diagnosed hyperthyroidism known issue heart valves severe chronic obstructive pulmonary disease copd experiencing shortness breath difficulty breathing significant way feel slightly dizzy lightheaded heart attack angina chest pain known heart defect feel heart beating fast racing irregularly missing beat feel palpitations traveled country last 4 weeks symptoms increased physical exertion alleviated rest
myocarditis psvt anemia atrial fibrillation chagas
Atrial fibrillation