Validation of a smartphone-based electrocardiography in the screening of QT intervals in children.

OBJECTIVE: A 12-lead electrocardiography is a critical component for the screening of long QT syndrome; however, besides, an electrocardiograph, trained personnel are also necessary which limits the screening capability of conventional electrocardiographs. The development of smartphone electrocardiography technologies provides a potential alternative platform for electrocardiography screening for selective purposes such as arrhythmias and QT interval abnormalities. The aim of this pilot study was to assess the reliability of a smartphone-based electrocardiography device in the measurement of QT and corrected QT intervals in children. METHODS: In all participants, 10-s smartphone electrocardiography tracing from AliveCor device and a standard 12-lead electrocardiograph were obtained simultaneously. Two pediatric electrophysiologists performed the measurements of QT and corrected QT intervals in a blinded manner with Bazett's formula. The results were compared statistically. RESULTS: A total of 285 children (mean age 9.8±4.9 years) who presented to our clinic were included in the study. The mean QT intervals obtained from 12-lead electrocardiographs and AliveCor devices were 343±40 ms and 340±41 ms, respectively. The mean corrected QT intervals obtained from 12-lead electrocardiographs and AliveCor devices were 419±28 ms and 415±33 ms, respectively. There was high correlation between the QT intervals of 12-lead electrocardiographs and AliveCor recordings (Pearson's correlation coefficient: 0.83 [p<0.001]) and significant correlation between the corrected QT intervals of 12-lead electrocardiographs and AliveCor recordings (Pearson's correlation coefficient: 0.57 [p<0.001]). CONCLUSION: AliveCor recordings can accurately detect QT intervals and can potentially be used for the screening of congenital long QT syndrome in children.

Long-term outcomes following cryoablation of atrioventricular nodal reentrant tachycardia in children.

BACKGROUND: Atrioventricular nodal reentrant tachycardia (AVNRT) is a common tachyarrhythmia substrate in children, which is successfully treated by catheter ablation using radiofrequency or cryothermal energy. In recent years, cryoablation (Cryo) using electroanatomical system guidance is more commonly preferred for use in children in order to decrease the risk of an atrioventricular block. However, there are concerns regarding the long-term efficacy of Cryo in treating AVNRT. We aimed to evaluate the feasibility, safety, and long-term efficacy of Cryo for AVNRT in children. METHODS AND RESULTS: A total of 275 consecutive children above 4 years of age diagnosed with AVNRT were included in our study. The EnSite system (St. Jude Medical, Inc., St. Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The study included 275 patients (148 females, age: 11.9 ± 3.6 years) undergoing catheter ablation for AVNRT from July 2012 to September 2016. Acute success was obtained in all (100%) patients with a mean procedure time of 140 ± 44 minutes. Fluoroscopy was used in only 12 (4.4%) patients. During a follow-up time of 25.6 ± 13.5 months (median: 23 months), AVNRT recurred in 12 of 279 (4.4%) of the patients. Age, sex, number of Cryo lesions, and catheter tip size (6-mm vs 8-mm) were not predictive for recurrence. In nine patients, a repeat ablation was successfully performed with cryoenergy. CONCLUSIONS: Cryo for AVNRT is a safe and effective procedure with excellent long-term outcomes. The use of electroanatomical systems during ablation significantly decreases exposure to fluoroscopy without compromising success.

Comparison of 6-mm Versus 8-mm-Tip Cryoablation Catheter for the Treatment of Atrioventricular Nodal Reentrant Tachycardia in Children: A Prospective Study.

Due to its safety profile, cryoablation (Cryo) for atrioventricular nodal reentrant tachycardia (AVNRT) is more commonly preferred over radiofrequency (RF) ablation in children in recent years. Recent studies demonstrated high long-term success rates comparable to radiofrequency ablation. The aim of this prospective study was to compare the efficacy and safety of an 8-mm-tip versus 6-mm-tip Cryo catheter in the treatment of AVNRT in children. A total of 125 consecutive patients over 10 years of age with AVNRT were included. EnSite system (St. JudeMedical, St Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The acute procedural success was 100% in both groups. The prodecure duration for the 8-mm-tip group was shorter (151.6 ± 63.2 vs. 126.6 ± 36.7 min, p < 0.01, respectively). Fluoroscopy was used in only 7 patients. The mean follow-up duration was 14.6 ± 8.4 months (median 13.5 months, min. 3 months and max. 27 months). The recurrence rate for AVNRT was also comparable between the two groups (6-mm tip: 9.6 vs. 8-mm tip: 8%). Cryo of AVNRT is a safe and effective procedure with comparable acute and mid-term follow-up success rates using 6-mm and 8-mm-tip catheters in children. In addition, procedure duration is shorter with an 8-mm-tip Cryo catheter.

Catheter ablation of idiopathic right ventricular arrhythmias in children with limited fluoroscopy.

INTRODUCTION: Definitive therapy of idiopathic right ventricular arrhythmias (VA) remains a challenge in interventional electrophysiology. The aim of this study was to evaluate the utility of EnSite Velocity system in the catheter ablation of RV tachycardia in children. METHODS: Thirty-five children with idiopathic right VA underwent catheter ablation procedure using the EnSite Velocity system guidance. RESULTS: The mean patient age was 12.0 ± 3.7 years and the mean patient weight was 43.6 ± 18.7 kg. The origin of right VA was divided into right ventricular outflow tract (RVOT) (30 patients) and other right ventricular localizations (five patients). The mean procedure and fluoroscopy times were 175 ± 67 min and 2.35 ± 1.89 min, respectively. No fluoroscopy was used in 19 patients. Acute success was achieved in 29 patients (83 %). The focus of VA was epicardial in three failed procedures. Cryocatheter (6-mm or 8-mm tip) was used in six patients, radiofrequency ablation (RFA) (4-mm or 8-mm tip) in 26 patients, and 4-mm tip irrigated RFA in three patients. During a mean follow-up of 15.9 ± 7.1 months, ventricular tachycardia recurred in six patients (20 %). There were three complications (transient atrioventricular block developed in one patient during parahissian cryoablation and two patients developed transient complete right bundle branch block). CONCLUSIONS: Catheter ablation of idiopathic right VA in children can be performed safely and effectively with limited fluoroscopy using the EnSite Velocity system.

A rare coronary anomaly with masked diagnosis: Anomalous left circumflex artery from right pulmonary artery.

Anomalous origin of the circumflex coronary artery from the pulmonary artery is a rare congenital coronary anomaly. While it generally follows an asymptomatic course, if undiagnosed it may lead to severe clinical outcomes, including sudden death. The condition can be masked by associated defects, so when it is clinically suspected, diagnosis must be confirmed by conventional and/or magnetic resonance angiography, even if echocardiography clearly shows coronary roots. This report describes a patient who underwent neonatal surgery for aortic coarctation and was diagnosed with coronary artery anomaly at 15 months old.