The cardiovascular mortality of the psychiatric patients is higher than the general population. The antipsychotics and their propriety of prolongation of the QT interval seems to be a possible track. We tried to analyze the epidemiological, clinical, biological, therapeutic and especially electrocardiographic (ECG) data in those patients, to determine the prevalence of the syndrome of prolongation of the QT interval and investigate its main risk factors.

We conducted a cross-sectional study, at the university psychiatric center Ibn Rochd of Casablanca, in collaboration with the cardiology department, over one year, concerning 134 patients receiving an antipsychotic treatment, we realized12 derivations ECG, and assessed clinical, biological and pharmacological data.

The mean age was 32, 48±10,9 year,82,8% men/17,2% women, the first psychiatric disorder was the paranoid schizophrenia 56%, hyperkalemia was present in1 patient, hyermagnesaemia (1), calcemia was normal, polytherapy has been found in the majority of cases(2.8±0.9), neuroleptics were prescribed for all patients(45.5% for long term), in association with benzodiazepines (25%) and anticholinergics (23%), antidepressant (21%) and lithium (10%).The mean dose antipsychotic chlorpromazine equivalent (CPZ eq) is 617.8±534, 3mg/d, 88% of patients are under moderate doses and only 6% receive very high doses>2000mg/d CPZ eq. the mean heart rate was 82.7±16.5 BPM, one patient had a bradycardia to 44 bpm. The mean QTc is 386.22±30,9ms, the prevalence of long QT syndrome (>440ms) in our series is 4.5% so lower than the literature. The mean value of QTc increases with age, and it is higher in female gender, the risk of QT prolongation is associated with multiple co-prescribed drugs, and gets higher with the number of prescribed drugs and with strong dosage. The risk increases also at the beginning of the treatment and in patients with long term treatment>6 months.

However, despite the proven toxicity of these treatments, it must be remembered that the QT prolongation does not necessarily induce a negative risk-benefit balance. This is to be assessed on a case-by-case, and in cooperation between psychiatrists, cardiologists, pharmacists, for a better control of the risk of sudden cardiac death from a psychiatric medication origin.