Recent clinical and experimental data on the long Q-T syndrome (LQTS) are presented and discussed. The pathogenesis of LQTS is dependent on an imbalance between various components of the cardiac sympathetic innervation. A congenital decreased activity through the right cardiac sympathetic nerves seems to be the more likely pathogenetic mechanism for the majority of cases. Other forms of sympathetic imbalance, including left or even right hyperactivity, are, however, possible in isolated cases. Beta-blockers, at full blocking dose, represent the therapy of choice and are greatly effective in reducing the mortality (from 73 per cent to 6 per cent). If syncopal attacks are not eliminated by the medical therapy, the the ablation of the left stellate ganglion along with the first thoracic ganglia is the most rational and specific therapy. The possiblity for the correctly diagnosed and treated patients to escape an otherwise impending death calls urgently for diffusion of the knowledge about the long Q-T syndrome.