Anaesthetic management of paediatric patients undergoing electrophysiology study and ablation for supraventricular tachycardia: A focused narrative review

Every year, 80,000-100,000 ablation procedures take place in the United States and approximately 1% of these involve paediatric patients. As the paediatric population undergoing catheter ablation to treat dysrhythmia is constantly growing, involvement of anaesthesiologists in the cardiac electrophysiology laboratory is simultaneously increasing. Compared with the adult population, paediatric patients need deeper sedation or general anaesthesia (GA) to guarantee motionlessness and preserve comfort. As a result, the anaesthesiologist working in this setting should keep in mind heart physiopathology as well as possible interactions between anaesthetic drugs and arrhythmia. In fact, drug-induced suppression of accessory pathways (APs) conduction capacity is a major concern for completing a successful electrophysiology study (EPS). Nevertheless, the literature on this topic is scarce and the optimal type of anaesthesia in EPS and ablation procedures in children is still controversial. Thus, the main goal of the present review is to collect the literature published so far on the effects on cardiac conduction tissue of the drugs commonly employed for sedation/GA in the cath lab for EPS and ablation procedures to treat supraventricular tachycardia in patients aged <18 years.

Recent Developments in Cardiology Procedures for Adult Congenital Heart Disease: The Anesthesiologist's Perspective

Many children born today with congenital heart disease can expect to live long into adulthood. Improvements in surgical technique and anesthetic and perioperative care have significantly increased the number of survivors. Unfortunately, as these patients progress through life they frequently require further interventions. Although surgical intervention may be required frequently, these patients can be managed in the cardiac catheterization or electrophysiology laboratory. Surgical correction of tetralogy of Fallot can leave patients with pulmonary valve dysfunction later in life. A percutaneous approach is now available for these patients, which can obviate the need for resternotomy. During deployment of the valve, anesthesiologists should be aware that compression of coronary arteries can occur. Adult congenital heart disease (ACHD) patients often require pacemaker/implantable cardioverter- defibrillator (ICD) insertion or ablation therapy. These patients may have altered cardiac anatomy, which can make endovascular procedures extremely challenging. Recent developments have made these procedures safer and more efficient. A number of congenital cardiac conditions can also be associated with orofacial abnormalities. ACHD patients, as a result, can present with challenging airways. The catheterization laboratory may not be the optimum environment for the anesthesiologist to manage a difficult airway. The requirement of transesophageal echocardiography for some cath eterization procedures needs to be considered when deciding on an airway management plan. Knowledge of the underlying cardiac anatomy and the planned procedure is advised when providing anesthesia for this complex patient group outside the theater setting.

Differential effects of sevoflurane and propofol on swine cardiac conduction system

OBJECTIVE

To compare the effects of sevoflurane and propofol on the porcine cardiac conduction system.

STUDY DESIGN

A prospective, comparative study of electrophysiological properties of anaesthetics agents in an experimental porcine model.

ANIMALS

A total of 36 hybrid Landrace-Large White pigs.

METHODS

After premedication with 20 mg kg^-1 of intramuscular ketamine, anaesthesia was induced with 4.5 mg kg^-1propofol intravenously. In 18 consecutive animals, anaesthesia was maintained with propofol (13 mg kg^-1 hour^-1) and in the remaining 18 animals with 2.66% sevoflurane. The femoral artery and vein were canalized for invasive monitoring, analytical blood gas sampling and intracardiac catheter insertion. Following instrumentation and after a period of stabilization, a customary electrophysiological evaluation was performed. We compared the electrophysiology of the sinus and atrioventricular node (AV) node under sevoflurane or propofol anaesthesia, and the effects of both anaesthetics on atrial and ventricular refractoriness.

RESULTS

There was a significant difference in sinus node recovery time between sevoflurane and propofol (907 ± 231 versus 753 ± 146 ms, p = 0.02). Sevoflurane in comparison with propofol significantly prolonged specialized AV conduction times, represented by an increased Wenckebach cycle length (272 ± 54 versus 235 ± 40 ms, p = 0.03) and AV nodal refractoriness (327 ± 34 versus 287 ± 30 ms, p = 0.002). In addition, sevoflurane prolonged ventricular refractoriness (298 ± 27 versus 255 ± 38 ms, p = 0.007) and the QT corrected interval (0.50 ± 0.05 versus 0.46 ± 0.09 ms, p = 0.005).

CONCLUSIONS AND CLINICAL RELEVANCE

Sevoflurane in comparison with propofol, depresses several parameters of sinus and AV nodal function and prolongs the ventricular refractoriness of the porcine cardiac conduction system. These findings should be taken into consideration for the choice of anaesthetic agents in clinical and experimental settings.

Anesthesia in the Electrophysiology Laboratory

The electrophysiology suite is a foreign location to many anesthesiologists. The initial experience was with shorter procedures under conscious sedation, and the value of greater tailoring of the sedation/anesthesia by anesthesiologists was not perceived until practice patterns had already been established. Although better control of ventilation with general anesthesia may be expected, suppression of arrhythmias, blunting of the hemodynamic adaptation to induced arrhythmias, and interference by muscle relaxants with identification of the phrenic nerve may be seen. We review a range of electrophysiology procedures and discuss anesthetic approaches that balance patient safety and favorable outcomes.

Anesthetic Management in Radiofrequency Catheter Ablation of Ventricular Tachycardia

Radiofrequency catheter ablation is increasingly being used to treat patients who have ventricular tachycardia, and anesthesiologists frequently manage their perioperative care. This narrative review is intended to familiarize anesthesiologists with preprocedural, intraprocedural, and postprocedural implications of this ablation. Ventricular tachycardia typically arises from structural heart disease, most often from scar tissue after myocardial infarction. Many patients thus affected will benefit from radiofrequency catheter ablation in the electrophysiology laboratory to ablate the foci of arrhythmogenesis. The pathophysiology of ventricular tachycardia is complex, as are the technical aspects of mapping and ablating these arrhythmias. Patients often have substantial comorbidities and tenuous hemodynamic status, necessitating pharmacologic and mechanical cardiopulmonary support. General anesthesia and monitored anesthesia care, when used for sedation during ablation, can lead to drug interactions and side effects in the presence of ventricular tachycardia, so anesthesiologists should also be aware of potential perioperative complications. We discuss variables that can help anesthesiologists safely guide patients through the challenges of radiofrequency catheter ablation of ventricular tachycardia.

Feasibility and safety of transseptal puncture procedures for radiofrequency catheter ablation in small children weighing below 30 kg: single-centre experience

AIMS

Transseptal puncture (TSP) has become a common approach in catheter ablation of arrhythmia originating from the left atrium. In paediatric patients, however, TSP can be a challenge due to narrower access vessels and small left atrial size, and the safety of TSP in smaller children is yet to be understood. The purpose of this study was to retrospectively evaluate the feasibility and safety of TSP in children weighing below 30 kg.

METHODS AND RESULTS

Among 655 paediatric patients who underwent catheter ablation of arrhythmia between July 2009 and April 2015, 43 cases having structurally normal hearts, weighing <30 kg and requiring TSP were included in the study. Age, height, body weight, diagnosis, and complications during TSP and catheter ablation were evaluated. The median age, height, and body weight (range) were 7.0 years (0.3-11.1), 116.8 cm (54.0-138.4 cm) and 21.5 kg (4.3-29.6 kg), respectively. Diagnosis included manifest (n = 27; 62.8%) and concealed accessory pathway (n = 14; 32.6%) and atrial tachycardia (n = 2; 4.6%). In 10 cases (23.2%), TSP using radiofrequency energy was performed. None of the patients had major complications. Pericardial effusion was recorded as a minor complication in one patient (2.3%).

CONCLUSION

TSP was feasible, safe, and of low risk of complications in children weighing <30 kg.

Anesthetic considerations for electrophysiologic procedures

The array of diagnostic and therapeutic procedures performed in the cardiology electrophysiology laboratory has expanded rapidly. Increasingly more facilities and cardiologists are performing these procedures, and the number of patients for whom these procedures are indicated is expanding. Because of the complexity of the procedures and associated patient comorbidity, anesthesia providers will become more involved in providing care in the electrophysiology laboratory. Therefore, anesthesia providers must be prepared to handle a broad range of case complexity. This article addresses the implications of providing anesthesia safely and effectively in the electrophysiology laboratory.

Anesthesia for Electrophysiology Studies and Catheter Ablations

Providing anesthesia in nonoperating room locations is becoming increasingly common. The field of electrophysiology and its patient population are growing, resulting in a greater need for anesthesiologists in the electrophysiology laboratory. The procedures are complex and of long duration with patients who have multiple comorbidities. The electrophysiology laboratory is a unique situation in that arrhythmias are sought and sometimes even provoked so that they may be eliminated. The focus of this review will be on anesthesia for electrophysiology studies and catheter ablation.