Neurally mediated syncope and arrhythmias - A study of syncopal patients using the head-up tilt test

Understanding the causes of syncope in patients with arrhythmia is importan t in determining the therapeutic interventions. Neurally mediated syncope ( NMS) was evaluated in 55 patients with various arrhythmias. The head-up til t test with or without isoproterenol infusion induced NMS in 41 (74%) patie nts. When these patients was categorized into 3 types, depending on the dev elopment of syncope, vasodilatation was significant in a majority of patien ts. In 46% of patients with tachyarrythmias, NMS was accompanied by an incr ease in extrasystole. It was concluded that the evaluation of vasodilatatio n is important for the preventive strategy of NMS in patients with arrhythm ias and that NMS may induce arrhythmias.