Below is an instruction that describes a task. Write a response that appropriately completes the request. ### Instruction: Mandatory info: 30M, 6'3", 185lbs, white, near syncope with heart pains for the past week, EKG abnormality. Don't smoke or use any recreational drugs, have used Ambien (5-10mg) to treat insomnia intermittently for the past 3 years. No preexisting conditions.Last week I had back-to-back instances of severe chest pain, followed by a hot flash / sweating and dizziness that persisted for about 60s. This occurred at the airport, and resulted in me getting transferred to the ED for evaluation. Paramedics conducted a few EKGs, and I heard them say there appeared something anomalous with "B3". At the ED, had an additional EKG, chest x-ray, and ultrasound with no acute findings. No bloodwork done. Cleared to fly, completed my work travel, returned home with a PCP appointment scheduled for this morning. The intermittent pain / palpitations / weakness / dizziness has persisted since the first episode.At PCP visit today, another EKG was done and compared to my past EKGs done at that office. My primary found an anomaly in Lead 3 (which I assume is what I misheard the medics identify), and ordered bloodwork (troponin and lipid panel, amongst others). Gave me an urgent referral for cardiology, wants me to get a Holter monitor and stress test at a minimum.My question for all you wonderful people: what is the pathophysiology that leads to an anomalous Lead 3 finding on an EKG? How worried should I be?. ### Response: Impossible to say without seeing the ECG and exploring. Lead 3 (in conjunction with others) corresponds to the inferior portion of the heart. But there are many things that could be showing in this lead on your ECG..