Tachyarrhythmias after the Norwood procedure: relationship and effect of vasoactive agents

Tachyarrhythmias are common after the Norwood stage I palliation. The effects of vasoactive medications on the development of post-operative tachyarrhythmias have not been studied. The primary objective was to identify associations between postoperative tachyarrhythmias and vasoactive medication usage after Norwood stage 1 palliation. Secondary objectives included evaluation for morbidities of tachyarrhythmias and for associations with anatomical or surgical variables. Retrospective chart review was performed on all patients who underwent the Norwood stage 1 palliation at Children's Hospital Colorado between January 2008 and June 2012. Primary outcomes were development of postoperative tachyarrhythmias and the effects of vasoactive medications. Dopamine, epinephrine, milrinone, and vasopressin duration, cumulative dose, highest dose, and dose at onset of tachyarrhythmia were identified. The effects of surgical variables and anatomy were also studied. Sixty-six patients underwent the Norwood procedure, and 33 (50 %) of these patients had postoperative tachyarrhythmias. Patients with tachyarrhythmias had longer ICU stays (p = 0.02) and hospital stays (p < 0.01), but no change in mortality (p = 1.0). Multivariate Cox regression analysis showed that the right ventricle to pulmonary artery shunt (p < 0.01), longer duration of epinephrine treatment (p = 0.02), and higher milrinone dose (p = 0.002) were associated with tachyarrhythmias. Postoperative tachyarrhythmias are common after the Norwood procedure and are associated with longer ICU and hospital stays. High doses of milrinone, longer duration of epinephrine treatment, and the right ventricle to pulmonary artery shunt were associated with for the development of tachyarrhythmias. Further studies are required to determine the effects of anatomy on post-operative tachyarrhythmias.