心筋梗塞
Historian and archaeologist Francisco Simón y Nieto, in his book "Una página del reinado de Fernando IV. Pleito seguido en Valladolid ante el rey y su corte en una sesión, por los personeros de Palencia contra el Obispo D. Álvaro Carrillo, 28 de mayo de 1298", published in 1912, noted that the ultimate cause of the death of Ferdinand IV may have been due to a coronary Thrombosis, but without discard others, such as Intracerebral hemorrhage, acute Pulmonary edema, Angina pectoris, Myocardial infarction, Embolism, Syncope or others.