Reduction in medical care cost associated with radiofrequency catheter ablation of accessory pathways

Feasibility and safety of same-day home discharge after radiofrequency catheter ablation

Interventional cardiology in a day-case setting might reduce logistic constraints on hospital resources. However, in contrast with coronary angioplasty, few data support the feasibility and safety of radiofrequency catheter ablation (RCA). The aim of this prospective, multicenter cohort study was to evaluate the feasibility and safety of RCA in 1,342 patients (814 men; mean age 57 +/- 17 years) considered eligible for ambulatory RCA, according to specific set of criteria, for common atrial flutter (n = 632), atrioventricular nodal reentrant tachycardia (n = 436), accessory pathways (n = 202), and atrial tachycardia (n = 72). Patients suitable for early discharge (4 to 6 hours after uncomplicated RCA) were scheduled for 1-month follow-up. Predictive factors for delayed complications were studied by multivariate analysis. Of the 1,342 enrolled patients, 1,270 (94.6%) were discharged the same day and followed for 1 month; no deaths occurred, and the readmission rate was 0.79% (95% confidence interval 0.30% to 1.27%). Six patients had significant puncture complications, 2 presented with symptomatic delayed pulmonary embolism, and 2 had new onset of poorly tolerated atrial flutter. None of these complications was life threatening. Multivariate analysis did not identify any significant independent predictors for delayed complications. In conclusion, these data suggest that same-day discharge after uncomplicated RCA for routine supraventricular arrhythmias is safe and may be applicable in clinical practice. This approach is known to be associated with significant patient satisfaction and cost savings and can be considered a first-line option in most patients who undergo routine ablation procedures.

Assessing the direct costs of treating nonvalvular atrial fibrillation in the United States

OBJECTIVE

To determine the health-care resource use and costs attributable to treating atrial fibrillation (AF) in the United States.

METHODS

Retrospective analyses of three federally funded US databases (2001 data): 1) hospital inpatient stays (the Healthcare Cost and Utilization Project [HCUP]); 2) physician office visits (the National Ambulatory Medical Care Survey [NAMCS]); and 3) emergency department (ED) and hospital outpatient department visits (OPD) (the National Hospital Ambulatory Medical Care Survey [NHAMCS]). Identification of AF medical encounters was based on occurrence of AF-specific International Classification of Diseases (9th Edition)--Clinical Modification (ICD-9-CM) diagnosis code 427.31 (principal discharge diagnosis for inpatient setting; any diagnosis field for other settings). For the 10 most common principal discharge diagnoses in the inpatient setting, case-control comparison analyses were performed to estimate annual incremental costs of AF as a comorbid discharge diagnosis for hospital stays. Regression models were used to assess the impact of AF on hospitalization costs. Costs were estimated in year 2005 US dollars.

RESULTS

Approximately 350,000 hospitalizations, 5.0 million office visits, 276,000 ED visits, and 234,000 OPD were attributable to AF annually within the United States. Total annual costs for treatment of AF were estimated at $6.65 billion, including $2.93 billion (44%) for hospitalizations with a principal discharge diagnosis of AF, $1.95 billion (29%) for the incremental inpatient cost of AF as a comorbid diagnosis, $1.53 billion (23%) for outpatient treatment of AF, and $235 million (4%) for prescription drugs. In all regressions, AF was a significant contributor to hospital cost.

CONCLUSIONS

Treatment of AF represents a significant health-care burden with the costs of treating AF in the inpatient setting outweighing the costs of treating AF in the office, emergency room or hospital outpatient settings. Further research is needed to fully capture the costs of treating AF.

Radiofrequency catheter ablation of supraventricular tachycardia in children and adolescents : feasibility and cost-effectiveness in a low-income country

The objective of this study is to provide results and costs of catheter ablation in children and adolescents in a low-income country. Reports from first-world countries have demonstrated the cost-effectiveness of radiofrequency catheter ablation (RFCA) compared to medical treatment of supraventricular tachycardia (SVT). The study included 28 patients younger than 18 years of age with SVT in a pediatric cardiology unit in Guatemala. All patients underwent RFCA. Clinical outcome and cost-effectiveness of RFCA compared to continued medical treatment were the end points. Twenty-four patients had successful ablation (85.7%). Mean age at RFCA was 11.42 +/- 3.49 years. Three patients underwent a second ablation, increasing the success rate to 96.4%. One remaining patient is awaiting a second procedure. At a mean follow-up of 13.69 +/- 7.16 months, all 27 patients who had a successful ablation remained in sinus rhythm. Mean cost per procedure was 4.9 times higher than that of medical treatment. However, the estimated cost of catheter ablation equal that of medical therapy after 5.1 years and is 3.4 times less after 20 years. Radiofrequency catheter ablation of SVT in children and adolescents is safe and cost-effective compared to medical therapy. Resources must be judiciously allocated, especially in low-income countries, to treat the largest number of pediatric patients.

Interventional catheterization for tachyarrhythmias

Catheter ablation of cardiac tachyarrhythmias is unique among our therapeutic armamentarium because it offers the ability to cure certain tachyarrhythmias permanently without implanted devices. TICM that is not distinguishable from idiopathic DCM can also resolve once the underlying tachyarrhythmia is eliminated. Current techniques are best suited to tachyarrhythmias in which a point lesion or small linear burn would result in disruption of the tachyarrhythmia's substrate. The equipment and expertise required limit the availability of this treatment modality in veterinary medicine. Its success with SVTs (particularly those secondary to accessory pathways), however, make it a viable option for many owners, even if they must travel some distance to reach a center performing these procedures.

Catheter ablation for cardiac arrhythmias

The safety and efficacy of catheter ablation for treatment of most types of cardiac arrhythmias are well established. These arrhythmias and arrhythmia substrates include AVNRT, accessory pathways, focal atrial tachycardia, atrial flutter, idiopathic ventricular tachycardia, and bundle-branch re-entry. Catheter ablation is considered as an alternative to pharmacologic therapy in the treatment of these cardiac arrhythmias.

Wolff-Parkinson-White Syndrome

In patients with the Wolff-Parkinson-White syndrome, atrial fibrillation can be lethal. Longitudinal natural history studies suggest that these patients have a lifetime risk of sudden death of about 4%. Although this risk is relatively low, the combination of this risk and the morbidity associated with recurrent cardiac arrhythmias has justified the widespread use of catheter ablation therapy to eliminate accessory pathway conduction. The efficacy of catheter ablation therapy is about 90% to 95%, and the procedure is associated with a low morbidity rate. Pharmacologic therapy is reserved for those rare patients who do not respond to catheter ablation or do not wish to undergo an invasive procedure. Although surgical therapy has been used to eliminate the Wolff-Parkinson-White syndrome definitively, patients now rarely undergo surgical ablation. The most important steps in the management of a patient with the Wolff-Parkinson-White syndrome are the recognition of the condition and subsequent referral of the patient to an electrophysiologist for curative catheter ablation.

Radiofrequency catheter ablation versus medical therapy for initial treatment of supraventricular tachycardia and its impact on quality of life and healthcare costs

We prospectively compared the impact on quality of life and cost effectiveness between ablation and medication as an initial strategy for patients with paroxysmal supraventricular tachycardia (SVT). Seventy-nine consecutive patients with newly documented paroxysmal SVT were treated with either ablation or medication. Health surveys (SF-36 and disease-specific questions) were obtained at baseline and after 12 months of follow up. Cost of health care utilization for the 6 months before and after treatment were measured. Both medication and ablation improved quality of life. However, ablation improved quality of life in more general health categories than medication. At follow up, ablation was associated with significantly improved quality of life in the bodily pain (63+/-24 vs 81+/-20, p <0.005), general health (69+/-21 vs 79+/-21, p <0.05), vitality (55+/-21 vs 66+/-22, p <0.05), and role emotion (78+/-36 vs 94+/-17, p <0.05) categories when compared with medication. Although both medication and ablation decreased frequency of disease-specific symptoms, ablation resulted in complete amelioration of symptoms in more patients (33% vs 74%). Potential long-term costs were similar for medication and ablation. In conclusion, ablation improves health-related quality of life to a greater extent, and in more aspects of general and disease-specific health than medication.

Paroxysmal supraventricular tachycardia in the general population

OBJECTIVES

We sought to determine the epidemiology and clinical significance of paroxysmal supraventricular tachycardia (PSVT) in the general population.

BACKGROUND

Current knowledge of PSVT has been derived primarily from otherwise healthy patients referred to specialized centers.

METHODS

We used the resources of the Marshfield Epidemiologic Study Area, a region covering practically all medical care received by its 50,000 residents. A review of 1,763 records identified prevalent cases as of July 1, 1991 and all new cases of PSVT diagnosed from that day until June 30, 1993. A mean follow-up period of 2 years was completed in all incident patients. Patients without other cardiovascular disease were labeled as having "lone PSVT."

RESULTS

The prevalence was 2.25/1,000 persons and the incidence was 35/100,000 person-years (95% confidence interval, 23 to 47/100,000). Other cardiovascular disease was present in 90% of males and 48% of females (p = 0.0495). Compared with patients with other cardiovascular disease, those with lone PSVT were younger (mean 37 vs. 69 years, p = 0.0002), had a faster PSVT heart rate (mean 186 vs. 155 beats/min, p = 0.0006) and were more likely to have their condition first documented in the emergency room (69% vs. 30%, p = 0.0377). The onset of symptoms occurred during the childbearing years in 58% of females with lone PSVT versus 9% of females with other cardiovascular disease (p = 0.0272).

CONCLUSIONS

There are approximately 89,000 new cases/year and 570,000 persons with PSVT in the United States. In the general population, there are two distinct subsets of patients with PSVT: those with other cardiovascular disease and those with lone PSVT. Our data suggest etiologic heterogeneity in the pathogenesis of PSVT and the need for more population-based research on this common condition.

Catheter ablation of accessory pathways

Radiofrequency catheter ablation is a highly effective, curative treatment for arrhythmias related to accessory atrioventricular connections. Compared with medical therapy, ablation is more definitive, is more cost-effective, and is associated with a lower risk of proarrhythmia. This article updates the reader on the current indications, techniques, and innovations related to ablation of accessory pathways using radiofrequency energy.

Intraventricular electrogram mapping and radiofrequency cardiac ablation for ventricular tachycardia

Since its first use in the early 1980s, radiofrequency catheter ablation has gained acceptance as primary therapy for many cardiac rhythm disorders. This article reviews fundamentals of cardiac mapping and radiofrequency ablation and their clinical use for treatment of ventricular tachycardia. The review concludes that the use of radiofrequency ablation to cure ventricular tachycardia has consistently increased over the years, as better mapping and ablation tools have been made available to the medical community. Presently, high success and low complication rates are achieved only in patients with bundle branch, idiopathic, or monomorphic and stable ventricular tachycardias. The reviewed studies and reports suggest that, in order to increase the success rates in patients with ventricular tachycardias caused by coronary artery disease, mapping systems that can identify arrhythmogenic pathways more accurately and more efficiently and ablation devices capable of generating larger lesions are needed.

Cost effectiveness of day stay versus inpatient radiofrequency (RF) ablation for the treatment of supraventricular tachyarrhythmias

BACKGROUND

It is well established that radiofrequency (RF) ablation is the most cost effective treatment strategy for patients with supraventricular tachycardia. Previous cost estimates assumed at least an overnight stay following RF ablation. Day stay RF ablation however appears to be a safe alternative.

AIMS

The aim of this study was to compare day stay and inpatient catheter ablation in terms of cost, efficacy and safety.

METHODS

This was a retrospective cost effectiveness analysis. The study population consisted of 25 consecutive patients who underwent day stay RF ablation and 25 consecutive patients who underwent inpatient RF ablation (historical controls). Economic analysis was based upon a detailed clinical costing.

RESULTS

The mean overall cost per patient of inpatient RF ablation in 1994 Australian dollar values is $2354 (SD, $642) compared with $1876 (SD, $595) for day stay RF ablation (p < 0.01). Day stay RF ablation is a cost effective alternative to inpatient RF ablation.

The clinical-economic trial: promise, problems, and challenges

The clinical-economic trial is a study design that is appearing with greater frequency in medical and public health literature. Some experienced investigators view these trials with skepticism; to policy makers they represent a promising step in the control of rising health care costs. The success of clinical-economic trials in meeting the important goal of more rational and efficient use of health care resources will depend on the strengths and limitations of the research method. As part of a report to the Office of Technology Assessment of the U.S. Congress on new health care assessment techniques, we describe the reasons why economic data collection and analysis are being considered in clinical trials, identify and discuss various designs and methods for gathering economic trial data, and evaluate the strengths and limitations of different methods for providing sound data for decision making on appropriate use of health care interventions. Because of the potential significance and increasing visibility of such research, experts in research methods should give more attention to methodological research for clinical-economic trials. Future efforts should be directed at comparing different techniques for collecting data, examining the incremental value of precision in economic measurements and ensuring appropriate interpretation of data from clinical-economic trials.

Catheter ablation for the treatment of paroxysmal supraventricular tachycardia

Radiofrequency catheter ablation has evolved into a front-line curative therapy for patients who have paroxysmal supraventricular tachycardia secondary to Wolff-Parkinson-White syndrome. AV nodal reentrant tachycardia, and atrial tachycardia. In patients with accessory pathways, cure rates exceed 90% in almost all anatomic locations. Equally high success rates are noted in patients with atriofascicular pathways and the permanent form of junctional reciprocating tachycardia. Complications secondary to catheter ablation of accessory pathways occur in 1% to 3% of patients and include cardiac perforation, tamponade, AV block, and stroke. In patients with AV modal reentrant tachycardia, selective slow pathway ablation is curative in over 95% of patients with a very low risk of AV block. Atrial tachycardias originating in both the left and right atria can be successfully ablated in over 80% of patients. Given the overall effectiveness of this procedure, radiofrequency catheter ablation should be considered as front-line therapy in patients with recurrent or drug-refractory paroxysmal supraventricular tachycardia. Although an effective therapy, the risks and benefits of this procedure need to be assessed in all patients who are candidates for this procedure.

Supraventricular tachyarrhythmias. Pharmacologic versus nonpharmacologic approaches

Nonpharmacologic approaches to the long-term management of SVTs have evolved rapidly and now offer to patients a safe, effective alternative for symptomatic relief from many SVTs. By far, radiofrequency catheter ablation, a technology less than 10 years old, offers the least invasive and most cost-effective nonpharmacologic alternative for many SVTs. Knowledge gained through electrophysiologic and ablation studies has enlarged the understanding of SVTs and may enable electrophysiologists to approach the more common and morbid condition of atrial fibrillation. From a societal standpoint, catheter ablation can remain a cost-effective mode of treatment if patient selection is stringent. The next 10 years should see further refinement in technique and in understanding of SVTs, improved technology, and enlarging applications of radiofrequency energy to cure or modify cardiac arrhythmias.

The effects of radiofrequency ablation versus medical therapy on the quality-of-life and exercise capacity in patients with accessory pathway-mediated supraventricular tachycardia: a treatment comparison study

This study aims to evaluate the impact of transcatheter radiofrequency ablation on quality-of-life (QOL) and exercise capacity in patients with paroxysmal supraventricular tachycardia (SVT) on stable medical therapy and the extent of symptomatic benefits of this treatment in patients with SVT of different clinical severity. A total of 55 patients with SVT on stable medications for 3 months were randomly selected for either radiofrequency ablation treatment (46 patients) or continuation of medical therapy (medical control group, 9 patients). Severity of SVT was classified based on the frequency and duration of SVT episodes, hemodynamic disturbance, and the presence of preexcited atrial fibrillation during an episode. Treadmill exercise capacity (Bruce protocol) and QOL (questionnaire study and interview) were assessed before and at 3-month intervals for 1 year after the radiofrequency procedure and at 3 months in the medical control group. Thirty-six of 46 patients were successfully ablated in one session, and a QOL measure before and at 3 months after ablation in these patients showed an improvement in total scores for "General Health Questionnaire" (20.3 +/- 6.2 vs 16.9 +/- 5.3, P < 0.01), "Somatic Symptoms Inventory" (73.0 +/- 6.0 vs 76.1 +/- 4.1, P < 0.02), and "Sickness Impact Profile" (12.6 +/- 1.7 vs 4.9 +/- 3.9, P < 0.01). This improvement in QOL was progressive and sustained over a 1-year period. Major arrhythmia limitations, such as apprehension of strenuous activities and long distance travel, were alleviated after a successful procedure. The extent of improvement in QOL was significant for patients considered to have "mild" or "severe" arrhythmia.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety of radiofrequency catheter ablation of accessory atrioventricular pathways

The acute anatomic and valvular consequences of radiofrequency catheter ablation of accessory pathways were evaluated in 62 patients by means of serial echocardiographic examinations. Semiquantitative assessment of valvular incompetence and classification into one of four grades according to the width and the extension of the jet from the valvular orifice were carried out. Segmental wall motion abnormalities were evaluated semiquantitatively with four grades of severity (normal, hypokinesia, akinesia, or dyskinesia). New echocardiographic abnormalities were observed in five patients. One thrombus on the ventricular aspect of the mitral valve, three hemodynamically insignificant pericardial effusions, and one increase in severity of tricuspid incompetence were found 1 day after radiofrequency catheter ablation. We conclude that echocardiographic changes after radiofrequency ablation of accessory pathways are rare and of minor significance. These findings confirm the safety of the procedure.

Radiofrequency catheter ablation of both atrial ventricular nodal reentrant and atrial ventricular reentrant tachycardia in a single session

Radiofrequency catheter ablation is a new therapeutic approach to treat patients with symptomatic drug-resistant paroxysmal supraventricular tachycardia. Ablation of two accessory atrioventricular pathways in a single session has been frequently described previously. However, ablation in a single session of both the fast pathway, involved in atrial ventricular nodal reentrant tachycardia, and a concealed atrioventricular accessory pathway involved in a circus movement tachycardia has rarely been reported. A 57-year-old man with a grade III aortic incompetence had the infrequent association of atrial ventricular nodal reentrant tachycardia and orthodromic circus movement tachycardia due to a concealed accessory pathway. He presented with drug-resistant reentrant supraventricular tachycardia and, in a single session, underwent a successful radiofrequency catheter ablation of the fast atrial ventricular nodal pathway and a concealed posteroseptal accessory pathway. During a 10-month follow-up he was free of palpitations without any antiarrhythmic therapy and underwent elective aortic valve replacement.

Follow-up of radiofrequency catheter ablation in children: results in 100 consecutive patients

OBJECTIVES

The purpose of this study was to determine the outcome of a group of closely followed-up pediatric patients who had undergone radiofrequency ablation for cardiac arrhythmias.

BACKGROUND

Although radiofrequency ablation in children has been shown to be effective and safe in the short term, results of longer term follow-up of these children must be considered when determining the place of radiofrequency ablation in the management of pediatric arrhythmias.

METHODS

One hundred children aged 2 months to 17 years underwent a total of 119 radiofrequency ablation procedures for cure of tachycardia. Follow-up clinical data, electrocardiograms and 24-h Holter monitors were obtained and analyzed.

RESULTS

All patients were alive, and none were lost to follow-up after a mean follow-up of 21.5 months (range 6 to 50). Success at last follow-up included accessory pathways in 66 (89%) of 74 patients, atrioventricular (AV) node reentry in 15 (88%) of 17, intraatrial reentry in 2 (67%) of 3, atrial flutter in 3 (100%) of 3, atrial ectopic tachycardia in 2 (67%) of 3, junctional ectopic tachycardia in 1 (100%) of 1 and ventricular tachycardia in 2 (100%) of 2 (overall success, 90 [90%] of 100). All recurrences were observed within 6 months of ablation. Major and minor complications (7%) included chest burn (one patient), foot microembolus (two patients), hematoma without pulse loss (four patients), femoral arteriovenous fistula requiring repair (one patient) and transient Mobitz I AV block (one patient). Immediate success, recurrence and complication rates were similar in the > or = 12-year old versus the < 12-year old group. Echocardiograms, available in 109 (92%) of 119 patients, showed possible procedure-related abnormalities in 2 (mitral regurgitation in 1, tricuspid regurgitation in 1, both mild), with no aortic insufficiency after 30 left-sided ablations performed by the retrograde approach. Follow-up Holter monitors, available in 77 (77%) of 100 patients, showed possible procedure-related abnormalities in 5 (frequent atrial ectopic tachycardia in 2, atrial flutter in 1, accelerated ventricular rhythm in 2). There were no early or late deaths.

CONCLUSIONS

In children, the risks of radiofrequency ablation are low at follow-up evaluation. Longer-term follow-up of children undergoing radiofrequency ablation will be necessary to determine whether coronary abnormalities or serious new arrhythmias will develop.

Potential ablation of accessory atrioventricular pathways: injection of alcohol into the atrioventricular groove

Accessory atrioventricular (AV) pathways responsible for the Wolff-Parkinson-White syndrome have been treated successfully by surgical and radiofrequency catheter ablation techniques. In this study, we explored the feasibility of permanent chemical ablation of accessory pathways by direct injection of 100% ethanol into the canine AV groove. Right coronary artery blood flow and AV compartment pressure were measured in 5 adult mongrel dogs (part I) during injection of saline solution (10 to 15 mL) into the right AV groove. Atrioventricular groove compartment pressure increased from 1 +/- 1 to 31 +/- 12 mm Hg (p < 0.0001) and right coronary artery blood flow increased slightly from 117 +/- 17 to 138 +/- 44 mL/min (p = not significant). In 8 additional dogs (part II), 100% ethanol (10 mL) was injected into the left AV groove. After 6 weeks (n = 6) or 12 weeks (n = 2), histologic examination of the left AV groove demonstrated localized fibrous replacement of injured epicardial muscle, with only scant inflammatory infiltrate. Mild intimal fibrosis and intimal proliferation were present in the circumflex artery and its larger branches, but no significant luminal narrowing was evident. Angiograms at 12 weeks (n = 2) demonstrated no significant narrowing of the circumflex artery. In summary, injection of 100% ethanol into the AV groove is capable of locally ablating myocardial tissue, presumably including conductive tissues, while sparing the coronary arteries.

Curative Therapy for Supraventricular Arrhythmia with Radiofrequency Catheter Ablation—Comparison with Surgical Therapy

Radiofrequency catheter ablation is a newly introduced technique that does not require open heart surgery and is designed for curing patients with arrhythmia. We present our experience with this technique in 223 patients, with recurrent supraventricular tachycardia due to accessory pathways associated with the Wolff-Parkinson-White syndrome or AV nodal reentrant tachycardia. Of the patients, 119 underwent radiofrequency ablation of accessory pathways, while 101 underwent AV nodal modification. Two patients underwent both AV nodal modification and accessory pathway ablation during the same session. One patient had AV nodal ablation. Mean age was 39.4 ± 14.1 years (13–73 years). There were 108 males and 115 females. Except for 1 patient, all had significant symptoms. Radiofrequency ablation performed during the first session was successful in 215 patients (96.4%). With repeat ablation, 218 (97.8%) of the patients were successfully ablated. When compared with surgery, the efficacy is similar; however, radiofrequency ablation is less costly and results in less morbidity. Radiofrequency catheter ablation is highly efficacious and is the treatment of choice in patients who are at risk for sudden death or have failed drug therapy. It should also be offered as an alternative to lifelong drug therapy.

Physics and engineering of transcatheter cardiac tissue ablation

Ablation of arrhythmogenic cardiac tissues has emerged as one of the most important advances in cardiac electrophysiology. With the introduction of transcatheter ablation, the treatment of ventricular tachycardia, Wolff-Parkinson-White syndrome and other cardiac arrhythmias has progressed from an expensive and painful surgical therapy accompanied by a long recovery period to the less expensive, less traumatic transcatheter approach. The feasibility of cardiac ablation, along with the increasing number of physicians using the technique, requires understanding of the anatomic and electrophysiologic bases of transcatheter ablation as well as the different technologies, their limitations and complications. This report provides an overview of the physical, scientific and technical aspects of cardiac ablation performed with the methods currently available and a summary of the limitations of each method and expected future technologic developments in this growing field. Emphasis is placed on radiofrequency and direct current energies, the primary methods now used. Methods such as cryoablation and laser, and microwave and chemical ablation are discussed with less detail because the method of delivering energy for these ablative procedures has not been fully developed.

Current management of the Wolff-Parkinson-White syndrome

In this review, we discuss the pathophysiology of the Wolff-Parkinson-White (WPW) syndrome and describe medical, surgical, and catheter based principles. WPW syndrome results from the congenital presence of impulse-conducting fascicles, known as accessory pathways (APs) or bypass tracts, which connect atria and ventricles across the annulus fibrosis and are capable of preexciting portions of the ventricular myocardium. Once triggered, atrioventricular reciprocating tachycardias (AVRTs) generally result from depolarization wavefronts moving anterograde through the AV node to the ventricles and returning retrograde to the atria along the AP. Rapid AVRT decreases ventricular filling time and cardiac output, resulting in symptoms. Medications that prolong AP refractory periods (flecainide, propafenone, and amiodarone) prevent rapid AP anterograde conduction (from atria to ventricles) in atrial tachycardias such as atrial fibrillation or flutter. In emergencies, adenosine can be used to terminate the AVRT of WPW syndrome. Otherwise, Class IA or IC antiarrhythmic agents are used to slow AP conduction either with or without AV nodal blocking agents. Open chest surgical ablation of a bypass tract in a symptomatic patient was first reported in 1968. The original endocardial surgical techniques for localizing and dividing APs were refined and an alternative epicardial approach has been developed. Reported mortality rates in experienced hands were 0% to 1.5% in large series for patients without additional cardiac abnormalities. Catheter delivered radiofrequency (RF) energy is now applied intravascularly to ablate APs. Since the first large series of patients undergoing RF ablation was reported in 1989, the procedure had proved safe, cost effective, and well tolerated. RF ablation has become the initial nonpharmacological treatment of choice for WPW syndrome; surgical ablation has become relegated to those cases where symptoms are intolerable and RF ablation is not feasible.

Radiofrequency current catheter ablation for control of supraventricular arrhythmias

With the advent of radiofrequency energy, catheter ablation techniques have become an accepted form of treatment for a variety of supraventricular arrhythmias. The ablation of the atrioventricular (AV) node was performed first and is now widely used in patients with refractory atrial fibrillation or flutter. Ablation has also replaced surgery in patients with preexcitation syndromes, and as the complication rate in experienced centers is low, it has become the first line of treatment in these institutions. The results of catheter ablation in AV nodal reentrant tachycardia are excellent as well, although there is still debate about whether "slow" pathway ablation is superior to "fast" pathway ablation. Radiofrequency current ablation has also contributed to a better understanding of the pathophysiology of AV nodal reentrant tachycardia, as it has provided evidence for atrial participation in the reentrant circuit. Experience with atrial tachycardias and tachycardias due to Mahaim fibers remains limited. The ideal source of energy for specific arrhythmias is still unknown and improvement in catheter technology is needed.

Safety, feasibility and cost of outpatient radiofrequency catheter ablation of accessory atrioventricular connections

OBJECTIVES

The purpose of this study was to evaluate prospectively the safety, feasibility and cost of performing radiofrequency catheter ablation of accessory atrioventricular (AV) connections on an outpatient basis in 137 cases.

BACKGROUND

The efficacy and low complication rate of radiofrequency ablation as performed in the hospital suggested that it might be feasible to perform it on an outpatient basis.

METHODS

In 100 cases (73%) performed between September 1, 1991 and April 20, 1992, patients met criteria for treatment as outpatients. Reasons for exclusion were age < 13 or > 70 years (4), anteroseptal location of the accessory AV connection (5 patients), obesity (> 30% of ideal body weight) (4 patients) or clinical indication for hospitalization (24 patients). Patients with only venous punctures had a recovery period of 3 h and those with arterial punctures had a recovery period of 6 h. There were 63 men and 32 women (5 patients underwent two ablation procedures > 1 month apart), with a mean age +/- SD of 36 +/- 13 years. The pathway was left-sided in 67 cases and right-sided or posteroseptal in 33.

RESULTS

The procedure was successful in 97 of 100 cases, with a mean procedure duration of 99 +/- 42 min. In 70 cases the patient was discharged the day of ablation, and in 30 cases the patient required a short (< or = 18-h) overnight stay because the procedure was completed too late in the day for recovery in the outpatient facility. The mean duration of observation was 4.8 +/- 1.5 h for outpatients and 15 +/- 1.4 h for patients who underwent overnight hospitalization. At follow-up study, two patients had a clinically significant complication; both had a femoral artery pseudoaneurysm detected > or = 1 week after the procedure and both required surgical repair. Thirty consecutive patients (22 outpatients and 8 hospitalized overnight) undergoing catheter ablation after January 1, 1992 were chosen for a cost analysis. The mean cost of the procedure was $10,183 +/- $1,082.

CONCLUSIONS

The majority of patients undergoing radiofrequency catheter ablation of an accessory AV connection can be treated safely on an outpatient basis.

Treatment of supraventricular tachycardias with transcatheter delivery of radiofrequency current

Medical therapy for the treatment of supraventricular tachycardias is frequently ineffective and associated with significant side effects, whereas curative surgical approaches have generally been limited by their considerable morbidity and cost. Greater understanding of the mechanisms underlying supraventricular tachycardias has improved our ability to precisely map endocardial areas critical to arrhythmogenesis. Advances in catheter ablation techniques and particularly the use of radiofrequency current to generate thermal energy for ablation have resulted in dramatic success rates for curative catheter ablation. This review examines the physics of radiofrequency current ablation and its application to the treatment of atrial fibrillation, atrial flutter, AV nodal reentrant tachycardia, and arrhythmias associated with the Wolff-Parkinson-White syndrome. The limitations, risks, and cost-effectiveness of this technique relative to medical and surgical approaches are also evaluated.