Is There a Difference in Tachycardia Cycle Length during SVT in Children with AVRT and AVNRT?

BACKGROUND: There are limited adult data suggesting the tachycardia cycle length (TCL) of atrioventricular reentry tachycardia (AVRT) is shorter than atrioventricular nodal reentry tachycardia (AVNRT), though little data exist in children. We sought to determine if there is a difference in TCL between AVRT and AVNRT in children. METHODS: A single-center retrospective review of children with supraventricular tachycardia (SVT) from 2000 to 2015 was performed. INCLUSION CRITERIA: Age ≤ 18 years, invasive electrophysiology study (EPS) confirming AVRT or AVNRT. EXCLUSION CRITERIA: Atypical AVNRT, congenital heart disease, antiarrhythmic medication use at time of EPS. Data were compared between patients with AVRT and AVNRT via t-test, χ2 test, and linear regression. RESULTS: A total of 835 patients were included (12 ± 4 years, 52 ± 31 kg, TCL 321 ± 55 ms), 539 (65%) with AVRT (270 Wolff-Parkinson-White, 269 concealed pathways) and 296 (35%) with AVNRT. Patients with AVRT were younger (11.7 ± 4.1 years vs 13.0 ± 3.6 years, P < 0.001) and smaller (49 ± 22 kg vs 57 ± 43 kg, P < 0.001). In the baseline state, the TCL was shorter in AVRT than AVRNT (329 ± 51 ms vs 340 ± 60 ms, P = 0.04). In patients requiring isoproterenol to induce SVT, there was no difference in TCL (290 ± 49 ms vs 297 ± 49 ms, P = 0.26). When controlling for age, there was no difference in TCL between AVRT and AVNRT at baseline or on isoproterenol. The regression equation for TCL in the baseline state was TCL = 290 + 4 (age), indicating the TCL will increase by 4 ms above a baseline of 290 ms for each year of life. CONCLUSIONS: When controlling for age, there is no difference in the TCL between AVRT and AVNRT in children. Age, not tachycardia mechanism, is the most significant factor in predicting TCL.

A Predictive Model for Intracardiac Pressures in Patients Free From Rejection or Allograft Vasculopathy After Pediatric Heart Transplantation.

BACKGROUND: Despite the routine use of hemodynamic assessment in pediatric heart transplant (HT) patients, expected intracardiac pressure measurements in patients free of significant complications are incompletely described. A better understanding of the range of intracardiac pressures in these HT patients is important for the clinical interpretation of these indices and consequent management of patients. METHODS: We conducted a retrospective chart review of pediatric HT recipients who had undergone HT between January 2010 and December 2015 at Lucile Packard Children's Hospital. We analyzed intracardiac pressures measured in the first 12 mo after HT. We excluded those with rejection, graft coronary artery disease, mechanical support, or hemodialysis. We used a longitudinal general additive model with bootstrapping technique to generate age and donor-recipient size-specific curves to characterize filling pressures through 1-y post-HT. RESULTS: Pressure measurements from the right atrium, pulmonary artery, and pulmonary capillary wedge pressure were obtained in 85 patients during a total of 829 catheterizations. All pressure measurements were elevated in the immediate post-HT period and decreased to a stable level by post-HT day 90. Pressure measurements were not affected by age group, donor-recipient size differences, or ischemic time. CONCLUSIONS: Intracardiac pressures are elevated in the early post-HT period and decrease to levels typical of the native heart by 90 d. Age, donor-to-recipient size differences, and ischemic time do not contribute to differences in expected intracardiac pressures in the first year post-HT.