Cardiac arrhythmia after infusion of cryopreserved stem cells.

A retrospective study of the cardiovascular side-effects of 17 patients during and after receiving unpurged cryopreserved autologous bone marrow and/or peripheral blood stem cells was performed. Fourteen (82%) patients developed cardiac arrhythmia, of which 11 (65%) developed sinus bradycardia, four (24%) second degree heart block and one patient had complete heart block. The onset of sinus bradycardia occurred at 15-513 (median 56) min and the onset of heart block ranged from 30 to 680 (median 234) min after starting the stem cell infusion. Hypertension was noted in seven patients (41%) and usually occurred within 2 hours of infusion. There was no mortality or symptoms associated with these findings. Since some of these arrhythmias could be quite severe as assessed electrophysiologically, continuous cardiac monitoring should be considered during and after the infusion of cryopreserved stem cells.