Bh. Dorman et al., Magnesium supplementation in the prevention of arrhythmias in pediatric patients undergoing surgery for congenital heart defects, AM HEART J, 139(3), 2000, pp. 522-528
Citations number
47
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Background The efficacy of magnesium in the prevention of arrhythmias in pe
diatric patients after heart surgery remains unknown. Therefore we prospect
ively examined the effect of magnesium treatment on the incidence of postop
erative arrhythmias in pediatric patients undergoing surgical repair of con
genital heart defects.
Methods and Results Twenty-eight pediatric patients undergoing heart surger
y with cardiopulmonary bypass were prospectively, randomly assigned in a do
uble-blind fashion to receive intravenous magnesium (magnesium group, n = 1
3; 30 mg/kg) or saline (placebo group, n = 15) immediately after cessation
of cardiopulmonary bypass. Magnesium, potassium, and calcium levels were me
asured at defined intervals during surgery and 24 hours after surgery. Cont
inuous electrocardiographic documentation by Holter monitor was performed f
or 24 hours after surgery. Magnesium levels were significantly decreased be
low the normal reference range for patients in the placebo group compared w
ith the magnesium group on arrival in the intensive care unit and for 20 ho
urs after surgery. Magnesium levels remained in the normal range for patien
ts in the magnesium group after magnesium supplementation. In 4 patients in
the placebo group (27%), junctional ectopic tachycardia developed within t
he initial 20 hours in the intensive care unit. No junctional ectopic tachy
cardia was observed in the magnesium group (P = .026).
Conclusions Although this study was originally targeted to include 100 pati
ents, the protocol was terminated because of the unacceptable incidence of
hemodynamically significant junctional ectopic tachycardia that was present
in the placebo group. Thus low magnesium levels in pediatric patients unde
rgoing heart surgery are associated with an increased incidence of junction
al ectopic tachycardia in the immediate postoperative period.