Amphotericin-Induced Heart-Rate Decrease in Children

We describe six children with acute decreases in heart rate temporally related to amphotericin B administration. All patients had achieved their maximal dose within 3 to 4 days. Heart-rate drops occurred as early as day 3 but could be delayed up to day 7 after start of therapy. The mean heart rate dropped from 104 ± 8/min (range 96 to 114) to 62 ± 8/min (range 48 to 72) (P= 0.0001). A slower heart rate than baseline was noted during the entire duration of drug administration, from 60 minutes of starting the infusion to 220 minutes (mean 120 ± 40) after discontinuation of the infusion. This reaction was noted in six of 90 (6.7%) patients who had amphotericin. These six children were compared with six age-matched children who received the drug but in whom such changes in heart rate did not develop. The method of administration of amphotericin B was similar in both patients and controls, starting with 0.25 mg/kg/day and increasing by 0.25 mg/kg/day up to 1 mg/kg/day. Children with heart-rate drop received amphotericin for 4.6 ± 1.8 days, significantly shorter than their controls (12.6 ± 6.9 days) (P= 0.02), suggesting that this adverse effect has led to early discontinuation of amphotericin therapy. Physicians and nurses caring for children receiving amphotericin B should be aware of this potential adverse effect, which can be serious in a patient with an underlying heart condition or in a patient who is already on heart-rate-lowering drugs.