Follow-up of children or teenagers with paroxysmal supraventricular tachycardia, but without pre-excitation syndrome

Supraventricular Tachycardia Without Preexcitation as a Cause of Sudden Cardiac Arrest in Pediatric Patients

Sudden cardiac arrest in pediatric patients is a rare occurrence. Supraventricular tachycardia without the presence of ventricular preexcitation in pediatric patients with a structurally normal heart is generally considered benign. Previous literature in adults reported a subset of patients in whom SVT was suspected to be the primary trigger of sudden cardiac arrest. We performed a single-center, retrospective cohort study of pediatric patients without known heart disease, 1-21 years of age, presenting with aborted SCA between 2009 and 2019. We collected diagnostic studies in all patients to identify the etiology of the aborted SCA. Thirty patients met the inclusion criteria. The median age at the time of SCA was 15.2 years. The etiology of SCA was identified in 23 (77%) patients. Of the seven patients with unknown diagnosis after initial diagnostic studies, three patients subsequently developed fast SVT that was presumed to be the etiology of the initial SCA. These three patients had varying diagnoses of atrioventricular nodal reentry tachycardia, ectopic atrial tachycardia, and a concealed accessory pathway with atrioventricular reentrant tachycardia. After ablation or medical treatment of the SVT substrate, no further tachyarrhythmias were observed. Pediatric patients presenting with an aborted SCA of unknown etiology ought to be considered for electrophysiology testing to elicit occult SVT substrates that may lead to a malignant ventricular tachyarrhythmia.

Therapeutic effect of radiofrequency ablation on children with supraventricular tachycardia and the risk factors for postoperative recurrence

The present study investigated the therapeutic effect of radiofrequency ablation on children with supraventricular tachycardia (SVT), and explored the risk factors for postoperative recurrence. A total of 312 patients with pediatric SVT were selected in the Affiliated Children's Hospital of Xuzhou Medical University from April, 2011 to March, 2017. All the patients were subjected to radiofrequency ablation, and clinical data were retrospectively analyzed. Tilt table test was performed before and after treatment, and heart rate, systolic and diastolic blood pressure before and after treatment were compared. Plasma levels of D-dimer (D-D), platelet α-granule membrane protein (GMP-140) and thrombin-antithrombin III complex (TAT) were detected by enzyme-linked immunosorbent assay before treatment, immediately after radiofrequency oblation, and at 1, 3 and 7 days after treatment. Treatment outcomes were compared between the atrioventricular reentrant tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT) groups. Risk factors for postoperative recurrence were analyzed. Supine position heart rate after treatment was not significantly different from that before treatment (P>0.05), while the upright position heart rate was significantly increased after treatment (P<0.05). Systolic pressures of the supine and upright positions were significantly reduced after treatment compared with the levels before (P<0.05), but no significant differences were found in diastolic blood pressure of supine and the upright position (P>0.05). No significant difference in radiofrequency ablation rate, recurrence rate and incidence of complications were found between the AVRT and AVNRT groups (P>0.05). After radiofrequency, the levels of D-D, GMP-140 and TAT ablation showed an upward trend, but decreased at day 7 to reach preoperative levels. Logistic regression analysis revealed that residual slow pathway (OR=6.718, P=0.005) and inaccurate targeting (OR=2.815, P=0.007) were independent risk factors for postoperative recurrence (P<0.05). Although radiofrequency ablation can damage the cardiac vagal nerve, resulting in an increase in the heart rate after ablation during the course of the tilt table test and changed hemagglutination state within one week after ablation, those changes returned to normal after one week. The efficacy of radiofrequency ablation in the treatment of pediatric SVT is clear, and recurrence rate is low. Residual slow pathway and inaccurate targeting were independent risk factors for postoperative recurrence.