Therapy For Supraventricular Tachyarrhythmias Research Articles

Rationale and design of the NO-PARTY trial: near-zero fluoroscopic exposure during catheter ablation of supraventricular arrhythmias in young patients

Radiofrequency catheter ablation is the mainstay of therapy for supraventricular tachyarrhythmias. Conventional radiofrequency catheter ablation requires the use of fluoroscopy, thus exposing patients to ionising radiation. The feasibility and safety of non-fluoroscopic radiofrequency catheter ablation has been recently reported in a wide range of supraventricular tachyarrhythmias using the EnSite NavX™ mapping system. The NO-PARTY is a multi-centre, randomised controlled trial designed to test the hypothesis that catheter ablation of supraventricular tachyarrhythmias guided by the EnSite NavX™ mapping system results in a clinically significant reduction in exposure to ionising radiation compared with conventional catheter ablation. The study will randomise 210 patients undergoing catheter ablation of supraventricular tachyarrhythmias to either a conventional ablation technique or one guided by the EnSite NavX™ mapping system. The primary end-point is the reduction of the radiation dose to the patient. Secondary end-points include procedural success, reduction of the radiation dose to the operator, and a cost-effectiveness analysis. In a subgroup of patients, we will also evaluate the radiobiological effectiveness of dose reduction by assessing acute chromosomal DNA damage in peripheral blood lymphocytes. NO-PARTY will determine whether radiofrequency catheter ablation of supraventricular tachyarrhythmias guided by the EnSite NavX™ mapping system is a suitable and cost-effective approach to achieve a clinically significant reduction in ionising radiation exposure for both patient and operator.

An approach to therapy of supraventricular tachyarrhythmias: an algorithm versus individualized therapy.

Approaches to the treatment of supraventricular arrhythmias, including atrial fibrillation, atrial flutter, atrial tachycardia, atrioventricular (AV) reentrant tachycardia, and AV nodal reentrant tachycardia, continue to evolve. Within the past two decades, many new and effective treatments have become available. These include several new antiarrhythmic agents, ablative therapies, pacing and surgical modalities, and cardioversion/defibrillation techniques. This paper provides an algorithm for the treatment of these supraventricular arrhythmias which includes therapy for the acute episode as well as the prevention of subsequent episodes of the tachyarrhythmia.

Management of Frequent or Refractory Supraventricular Tachyarrhythmias

The delivery of inappropriate therapy for supraventricular tachyarrhythmias (SVT), with rapid ventricular rates remains a vexing problem for patients with implantable cardioverter de~brillators (ICDs). Studies in the early 1990’s reported that the incidence of inappropriate therapy occurred in 20–40% of all patients [1–3]. Along with signi~cant discomfort from shocks and additional hospitalizations, inappropriate therapy has been shown to induce ventricular arrhythmias in up to 5% of patients [1,2,4]. Strategies to minimize this important complication may involve both better classi~cation of arrhythmias by the device and therapies to prevent supraventricular rhythms with rapid rates.

Flecainide therapy in patients treated for supraventricular tachycardia with near normal left ventricular function

Concerns about the safety and efficacy of class IC antiarrhythmic agents have arisen as a result of the recent CAST data. We reviewed records of 175 consecutive patients treated with flecainide between July 1, 1988 and July 5, 1989. One hundred ten patients with normal or mildly impaired left ventricular function and symptomatic supraventricular arrhythmias were identified. Follow-up data were obtained on 102 patients for a mean of 14 months. The average duration of flecainide therapy was 13 months. Tachyarrhythmias treated included atrial fibrillation/flutter, atrioventricular reentry, and atrioventricular nodal reentry. Flecainide provided effective antiarrhythmic therapy in 62% of the patients and was discontinued in 38% of the patients. Left atrial size did not predict treatment failure. Two patients developed proarrhythmic events (nonsustained ventricular tachycardia). There were no deaths during the follow-up period. In conclusion, flecainide provides safe and effective therapy for supraventricular tachyarrhythmias in patients with normal or mildly impaired left ventricular function.

What Determines the Choice of Treatment in Patients with Supraventricular Tachycardia?

I have outlined the approach to therapy of supraventricular tachyarrhythmias practiced by a cardiologist who is not performing special studies in the cardiac electrophysiology laboratory. This review includes the list of common and rare supraventricular arrhythmias, application of diagnostic noninvasive procedures, indications for referral for special electrophysiologic studies, and brief description of drugs and procedures used in the therapy of supraventricular tachyarrhythmias. In addition to general guidelines for treatment of these arrhythmias, I have outlined specific recommendations for patients with acute myocardial infarction, angina pectoris, ventricular dysfunction and congestive heart failure, obstructive cardiomyopathy, hyperthyroidism, AV accessory pathways, chronic obstructive lung disease, diabetes mellitus, hypertension, concomitant ventricular arrhythmias, tachycardia-bradycardia syndrome, and anxiety.

Summary of efficacy and safety of flecainide for supraventricular arrhythmias

This report provides an overview of the safety and efficacy of flecainide for supraventricular tachyarrhythmias (SVT) based on a review of the world literature. This review provided 107 entries, but 5 were review articles and 22 were articles not tranlated into English. The remaining 80 articles or published abstracts form the basis for this report. A total of 1,371 courses of therapy with intravenous or oral flecainide, or both, were represented. Efficacy was defined by each investigator. Intravenous flecainide was successful in terminating ongoing tachycardias in 81% of reported cases of atrioventricular (AV) nodal reentrant tachycardias, 88% of AV reentrant tachycardias and 100% of atrial tachycardias. Atrial fibrillation or flutter was terminated by intravenous flecainide in 62% of cases and arrhythmias associated with Wolff-Parkinson-White syndrome in 73%. Oral flecainide was successful in longer-term management of arrhythmia in 74 and 81% of patients with AV nodal and AV reentrant tachycardia, respectively, and in 83% with atrial tachycardia. Atrial flutter or fibrillation responded to oral drug in 61% of cases and arrhythmias related to Wolff-Parkinson-White syndrome in 61%. Adverse experiences were reported in studies totaling 695 patients (designated “at-risk patients”). They were not commented on in studies with the remaining 594 patients. Overall, a total of 6.9% of at-risk patients (3.7% of total patients) reported cardiac adverse experiences; 19% of at-risk patients (10% of total patients) reported at least 1 noncardiac adverse effect. Cardiac adverse events included worsened arrhythmias in 28, conduction disturbances in 15 and congestive heart failure in 5. The most frequent noncardiac adverse experiences were paresthesia and visual disturbance. In conclusion, flecainide provides effective therapy for SVT in two-thirds to three-fourths of patients, most of whom had no success with standard therapies, and is generally well tolerated. Patients with AV and AV nodal reciprocating tachycardias and atrial tachycardias are particularly responsive (>80%). Two-thirds of patients with Wolff-Parkinson-White syndrome-related SVT and recent-onset atrial fibrillation had successful results. Insufficient data with chronic atrial fibrillation are available to assess the use of flecainide. This experience suggests that flecainide represents an important addition to the treatment of symptomatic SVT.

Antiarrhythmic agents. II. Therapeutic considerations.

Clinical management of cardiac tachyarrhythmias is fundamentally founded on precise determination of their nature and the clinical condition in which they occur, together with knowledge of the mechanisms of action and pharmacodynamics of the antiarrhythmic drugs and understanding of the related electrical therapeutic modalities. The initial objective in the therapy of supraventricular tachyarrhythmias is control of ventricular rate and then restoration of normal sinus rhythm. In general, supraventricular disorders are treated with digitalis, vagal stimulation, quinidine, procainamide, propranolol and direct current electroshock. Ventricular tachyarrhythmias are managed with lignocaine, procainamide, quinidine, propranolol, phenytoin (diphenylhydantoin), bretylium, direct current electroshock and electrical pacemaker ventricular overdrive.