Risk of corrected QT interval prolongation after pamidronate infusion in children.
BACKGROUND
Hypocalcemia carries a risk of cardiac conduction incidents and death. Hypocalcemia is a frequent adverse effect of pamidronate.


OBJECTIVE
The objective of this study was to investigate whether pamidronate infusion lengthens the ventricular repolarization in children.


METHODS
Thirty-four children with cerebral palsy and severe osteoporosis were treated for approximately 1 yr with pamidronate (three times per year). Calcemia and corrected QT interval (QTc) (in which the QT interval is a measure between the Q and T waves in the electrical cycle of the heart) were measured before and after each cycle of intravenous infusions.


RESULTS
Pamidronate decreased calcemia in all patients from 2.40 to 2.21 mm (P<0.0001) and increased QTc from 390 to 403 ms (P<0.0001), with 7.4% of postinfusion QTc becoming longer than 440 ms. QTc at baseline was significantly correlated to final QTc (P<0.0001; r2=0.27).


CONCLUSIONS
Because we observed a lengthening in QTc after bisphosphonate infusion, we recommend that children treated with pamidronate should receive attention as to other possible risk factors of prolonged QT and have a preinfusion and postinfusion measurement of their QTc.
Rothenbuhler
Anya
A
Department of Pediatric Endocrinology and Diabetology, French Reference Center for Rare Diseases of the Calcium and Phosphate Metabolism, Hôpital Saint Vincent de Paul, Assistance Publique/Hôpitaux de Paris, Université Paris Descartes and Institut National de la Santé et de la Recherche Médicale, Unité 986, 82 avenue Denfert-Rochereau, 75014 Paris, France.
Marchand
Isis
I
Bougnères
Pierre
P
Linglart
Agnès
A
D000293:Adolescent; D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000503:physiopathology; D002547:Cerebral Palsy / Q000188:drug therapy*; D002648:Child; D004164:Diphosphonates / Q000009:adverse effects* / Q000627:therapeutic use; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D008297:Male; D010024:Osteoporosis / Q000188:drug therapy*; D000077268:Pamidronate; D012307:Risk Factors
D004164:Diphosphonates; D000077268:Pamidronate