When the study began, some heart specialists said it could never enroll enough patients. Who would agree to be randomly assigned to a placebo or a drug to ease breathing?

• 研究开始时，有些心脏病专家称根本无法找到足够的患者。谁会同意被随机安排接受安慰剂或者接受药物来缓解呼吸困难呢？