Previous clinical trials examining thrombolytics used to treat Acute Submassive PE, many times will use fixed dose and duration. Little research has been conducted on the physiologic implication of resolution of symptoms. It seems reasonable, that symptomatic relief results from some degree of hemodynamic normalization. This study will seek to examine the extent to which the hemodynamic impairment is normalized from a thrombolytic treatment protocol with an endpoint of therapy determined as resolution of presenting symptoms. Treatment plans will utilize the MBS (Modified Borg Scale) score to help evaluate and measure outcome-based care, quantifying shortness of breath.