Invasive electrophysiology in children: state of the art

Wolff-Parkinson-White Syndrome in a Term Infant Presenting With Cardiopulmonary Arrest

BACKGROUND

Wolff-Parkinson-White syndrome is a congenital abnormality of the cardiac conduction system caused by the presence of an abnormal accessory electrical pathway between the atria and the ventricles. This can result in intermittent tachyarrhythmias such as supraventricular tachycardia. In rare occasions, sudden death may occur from atrial fibrillation with rapid ventricular conduction. Supraventricular tachycardia typically has a sudden onset and offset, classified as a paroxysmal arrhythmia. Because of the variable occurrence, Wolff-Parkinson-White syndrome may go undiagnosed in the immediate newborn period.

PURPOSE

To highlight arrhythmia as a possible cause of sudden decompensation in infants.

CASE FINDINGS/RESULTS

The clinical presentation of this infant is complex and a number of potential diagnoses were considered. Preexcitation on electrocardiogram resulted in the diagnosis of Wolff-Parkinson-White syndrome.

IMPLICATIONS FOR PRACTICE

Nurses caring for infants should be alert to tachycardia and irregularities of the heart rate, including those in the prenatal history, and should report them for evaluation. While all parents should be taught to watch for signs of illness, parents of infants with Wolff-Parkinson-White have additional learning needs, including recognizing early signs and symptoms of heart failure.

Minimally invasive approach to the child with palpitations

Palpitations are a common reason for referral to a pediatric cardiologist. Although generally benign, palpitations are a significant cause for concern in the individual and their family. Similarly, palpitations may be the initial presentation of significant heart disease, resulting in heightened concern in the referring physician. Although emphasis is usually placed on excluding arrhythmia as the cause for palpitations, there are a variety of noncardiac causes for palpitations. The patient history and physical examination are the key components of the evaluation and guide subsequent investigations. In many cases, an immediate diagnosis cannot be made and additional testing may be required; this often includes further monitoring for episodes, cardiac imaging and ambulatory monitoring. Current technologies for ambulatory monitoring during symptoms include Holter monitoring and a variety of patient-activated event recorders, including implantable loop recorders. Each presents its own unique advantages and disadvantages to aid diagnosis in the management of a child with palpitations. The primary focus for the clinician is to determine whether the etiology is benign in nature or whether there is underlying heart disease that may carry a more serious prognosis.

Coronary microcatheter mapping of coronary arteries during radiofrequency ablation in children

INTRODUCTION

Radiofrequency catheter ablation (RFCA) is a safe and effective treatment option for children with refractory supraventricular tachycardias. RFCA of right-sided accessory pathways (APs) continues to be challenging, resulting in lower success rates and higher recurrence rates. One of the reasons for a prolonged or failed procedure is mapping error and changes in cardiac anatomy. The right coronary artery (RCA) runs along the ventricular aspect of the right epicardial atrioventricular groove, and RCA mapping had been reported facilitating difficult right-sided AP RFCA in the pediatric population. We reported that microcatheter-assisted mapping during RFCA can improve localization of right-sided and some left-sided APs particularly in children with congenital heart disease.

METHODS

This technique was used in seven patients with a mean age of 15.3+/-1.6 years and a mean weight of 52.6+/-6.5 kg. Five patients (71%) had manifest preexcitation on surface electrocardiogram, and two patients had a concealed AP. In two of them, there were single ventricle anatomies. In the other two patients, venous access problem to the heart and enormous cardiac hypertrophy were the major problems. In the remaining three patients with normal cardiac anatomy, RCA mapping was used because a standard procedure was not successful. Previous RFCA ablation was not successful in two patients. Either a 150-cm eight-electrode pair (2-6-2 mm, 2.5 French) or a four-electrode pair (2-6-2 mm, 2.3 French) microcatheter (2.3 French octapolar microcatheter) was used.

RESULTS

Average time of the multielectrode RCA mapping was 42+/-14.5 min. All eight (100%) APs were successfully ablated. No complications occurred.

CONCLUSIONS

Microcatheter-assisted coronary artery mapping during RFCA is a useful adjunctive mapping technique in children with difficult to map right-sided APs and patients with APs who has complex cardiovascular anomalies.

Pediatric arrhythmias: which are the news?

Knowledge about cardiac arrhythmias has significantly improved in the last 20 years, and the improvements in diagnosis and in therapy have also had important effects on the management of pediatric arrhythmias. In this paper, the most important developments in the field of management of pediatric arrhythmias (fetal arrhythmias, genetics, pharmacological strategies, radiofrequency ablation, new technologies) as well as the remaining problems (risk stratification of some arrhythmic forms as for example Wolff-Parkinson-White and ventricular arrhythmias) will be discussed.

Improved Localization of Right‐Sided Accessory Pathways with Microcatheter‐Assisted Right Coronary Artery Mapping in Children

INTRODUCTION

Radiofrequency ablation of some right-sided accessory pathways continues to be challenging. The purpose of this study was to evaluate the efficacy of introducing a multielectrode microcatheter in the right coronary artery to localize accessory pathways when conventional mapping was unsuccessful.

METHODS AND RESULTS

A retrospective study was conducted of all right-sided accessory pathway radiofrequency ablation procedures in which a multielectrode microcatheter as a reference in the right coronary artery was used to assist mapping. Between January 1998 and January 2002, 10 patients (5 males) underwent mapping of 11 accessory pathways with this technique at mean age of 12.3 +/- 3.8 years. Five patients had Ebstein's anomaly of the tricuspid valve. Accessory pathways were identified in the following locations: right anterior 3, right anterolateral 2, right lateral 1, right posterolateral 2, and right posterior 3. Mean procedure time was 285 +/- 70.3 minutes, and fluoroscopy time was 68.7 +/- 21 minutes. Average mapping duration prior to microcatheter insertion in the right coronary artery was 136 +/- 40 minutes. After microcatheter placement in the right coronary artery, the time to successful ablation of accessory pathways was 38 +/- 11 minutes. All 11 (100%) accessory pathways were successfully ablated.

CONCLUSION

Mapping in the right coronary artery with a microcatheter is an effective method to improve localization and successful ablation of difficult right-sided accessory pathways.

Anaesthesia for children with congenital heart disease undergoing diagnostic and interventional procedures

PURPOSE OF REVIEW

Anaesthesiologists are often asked to administer sedation and anaesthesia to infants and children with congenital heart disease undergoing diagnostic and interventional procedures. A number of issues are pertinent to a safe and effective provision of care for these patients. The anaesthetic should ensure haemodynamic stability, provide real-life circumstances to ensure diagnostic accuracy, should be easy and reliable to titrate in order to cope with rapidly changing loading conditions and intense but short-lived haemodynamic disturbances. The anaesthetic drugs should not interfere with electrophysiological processes in the cardiac conduction system, and above all anaesthetic recovery should be swift and devoid of side-effects.

RECENT FINDINGS

In recent years, new agents have been introduced in the anaesthetic care of these patients. One has studied the haemodynamic and electrophysiological properties of agents such as remifentanil, desflurane, sevoflurane and propofol and their use in children with congenital heart disease. New and older drugs have been combined in balanced techniques to decrease the side-effects associated with monotherapy. Besides these anaesthetic concerns, the controversy about the presence of an anaesthesiologist versus a non-anaesthesiologist still continues.

SUMMARY

The newer anaesthetic agents, such as desflurane, remifentanil, sevoflurane and propofol are an integral part of our armamentarium to care for children with congenital heart disease. The combination of these and older drugs allow us to provide anaesthetic care in an effective and efficient way.