The acute porphyric crisis is a characteristic clinical feature common to all hereditary hepatic porphyrias (acute intermittent porphyria [AIP], porphyria variegata and hereditary coproporphyria). The crisis is marked by an acute disorder of the central, peripheral and autonomic nervous system. Autonomic disorders may play a major part and may provoke severe cardiovascular symptoms. According to the literature our findings support data describing supraventricular tachycardia as the most important sign, followed by hypertension--or, rarely, hypotension--cardioarrhythmias and cardiomyopathy. While tachycardia, blood pressure disturbances and cardioarrhythmia indicate sympathetic overactivity, cardiomyopathic alterations suggest functional or structural coronary dysfunction. The existence of a specific "angiopathia porphyrica"--based on functional, angiospastic or secondary hypertensive disorders--has been discussed for a long time. Recent results concerning a 20-year follow-up study of AIP patients revealed chronic hypertension as being the most significant disorder and seem to support a hypertensive aetiology.