Chin-Juey Yang

Sustained atrial tachycardia in adult patients. Electrophysiological characteristics, pharmacological response, possible mechanisms, and effects of radiofrequency ablation.

BackgroundMechanisms and electropharmacological characteristics in adult patients with atrial tachycardia (AT) are not well described. We proposed that a combination of electropharmacological characteristics, recording of monophasic action potential, and effects of radiofrequency ablation could further determine the mechanisms and achieve a new classification in adults with various types of AT because they were important in regard to the correlation between mecha-nisms and pathophysiology, clinical syndrome, and responses to specific pharmacological or nonpharmacological therapies. Methods and ResultsThirty-six patients (11 female, 25 male; mean age, 57±13 years) with AT were referred for electropharmacological studies and radiofrequency ablation. Resetting response pattern, entrainment phenomenon, recording of monophasic action potential, serial drug test, response to Valsalva maneuver, endocardial mapping technique, and radiofrequency ablation were performed. Seven patients had automatic AT provocable with isoproterenol; neither initiation nor termination was related to programmed electrical stimulation. The other 29 patients had AT initiated or terminated by electrical stimulation and mechanisms related to triggered activity or reentry; nine of them needed isopro-terenol to facilitate initiation of AT, associated with delayed afterdepolarization in monophasic action potential. All responded to adenosine (15 to 60 μg/kg) and Valsalva maneuver. Dipyridamole terminated AT and decreased the slope of afterdepolarization. Afterdepolarization was not found in the patients with automatic or reentrant AT. In 40 of 41 (98%), AT was ablated successfully, with late recurrence in 2 of 40 (5%) (follow-up, 18±4 months). ConclusionsThis study demonstrates the diverse mechanisms and electropharmacological characteristics of AT in adults. Furthermore, radiofrequency ablation of various types of AT could achieve high success and low recurrence rates.

Selective radiofrequency catheter ablation of fast and slow pathways in 100 patients with atrioventricular nodal reentrant tachycardia

One hundred patients received selective radiofrequency ablation of retrograde fast pathway (32 patients, group I) or slow pathway (68 patients, group II) to treat drug-refractory atrioventricular nodal reentrant tachycardia. In group I, a mean of 6 +/- 3 radiofrequency pulses eliminated the retrograde fast pathway. Thirty patients were free of symptoms and were not receiving antiarrhythmic drugs; two patients had accidental atrioventricular block. One patient had recurrent tachycardia and received a repeated ablation (slow pathway ablation). In group II, a mean of 9 +/- 4 radiofrequency pulses eliminated the slow pathway in 68 patients. All patients were free of symptoms and were not receiving antiarrhythmic drugs. One patient had recurrent tachycardia and received a repeated ablation. Serial follow-up electrophysiologic studies (immediate [20 to 30 minutes], early [5 to 7 days], and late [3 to 6 months]) showed that selective ablation of retrograde fast pathway was associated with nonspecific injury on the antegrade fast pathway (increase of AH interval) without effects on the slow pathway. Selective ablation of slow pathway was associated with nonspecific injury on the retrograde fast pathway in 15 patients (22%), but the antegrade fast pathway conduction parameters did not change significantly. Thus retrograde and antegrade fast pathway may be anatomically similar or have different sensitivities to radiofrequency energy, and slow pathway may be anatomically distinct from fast pathway. We conclude that (1) selective radiofrequency ablation of retrograde fast or slow pathway could cure atrioventricular nodal reentrant tachycardia with a high success rate (98%) and a low recurrence rate (2%) during a follow-up period of 6 to 18 months, but fast pathway ablation was associated with accidental atrioventricular block (5%), and (2) serial follow-up electrophysiologic studies elucidated the possible mechanisms of cure in atrioventricular nodal reentrant tachycardia.

Accessory pathway and atrioventricular node reentrant tachycardia in elderly patients: clinical features, electrophysiologic characteristics and results of radiofrequency ablation.

OBJECTIVES This study was designed to evaluate the clinical features, electrophysiologic characteristics and results of radiofrequency ablation in elderly patients with accessory atrioventricular (AV) pathways or AV node reentrant tachycardia. BACKGROUND Radiofrequency ablation in elderly patients with paroxysmal supraventricular tachycardia has not been well described, and comparative study between elderly and younger patients is limited. METHODS Electrophysiologic studies and radiofrequency ablation were performed in 92 elderly patients (45 with an accessory pathway, 47 with AV node reentrant tachycardia). RESULTS The elderly patients had poorer electrophysiologic properties in accessory pathways and dual AV node pathways than those of younger patients. The success rate of radiofrequency ablation was similar in elderly and younger patients. However, elderly patients had more complications (14%) in left-sided accessory pathways. CONCLUSIONS Radiofrequency ablation in elderly patients with supraventricular tachycardia was effective. However, it must be performed cautiously in those patients with left-sided accessory pathways.

Reappraisal of radiofrequency ablation of multiple accessory pathways

Complete electrophysiologic study and radiofrequency ablation were performed in 145 consecutive patients with Wolff-Parkinson-White syndrome. Presence of multiple accessory atrioventricular pathways was documented in 20 patients (13.8%); 17 had two, two had three, and one had four accessory pathways. Location of accessory pathways was posteroseptal in 18, left free wall in 15, right free wall in nine, and right midseptal in two. Of the 44 pathways, 36 were found during baseline electrophysiologic study and eight were found after successful ablation of the initially attempted pathways. After delivery 20 +/- 23 pulses (per patient) of radiofrequency energy (37 +/- 6 W, 70 +/- 30 seconds), 43 accessory pathways were ablated successfully without complications. Duration of the procedure (4.5 +/- 1.7 vs 3.7 +/- 1.6 hours, p < 0.05) and radiation exposure time (53 +/- 30 vs 38 +/- 18 minutes, p < 0.05) were longer in patients with multiple pathways, whereas the success rate (95% vs 95%, p > 0.05) and incidence of recurrent conduction (11% vs 11%, p > 0.05) were similar in patients with single or multiple accessory pathways. These findings confirmed that multiple accessory pathways were common in patients with Wolff-Parkinson-White syndrome, and these pathways could be ablated successfully by radiofrequency energy with a success rate comparable to that of a single accessory pathway.

Recurrent conduction in accessory pathway and possible new arrhythmias after radiofrequency catheter ablation

Radiofrequency catheter ablation was performed in 142 patients with 166 accessory pathways. One hundred thirty-six patients with 160 accessory pathways underwent successful ablation in the first ablation session. Serial follow-up electrophysiologic studies were performed immediately (30 minutes), early (5 to 7 days), and late (3 to 6 months) after successful ablation to determine the recurrent accessory pathway conduction and possible new arrhythmias. After a minimum follow-up period of 6 months (mean, 14 +/- 3 months), accessory pathway conduction recurred in 13 patients (9.6%), with recurrent tachycardia in three patients (2.2%). Five of the recurrent accessory pathways had decremental conduction properties. Incidence of recurrent accessory pathway conduction was similar in different accessory pathway locations (6.4% to 9.0%). Patients with concealed accessory pathways (12.2 vs 2.9%; p < 0.05), and patients without accessory pathway potentials in the ablation site (15.5% vs 2.2%; p < 0.05) had a higher recurrence rate. Patients without tachycardia in the late electrophysiologic study did not have recurrent tachycardia during follow-up. New arrhythmias, including atrial and ventricular arrhythmias, which were detected by 24-hour Holter monitoring, were apparent only on the first day after ablation. The findings indicate that the overall incidence of recurrent accessory pathway conduction was low and that possible new arrhythmias were rare in the late follow-up period.

Reversibility of left ventricular dysfunction after successful catheter ablation of supraventricular reentrant tachycardia

Fourteen patients (mean age, 48 +/- 19 years) with left ventricular dysfunction in the absence of underlying organic heart disease underwent catheter ablation (nine with direct-current energy and five with radiofrequency energy) to treat drug-refractory, symptomatic supraventricular reentrant tachycardia (mean duration of tachycardia, 22 +/- 17 years). Clinical tachycardias were accessory pathway-mediated tachyarrhythmia (12 patients) and atrioventricular nodal reentrant tachycardia (two patients). Changes of ventricular function after successful ablation, as assessed by radionuclide ventriculography and echocardiography, showed a decrease in left ventricular end-systolic dimension (39 +/- 6 mm to 34 +/- 6 mm; 32 +/- 6 mm; p < 0.05) and in left ventricular end-diastolic dimension (55 +/- 5 mm to 52 +/- 3 mm; 51 +/- 3 mm; p < 0.05) in the early (2 to 3 months) and late (6 to 8 months) follow-up periods, increase of nuclear ejection fraction (38% +/- 8% to 46% +/- 7%; p < 0.05) and fractional shortening (28% +/- 7% to 36% +/- 8%; p < 0.05) in the late follow-up period. Increase of fractional shortening was mainly due to decrease in the end-systolic dimension. These findings suggest that prolonged attacks of uncontrolled supraventricular tachycardia may result in left ventricular dysfunction, which is reversible after successful catheter ablation of the arrhythmias.

Radio frequency Catheter Ablation of Sustained Intraatrial Reentrant Tachycardia in a Patient With Mirror-Image Dextrocardia

RF Catheter Ablation in Dextrocardia. Introduction: There has been limited experience with radio frequency catheter ablation in patients with Dextrocardia. This report describes a 37‐year‐oid man who had corundum type Atrial septal defect, mirror‐image Dextrocardia, and drug‐refractory Atrial tachycardia, in whom catheter‐mediated radio frequency energy successfully eliminated the tachycardia without complication.

Clinical features and electrophysiologic characteristics of accessory atrioventricular pathways and atrioventricular nodal reentrant tachycardia: Comparative study between young and elderly patients

Information focused on elderly patients with paroxysmal supraventricular tachycardia, and a comparative study between the elderly and younger patients was limited. The aim of this study was to investigate the clinical features and electrophysiologic characteristics in elderly patients (> or = 65 years of age) with accessory atrioventricular pathway-mediated tachyarrhythmia or atrioventricular nodal reentrant tachycardia. Electrophysiologic studies of 45 elderly patients with accessory pathway-mediated tachyarrhythmia and 47 elderly patients with atrioventricular nodal reentrant tachycardia were performed. When compared with younger patients, the elderly patients had a similar incidence of critical clinical manifestation, higher incidence of other cardiac disease or systemic disease, similar inducibility of tachycardia, greater baseline electrophysiologic parameters (sinus node, atrioventricular node, atrium and ventricle), and poorer properties of accessory pathways and dual atrioventricular nodal pathways. These results suggest that conduction properties of accessory pathways and dual atrioventricular nodal pathways were poorer in elderly patients, but similar critical manifestations and tachycardia events were found in elderly and younger patients.

Usefulness of serial follow-up electrophysiologic studies in predicting late outcome of radiofrequency ablation for accessory pathways and atrioventricular nodal reentrant tachycardia

A total of 408 patients received radiofrequency catheter ablation for paroxysmal supraventricular tachycardia, and 326 patients underwent serial follow-up electrophysiologic studies (early and late) after initially successful radiofrequency catheter ablation of accessory pathways (group 1, 186 patients with Wolff-Parkinson-White syndrome) and slow atrioventricular (AV) nodal pathways (group 2, 140 patients with AV nodal reentrant tachycardia). Among the patients in group 1, early (4 +/- 1 days) and late (129 +/- 14 days) studies found recurrent conduction through the accessory pathways in 12 and 16 patients, respectively. During a follow-up period of 21 +/- 7 months, recurrence of accessory pathway-mediated tachyarrhythmias was noted in six patients. Of these six patients, all had tachycardia inducible in the late study but not in the early study. Among the patients in group 2, four had recurrence of AV nodal reentrant tachycardia during a follow-up of 16 +/- 6 months. Of the four patients, one had tachycardia inducible in the early (4 +/- 1 days) study and three in the late (130 +/- 12 days) study. The results demonstrated that the early study was not as sensitive as the late follow-up electrophysiologic study in predicting late outcome of radiofrequency ablation, but both the early and late studies had a high total predictive accuracy (> 90%) in groups 1 and 2. Furthermore, only 4 of the 326 patients had initial evidence of recurrent tachycardia activated by programmed electrical stimuli during follow-up studies, suggesting that follow-up electrophysiologic studies in asymptomatic patients are not warranted.