P wave and QT changes among inpatients with schizophrenia after parenteral ziprasidone administration.

OBJECTIVE: Although ziprasidone has been reported to cause ventricular arrhythmias, there have been no studies regarding the influence of ziprasidone on atrial conduction. Intraatrial and interatrial conduction time prolongation and inhomogeneous propagation of sinus impulses are indicated by P wave changes on surface electrocardiography. We aimed to evaluate proneness to atrial fibrillation after intramuscular ziprasidone in drug-free inpatients with schizophrenia. METHODS: We evaluated 11 eligible inpatients who were drug free for at least 4 weeks with a primary diagnosis of schizophrenia disorder and 11 healthy controls who were hospital staff members. Electrocardiography was performed at baseline and 1.5-2h after ziprasidone injection. A 12-lead surface electrocardiogram was obtained from each subject in the supine position at a paper speed of 50mm/s and 2mV/cm. RESULTS: The changes between baseline and the period after parenteral ziprasidone administration in P-wave duration, P-wave dispersion, QTc, QTc(max), QTc(min), and QT dispersion variables were significant (p>0.05). The initial P-wave dispersion was significantly longer in patients than in healthy controls (p<0.05). There were no correlations between electrocardiography parameters and clinical severity scores or demographic variables in either group. CONCLUSION: Intramuscular ziprasidone administration does not seem to influence atrial and ventricular electrical conduction in drug-free inpatients with schizophrenia. However, schizophrenia might affect atrial conduction resulting in atrial fibrillation, which may be a cause of some complications in inpatients with this schizophrenia.