The effect of hypertonic sodium bicarbonate on QRS duration in rats poisoned with chloroquine.
OBJECTIVE
To determine efficacy of hypertonic sodium bicarbonate in narrowing QRS prolongation produced by chloroquine.


METHODS
Randomized, controlled animal experiment using an accepted rat model of sodium channel blockade.


METHODS
Hypotension and widening of QRS complexes (lead II) of the ECG were produced in 16 rats by administration of a total of 87 mg/kg chloroquine intravenously over 20 minutes. Eight rats were treated with 6 mL/kg 1 M sodium bicarbonate intravenously over two minutes beginning ten minutes into the chloroquine infusion. Serial measurements of QRS duration and systolic blood pressure were obtained for 30 minutes.


RESULTS
QRS intervals narrowed more rapidly in animals receiving sodium bicarbonate (p = .045), although the difference in mean rate of narrowing between groups was modest at only .23 msec/min. Because of large variances, no statistically significant differences could be demonstrated in systolic blood pressure.


CONCLUSIONS
Hypertonic sodium bicarbonate partially reversed sodium channel blockade and resultant QRS interval prolongation produced by chloroquine in rats. These data should be interpreted with caution, given the need to extrapolate to humans and the modest effect of sodium bicarbonate on QRS narrowing.
Curry
S C
SC
Good Samaritan Regional Medical Center, Phoenix, AZ 85006, USA.
Connor
D A
DA
Clark
R F
RF
Holland
D
D
Carrol
L
L
Raschke
R
R
D000563:Amebicides / Q000506:poisoning*; D000818:Animals; D000962:Antimalarials / Q000506:poisoning*; D002738:Chloroquine / Q000506:poisoning*; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017693:Sodium Bicarbonate / Q000494:pharmacology*
D000563:Amebicides; D000962:Antimalarials; D002738:Chloroquine; D017693:Sodium Bicarbonate