The purpose of this study was to determine if the electrophysiologic properties and the anatomic location of manifest accessory pathways affect the local electrogram intervals recorded at sites of successful radiofrequency ablation. Accessory pathways in 149 consecutive patients were categorized according to their anatomic location on the basis of the site of successful ablation. Three anatomic groups comprised 90 left free wall, 28 right free wall, and 31 posteroseptal pathways. The accessory pathways were also categorized according to their electrophysiologic properties on the basis of a hierarchical classification of the accessory pathway block cycle length. Four electrophysiologic groups (A, B, C, and D) comprised 54, 51, 28, and 16 accessory pathways, with mean accessory pathway block cycle lengths of 254 +/- 9, 288 +/- 10, 347 +/- 19, and 458 +/- 56 msec, respectively. The local atrial to ventricular (A-V) and atrial to accessory (A-K) pathway electrogram intervals recorded in sinus rhythm at the successful ablation site were significantly affected by the electrophysiologic group and were longest in group D compared with groups A, B, and C (A-V interval F(3,145)= 13.6, p < 0.001; A-K interval F(3,88)= 12.6, p < 0.001). The local A-V interval was also affected by the anatomic group and was longer in posteroseptal compared with free wall accessory pathways (F(2,146)= 15.0, p < 0.001). In contrast, the timing of the local ventricular activation to the delta wave onset (delta-V) was not significantly affected by the electrophysiologic group or the anatomic location of the accessory pathway. Thus the local A-V interval at the successful ablation site may vary because it is affected by the electrophysiologic properties and location of the accessory pathway, whereas the delta-V interval remains unaffected. These effects should be taken into account when selecting ablation sites in patients with manifest accessory pathways.

OBJECTIVES. The purpose of this study was to evaluate the inducibility of atrial flutter in patients with atrioventricular (AV) node reentrant tachycardia and to determine the effect of radio-frequency ablation of the slow AV node pathway on the inducibility of atrial flutter. BACKGROUND. Studies have shown that both AV node reentrant tachycardia and atrial flutter are reentrant arrhythmias having an area of slow conduction that is located in the low posterior right atrium near the ostium of the coronary sinus. METHODS. Ninety-one patients were prospectively evaluated using a standardized atrial pacing protocol. Three groups of patients were analyzed: 42 patients with inducible AV node reentrant tachycardia, 13 with a history of spontaneous atrial flutter and 36 control patients. A subgroup of 34 patients with AV node reentrant tachycardia who underwent successful radiofrequency ablation of the slow AV node pathway underwent atrial pacing again after ablation. RESULTS. Atrial flutter was more frequently inducible in patients with AV node reentrant tachycardia (88%) and in those with a history of atrial flutter (92%) than in control patients (36%)(p = 0.0001). There were no differences between the patient groups with respect to atrial effective refractory period, P wave duration or PA interval at the His position. Among the 34 patients with AV node reentrant tachycardia who underwent atrial pacing before and after radiofrequency ablation, there were 30 with atrial flutter and 4 with atrial fibrillation before ablation and 29 with atrial flutter and 5 with atrial fibrillation after ablation (p = NS). There was no difference in the duration of the induced atrial flutter before and after ablation. The mean atrial flutter cycle length before ablation (206 +/- 22 ms) was not different from that after ablation (196 +/- 20 ms)(p = NS). CONCLUSIONS. There is a strong association between AV node reentrant tachycardia and inducible atrial flutter, suggesting that there may be a common area of perinodal atrium participating in the two tachycardia circuits. However, radiofrequency ablation of the slow pathway of the AV node reentrant tachycardia circuit does not influence the inducibility of atrial flutter.

BACKGROUND. Two different techniques have been developed for radiofrequency catheter ablation of typical atrioventricular nodal reentry (AVNRT). Lesions made anteriorly near the apex of the triangle of Koch usually eliminate fast pathway function, whereas lesions made posteriorly near the ostium of the coronary sinus selectively affect slow pathway function. The current study compares the safety, efficacy, and electrophysiological effects of these two techniques in a prospective, randomized fashion. METHODS AND RESULTS. Fifty consecutive patients with typical AVNRT were randomly assigned to receive radiofrequency lesions either anteriorly (n = 22) or posteriorly (n = 28). If the initial approach failed to eliminate inducibility of AVNRT after 1 hour or 10 applications of radiofrequency energy, the alternative ablation technique was used. Patients underwent repeat electrophysiological testing 48 hours and 3 months after ablation. The primary success rates of the anterior and posterior techniques were similar (55% versus 68%, p = NS). All of the patients who failed the initial approach were successfully treated by the alternative technique without developing high-grade atrioventricular block. One patient developed right bundle branch block during an anterior lesion, and another patient developed complete atrioventricular block as the result of a posterior lesion. CONCLUSIONS. The posterior approach to radiofrequency catheter modification of the atrioventricular node is as effective as the anterior approach, and both techniques are associated with a low risk of complications. As long as AVNRT persists, it appears safe to cross over from one technique to the other.

The results of radiofrequency catheter ablation of ventricular tachycardia (VT) in patients without structural heart disease are reported. Particular attention was focused on the relation between efficacy and the site of origin of the VT. Eighteen consecutive patients (5 women and 13 men; mean age 41 +/- 13 years) with idiopathic VT underwent catheter ablation using radiofrequency energy. Sites for radiofrequency energy delivery were selected on the basis of pace mapping. A follow-up electrophysiologic test was performed 1 to 3 months after the ablation procedure. Twenty VTs were induced. Radiofrequency catheter ablation was successful in eliminating all 10 VTs originating from the right ventricular outflow tract, and 5 of 10 from other sites in the left or right ventricle. There were no complications. The duration of ablation sessions was shorter, the frequency of identifying a site resulting in an identical pace map was higher, and the efficacy of catheter ablation was greater for VTs originating from the right ventricular outflow tract than for those from other locations. The results of this study demonstrate that radiofrequency catheter ablation of idiopathic VT is safe and effective. The efficacy of the procedure is dependent on the site of origin of the VT, with the efficacy being greater for VTs originating from the outflow tract of the right ventricle than for those from other locations.

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.

BACKGROUND. Radiofrequency (RF) ablation of idiopathic ventricular tachycardia (VT) has been demonstrated to be highly efficacious, but the efficacy of RF ablation of VT in patients with coronary artery disease has been unknown. Therefore, the purpose of this study was to determine the feasibility of RF ablation of VT in patients with coronary artery disease. METHODS AND RESULTS. Fifteen consecutive patients with coronary artery disease and a history of myocardial infarction underwent an attempt at RF ablation of 16 hemodynamically stable monomorphic VTs that had been documented clinically on a 12-lead ECG and that had not been successfully managed by pharmacological or device therapy. One VT was incessant, five occurred more than 25 times, and the remainder occurred two to 20 times. An additional four VTs that had not been documented clinically also were targeted for ablation. The mean age of the patients was 68 +/- 7 years (+/- SD), and their mean left ventricular ejection fraction was 0.27 +/- 0.08. The mean cycle length of the 20 VTs targeted for ablation was 438 +/- 82 msec. Ablation sites were selected based on endocardial activation mapping, pace mapping, identification of an isolated mid-diastolic potential, or concealed entrainment. Sixteen of the 20 VTs (80%) were successfully ablated in 11 of 15 patients (73%), using a mean of 4.2 +/- 3 applications of RF energy, and no recurrences of the ablated VTs occurred during 9.1 +/- 3.3 months of follow-up. The mean duration of the ablation procedures was 128 +/- 30 minutes. No complications occurred in any of the patients. CONCLUSIONS. The results of this study demonstrate that RF ablation of hemodynamically stable VT is feasible as adjunctive therapy in selected patients with coronary artery disease.

OBJECTIVES. The purpose of this study was to evaluate the utility of the 12-lead electrocardiogram (ECG) for differentiating paroxysmal narrow QRS complex tachycardias. BACKGROUND. Previous studies evaluating the utility of the 12-lead ECG for differentiating paroxysmal supraventricular tachycardia types have shown conflicting results on the usefulness of some ECG criteria, and some criteria that are considered to be useful have never been formally evaluated. METHODS. Two hundred forty-two ECGs demonstrating paroxysmal narrow QRS complex (< 0.11 ms) tachycardia (rate > or = 120 beats/min) were analyzed. All ECGs were analyzed by an observer who had no knowledge of the mechanism of the tachycardia. RESULTS. There were 137 atrioventricular (AV) reciprocating tachycardias, 93 AV node reentrant tachycardias and 12 atrial tachycardias. Six criteria were found to be significantly different between tachycardia types by univariate analysis. A P wave separate from the QRS complex was observed more frequently in AV reciprocating tachycardia (68%) and atrial tachycardias (75%). A pseudo r' deflection in lead V1 and a pseudo S wave in the inferior leads were more common in AV node reentrant tachycardia (58% and 14%, respectively); QRS alternans was present more often during AV reciprocating tachycardia (27%). When a P wave was present, an RP/PR interval ratio > or = 1 was more common in atrial tachycardias (89%). During sinus rhythm, manifest pre-excitation was observed more often in patients with AV reciprocating tachycardia (45%). By multivariate analysis, the presence of a P wave separate from the QRS complex, pseudo r' deflection in lead V1, QRS alternans during tachycardia and the presence of pre-excitation during sinus rhythm were independent predictors of tachycardia type. These criteria correctly identified 86% of AV node reentrant tachycardias, 81% of AV reciprocating tachycardias and incorrectly assigned the tachycardia type in 19% of cases. CONCLUSIONS. Several features on the ECG are useful for differentiating supraventricular tachycardia type. However, approximately 20% of tachycardias may be incorrectly classified on the basis of analysis of the ECG; therefore, the ECG should not serve as the sole means for determining tachycardia mechanism.

OBJECTIVES. The purpose of this study was to compare direct current and radiofrequency ablation of the atrioventricular (AV) junction in a prospective randomized fashion. BACKGROUND. Catheter ablation of the AV junction can be performed using either direct current shocks or radiofrequency energy. To date, these two techniques have never been compared prospectively or in a randomized study. METHODS. Forty patients with drug-refractory uncontrolled atrial fibrillation-flutter (38 patients) or inappropriate sinus tachycardia (2 patients) were randomly assigned to undergo direct current ablation (20 patients) using up to four shocks of 200 to 300 J or radiofrequency ablation (20 patients) using up to 15 applications of 16 to 25 W for 30 s. If complete AV block was not successfully induced, the ablation procedure was repeated using the alternate type of energy. A rate-responsive ventricular pacemaker was implanted in each patient. The intrinsic escape rhythm was evaluated 15 min, 2 days and 3, 6 and 12 months after ablation. RESULTS. Persistent complete AV block was successfully induced during the first ablation session in 13 (65%) of 20 patients randomly assigned to undergo direct current ablation, compared with 19 (95%) of 20 patients randomly assigned to undergo radiofrequency ablation (p < 0.05). Each patient whose first ablation attempt failed had a successful outcome with the alternate type of energy. The overall efficacy of radiofrequency ablation (26 [96%] of 27 patients) was significantly greater than that of direct current ablation (14 [67%] of 21 patients, p < 0.01). The duration of the direct current and radiofrequency ablation sessions did not differ significantly. The mean peak plasma creatine kinase MB fraction concentration was significantly higher after direct current ablation (58 +/- 29 IU/liter) than after radiofrequency ablation (2 +/- 2 IU/liter)(p < 0.001). An escape rhythm was present 15 min after ablation in an equal proportion of patients undergoing direct current and radiofrequency ablation (78% and 85%, respectively, p = 0.6). An escape rhythm was present in all patients 3, 6 and 12 months after ablation. The mean escape rhythm cycle length 15 min after direct current ablation (2,074 +/- 677 ms) was significantly longer than that 15 min after radiofrequency ablation (1,460 +/- 294 ms)(p < 0.05); however, the mean escape rhythm cycle lengths did not differ significantly at 2 days or 3, 6 or 12 months after ablation. Immediate arrhythmic complications did not occur after either procedure. One patient died suddenly 6.5 months after direct current ablation. CONCLUSIONS. Radiofrequency ablation of the AV junction is more efficacious and safer than direct current ablation and should be the preferred method for inducing complete AV block in patients who are appropriate candidates for ablation of AV conduction.

OBJECTIVES. The purpose of this study was to characterize left-sided accessory pathways that traverse the atrioventricular (AV) groove subepicardially and to describe results of radiofrequency catheter ablation within the coronary sinus in the patients studied. BACKGROUND. Radiofrequency catheter ablation has proved to be a safe and effective method for treatment of accessory pathways; however, subepicardial accessory pathways may account for some of the failures encountered during endocardial ablation. METHODS. The study group comprised 51 consecutive patients with a left-sided accessory pathway who were undergoing radio-frequency catheter ablation. Initially, the ablation catheter was introduced into a femoral artery and positioned on the ventricular aspect of the mitral annulus. If this endocardial approach was unsuccessful, the ablation catheter was introduced into the coronary sinus and energy applied at sites with shorter activation times than those recorded from the endocardium. RESULTS. Five (10%) of 51 patients with a left-sided accessory pathway could not have accessory pathway conduction interrupted with a median of 18 endocardial radiofrequency energy applications. Accessory pathway potentials were less frequent during endocardial mapping in these 5 patients than in the 46 patients whose accessory pathway was successfully ablated from the endocardial surface. All five of these patients later had successful ablation using one or two applications of radiofrequency energy from within the coronary sinus. Effective target site electrograms in the coronary sinus were characterized by an accessory pathway potential that was larger than the corresponding atrial or ventricular electrogram. There were no complications or recurrences after ablation within the coronary sinus. CONCLUSIONS. Some left-sided accessory pathways may be difficult to ablate from the endocardial surface because they traverse the AV groove subepicardially. The absence of an accessory pathway potential during endocardial mapping in combination with a relatively large accessory pathway potential within the coronary sinus may be a useful marker of a subepicardial pathway. In this select group of patients, radiofrequency catheter ablation from within the coronary sinus appears to enhance efficacy.

We present a case of successful surgical ablation of an oblique epicardial accessory pathway on the right coronary artery in a 56-year-old female patient with Wolff-Parkinson-White (WPW) syndrome, for which the radio-frequency (RF) catheter ablation had not been effective 3 times. The heart was exposed via a T-shaped sternotomy, and positioned for adequate exposure using a suction device. Epicardial mapping was performed with a multi-electrode catheter fixed on the atrioventricular sulcus. The epicardium just above the right coronary was dissected with an ultrasonic scalpel and we confirmed complete electrophysiological block of the accessory pathway. For 3 years since the surgery, there has been no recurrence of arrhythmia in the patient. Although an RF ablation through a transcutaneous intrapericardial approach can be an alternative, surgical ablation seems to be a safer and more curative approach to failed RF catheter ablation of accessory pathway. Such surgical skills should be maintained.

Radiofrequency lesions can, theoretically, be the substrate for new persistent arrhythmias. As far as we know, this has never previously been encountered after transcatheter ablation of accessory pathways. A child with Wolff-Parkinson-White syndrome was referred for radiofrequency catheter ablation of a left-sided accessory pathway. After successful ablation of the accessory pathway using a retrograde transaortic approach, the child developed an incessant wide QRS complex tachycardia at slow rate that was resistant to pharmacologic interventions. The focus of the tachycardia was identical to the ventricular site of insertion of the eliminated accessory pathway.

Radiofrequency (RF) catheter ablation has become standard therapy for many types of arrhythmias. RF energy may cause deterioration in left ventricular function by damaging the myocardium. The aim of the present study was to assess the changes in left ventricular function after catheter ablation using various echocardiographic parameters. Forty patients (22 women), aged 37 +/- 14 years (range, 15-76 years), underwent catheter ablation for various tachycardias. Routine echocardiogaphic examination was done in all patients. Left ventricular systolic function was evaluated by the modified Simpson method and tissue Doppler. With regard to left ventricular diastolic function parameters, diastolic early (E) and late (A) transmitral filling velocities, deceleration time (DT), isovolumetric relaxation time (IVRT), and tissue Doppler parameters were assessed. All ventricular function parameters were assessed before, and 1 hour, 1 day, and 1 month after the catheter ablation procedure. To avoid any influence of heart rate on diastolic function parameters, the E/A ratio, DT, and IVRT were adjusted to heart rate (cE/A, cDT, cIVRT). No changes in left ventricular systolic function after the ablation were observed. After the ablation procedure (1 hour, 1 day, and 1 month) the cE/A ratio decreased from 1.42 +/- 0.43 to 1.19 +/- 0.40, 1.18 +/- 0.40, and 1.30 +/- 0.33 (P = 0.009), respectively. cDT increased from 210 +/- 54 to 272 +/- 64, 255 +/- 60, 240 +/- 64 (P = 0.001), respectively. Likewise cIVRT increased from 113 +/- 22 to 133 +/- 54, 123 +/- 27, 117 +/- 19 (P = 0.007), respectively. Significant changes were also observed concerning tissue Doppler parameters in assessing diastolic function. Although no significant changes were observed in systolic function after RF ablation, this procedure may have some detrimental effects on ventricular diastolic function para-meters.

This case report describes a patient with Wolff-Parkinson-White syndrome in whom the ECG exhibited a typical pattern of an anteroseptal (superoparaseptal) accessory pathway. Successful radiofrequency catheter ablation was achieved from the septal side of the left ventricular outflow tract. It might be worthwhile to map the left side of the anterior septum if an accessory pathway potential is not appreciable along the tricuspid annulus to avoid the potential complication of AV block in patients with a typical anteroseptal accessory pathway ECG pattern.

A case of Wolff-Parkinson-White syndrome successfully treated by transcutaneous epicardial radiofrequency ablation is described in a patient with a posteroseptal accessory pathway who had failed prior attempts of conventional endocardial and coronary venous system approaches. Simultaneous endocardial and pericardial space mapping was performed and only ablation from the pericardial space was successful, suggesting an epicardial course of the accessory pathway.

BACKGROUND: Young age and inducibility of atrioventricular reciprocating tachycardia or atrial fibrillation during invasive electrophysiological testing identify asymptomatic patients with a Wolff-Parkinson-White pattern on the electrocardiogram as being at high risk for arrhythmic events. We tested the hypothesis that prophylactic catheter ablation of accessory pathways would provide meaningful and durable benefits as compared with no treatment in such patients. METHODS: From 1997 to 2002, among 224 eligible asymptomatic patients with the Wolff-Parkinson-White syndrome, patients at high risk for arrhythmias were randomly assigned to radio-frequency catheter ablation of accessory pathways (37 patients) or no treatment (35 patients). The end point was the occurrence of arrhythmic events over a five-year follow-up period. RESULTS: Patients assigned to ablation had base-line characteristics that were similar to those of the controls. Two patients in the ablation group (5 percent) and 21 in the control group (60 percent) had arrhythmic events. One control patient had ventricular fibrillation as the presenting arrhythmia. The five-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7 percent among patients who underwent ablation and 77 percent among the controls (P<0.001 by the log-rank test); the risk reduction with ablation was 92 percent (relative risk, 0.08; 95 percent confidence interval, 0.02 to 0.33; P<0.001). CONCLUSIONS: Prophylactic accessory-pathway ablation markedly reduces the frequency of arrhythmic events in asymptomatic patients with the Wolff-Parkinson-White syndrome who are at high risk for such events.

We present the case of an 18-year-old male patient with diagnosis of Wolff Parkinson-White syndrome due to a left free wall accessory pathway. We performed an electrophysiology study and transseptal punction guided by transesophageal echocardiogram to via access to the left atrium. We performed successful radiofrequency ablation of the accessory pathway, observing disappearance of the delta wave on the first attempt. There were no complications. In follow-up a 10 months, the patient had no clinical nor electrocardiographic evidence of recurrence. Transseptal radiofrequency ablation is an alternative for treatment of some arrhythmias localized in the left side of the heart.

Radiofrequency catheter ablation of accessory pathways can not routinely be performed during preexcited atrial fibrillation. However, atrial fibrillation occurs frequently in patients with Wolff-Parkinson-White syndrome during an electrophysiologic study, causing difficulty for both the patient and the operator. In this case report we present two cases with Wolff-Parkinson-White syndrome treated by catheter ablation during preexcited atrial fibrillation. The localizations of accessory pathways were left lateral in one case, and right posteroseptal in the other.

This report describes a male patient with WPW syndrome who underwent surgical repair of sudden, severe mitral valve regurgitation through the posterior leaflet 20 months after successful RF catheter ablation for Kent bundle at the age of 14, and discusses the problem of valvular damage caused by this technique.