Antonella De Santis

Cryoablation of Typical Atrioventricular Nodal Reentrant Tachycardia in Children: Six Years’ Experience and Follow‐Up in a Single Center

Background: Cryoablation is an effective and safe treatment for children with supraventricular tachycardias when the reentry circuit is located near the atrioventricular (AV) junction. We retrospectively reviewed consecutive cryoablation procedures for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT) in children and young adults in a single pediatric center.

Atrioventricular nodal reentrant tachycardia in children

The purpose of this study was to identify the clinical and electrophysiological characteristics of children with atrioventricular reentry tachycardia (AVNRT) and to define the prognosis and the treatment strategy. Sixty-two children (28 males and 34 females mean age, 10.2 ± 3.2 years) with AVNRT (“slow–fast” type) were included in the study. Patients were divided into two groups: 47 patients with severe symptoms (group A) and 15 with mild symptoms (group B). The severity of the symptoms was not related to the electrophysiological parameters. Females were more symptomatic than males. Patients in group B did not receive any treatment (except 1 because of parents’ choice) nor did they develop symptoms, and 5 patients had resolution of palpitations. Forty-one of 46 patients in group A were successfully treated with medical therapy as initial treatment. Thirty-one patients in group A underwent slow pathway ablation. There were late recurrences of AVNRT in 6 patients. Typical AVNRT in young patients does not appear to be life threatening. Patients with mild or no symptoms do well without therapy. Medical therapy and slow pathway ablation appear to be effective in the more symptomatic patients. Age and electrophysiological variables are not related to the symptoms or response to treatment. Females with AVNRT are more symptomatic and more likely to present with syncope.

Paroxysmal reciprocating supraventricular tachycardia in infants: electrophysiologically guided medical treatment and long-term evolution of the re-entry circuit

AIMS The aim of this study is to evaluate the long-term prognosis in infants affected by paroxysmal reciprocating supraventricular tachycardia (SVT), to identify predictors of SVT disappearance, and to assess the efficacy of electrophysiologically guided drug therapy in preventing recurrences. METHODS AND RESULTS A six step regimen of oral therapy was used in 55 infants with SVT: (i) propafenone (P); (ii) flecainide (F); (iii) flecainide plus propranolol (FP); (iv) amiodarone (A); (v) amiodarone plus propranolol (AP); (vi) amiodarone plus flecainide plus propranolol (AFP). If one step was not successful, the patient was passed on to the next treatment step and so on. Transesophageal atrial pacing (TAP) was used to evaluate treatment efficacy and the evolution of SVT at the end of the first, second, and third year. Propafenone was successful in 32.7% of the patients, F in 14.5%, FP in 23.6%, A alone in 5.4%, and AP in 18.1%; only 7.2% reached step 6. At month 12, after therapy wash out, SVT recurred spontaneously in 2 patients (3.6%) and remained inducible in 25 (45.5%). Inducibility was significantly higher in patients treated with A. At 24 months, SVT was inducible or spontaneous in 86% of the cases and at 36 months in 87%. There were no recurrences using the treatment confirmed by TAP. No further predictor of SVT inducibility was identified. CONCLUSION Supraventricular tachycardia disappeared in approximately 50% of the patients during the first year of life and in another 20% thereafter. The necessity for A treatment is the only predictor of persistence of the re-entry circuit during the first year of life. Transesophageal atrial pacing is useful in guiding the medical treatment.

Beat-to-Beat Heart Rate Adaptation in Pediatric and Late Adolescent Patients with Closed Loop Rate-Responsive Pacemakers

The aim of this study was to evaluate the efficacy of physiological rate‐responsive pacemakers (Closed Loop Stimulation – CLS) to pace pediatric and late adolescent patients undergoing rest, mental, standing, and exercise testing. Dual‐chamber pacemaker is increasingly indicated for young patients. A new physiological pacing mode based on the indirect measure of ventricular contractility (CLS), has shown interesting results in adults, while no data on pediatric patients are available. RR intervals and beat‐to‐beat systolic and diastolic pressures were monitored in 12 pediatric patients (6 males, mean age 17 years [12–22 years]) who had a transvenous implant of Inos2+‐CLS dual‐chamber pacemaker (Biotronik GmbH, Berlin, Germany) and endocardial leads. All the patients showed correct electrical parameters at the implant and during the follow‐ups. Paced RR intervals decreased significantly (F = 7.28, P = 0.01) from 0.85 ± 0.08 seconds (rest) to 0.73 ± 0.10 seconds (mental) and to 0.75 ± 0.010 seconds (standing); systolic/diastolic pressure was significantly higher (F = 12.2, P = 0.002/F = 13.6, P = 0.001) in mental (134.4 ± 19.9/74.4 ± 8.1 mmHg) with respect to rest (115.1 ± 18.3/61.0 ± 6.1 mmHg), and standing (118.7 ± 23.9/67.3 ± 0.1 mmHg). During exercise the paced RR interval showed significant decrease of about 35% from baseline to maximum load (F = 24.90, P = 0.001) and systolic pressure increased significantly (F = 4.91, P = 0.019) by about 34% from baseline to maximum load. The comparison between paced and spontaneous rates showed very similar values and trend. In addition, CLS mode does not seem to overrun the spontaneous heart activity, when present. This is a study to evaluate CLS pacing in pediatric and late adolescent patients. The study shows that CLS pacing responds to both physical and non‐physical stressors, providing physiological pacing rates, as previously observed in adults.

Molecular analysis of PRKAG2, LAMP2, and NKX2‐5 genes in a cohort of 125 patients with accessory atrioventricular connection

Molecular Analysis of PRKAG2, LAMP2, and NKX2-5 Genes in a Cohort of 125 Patients With Accessory Atrioventricular Connection Giorgia Esposito, Giorgia Grutter, Fabrizio Drago, Mauro W. Costa, Antonella De Santis, Giovanna Bosco, Bruno Marino, Emanuele Bellacchio, Francesca Lepri, Richard P. Harvey, Anna Sarkozy,* and Bruno Dallapiccola IRCCS-Casa Sollievo della Sofferenza, San Giovanni Rotondo, Rome, Italy Casa Sollievo della Sofferenza-Mendel Institute, Rome, Italy Department of Experimental Medicine and Pathology, University ‘‘La Sapienza’’, Rome, Italy Department of Pediatric Cardiology, Bambino Gesu? Hospital, IRCCS, Rome, Italy Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, Australia Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil Section of Pediatric Cardiology, Department of Pediatrics, University ‘‘La Sapienza’’, Rome, Italy

Transcatheter closure of coronary artery fistula using the new Amplatzer vascular plug and a telescoping catheter technique.

Coronary artery fistulas (CAFs) are rare congenital or acquired anomalies characterized by an abnormal communication between the coronary arteries and the cardiac chambers or great vessels. Most patients are asymptomatic during childhood but symptoms and complications have been reported with advancing age. Until recently, surgery was the routine mode of treatment for CAFs but, today transcatheter closure is recommended using a variety of devices, such as occlusion coils, vascular plugs, umbrella devices and covered stents. The case described here is of a 47-year-old woman with a large bilateral CAF draining into the pulmonary artery, successfully treated by implantation of two Amplatzer vascular plugs using a telescoping catheter technique.

Use of DDDRP Pacing Device in Prevention and Treatment of Tachy-Brady Syndrome After Mustard Procedure

A 13‐year‐old male patient, who underwent Mustard operation for a very complex congenital heart disease (CHD), after palliation presented a decrease of the sinus node function, developing a tachy‐brady syndrome and a mild dysfunction of atrioventricular (AV) conduction. He was successfully treated using a DDDRP pacemaker, which ensured a suitable atrial rhythm and was able to interrupt supraventricular tachycardia episodes. Until now, hospitalization related to episodes of heart failure or symptomatic arrhythmia, has not been necessary. (PACE 2004; 27:530–532)

Circadian pattern of atrial pacing threshold in the young

AIM The aim of this study was to evaluate the circadian variation of atrial pacing threshold in young patients. METHODS AND RESULTS Atrial Capture Management (ACM) algorithm is a Medtronic EnPulse pacemaker (PM) feature that uses two algorithms: atrioventricular conduction (AVC) (atrial pacing and spontaneous AVC) and atrial chamber reset (ACR) [intrinsic atrial activity with atrioventricular block (AVB)]. For this prospective, non-randomized study, ACM automatically measured and recorded thresholds every 4 h. Data are reported as median (range) or mean +/- SD. In 2004-05, 14 consecutive patients (11 males, 79%), aged 12 years (1 day-24 years) received an EnPulse DDD/R PM for AVB (eight patients, 57%) or sinus node dysfunction. A new pacing system was implanted in eight patients (57%) and a replaced PM in six patients. Epicardial leads were implanted in 10 patients (71%). The follow-up duration is 11 (1-18) months: 9742 threshold measurements were attempted (6328 AVC, 3414 ACR), of which 3797 (39%) were successful (1807 AVC, 29%, 1990 ACR, 58%) in 11 (79%) patients. Three infants had no successful measurements. Measurement success was 42 +/- 34% (AVC 27 +/- 39%, ACR 41 +/- 29%). Higher thresholds were found between 00.00 and 12.00 a.m. and lower between 12.00 and 20.00. CONCLUSION Young patients show a circadian variability of atrial threshold with higher thresholds between 00.00 and 12.00.

Transcatheter Ablation of Supraventricular Tachycardias in Pediatric Patients

Ablation has become an important treatment for many pediatric patients with common supraventricular tachycardias (SVTs). Many multicenter studies have documented that radiofrequency (RF) catheter ablation is a safe and effective procedure for treatment of a large variety of SVTs in children and adults with a high success rate and minimal complications. Novel electrophysiology technologies such as electroanatomic mapping and sophisticated ablating catheters have improved success rates and decreased complications of transcatheter ablation. Moreover, within the last several years, a new energy source using cryoenergy has evolved as a safe and effective alternative for catheter ablation for arrhythmogenic substrates traditionally associated with increased risk when using RF ablation. In this review pediatric transcatheter ablation practice is analysed and discussed with reference to current clinical guidelines.

AMPLATZER versus Figulla occluder for transcatheter patent foramen ovale closure

AIMS The aim of this observational study was to compare acute and 12-month results of percutaneous closure of patent foramen ovale (PFO) with two occluder devices. METHODS AND RESULTS Between June 2007 and October 2014, 406 consecutive patients (48.1±13.3 years, 243 women) underwent percutaneous PFO closure with either the AMPLATZER (n=179) or the Figulla (n=227) device after a stroke or a transient ischaemic attack ascribed to the PFO. A right-to-left shunt grade >1 was previously detected in all patients and atrial septal aneurysm was present in 111 (27.5%) patients. Patients were followed up with a contrast transthoracic echocardiogram and clinically at 24 hours, six months, and 12 months after the procedure. A high procedural success was observed in both groups. Despite a trend towards a higher incidence of acute residual shunt immediately after device deployment among Figulla occluder patients, a residual grade ≥2 right-to-left shunt was observed in 4.5% of patients, independently of the device used for PFO closure. The only difference reported after Figulla device implantation was a lower rate of supraventricular arrhythmias (9% vs. 17%, p=0.02). CONCLUSIONS According to this two-centre study, PFO closure appears safe and effective with the Figulla occluder as well as with the AMPLATZER device.