Radiofrequency ablation in pediatric and adult patients: comparative results.

BACKGROUND: Radiofrequency (RF) catheter ablation has been widely and successfully employed to cure adult and pediatric patients of a variety of arrhythmias. Only limited data exist which compare the results in these two groups. The aim of this study was to compare the efficacy and safety of RF catheter ablation in pediatric versus adult patients performed by an adult electrophysiology (EP) team. METHODS: The study group included 327 consecutive pediatric (n=47) and adult (n=280) patients, aged 7-82 years (mean 40+/-19), with symptomatic tachyarrhythmias, who underwent RF ablation during the last 6 years. All but ten patients underwent a full EP study during the same session. Procedures were performed in all but five patients with use of local anesthesia and deep or light sedation. The left heart was approached with use of transaortic (n=36) or transseptal (n=55) or both (n=6) techniques. RF ablation was performed for manifest or concealed accessory pathways in 132 patients, AV nodal slow pathway in 119, atrial tachycardia in 24, atrial flutter in 15, atrial fibrillation in one, ventricular tachycardia in 29, and AV node/His bundle in 7 patients. RESULTS: RF ablation was successful in 271 (96.8%) patients in the adult group and in all patients (100%) in the pediatric group, with a mean of 15+/-18 (median: 8) vs 12+/-10 (median: 8) RF applications respectively (P=NS). Complications occurred in four patients (1.4%) in the adult group and in one patient (2.1%) in the pediatric group (P=NS). Fluoroscopy time averaged 43+/-40 min vs 39+/-27 min and procedures lasted for 3.0+/-1.9 hours vs 2.8+/-1.4 hours respectively (P=NS). During long-term follow-up of 25+/-19 months, there were 12 (4.4%) recurrences among the adult patients, and three (6.4%) recurrences in children, with nine of them successfully treated with repeat RF ablation. Procedural variables were dependent on the type of arrhythmia ablated, rather than on patient's age. Patients with multiple accessory pathways or atrial flutter required the greatest number of RF applications and the longest fluoroscopy exposure and duration of the procedure; the lowest values of these variables concerned ablation of the slow AV nodal pathway or the AV node/His bundle. CONCLUSION: RF ablation in adult and pediatric patients performed by an adult EP team is equally efficacious and safe offering cure of symptomatic cardiac tachyarrhythmias in both patient populations.

Ancillary tools in pacemaker and defibrillator lead extraction using a novel lead removal system.

A previous report described our preliminary experience with a highly successful pacing lead removal system (VasoExtor). Extending this experience, we found it necessary to use additional tools to enhance the success of percutaneous lead extraction with this system. In the present series, we used the standard locking stylets (S and K), and recently, one newer type of stylet (Magic) over the last 3 years in 34 patients to extract 48 pacemaker leads in 31 patients and 3 defibrillator (ICD) leads in 3 patients. Lead extraction was carried out in 23 men and 11 women (aged 64 +/- 17 years) because of pacemaker infection (n = 21), pacemaker (n = 8) or ICD (n = 3) lead malfunction, or prior to ICD implant (n = 2). Leads were in place for 3.5 +/- 3.7 years. Infections, involving pocket and lead(s), were due to S. epidermidis (n = 13), S. aureus (n = 6), S. aureus plus E. coli (n = 1), for fungi (n = 1). Of the 48 pacing leads, 31 were ventricular, 15 atrial, and 2 were VDD leads. The ICD leads were two double-coil leads (CPI) and one single-coil lead (Telectronics). Using the S (n = 12), K (n = 8), or Magic (n = 3) stylets, all pacing leads in 23 patients and the ICD leads in 2 patients were successfully removed from a subclavian approach using the locking stylets. However, in nine (26.5%) patients ancillary tools were required. In four patients, lead fragments were captured with use of a noose catheter, a pigtail catheter, and a bioptome from a right femoral approach. In two patients, locking could not be effected and a noose catheter from the right femoral vein was used, aided by a pigtail and an Amplatz catheter and a bioptome to remove three leads. In a patient with an ICD lead, a combined subclavian (stylet S) and right femoral approach (noose catheter) was required. In a patient with a dysfunctional ventricular lead 12 years old, a motor drive unit was used to facilitate the exchange of locking stylets, but extraction failed. In another patient, a fragment of a dysfunctional ventricular lead remained intravascularly despite resorting to a femoral approach. Finally, lead removal was completely (32/34, 94%) or partially (1/34, 3%) successful in 33 (97%) of 34 patients for 50 (98%) of 51 leads without complications. In conclusion, to enhance the success of pacing or ICD lead extraction with use of the VascoExtor locking stylets, an array of ancillary tools were required in more than one fourth of patients.

Two-coil versus single-coil transvenous cardioverter defibrillator systems: comparative data.

Two types of new-generation transvenous implantable cardioverter defibrillator (ICD) systems, incorporating a two-coil (62 patients, group 1) versus single-coil (32 patients, group 2) lead system were compared among 94 consecutive patients. The two groups were comparable in age (58 +/- 13 vs 59 +/- 14 years), presenting arrhythmia (ventricular tachycardia versus ventricular fibrillation 77%/21% vs 84%/13%), cycle length of induced VT (294 +/- 4 vs 289 +/- 44 ms), number of unsuccessful antiarrhythmic drugs (1.7 +/- 0.8 vs 1.7 +/- 0.7), and left ventricular ejection fraction (35 +/- 12% vs 34 +/- 9%). Both systems were successfully implanted strictly transvenously in all patients. Biphasic shocks were used in all patients. Active shell devices were used in 79% and 84% patients of groups I and II, respectively (P = NS). Intraoperative testing revealed comparable defibrillation threshold (DFT) values (10.2 +/- 3.7 J in group 1 versus 9.3 +/- 3.6 J in group 2 system), and pacing threshold (0.7 +/- 0.3 vs 0.7 +/- 0.3 V), but R wave amplitude and lead impedance were lower in group 1 (13 +/- 5 vs 16 +/- 5 mV, P = 0.003; and 579 +/- 115 vs 657 +/- 111 ohms, P = 0.002, respectively). Lead insulation break requiring reoperation occurred in one patient with an Endotak lead, and two patients with Transvene leads had initially high DFT with a single one-lead/active can system, which was converted to a two- or three-endocardial-lead/inactive can configuration. We conclude that both single-coil and two-coil transvenous ICD systems were associated with high rates of successful strictly transvenous ICD implantation and a low incidence of lead-related complications. Significant differences were noted in the sensed R wave and lead impedance, probably reflecting the active fixation characteristics of the Transvene lead. However, in order to obviate the sporadic need for implantation of additional endocardial leads, as was the case in two patients in this series, a double-coil lead may be preferable.

Percutaneous extraction of transvenous defibrillator leads using the VascoExtor pacing lead removal system.

In the implantable cardioverter defibrillator era the necessity for lead removal is not negligible. A specially designed extraction lead system for percutaneous removal of such leads is lacking, in contrast to the existing pacing lead extraction systems. We report the successful percutaneous extraction of four implantable cardioverter defibrillator leads in three patients because of lead malfunction using a novel pacemaker lead extraction system, the VascoExtor (VascoMed) system. Three leads were successfully removed in two patients using traction with special locking stylets from the superior approach. One lead was removed using the system's additional extraction tools through the femoral approach. There were no complications. This preliminary experience shows that the VascoExtor (VascoMed) pacemaker lead extraction system can also be used in implantable cardioverter defibrillator lead extraction safely and effectively. In addition to the locking stylets, adjunct percutaneous extraction tools may be needed in some cases.

Radiofrequency ablation in older children and adolescents by an adult electrophysiology team.

BACKGROUND: Radiofrequency (RF) catheter ablation has been widely and successfully employed to cure adult patients of a variety of arrhythmias. Only a few centers have a pediatric electrophysiology (EP) service available and have presented similar results in children. The aim of this study was to investigate the efficacy and safety of RF ablation in pediatric patients performed by an adult EP team. PATIENTS AND METHODS: The study group included 33 consecutive pediatric patients, aged 7-18 years (mean 14.1 +/- 3.1), with symptomatic supraventricular tachyarrhythmias, who underwent RF ablation during the last 3 years. All but two patients underwent a full EP study during the same session. Procedures were performed in all but five patients with use of local anesthesia and deep or light sedation. The left heart was approached with use of transaortic (n = 3) or transseptal (n = 7) techniques. RF ablation was performed for manifest (n = 11) or concealed (n = 9) (9 left, 4 anteroseptal, 3 midseptal, and 4 posteroseptal) or right atriofascicular (Mahaim) (n = 1) accessory pathways in 19 patients, 12 slow AV nodal pathways and 2 atrial tachycardia foci in the other 14 patients. RESULTS: RF ablation was successful in all patients (100%) with 1-27 RF applications (mean: 10 +/- 7). There was one complication in a patient with 2 accessory pathways; after RF ablation of a posteroseptal accessory pathway, complete heart block occurred during successful ablation of a second midseptal accessory pathway. Fluoroscopy time averaged 35 +/- 23 min and procedure duration 2.8 +/- 1.4 hours. During long-term follow-up of 19 +/- 10 months, there was one AV nodal tachycardia recurrence at 2.5 months, successfully treated with repeat RF ablation. CONCLUSION: RF ablation in pediatric patients performed by an adult EP team is efficacious and safe offering cure of symptomatic cardiac tachyarrhythmias in this patient population.

Successful percutaneous extraction of pacemaker leads with a novel (VascoExtor) pacing lead removal system.

A new pacing lead extraction system (VascoExtor, VascoMed, Germany) with a universally applicable locking stylet was used over a period of 12 months to extract 25 permanent pacemaker leads (mean implantation time 3.9 +/- 3.8 years) in 16 patients who had pacemaker infection (n = 13), lead dysfunction (n = 2), or before an automatic defibrillator implant (n = 1). With use of this system, we were able to successfully and safely remove 24 of 25 chronic pacing leads (96%) in 15 of 16 patients (93%) with sole use of the locking stylet in 81%, and with use of an array of ancillary tools in the remaining 19% of patients.

Successful radiofrequency catheter ablation of automatic atrial tachycardia with regression of the cardiomyopathy picture.

Ectopic atrial tachycardia (EAT) is often refractory to pharmacological suppression, and if uncontrolled, it can lead to cardiomyopathy. Although RF current catheter ablation therapy has been effective in eliminating the arrhythmia, there is limited information, particularly in adult patients with regard to the reversal of the tachycardia induced cardiomyopathy. Four adult patients, 20-56 years of age, and a 6-year-old boy, were referred with refractory EAT. Four patients had heart failure and three had depressed LV function by echocardiographic criteria. All patients underwent electrophysiological study, and RF ablation was successful in abolishing the arrhythmogenic foci. Of these, four were located in the right atrium and one in the left atrium, and were identified by recording of the earliest atrial activation. No complications occurred. Termination of the EAT resulted in symptomatic improvement. Serial echocardiographic assessment of LV function indicated a significant reversal of the cardiomyopathy picture with reduction in chamber size and recovery in systolic function; indices of diastolic dysfunction persisted in one patient. Chronic, uncontrolled EAT can cause tachycardia induced cardiomyopathy. The picture of the cardiomyopathy resolves after elimination of the focus. RF ablation is both effective and safe, and may be considered as early therapy, particularly in patients with incessant EAT and ventricular dysfunction.

Comparison of signal-averaged electrocardiograms with different levels of noise: time-domain, frequency-domain, and spectrotemporal analysis.

In order to test the effect of noise on the various parameters of the SAECG, 83 patients underwent three consecutive recordings at different noise levels. The high noise (HN) recordings had a noise level of 0.60-0.74 microV, the intermediate noise (IN) had 0.31-0.59 microV, and the low noise (LN) had < or = 0.30 microV. For the calculation of noise we used the standard deviation of the mean noise of the composite lead high pass filtered at 40 Hz. The recordings were compared using time-domain, frequency-domain, and spectrotemporal analysis. The time-domain parameters of the LN recordings, using 25-Hz, 40-Hz, and 60-Hz high pass cutoffs, were significantly different from those of the HN or IN recordings (P < 0.05). In the frequency-domain analysis, significant differences were found in some of the parameters of the LN compared to the HN. The spectrotemporal analysis of the X and Z leads also showed significant differences among the LN and the other recordings. In the time-domain analysis, both at 40 Hz and 25 Hz, there were more abnormal LN compared to the HN recordings (P < 0.05). In the spectrotemporal analysis, there were significantly more abnormal HN and IN recordings compared to the LN (P < 0.001 and P < 0.01, respectively). Therefore, the level of noise, even within the acceptable range, can significantly affect the SAECG. In the time domain at the lower noise levels the parameters become more abnormal, while the opposite seems to occur in the spectral and the spectrotemporal analysis.

Pretreatment with aspirin and ticlopidine confers lower thrombogenic potential of radiofrequency catheter ablation.

In the present study we pretreated 31 patients undergoing radiofrequency catheter ablation (RFA) with combined aspirin and ticlopidine for 3 days before the procedure, whereas 37 patients did not receive pretreatment. D-dimer levels reflecting the thrombogenic potential of RFA were significantly lower in the pretreated group at each stage before, during, and after the procedure, whereas there were no significant differences between the 2 groups in the number of RFA lesions or duration of the procedure.