Abstract Background Physiological functioning of the testes is important for cardiac health besides for virilisation, physical strength, behavior and reproduction; moreover, hypogonadism has been demonstrated as a significant risk marker of increased all-cause and cardiovascular mortality. Cases presentation We reported two cases of long-standing hypogonadotropic hypogonadism presenting with wasting, bradycardia and heart failure. The two patients were admitted to emergency department for deep weakness, unresponsive anemia and severe bradycardia, requiring in one case the implanting of a monocameral pace-maker for treatment of heart failure. No previous cardiologic disorders were known and cardiac ischemia was ruled out in both patients. The first patient presented congenital hypogonadotropic hypogonadism combined with mild central hypothyroidism and growth hormone deficiency occurred in the peripubertal age, while the second one was diagnosed with isolated adult-onset severe central hypogonadism. Testosterone deficiency was the main feature in both patients as physical examination revealed clinical stigmata of hypogonadism and testosterone replacement induced a dramatic improvement of general condition. Genetic analysis of genes involved in hypogonadotropic hypogonadism failed to identify alterations. Conclusion Long-standing hypogonadism in males can be associated with life threatening body alterations including severe bradycardia and heart failure.