrhythmia, the presence of Wolff-Parkinson-White syndrome, the presence of an accessory pathway, the ablation rate, and the recurrence rate. There was no difference in the anesthetic agents, except there was a lesser amount of propofol used in the dexmedetomidine groups (χ2(2) = 48.2, P < 0.001). There was no difference in the electrophysiological parameters among groups, except the Group 1 patients did require the use of isoproterenol in the preablation period less often compared to the dexmedetomidine groups (χ2(2) = 15.2, P < 0.01). However, with the greater use of isoproterenol, there was no difference in the ability to induce the arrhythmia. Moreover, the percentage of patients ablated, and the recurrence rate among groups was the same. We conclude that dexmedetomidine does not interfere with the conduct of electrophysiological studies for SVT and the successful ablation of such arrhythmias. However, dexmedetomidine use did result in a greater need for isoproterenol.

How 'cool' is cryoablation in the vicinity of the atrioventricular node?

This editorial refers to ‘Cryoablation of substrates adjacent to the atrioventricular node: acute and long-term safety of 1303 ablation procedures’ by P. Insulander et al ., on page 271. In this issue of the Journal , Insulander et al .1 report on the safety of cryoablation for tachycardias mediated by therapeutic targets located near the atrioventricular (AV) node, including accessory pathways, AV nodal reentrant tachycardia (AVNRT), and atrial tachycardias.1 The focus of their study was the short- and long-term risk of AV block due to injury to the normal conduction system in 1303 cryoablation procedures. The median age of the study population was 51 years. The primary diagnosis was AVNRT in 1116 (86%) patients, septal or para -hisian accessory pathways in 100 (7.5%), and focal atrial tachycradia in 87 (6.5%). Transient AV block was observed during 158 procedures, including first-, second-, and third-degree block in 74, 67, and 17 cases, respectively. In 38 patients, AV block developed during cryomapping and in 120 during cryoablation. Except for two cases of recovery after 21 and 45 min, respectively, all episodes of the AV block resolved within seconds. No late AV block was observed. This large safety study of focal cryoablation adjacent to the AV node suggests that transient AV block occurring during the procedure is a benign finding. Cryotherapy, or the use of freezing temperatures to elicit a specific tissue response, has a long history of safety and effectiveness in the treatment of arrhythmias. Radiofrequency (RF) energy is highly effective in the treatment of supraventricular tachyarrhythmias; however, it may create immediate irreversible lesions which may cause permanent AV nodal injury. When RF ablation only is available, the procedure may be interrupted and left unfinished because of the proximity of the therapeutic target to the normal conduction system. One of the major …

Novel use of the ultra-short-acting intravenous β1-selective blocker landiolol for supraventricular tachyarrhythmias in patients with congestive heart failure

The purpose of this study was to find a safe dosing regimen for landiolol, an ultra-short-acting β-adrenergic blocking agent, to rapidly control supraventricular tachyarrhythmias (SVTs) in patients with heart failure (HF). Landiolol is reported to have good effects in the treatment of SVTs after cardiac surgery. We evaluated 52 patients with SVT and symptoms of HF (NYHA class III/IV, 10/42; EF 32 ± 12 %) on admission because of ischaemic disease (n = 10), non-ischaemic cardiomyopathy (n = 32), or valvular disease (n = 10). Paroxysmal/persistent atrial fibrillation and atrial tachycardia were present in 16 (30 %), 23 (45 %), and 13 (25 %) patients, respectively. The patients first underwent conventional therapy with carperitide, dobutamine, or milrinone. Intravenous landiolol was administered at an infusion rate of 1 μg/kg/min and, if no adverse effects developed, the maintenance dose, titrated to HR and blood pressure response, was increased. At an average dose of 10.8 ± 9.4 μg/kg/min, mean HR significantly decreased significantly from 133 ± 27 to 82 ± 15 beats/min (P < 0.01), whereas systolic blood pressure did not differ from baseline to attainment of an effective dose level (105 ± 21 vs. 101 ± 19 mmHg, P = ns). Within 60 min after initiation of therapy, all patients had achieved a 20 % reduction in HR at the maintenance dose. Transient asymptomatic hypotension requiring cessation of landiolol therapy occurred in three patients. Intravenous administration of landiolol was both effective in rapidly controlling HR for up to 24 h and useful as bridging treatment to additional therapy of oral β blockade, pulmonary vein catheter ablation, or cardiac resynchronisation therapy in patients with HF.

The Acute Treatment of Maternal Supraventricular Tachycardias During Pregnancy: A Review of the Literature

ObjectiveSince evidence-based guidelines for the treatment of acute supraventricular tachyarrhythmia (SVT) in pregnancy are not available, our objective was to document published reports and immediate outcomes in this patient population. Data sourcesA search of the literature was performed using Medline, Embase, CINAHL, American College of Physicians Journal Club, Database of Abstracts of Reviews of Effects, and Cochrance Central Register of Controlled Trials, using key word searching and citations in the English language literature from January 1950 to March 2010, on the subject of SVT. Study selection/data extractionWe reviewed 38 studies (case-controlled cohort studies, case series, and case reports) using the key words “supraventricular tachycardia,” “paroxysmal tachycardia,” and “atrial tachycardia,” combined with “pregnancy” or “pregnancy complications.” ConclusionNo randomized controlled trials have addressed the acute treatment of SVT in pregnancy. If non-invasive manoeuvres fail, adenosine should be the first-line agent for treatment if needed during the second and third trimester. There is a paucity of data on management of SVT in the first trimester.

Treatment of Supraventricular Tachyarrhythmias in Patients with Acutely Decompensated Congestive Heart Failure: A Retrospective Analysis of the Effect of Amiodarone

Treatment of Supraventricular Tachyarrhythmias in Patients with Acutely Decompensated Congestive Heart Failure: A Retrospective Analysis of the Effect of Amiodarone

Transcatheter cryotherapy for the treatment of supraventricular tachyarrhythmias in children: A single center experience

Transcatheter cryotherapy is an emerging technology for the treatment of children with supraventricular tachyarrhythmias. Limited data exist regarding the use of cryoablation therapy in children. We report a single center's experience with transcatheter cryoablation in the pediatric population. A retrospective review of demographic, procedural and outcome data was performed for patients undergoing cryoablation for treatment of supraventricular tachycardia (SVT). A historical control group was taken from the 3 years preceding the introduction of cryoablation. Between August 2003 and November 2005, 83 cryoablation procedures were performed in 81 patients (age: 4 to 21 years, mean: 13.4 years) for AV nodal reentrant tachycardia (AVNRT--53), AV reentrant tachycardia (AVRT--20), ectopic atrial tachycardia (EAT--9), and junctional ectopic tachycardia (JET--1). The acute success rate for all procedures was 88% (AVNRT: 96%, AVRT: 85%, EAT: 55%, and JET: 100%). Of 72 patients that underwent successful cryoablation, nine experienced recurrence of SVT (12.5%). The control group consisted of 73 patients (AVNRT--60, AVRT--13). There were no differences in demographic data between the two groups. The overall success rate for the RFA group (96%) was identical to that for patients with AVNRT and AVRT undergoing cryoablation. The recurrence rate for RFA (10%) was less but not significantly different than that for cryoablation (12%). There were no complications in either group. Cryoablation is a safe and effective alternative for the treatment of SVT in children.

High-dosage continuous amiodarone therapy to treat new-onset supraventricular tachyarrhythmias in surgical intensive care patients: an observational study.

New-onset supraventricular tachyarrhythmias (SVTA) are a complication contributing significantly to morbidity and mortality in surgical intensive care unit (SICU) patients. Although only few data on efficiency can be found in the literature, class III antiarrhythmics have become popular in the treatment of SVTA in critically ill patients. 12-bed general and surgical ICU in a university teaching hospital. Observational, retrospective study. 131 SICU patients with SVTA (narrow-complex non-sinus tachyarrhythmias with heart rates > or = 100 bpm). High-dosage amiodarone infusion according to an institutional protocol. Hemodynamic data, acid-base status, and single organ functions were obtained in all patients before amiodarone infusion and at 12, 24, and 48 hours afterwards. Patients were divided into responders and nonresponders. Amiodarone infusion (mean dosage 24 h: 1625+/-528 mg; 48 h: 2708+/-895 mg) restored sinus rhythm in 54% of study patients within 12 h, in 64% within 24 h, and in 75% within 48 h. Heart rate, central venous pressure, and milrinone requirements significantly decreased in all patients; this was accompanied by a significant increase in stroke-volume index and mean arterial pressure. Serum concentrations of creatinine and bilirubin increased in all patients. High-dosage continuous amiodarone infusion during a period of 48 hours resulted in restoration of SR in 75% of SICU patients with new-onset SVTA and moderate to severe multiple-organ dysfunction syndrome. A significant improvement in cardiocirculatory function was more pronounced in responders but could be demonstrated irrespective of restoration of sinus rhythm in all patients. Apart from a possibly amiodarone-mediated increase in concentrations of creatinine and bilirubin, no major drug-related adverse effects occurred during the observation period.

Treatment of supraventricular tachyarrhythmias with the cryoCor cryoablation system: Worldwide results

Treatment of supraventricular tachyarrhythmias with the cryoCor cryoablation system: Worldwide results

BJCP 25th anniversary

Professor Andrew Renwick and I send the Journal our heartiest congratulations on its 25th anniversary. We had the privilege of acting as Assistant Secretary and Secretary to the Editorial Board in the years 1985–1987 and would have been happy to continue for a longer period but for the fact that I became Dean of the Faculty of Medicine in Southampton in September 1986, as well as Chairman of the Joint Formulary Committee, which oversees production of the British National Formulary. The move of the Journal to Southampton represented a major change in modus operandi for the Journal. Hitherto, Paul Turner and Alan Richens had been able to make frequent visits to the Editorial Offices in John Street close to St Bartholomew’s Hospital. However, despite some trepidations concerning the reliance on the postal system and periodic telephone calls, the transition proved to be a smooth one, thanks in large part to the efficiency of Elizabeth Whelan at Blackwell’s London office. Our time at the helm represented a phase of consolidation. The Journal comprised original manuscripts, short reports and letters and volumes 19–22 were accompanied by an average of 2 supplements each. Published articles during that time focused primarily on the pharmacodynamics of cardiovascular agents, notably β-adrenoceptor antagonists, calcium antagonists and the emergence of ACE inhibitors, as well as a variety of benzodiazepines. Developments included studies on drugs in the elderly and a series of papers from Liverpool and from Thailand/Oxford on the pharmacology and pharmacokinetics of drugs used in the treatment of malaria and other tropical diseases. Other important papers published included early studies on drug metabolism by human isolated hepatocytes, the stereo-selective metabolism of non-steroidal anti-inflammatory drugs, the recognition of the importance of α1-acid glycoprotein as a carrier of basic drugs and pivotal work on the pharmacology of adenosine when used in the treatment of supraventricular tachyarrhythmias. From volume 22, no 3 onwards (September 1986) we attempted to implement the wishes of our readers following a survey carried out by Dr Mark Chaput de Saintonge. Readers had indicated that they would like to see more methodologic and general review articles, more editorials and fewer phase 3 clinical trial reports. After a comparatively slow start, I am pleased to note that this policy is now fully implemented and I congratulate my successors on that achievement. Important papers published during the second half of our time as Editorial Secretary/Assistant Secretary related to caffeine metabolism, early studies on new anticonvulsants, especially lamotrigine, the demonstration that quinidine inhibits metabolism by CYP2D6 and the assignment of this isozyme to chromosome 22. Finally, volume 24 saw the introduction of a new technique, that of low dose phenobarbitone, as an indicator of compliance with drug therapy, plus exciting studies on dermatopharmacology and post-marketing surveillance. We are pleased to have played a minor role in the development of what has become a prestigious international journal in clinical pharmacology. We wish it continuing success under the direction of the Liverpool and Glasgow team.

Rate-dependent effects of the class III antiarrhythmic drug almokalant on refractoriness in the pig.

The electrophysiologic effects of intravenously administered almokalant, a new class III antiarrhythmic drug, in 7 isoflurane-anesthetized pigs after low and high dose were investigated. Low-dose almokalant included bolus infusion of 0.05 mumol/kg/min for 5 min followed by a continuous infusion of 0.0025 mumol/kg/min for 40 min. Thereafter, a high dose of 0.2 mumol/kg/min for 5 min and 0.01 mumol/kg/min for 40 min was given. PR, QRS, AH, and HV intervals did not change during almokalant administration. The QT interval increased dose dependently from 337 +/- 17 to 442 +/- 20 ms at high dose (p < 0.05). Atrial refractory periods (AERP) were prolonged dose dependently at a 500-ms pacing cycle length from 178 +/- 15 at baseline to 227 +/- 27 and 253 +/- 23 ms during low- and high-dose almokalant infusion, respectively. For pacing cycle lengths of 400 and 300 ms, these values were 180 +/- 11, 207 +/- 25, and 259 +/- 34 and 157 +/- 12, 193 +/- 21, and 234 +/- 28 ms, respectively. At a pacing cycle length of 500 ms, mean ventricular effective refractory period (VERP) was 270 +/- 25 ms as compared with 306 +/- 24 and 337 +/- 17 during low and high dose, respectively. A similar pattern of VERP changes during both low- and high-dose infusion was noted at the shorter pacing cycle lengths, with an increase from 240 +/- 23 to 274 +/- 22 and 279 +/- 24 ms during a 400-ms cycle length and from 210 +/- 17 to 235 +/- 19 and 234 +/- 21 ms during a 300-ms cycle length. The ratio of the VERP and ventricular monophasic action potential duration (VAPD) did not change significantly. The Wenckebach cycle length increased by 36 +/- 36 and 83 +/- 37 ms with low- and high-dose almokalant infusion, respectively. The percent increase of AERP at pacing cycle lengths of 500, 400, and 300 ms during high-dose almokalant was 42, 44, and 49%, respectively; these increases for VERP were 25, 16, and 11%, respectively. In conclusion, prolongation of refractoriness by almokalant was more pronounced at the atrial than the ventricular level. Prolongation of refractoriness was maintained at short pacing cycle lengths especially in the atrium, indicating absence of reverse-use dependence of almokalant in the porcine heart. The marked atrial effects, paralleled by atrioventricular conduction slowing, and the absence of reverse use-dependence all contribute to the feasibility of use of almokalant, in particular in the treatment of supraventricular tachyarrhythmias.

Ablation for the treatment of arrhythmias

Surgical ablation of supraventricular cardiac arrhythmias has been rendered obsolete by the various modalities of electromagnetic transcatheter ablation techniques. Any ablation technique, including surgery is essentially the controlled destruction of a substrate which is acting as a source or a critical circuit limb of an arrhythmia. The most successful and popular modality is radio frequency (RF) ablation although other modalities such as dc shock, laser, microwave, and ultrasound are also being investigated. This review discusses the role of electrical ablation, especially RF ablation, as a treatment for supraventricular tachyarrhythmia and reviews the engineering principles and biological responses to ablation. A brief synopsis of the results of electrical catheter ablation procedures is presented. RF catheter ablation is a successful technique in clinical arrhythmia management, with reported success rates of greater than 95% in many series. The indications for clinical RF catheter ablation continue to broaden.

Spatial and Temporal Inhomogeneity of Adenosine's Effect on Atrial Refractoriness in Humans:

Adenosine is an antiarrhythmic agent widely used for the diagnosis and treatment of supraventricular tachyarrhythmias. Bolus administration of adenosine has been associated with transient atrial fibrillation, but the underlying mechanisms have not yet been delineated, due in part to the technical limitations resulting from adenosine's short half-life. In this study, the rapid, repetitive activation of atrial tissue during atrial fibrillation was exploited to yield a nearly continuous estimate of atrial refractoriness, enabling a description of adenosine's action on atrial refractoriness in humans. Simultaneous right and left atrial, narrow-spaced, bipolar electrograms were recorded in 15 patients before, during, and after bolus administration of 12 mg of adenosine during atrial fibrillation. By estimating the local cycle length of excitation from the atrial activation frequency, a refractory period index (RPI) of local tissue was obtained. Adenosine dramatically increased the activation frequency from 6.4 +/- 0.7 to 12.2 +/- 12.2 Hz in the right atrium and from 6.1 +/- 0.6 to 8.7 +/- 1.2 Hz in the left atrium, corresponding to a decrease in the RPI from 156 to 82 msec (P < 0.0001) and from 163 to 116 msec (P < 0.0001), respectively. The magnitude of adenosine's effect was greater (47% vs 29% shortening) (P < 0.001) and the duration of adenosine's effect longer (28 vs 19 sec) (P < 0.05) in the right compared to the left atrium. Adenosine, at doses routinely used clinically, produces a transient, but spatially and temporally inhomogeneous, shortening of atrial refractoriness, which may explain the increased propensity toward atrial fibrillation associated with its use.

A new dosing regimen for esmolol to treat supraventricular tachyarrhythmia in Chinese patients

Objective. The purpose of this study was to find a safe dosing regimen for esmoiol infusion to rapidly control supraventricular tachyarrhymia after cardiac surgery to Chinese patients.Background. Tachycardia increase cardiac work but reduces myocardial perfusion. Thus, in the critical period immediately after cardiac surgery, tachycardia itself warrants urgent intervention. Esmolol an ultrashort-acting beta-adrenergic blocking agent, has been reported In western published reports to have good remits and few side effects In the treatment of supraventricular tachyarrhythmia. However, its clinical application in Chinese patients has not yet been reported.Methods. When supraventricular tachyarrhymia with a rapid ventricular response (>110/min) was found early after surgery esmolol infusion with a different dosing regimen was used to control the tachyarrhythmia.Results. With the dosing regimen recommended in western published reports (repeated loading infusion with stepwise increment), acute hypotension with systolic pressure <80 mm Hg occurred in all ste patients after 1 min of loading infusion of esmolol (500 μg/kg body weight per min). To avoid the aforementioned complications, a new dosing regimen was constructed. The initial infusion rate of esmolol was set at 150 or 100 μg/kg per min, depending on the patient's age and blood pressure. When the desired heart rate was achieved, the initial infusion rate was reduced to the maintenance infusion rate to maintain the therapeutic effect [Maintenance infusion rate = Initial infusion rate x (1 − e−0.077t), where t is the time period in minutes required by the initial infusion of esmolol to achieve the therapeutic effect]. With this new dosing regimen, tachycardia in most patients (9 of 11) could be controlled within 10 mm, and no one experienced the side effect of hypotension. The maintenance infusion rate of esmolol needed to control supraventricular tachyarrhythmia in our patients was only 73 ± 42 μg/kg per min (mean ± SD), much less than that noted hi western reports.Conclusions. The dosing reghnen for esmolol infusion recommended in western studies is not suitable for Chinese patients. In this report we propose a new dosing regimen for esmolol infusion that is both safe and rapid in the treatment of supraventricular tachyarrhythmia in Chinese patients.

Drugs and ablation in the treatment of supraventricular tachyarrhythmias in children.

The vast majority of children who have symptoms (ie, cardiac failure, palpitations, dizziness) due to supraventricular tachycardias are successfully managed by medical treatment. Antiarrhythmic drug therapy may be complicated by side effects or become ineffective so that radiofrequency catheter ablation, which destroys the myocardial structure responsible for arrhythmias, can now offer an attractive option to lifelong drug therapy. Immediate results for supraventricular tachycardias due to a reentry mechanism or to an atrial ectopic focus are good, with a success rate over 80% and rare immediate complications. However, the long-term sequelae of the procedure on the growing heart have not been established and the risk of subsequent atrial and ventricular arrhythmias must be considered in young patients. For this reason, I believe that today, radiofrequency ablation should be reserved for young patients who have life-threatening symptoms or who have arrhythmias that are refractory to medical treatment, and for older patients who will need a lifelong drug therapy.