SummaryWe report on two patients with exercise-induced left bundle-branch block and without any evidence of cardiac disease. The first case is a sportsman; therefore his block could be considered as a particular form of the«athletic heart syndrome». The second patient complains of non-anginal chest pain and there is no sign of coronary heart disease.The exercise-induced left bundle-branch block is most often the consequence of a coronary heart disease. However, the existence of cases without any demonstrable cardiopathy seems undeniable. Given the rarity of these cases, follow up is necessary, in order to rule out subsequent development of a definite cardiopathy.