RESUMO
OBJECTIVE: Among causes of sudden death presumed to be related with use of atypical antipsychotics, all drugs which could induce torsade de pointes had been known to prolong QTc interval. Therefore, to monitor the changes of QTc interval on EKG seemed to be an important marker for the antipsychotic-induced cardiotoxicity, further to prevent sudden death due to fatal ventricular arrythmia. There are several studies and case reports about cardiac toxicity in some patients who were administered newly developed atypical antipsychotics. The aims of this study were to know whether quetiapine causes changes in QTc interval, and to identify affecting factors. METHODS: For the 31 inpatients (21 females, 10 males) with schizophrenia (N=25) or schizoaffective disorder (N=5), schizophreniform disorder (N=1) according to DSM-IV, the EKG monitoring was successively taken on baseline and the 2nd, 4th and 6th weeks after quetiapine administration, and serial changes of every EKG parameters including QTc interval was comparatively analyzed. Furthermore, variables such as cardiovascular risk factors (weight gain, hyperlipidemia, thyroid function, etc.), dose of drugs, drug combination, severity of psychotic symptoms, changes in the activity of autonomic nervous system despite of sex and age were also successively assessed on baseline and the 2, 4, and 6 weeks after quetiapine administration. RESULTS: 1) Every EKG parameters (heart rate, PR interval, QRS and QT) including QTc interval and diastolic blood pressure were not changed significantly on the 2, 4, and 6 weeks after quetiapine administration as compared with baseline. The systolic pressure was significantly declined form the 2 weeks after quetiapine administration as compared with baseline (p<0.05). 2) Among variables affecting the EKG parameters including QTc interval, age, dose of drugs, hyperlipidemia and thyroid function were not correlated with. However, the body weight on the 6 weeks after quetiapine administration had significant negative correlation with QT (gamma=-0.427)and QTc interval (gamma=-0.406), and the drug combination on the 6 weeks after quetiapine treatment had significant positive correlation with QRS (gamma=0.393) and QT (gamma=0.415), while severity of psychotic symptoms on the 4th week had correlation with QT (gamma=0.380) (p<0.05, respectively). Otherwise, the QTc interval on the 6 weeks after was significantly prolonged in female patients (p<0.05). CONCLUSION: Even though the administration of quetiapine did not cause significant changes in the QTc interval in this study, we need to pay attention toward the possibly related factors.
