Use of sodium bicarbonate to treat tricyclic antidepressant-induced arrhythmias in a patient with alkalosis

Sodium bicarbonate has been recommended for the treatment of arrhythmias induced by tricyclic antidepressants. It is unclear, however, whether this therapy is effective only in the presence of acidosis. A case is presented in which there was an immediate response to sodium bicarbonate in three episodes of ventricular tachycardia despite the presence of alkalosis on two of the three occasions. Given the poor response to conventional therapy of arrhythmias induced by tricyclic antidepressants the use of sodium bicarbonate may be reasonable even in the presence of alkalosis. However, in the presence of pre-existing respiratory or metabolic alkalosis, such therapy is not without risk, and it is suggested that it be reserved for life-threatening situations when the arrhythmia has failed to respond to hyperventilation or antiarrhythmics or both.