When a new antidepressant is put on the market, everyone is afraid of its possible cardiac effect. The control of unicellular potentials can give an hint about that effect, without being able to assess its severity; the 27 antidepressants commercialized in France have been reviewed. 180 cases of conduction delays from 10,060 overdosage in the Paris poison center were found, 7 times more often than with other drugs. In addition the 30 centers for monitoring of side effects of drugs have collected 38 cardiac side effects, as well arrhythmias or conduction disturbances.