[Statistical notes. Hazard curves of sudden death: their role in the cardiologist's clinical decision].

In long-term studies researchers are mainly concerned with occurrence of death during the follow-up period. This statistical note is focused on survival analysis which is the main tool to process this kind of data. Survival curve, cumulative mortality curve and hazard curve are here introduced together with an appropriate effect indicator: hazard ratio. In particular, the use of the latter is shown by resorting to the randomized controlled clinical trial TARGET.