To the Editor:
Olanzapine is an atypical antipsychotic used in the treatment of schizophrenia and bipolar disorder. There are several case reports of antipsychotic drugs associated with atrial fibrillation (AF). We present a case of new onset AF after a suicide attempt with an overdose of olanzapine.
A 21-year-old woman presented to the emergency room with nausea, dizziness, and vomiting after attempting to commit suicide by ingesting 14 olanzapine tablets (10 mg) approximately 1 h before admission. She was a nonsmoker and did not consume other medicines, alcohol, or excess caffeinated beverages. She had no significant medical history. Her family history was negative for heart disease. Her blood pressure was 110/80 mmHg and her pulse was 70 beats per minute and regular. Oxygen saturation was 100% on room air. Cardiovascular examination revealed normal heart sounds without any rubs, murmurs, or gallop; the chest was clear on auscultation. An abdominal and neurological examination was normal.
Gastric aspiration and lavage was performed with the patient's cooperation. Activated charcoal was given after gastric lavage. She was admitted to the intensive care unit for monitoring. A 12-lead ECG showed normal sinus rhythm. Four hours later, we observed AF on the monitor, with large fibrillatory waves and normal ventricular rate. The electrocardiogram showed no ST segment or T wave abnormalities. Monitoring was for 72 h. The arrhythmia converted to normal sinus rhythm spontaneously after 10 min. Chest radiograph and routine laboratories, including cardiac enzymes and thyroid function tests, were normal. Repeat cardiac enzyme tests were also within normal ranges. An echocardiographic study showed preserved systolic function without any valve disorder. She was discharged without antiarrhythmic medication.
AF is the most common rhythm disorder observed in clinical practice. Several case reports have associated this condition with the use of antipsychotic drugs. However, to our knowledge, only one case of AF by olanzapine has been reported previously.Citation1,2
Olanzapine is a thienobenzodiazepine derivative of clozapine with which it shares a strong in vitro affinity for muscarinic receptors.Citation3 Their predominant effects on autonomic neurocardiac function seem to be mediated through anticholinergic and antiadrenergic mechanisms with a net rise in sympathetic tone and a reduction in parasympathetic tone that may predispose to dysrhythmias and sudden cardiac death.Citation4
In our case, we ruled out other pathologies that could have caused this arrhythmia.Citation5 AF developed approximately 4 h after the patient's admission; she had no previous history of arrhythmias. The self-resolving and time-limited nature of the dysrhythmia is supportive of an association with olanzapine intake. Sinus rhythm was restored spontaneously in the patient without any medication. We suggest there is a need for more studies to elucidate the autonomic effects and dysrhythmogenic properties of novel antipsychotic drugs.
References
- Low RA, Fuller MA, Popli A. Clozapine induced atrial fibrillation. J Clin Psychopharmacol 1998; 18:170.
- Waters BM, Joshi KG, Flynn J. Olanzapine-associated new-onset atrial fibrillation. J Clin Psychopharmacol 2008; 28:354–355.
- Mueck-Weymann M, Rechlin T, Ehrengut F, Rauh R, Acker J, Dittmann RW, . Effects of olanzapine and clozapine upon pulse rate variability. Depress Anxiety 2002; 16:93–99.
- Agelink MW, Majewski T, Wurthmann C, Lukas K, Ullrich H, Linka T, Klieser E. Effects of newer atypical antipsychotics on autonomic neurocardiac function: a comparison between amisulpride, olanzapine, sertindole, and clozapine. J Clin Psychopharmacol 2001; 21:8–13.
- , European Heart Rhythm Association; Heart Rhythm SocietyFuster V, Rydén LE, Cannom DS, Crijns HJ, . ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation. J Am Coll Cardiol 2006; 48:854–906.