Abstract: A wearable medical device, system and method are disclosed herein. The wearable medical device is placeable on a target site of a subject's body and includes a rotary coupling component and an electrode patch. When the electrode patch is attached to the rotary coupling component, electrodes of the patch's electrode array are electrically coupled to corresponding tracks of the conductive tracks. The wearable medical device also includes an ultrasound scanning and biomarker monitoring module having a set of conductive contacts. When the ultrasound scanning and biomarker monitoring module is attached to the rotary coupling component opposite the electrode patch, the set of conductive contacts are engaged with corresponding tracks of the conductive tracks. The ultrasound scanning and biomarker monitoring module is further configured to rotate about the rotary coupling component with the conductive contacts remaining engaged with the corresponding tracks during rotation.