Controlled ventilation enhances catheter stability during radiofrequency ablation

Comparison of Outcomes of Pediatric Catheter Ablation by Anesthesia Strategy: A Report From the NCDR IMPACT Registry

[Figure: see text].

A Prospective Assessment of Optimal Mechanical Ventilation Parameters for Pediatric Catheter Ablation

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H₂O (PEEP) or 0 cm H₂O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.

Perioperative management of patients with pre-excitation syndromes

Patients with pre-excitation abnormalities are at a high risk for life-threatening perioperative arrhythmias. In Wolff-Parkinson-White syndrome, the anaesthetics used for invasive diagnostic testing/ablation, should not affect cardiac electrophysiology; propofol, sevoflurane, fentanyl, sufentanil, alfentanil are suitable. In non-ablative surgery, propofol, sevoflurane, isoflurane, fentanyl, alfentanil, sufentanil have been used safely. Among neuromuscular blockers, cis-atracurium, rocuronium and vecuronium are good choices. Ketamine, pancuronium and pethidine should be avoided because of their sympathomimetic actions. Anticholinergic/ anticholinesterase combinations for neuromuscular block reversal should preferably be omitted, while sugammadex seems more attractive. In regional anaesthesia, addition of epinephrine and high sympathetic blocks should be avoided. Hypotension should be treated with pure alpha-adrenergic agonists. Other pre-excitation abnormalities associated with different accessory pathways are the Mahaim Fiber and Lown-Ganong-Levine syndrome. Sympathetic activation should be avoided. Total intravenous anaesthesia with propofol probably represents the safest option. A careful anaesthetic plan and close cooperation with cardiologists are mandatory for successful management.

Radiofrequency catheter ablation for dyssynchrony-induced dilated cardiomyopathy in an infant

The relationship between accessory pathway-mediated ventricular preexcitation and left ventricular dyssynchrony-induced dysfunction has been described in patients with Wolff-Parkinson-White (WPW) syndrome in the absence of sustained supraventricular tachycardia (SVT). Supraventricular tachycardia in infants is usually successfully suppressed with antiarrhythmic medications, but catheter ablation has ultimately been required as definitive treatment in medically resistant cases. Catheter ablation has not been described in young infants for dyssynchrony-related dilated cardiomyopathy in the absence of SVT. We describe a case of an infant with WPW who did not have sustained supraventricular tachycardia, but who developed rapid progression of ventricular dysfunction after birth. Preexcitation could not be medically suppressed but was successfully ablated. This was followed by complete resolution of ventricular dysfunction within 2 months.

Postoperative nausea and vomiting in children and adolescents undergoing radiofrequency catheter ablation: a randomized comparison of propofol- and isoflurane-based anesthetics

In children, radiofrequency catheter ablation (RFCA) is typically performed under general anesthesia. With the use of volatile anesthetics, postoperative nausea and vomiting (PONV) are common, with an incidence of emesis as frequent as 60%. We tested the hypothesis that a propofol (PRO)-based anesthetic would have a less frequent incidence of PONV than an isoflurane (ISO)-based anesthetic. Patients were randomly assigned to receive either an ISO- or PRO-based anesthetic. Prophylactic ondansetron was given to all patients and droperidol was used as a rescue antiemetic postoperatively while PONV was monitored postoperatively for 18 h. The incidence of nausea, vomiting, use of rescue antiemetic drugs, and sedation scores were recorded. The cost for the anesthetic was also calculated. Fifty-six subjects were included in this study. The cumulative incidence of PONV was significantly more frequent in group ISO (63% nausea/55% emesis) compared with group PRO (21% nausea/6% emesis). After the administration of droperidol, further vomiting occurred in 70% of the patients in group ISO versus 0% of the patients in group PRO. We conclude that RFCA using ISO has a high PONV risk and the prophylactic use of ondansetron as well as antiemetic therapy with droperidol are ineffective. In contrast, a PRO-based anesthetic is highly effective in preventing PONV in children undergoing RFCA.

IMPLICATIONS

In children undergoing radiofrequency catheter ablation and receiving prophylactic ondansetron, a frequent incidence (60%) of postoperative vomiting was observed under an isoflurane-based anesthetic, whereas the incidence was significantly reduced to a very low level (5%) under a propofol-based anesthetic.

Radiofrequency catheter ablation of left-sided accessory pathways in pediatric patients

In many cases, radiofrequency catheter ablation has replaced the long-term use of antiarrhythmic medication for symptomatic tachycardia, and has all but eliminated arrhythmia surgery. The most common substrate for radiofrequency catheter ablation in pediatric patients is atrioventricular (AV) reentry tachycardia due to a concealed or manifest accessory pathway. Accessory pathways are distributed unevenly along the right and left atrioventricular valve annuli, and left-sided accessory pathways are most common. Although some centers advocate an abbreviated diagnostic and mapping approach to both concealed and manifest left-sided accessory pathways, most still use a complete electrophysiological evaluation and complex catheter manipulation for mapping, followed by the application of radiofrequency energy. Left-sided accessory pathways may be approached from the transatrial approach, the retrograde aortic approach, or less commonly from within the coronary sinus. Each approach has proven to be associated with success, but also with a distinct set of risks. Possibly because left-sided accessory pathways are most common, catheter ablation of this substrate has proven highly successful and has the lowest risk of recurrence. However, recent data also suggest that this substrate is associated with greater risk of complications than of right-sided accessory pathways or pathways located in the posteroseptal region. The following report reviews some of the recently described diagnostic and mapping techniques, success rates, risks and follow-up data in pediatric patients undergoing radiofrequency catheter ablation of left-sided accessory pathways.