Influence of Heart Rate on Hemodynamics in Fontan Circulation.

The standard value of heart rate (HR) and the effect of HR on Fontan circulation remain unclear. HRs and hemodynamic parameters were evaluated in 59 adults with Fontan circulation without pacemaker (PM) and then compared with those of 15 patients with PM. The minimum HR in Holter monitoring, HR in resting electrogram, resting HR in cardiopulmonary exercise (CPX), maximum HR in Holter, and peak HR in CPX were observed during sleep, supine, sitting, maximum daily activity, and exercise, respectively. HRs in 15 patients with excellent status of Fontan circulation were 50 ± 6, 75 ± 15, 81 ± 7, 86 ± 11, 141 ± 19, and 165 ± 17 bpm in sleep, in supine, Holter mean, in sitting, during maximum daily activity, and during exercise, respectively. Among 59 patients, the higher HR during exercise and higher ΔHR between exercise and sleep were associated with favorable values of hemodynamics. The PM group had higher HR during sleep and lower HR during the activities above the sitting position, compared with the non-PM group. The standard values for adults with Fontan circulation would be approximately 50, 75, 80, 85, 140, and 165 bpm during sleep, in the supine position, Holter mean, in the sitting position, during maximum daily activity, and during exercise, respectively. The higher HR during activities may facilitate the maintenance of good Fontan circulation. After PM implantation for Fontan circulation, the setting of increased HR during activities as well as the efforts to maintain narrow QRS duration and atrioventricular synchrony should be kept in mind.