1临床资料青年女生,20岁,以“发作性晕厥6年,胸闷、气短20d”主诉于2015年10月28日入院。6年前无明显原因突发晕厥,无口吐白沫,无双眼上翻等,醒后不能回忆当时情况。经常于劳累或情绪激动时出现轻微胸闷、呼吸困难、心慌,经休息后可逐渐缓解。20d前活动后呼吸困难、心慌、胸闷,伴黑矇,无猝倒,无晕厥。体格检查:血压90/54mm Hg(1mm Hg=0.133kPa), 1 clinical data of young girls, 20 years old, to “paroxysmal syncope for 6 years, chest tightness, shortness of breath 20d ” chief complaint on October 28, 2015 admission. 6 years ago, no obvious reason Sudden syncope, no spit foam, no binocular upside down, can not recall the situation woke up. Often tired or excited when there is a slight chest tightness, breathing difficulties, palpitation, after the rest can be gradually alleviated. 20d after the activity before breathing difficulties, palpitation, chest tightness, with dark, no cataplexy, no syncope. Physical examination: Blood pressure 90/54 mm Hg (1 mm Hg = 0.133 kPa),