Nonfluoroscopic imaging systems reduce radiation exposure in children undergoing ablation of supraventricular tachycardia

Nonfluoroscopic Ablation of Atrial Fibrillation Using Cryoballoon

BACKGROUND

The conventional method of cryoballoon ablation of atrial fibrillation involves the use of fluoroscopy for visual guidance. The use of fluoroscopy is accompanied by significant radiation risks to the patient and the medical staff. Herein, we report our experience in performing successful nonfluoroscopic pulmonary vein isolation using cryoballoon ablation in 5 consecutive patients with paroxysmal atrial fibrillation.

METHODS AND RESULTS

Five consecutive patients with paroxysmal atrial fibrillation underwent cryoballoon ablation for pulmonary vein isolation using a nonfluoroscopic approach. Pre-procedural cardiac computed tomography or cardiac magnetic resonance imaging was not performed in any patient. A total of twenty pulmonary veins were identified and successfully isolated (100%) with the guidance of intracardiac echocardiography and 3-dimensional electroanatomic mapping. No fluoroscopy was used for the procedures. There were no major procedural adverse events.

CONCLUSION

In an unselected group of patients undergoing cryoballoon ablation, a nonfluoroscopic approach is feasible and can be performed safely and effectively while eliminating the risks associated with radiation to both the patient and the medical staff.

The use of an integrated electroanatomic mapping system and intracardiac echocardiography to reduce radiation exposure in children and young adults undergoing ablation of supraventricular tachycardia

AIMS

Non-fluoroscopic imaging (NFI) devices are increasingly used in ablations. The objective was to determine the utility of intracardiac echocardiography (ICE) in ablating paediatric supraventricular tachycardias (SVTs) and assess whether its integrated use with electroanatomic mapping (EAM) resulted in lower radiation exposure than use of EAM alone.

METHODS AND RESULTS

Prospective, controlled, single-centre study of patients (pts) age ≥10 years, weight ≥35 kg, with SVT and normal cardiac anatomy. Patients were randomized to ICE + EAM (ICE) or EAM only (no ICE). Both had access to fluoroscopy as needed. Eighty-four pts were enroled (42 ICE, 42 no ICE). Median age was 15 years (range 10.4-23.7 years); 57% had accessory pathways, 42% atrioventricular nodal reentry tachycardia. There was no difference in radiation dose (9 mGy ICE vs. 23 mGy no ICE, P = 0.37) or fluoroscopy time (1.1 min ICE vs. 1.5 min no ICE, P = 0.38). Transseptal punctures were performed in 25 pts (16 ICE, 9 no ICE), with ICE reducing radiation (8 mGy ICE vs. 62 mGy no ICE, P = 0.002) and fluoroscopy time (1.1 min ICE vs. 4.5 min no ICE, P = 0.01). Zero fluoroscopy was achieved in 13 pts (15% of total, 5 ICE, 8 no ICE), and low-dose cases (<50 mGy) in 57 pts (68% of total, 33 ICE, 24 no ICE). Acute success was 95% for ICE, 88% for no ICE.

CONCLUSION

Use of an integrated EAM/ICE system was no better than EAM alone in limiting radiation, but can be helpful for transseptal punctures. Given the low dose savings, use of ICE may be weighed against its financial cost. Low-fluoroscopy cases are performed in most NFI procedures.

Consequence of use of lower dose flat plate fluoroscopy in pediatric patients undergoing ablation for supraventricular tachycardia

Traditional imaging for ablation of supraventricular tachycardia has been fluoroscopy, although 3-dimensional electroanatomic mapping (3D) has been demonstrated to reduce radiation exposure. This study compares a technique for the reduction of radiation, low-dose fluoroscopy (LD), with standard-dose fluoroscopy (SD) and 3D with SD (3D-SD). This was a single institutional retrospective cohort study. All patients undergoing initial ablation for atrioventricular reentrant tachycardia (AVRT) or atrioventricular nodal reentrant tachycardia (AVNRT) from 2009 to 2012 were reviewed and divided into 3 groups: (1) SD, (2) 3D (CARTO or NavX) with SD, or (3) LD. LD uses the same equipment as SD but includes customized changes to the manufacturer's lowest settings by decreasing the requested dose to the detector. Primary outcomes were fluoroscopy time and dose area product exposure. One hundred eighty-one patients were included. The median age was 15.0 years (3.3-20.8); 59% had AVRT, 35% had AVNRT, and 6% had both AVRT and AVNRT. LD decreased the dose area product (DAP) compared with SD (637.0 vs 960.1 cGy*cm², p = 0.01) with no difference in fluoroscopy time. 3D-SD decreased fluoroscopy time compared with SD (9.9 vs 18.3 minutes, p <0.001) with DAP of 570.1.0 versus 960.1 cGy*cm² (p = 0.16). LD and 3D-SD had comparable DAP (637.0 vs 570.1 cGy*cm², p = 0.67), even though LD had significantly longer fluoroscopy time (19.9 vs 9.9 minutes, p <0.001). In conclusion, LD during catheter ablation of AVRT and AVNRT significantly reduced the DAP compared with SD and had similar radiation exposure compared with 3D with SD.

Single center experience of fluoroless AVNRT ablation guided by electroanatomic reconstruction in children and adolescents

BACKGROUND

Anatomical considerations and risks related to x-ray exposure make atrioventricular nodal reentrant tachycardia (AVNRT) ablation in pediatric patients a concerning procedure. We aimed to evaluate the feasibility, safety, and efficacy of performing fluoroless slow-pathway cryoablation guided by the electroanatomic (EA) mapping in children and adolescents.

METHODS

Twenty-one consecutive patients (mean age 13.5 ± 2.4 years) symptomatic for AVNRT were prospectively enrolled to right atrium EA mapping and electrophysiological study prior to cryoablation. Cryoablation was guided by slow-pathway potential and performed using a 4-mm-tip catheter.

RESULTS

Sustained slow-fast AVNRT was inducible in all the patients with a dual AV nodal physiology in 95%. Acute success was achieved in 100% of the patients with a median of two cryo-applications. Fluoroless ablation was feasible in 19 patients, while in two subjects 50 seconds and 45 seconds of x-ray were needed due to difficult progression of the catheters along the venous system. After a mean follow-up of 25 months, AVNRT recurred in five patients. All the recurrences were successfully treated with a second procedure. In three patients, a fluoroless cryoablation with a 6-mm-tip catheter was successfully performed, while in the remaining two patients, a single pulse of 60 seconds of radiofrequency energy was applied under fluoroscopic monitoring. No complications occurred.

CONCLUSIONS

Combination of EA mapping systems and cryoablation may allow to perform fluoroless slow-pathway ablation for AVNRT in children and adolescents in the majority of patients. Fluoroless slow-pathway cryoablation showed a high efficacy and safety comparable to conventional fluoroscopy guided procedures.

Reducing patient radiation dosage during pediatric SVT ablations using an "ALARA" radiation reduction protocol in the modern fluoroscopic era

BACKGROUND

Ablation for supraventricular tachycardia (SVT) relies upon fluoroscopy (fluoro), which exposes the patient and staff to ionizing radiation. The objective of this work was to present a new "ALARA--As Low As Reasonably Achievable" protocol with alterations to fluoroscopic x-ray parameters to reduce dose without an electroanatomical (EAM) approach.

METHODS

All patients <21 years of age undergoing ablation of SVT at our institution from June 2011 to April 2012 were included. EAM was not utilized in any case. An ALARA protocol of low frame rates (2 or 3 fps), low fluoro dose/frame (10-18 nGy/frame), and other techniques aimed at reducing use of fluoroscopy were employed. Demographics, procedural, and radiation data were analyzed.

RESULTS

Forty-two patients underwent ablation and were studied. Median age was 14.1 years (range 4.8-21.1 years), weight was 51 kg (range 18.2-75 kg), and body surface area was 1.51 m(2) (range 0.72- 1.94 m(2)). Seventeen (41%) had Wolff-Parkinson-White syndrome, 14 (33%) atrioventricular nodal reentrant tachycardia, and 11 (26%) concealed pathways. Median procedural time was 114 minutes (57-246 minutes). Median dose area product (DAP) for posterioanterior and lateral fluoroscopy was 343.2 uGym(2) (range 38.2-3,172 uGym(2)); the median air Kerma product (K) was 45.4 mGy (range 6.7-567.5 mGy). DAP and K are lower than prior data from EAM and fluoroscopy techniques. The acute success rate was 95%; no procedural complications.

CONCLUSIONS

An ALARA protocol for ablation of SVT reduced radiation to below levels previously reported for combined EAM/fluoro approaches. Success rates were excellent with no complications and without the costs of EAM.

Perspectives in ablation of arrhythmias in children and patients with congenital heart disease

Although most arrhythmias in children have a benign outcome, recurrent arrhythmic events have a significant impact on quality of life. Electrophysiology studies with ablation have good short-term success and an acceptably low complication rate. The long-term outlook for this patient group is incompletely defined, however. Factors that require special consideration in children include the need to limit the size, depth and number of lesions, and the radiation exposure incurred during fluoroscopy-guided catheters manipulation. The use of cryoablation seems promising in limiting lesion size. Three-dimensional (3D) mapping systems clearly have been shown to reduce the radiation dose. In congenital heart disease, these advances in technology have helped to further our understanding of the mechanisms underlying arrhythmias. It is anticipated that earlier intervention and newer operative techniques will reduce the incidence of postoperative arrhythmias in the future. For those patients who still develop tachyarrythmias after cardiac surgery, the use of three-dimensional systems and other new technologies permits more efficient intervention in the electrophysiology laboratory.

Magnetic Versus Manual Catheter Navigation for Ablation of Free Wall Accessory Pathways in Children

Background—

Transcatheter ablation of accessory pathway (AP)–mediated tachycardia is routinely performed in children. Little data exist regarding the use of magnetic navigation (MN) and its potential benefits for ablation of AP-mediated tachycardia in this population.

Methods and Results—

We performed a retrospective review of prospectively gathered data in children undergoing radiofrequency ablation at our institution since the installation of MN (Stereotaxis Inc, St. Louis, MO) in March 2009. The efficacy and safety between an MN-guided approach and standard manual techniques for mapping and ablation of AP-mediated tachycardia were compared. During the 26-month study period, 145 patients underwent radiofrequency ablation for AP-mediated tachycardia. Seventy-three patients were ablated with MN and 72 with a standard manual approach. There were no significant differences in demographic factors between the 2 groups with a mean cohort age of 13.1±4.0 years. Acute success rates were equivalent with 68 of 73 (93.2%) patients in the MN group being successfully ablated versus 68 of 72 (94.4%) patients in the manual group ( P =0.889). During a median follow-up of 21.4 months, there were no recurrences in the MN group and 2 recurrences in the manual group ( P =0.388). There were no differences in time to effect, number of lesions delivered, or average ablation power. There was also no difference in total procedure time, but fluoroscopy time was significantly reduced in the MN group at 14.0 (interquartile range, 3.8–23.9) minutes compared with the manual group at 28.1 (interquartile range, 15.3–47.3) minutes ( P <0.001). There were no complications in either group.

Conclusions—

MN is a safe and effective approach to ablate AP-mediated tachycardia in children.

Significant reduction of fluoroscopy in pediatric catheter ablation procedures: long-term experience from a single center

BACKGROUND

Traditionally fluoroscopy has been used for navigation of catheters during electrophysiological procedures. Recent advances in electroanatomic mapping technologies resulted in a decrease and even in elimination of fluoroscopy exposure during these procedures.

METHODS

Electrophysiological procedures were performed with the use EnSite NavX™ or Velocity™ (St. Jude Medical, St. Paul, MN, USA) systems. Following construction of the right atrial geometry, other relevant geometries were formed (right ventricle, coronary sinus, or left atrium). Fluoroscopy was used in patients with complex congenital heart disease, in younger children, and during transseptal punctures. Cryoablation or radiofrequency was used for catheter ablation.

RESULTS

A total of 305 patients underwent catheter ablation for various supraventricular and ventricular tachyarrhythmia substrates using EnSite system guidance. No fluoroscopy was used in 191 (63%) of these cases. The mean fluoroscopy time in the rest of the procedures was 13.9 ± 11.6 minutes (0.2-60 minutes). The mean procedure time was 184 ± 71 minutes. No complications were noted except for temporary diaphragmatic paralysis in one patient and temporary AV block in another patient following cryoablation. Acute success rate in achieving complete elimination of arrhythmia substrates was 95% (290/305). The recurrence rate was (31/271) 11.4% at a mean follow-up time of 42 ± 23 months.

CONCLUSIONS

Fluoroscopy can be significantly decreased or even eliminated in the majority of catheter ablation procedures. Long-term results demonstrate that this can be done efficiently and safely.