LAUSR

To the Editors: C lozapine remains the criterion standard treatment for patients with schizophreniawho have previously failed adequate trials of 2 other antipsychotics. In addition to its designation for treatment-resistant schizophrenia, it has also shown ability to reduce suicidality in patients with schizophrenia and has shown efficacy in patients with treatment-resistant schizoaffective disorder. The potential benefits of clozapine are not limited to the treatment of symptoms of a psychiatric illness, because it has also shown evidence of improving movement disorders that have developed in patients as a result of long-standing antipsychotic use. Despite the unique properties of clozapine, its use remains limited because of the potential of serious adverse effects including agranulocytosis, myocarditis, cardiomyopathy, QTc prolongation, seizure, and ileus. Of the cardiac complications associated with clozapine treatment, sinus tachycardia is the most common occurring in an estimated 10% of clozapinetreated patients. A consensus on the occurrence of more severe and potentially life-threatening complications has not been reached with estimates ranging from 0.001% to 3% and from 0.02% to 4.65% for myocarditis and cardiomyopathy, respectively. Clozapine has been shown to increase the QTc interval in a dose-dependent manner, although the development of polymorphic ventricular tachycardia as a result of this prolongation is rare. There are few case reports of atrial arrhythmias associated with clozapine use. As a result, only general guidelines exist regarding rechallenging patients with clozapine after development of an atrial arrhythmia. Here, we present and discuss the case of a patient with newly developed atrial flutter after titration of clozapine in which the arrhythmia was medically managed to allow for successful rechallenge of clozapine.