irregular heartbeat, chest tightness, feeling that I cant catch my breath, occasional feeling of stomache fullness, excessive burping......these symptoms started five days ago. Symptoms are present 60%+++ of the time. I went to the ER yesterday morning, ER doc did blood test to check for heart attack...came back negative. Chest xray was fine. Oxygen levels around 98%. EKG looked fine. Dr discharged me and said to follow up with my family doc and possibly with a cardiac doctor.