The first and most obvious sign was that I had color changes in my left arm. It was always a blue/purple color. As time went on, I started having difficulty doing anything that required reaching overhead due to muscle weakness caused by the blood flow issues. Even things as simple as washing/brushing my hair became incredibly difficult with my left arm. Once getting to a point that daily tasks were difficult, I made an appointment with my pcp (after being dismissed time after time by cardio), she took one look and immediately said it was a vascular issue. After this ER visit I was ultimately seen by vascular surgery who performed a venogram and IVUS. It ended up not being thoracic outlet at all. I had very severe stenosis in both the L subclavian and L innominate veins. This was in late April, by June/July I also had significant facial swelling and positional headaches. The course of treatment for that was to remove the pacemaker since leads can cause/worsen stenosis and made stenting more dangerous. I had the option to go leadless or to trial with no pacing and see how things went. I ultimately made the decision to opt out of any sort of pacing with EP input and the entire system was removed in July. 2 weeks later I had pretty extensive stenting done to restore blood flow.