Catheter Ablation ; Child ; Humans ; Male ; Tachycardia, Atrioventricular Nodal Reentry ; surgery

Abnormalities, Multiple ; surgery ; Adolescent ; Catheter Ablation ; Dextrocardia ; Humans ; Male ; Tachycardia, Atrioventricular Nodal Reentry ; surgery

BACKGROUNDAtrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias. The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.

METHODSPatients with AVNRT diagnosed by electrophysiological tests were randomized into two groups. In the conventional technique group (CMT), a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. The following parameters were collected and compared between the two groups: ablation procedure time, patient fluoroscopy time, operator fluoroscopy time, energy delivery numbers, maximal energy per deployment, success rate, complication rate and operative cost.

RESULTSForty patients were enrolled and randomized into CMT and MNS groups. The age, gender, tachycardia history and basic cardiovascular diseases of the two groups were comparable (P > 0.05). All procedures were conducted successfully without complications. No tachycardia recurred during the follow-up period of (9.3 ± 2.6) months. In the MNS group, the patient and operator fluoroscopy times ((11.5 ± 4.3) min, (4.2 ± 1.5) min), energy delivery numbers (3.2 ± 0.9), and maximal energy per deployment ((16.9 ± 3.4) W) were shorter or lower than those of the CMT group ((14.3 ± 6.2) min, (13.6 ± 3.5) min, 6.3 ± 2.1, (23.7 ± 1.3) W, respectively) (P < 0.05). But the operative cost for the MNS group was higher than that of the CMT group (P < 0.01).

CONCLUSIONMagnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

Catheter Ablation ; methods ; Humans ; Tachycardia, Atrioventricular Nodal Reentry ; surgery ; Treatment Outcome

Adolescent ; Catheter Ablation ; methods ; Humans ; Male ; Pre-Excitation, Mahaim-Type ; Tachycardia, Atrioventricular Nodal Reentry ; surgery

Catheter Ablation ; methods ; Coronary Sinus ; surgery ; Electrocardiography ; Female ; Humans ; Middle Aged ; Tachycardia, Atrioventricular Nodal Reentry ; pathology ; surgery

A multipoint and computerized intraoperative mapping system has been known to be of value in improving the results of surgery for cardiac arrhythmia. It shows great potential as a new tool in the surgical intervention of the more common and lethal types of supraventricular tachyarrhythmias such as atrial flutter and atrial fibrillation. In addition, it also enhances the ability of the investigators to map and ablate the sometimes fleeting automatic atrial tachycardia. The authors developed a 64 channel computerized cardiac mapping system using a microcomputer (Macintosh IIx) and this has been used for basic research in cardiac electrophysiology as well as in arrhythmia surgery. In this system, bipolar electrograms are obtained from 64 different cardiac sites simultaneously at a sampling rate of 1 Ksample/sec and with a continuous and total data storage of up to 30 seconds. When the reference electrode is selected, delay time from the reference point is displayed on a two dimensional diagram of the heart. This system was used in one patient who underwent a surgical ablation of a ventricular tachycardia in whom we observed a ventricular activation sequence involving a variety of rhythms over several minutes. The system design permits easy expansion to a simultaneous sampling from 256 sites. This 64-channel mapping appeared to have the potential to be of great help in our understanding of cardiac arrhythmia as well as in its diagnosis and surgical treatment.
Arrhythmia/*physiopathology/*surgery ; *Cardiac Surgical Procedures ; *Diagnosis, Computer-Assisted ; Electrophysiology/*methods ; Heart/*physiopathology ; Heart Septal Defects, Atrial/surgery ; Human ; Support, Non-U.S. Gov't ; Tachycardia, Atrioventricular Nodal Reentry/surgery

BACKGROUNDTypical accessory pathways (APs) of Wolf-Parkinson-White syndrome have been widely discussed in recent decades. However, the characteristics of the special AP, Mahaim fibre, are not so clear. It is known that these fibres have antegrade conduction only, long conduction time, decremental node-like conduction and automaticity properties. This study was to elucidate the automaticity of Mahaim fibre and its response to effective ablation.

METHODSThirteen patients with Mahaim fibre (ten atrioventricular and three atriofascicular accessory pathways) were subjected to electrophysiological study and radiofrequency ablation via catheter. The incidence and characteristics of anautomatic rhythm originating from Mahaim fibre were observed during the whole procedure, especially during radiofrequency current delivery.

RESULTSRepetitive and short-run automatic rhythm (rate: 65-72 beats per minute), with a QRS morphology similar to that of clinical pre-excited atrioventricular re-entrant tachycardia (AVRT), occurred in two patients during sinus rhythm. Conduction via Mahaim fibre was successfully eliminated by radiofrequency current. Fourteen applications of RF were associated with irregularly accelerated automatic tachycardia of Mahaim fibre (with a sensitivity of 78%), lasting for 1.2-14 seconds. However, such automatic tachycardia of Mahaim fibre did not occur during 54 failed applications of radiofrequency current.

CONCLUSIONSMahaim fibre has the function of automaticity. The accelerated automatic tachycardia of Mahaim fibre occur red during radiofrequency catheter ablation can be used as a predictor for successful procedure.

Adolescent ; Adult ; Catheter Ablation ; Child ; Female ; Humans ; Male ; Middle Aged ; Pre-Excitation, Mahaim-Type ; physiopathology ; surgery ; Tachycardia, Atrioventricular Nodal Reentry ; physiopathology ; surgery

PURPOSE: Although the data of radiofrequency catheter ablation (RFCA) of supraventricular tachycardia in adults has been accumulated in several centers in Korea, few data are available on its efficacy and safety in pediatric ages. We reviewed the data in young patients who underwent this procedure in a pediatric cardiology center, to evaluate the indications, early results, complications, and short-term follow-up data. METHODS: We retrospectively reviewed the medical records and RFCA procedure reports of 17 children who underwent this procedure in pediatric cardiology center, Asan Medical Center, Seoul, Korea from January 1992 to July 1996. The mean follow-up periods was 17.8 months. RESULTS: 1) The median age of the patients was 12.3 years and all of them except two patients had structurally normal hearts. The indications of RFCA were preoperative open heart surgery in a patient, drug refractory tachycardia in 4 patients and patient's choice in other 12 patients. 2) The mechanisms of supraventricular tachycardia were 9 atrioventricular reentrant tachycardia, 6 atrioventricular nodal reentrant tachycardia (AVNRT), 1 atrial flutter and 1 atrial ectopic tachycardia (AET). Among accessory pathways, preexcitation was in 6 patients and accessory pathway located in the right side in 7 patients. In all patient with AVNRT except one, slow pathway was ablated. In the case of AET, ectopic focus located in the left atrium near the orifice of right lower pulmonary vein. 3) 16 of 18 procedures (88.9%) were successful and in 2 occasions with right sided accessory pathway and AET, the procedure failed. Ectopic focus was successfully ablated at the second attempt. The mean total procedure time was 2.7 hours (n=16) and the mean fluoroscopic time was 45.3 minutes (n=12). The average number of RF application was 11 times. There was no significant complications related with procedures. 4) There were 5 recurrences (29.4%), in 2 patients with accessory pathway and 2 patients with AVNRT. Most recurrences occured in 6 weeks after procedure. CONCLUSIONS: RFCA is a good alternative for the treatment of supraventricular tachycardia also in young patients as in adults. Early results of RFCA shows resonably good success rate but somewhat higher rate of recurrence in our center. We expect the results of RFCA in children will be improved in near future after some period of learning curve.
Adult ; Atrial Flutter ; beta-Aminoethyl Isothiourea ; Cardiology ; Catheter Ablation* ; Child* ; Chungcheongnam-do ; Follow-Up Studies ; Heart ; Heart Atria ; Humans ; Korea ; Learning Curve ; Medical Records ; Pulmonary Veins ; Recurrence ; Retrospective Studies ; Seoul ; Tachycardia ; Tachycardia, Atrioventricular Nodal Reentry ; Tachycardia, Ectopic Atrial ; Tachycardia, Supraventricular* ; Thoracic Surgery