Pediatric/Adult Congenital Heart Disease -> Pediatric Cardiology D-PO05 - Poster Session V (ID 39) Poster

D-PO05-032 - Selecting HR For Pacing In Pediatric Fontan Patients (ID 615)

 R. Madani: Nothing relevant to disclose.


Background: Cardiac output in pts following Fontan procedures (FPs) is limited and further compromised by chronotropic incompetence. For those pts requiring pacemakers, optimal programming to maximize cardiac output is unclear. Oxygen pulse (O2P) measured during an exercise stress test (EST) is a reflection of ventricular stroke volume.
Objective: To investigate the relationship of HR and O2P in FPs during EST with the goal of optimizing pacemaker settings.
Methods: In a single large center, O2P in FPs with (FP+PM) and without (FP-PM) pacemakers performing EST’s from June 2017-September 2019 were compared to EST’s in pts with chest pain and structurally normal hearts (control group).
Results: In 201 patients (217 EST’s) were identified. There were 29 FP+ PM (36 ESTs), 79 FP- PM (88 ESTs) and 93 controls (93 ESTs). Median age was 14y in FP+PM, 14y in FP+PM and 14.5y in controls (p= 0.23). Mean peak HR was higher for controls (195bpm), compared to FP- PM (169bpm) and FP+ PM (155bpm) p= 0.005. Subjects were divided into four groups based on HR and corresponding max O2P values were identified. Among FP+ PM, HRs 115-145bpm had the highest O2P (mean 10.6ml/beat) vs FP- PM whose O2P was max at HR 135-174bpm (mean O2P 10.8ml/beat). VO2max for both Fontan groups was equal at 71% predicted. The control group had higher O2P values overall compared to both FP groups. (74% of controls had O2 pulse 10 or greater vs. 36% in FP- PM and 36% in FP+ PM)
Conclusion: At peak HR FP+ PM had lower HRs than FP- PM with no difference in predicted VO2max. This suggests that adjusting FP+ PM settings to simulate FP- PM HR curves may not be necessary or desirable.