We present the case of a 60-year-old woman who suddenly suffered a witnessed cardiac arrest and did not achieve return of spontaneous circulation despite being given 150-minute ultra-long cardiopulmonary resuscitation (CPR). During CPR, pulmonary embolism was suspected and was eventually diagnosed based on refractory pulseless electrical activity, elevated serum D-dimmer, and a markedly enlarged right ventricle chamber. After rescue thrombolytic alteplase therapy, the patient was successfully resuscitated and had a good neurological recovery.