We discussed a case of a middle aged woman who presented with subacute to acute shortness of breath on exertion. We discussed her EKG with S1Q3T3 findings which is not specific for PE but indicative of cor-pulmonale. The differential for cor-pulmonale is COPD, ARDS, PNA, Pneumothorax and PE. More specifically, her CTA showed bilateral pulmonary embolus and RV enlargement and her labs indicated elevation in BNP and troponin. Due to her hemodynamic stability but clear evidence of RV strain, troponin and BNP elevation – she was classified as submassive PE (these days known as intermediate high risk classification). In addition to starting heparin infusion, with all submassive PE, it is important to consider systemic thrombolysis (low dose vs high dose) AND catheter directed thrombolysis / thrombectomy. This will be a nuanced discussion but admission to ICU and early consults to IR, Cardiology and Pulmonology are required.