Values of Using QTc and N-Terminal Fragment of B-Type Natriuretic Peptide as Markers for Early Detection of Acute Antipsychotic Drugs-Induced Cardiotoxicity

We aimed at studying the acute cardiotoxicity of the most commonly used antipsychotics in Egypt using QTc interval and NT-proBNP as markers for the early detection of such cases. Eighty-two admitted patients, at El-Minia PCC (period from 1-7-2005 to 30-6-2010), were classified into 3 groups: I: acute thioridazine overdose (n = 28), II: acute pimozide overdose (n = 23), and III: acute clozapine overdose (n = 31). Patients were investigated for NT-proBNP level and QTc on admission (day 0) and after 24 h (day 1). All the studied drugs had the ability to induce cardiotoxicity in the form of hypotension and dysrhythmias. Thioridazine and pimozide had potentially serious cardiotoxic effects than clozapine. NT-proBNP levels were elevated significantly in all groups on days 0 and 1 when compared with the reference value and a significant decrease in the same parameter on day 1 when compared with that of day 0 within the same group. QTc showed a significant prolongation in all studied groups on days 0 and 1, and there was a significant shortening of QTc on day 1 when compared with that of day 0 within the same group. A significant positive correlation of NT-proBNP level elevation with QTc prolongation was reported in all groups on days 0 and 1. Serious dysrhythmias were associated with QTc prolongation greater than 500 ms. And it was concluded that NT-proBNP, in adjunction with QTc measurement, may be a valuable and sensitive laboratory biomarker to predict cardiotoxicity of antipsychotic overdose. Larger multicenter studies are still needed to verify this possible relationship.