Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. I passed carefully through your question and would explain that we can not exclude a possible cardiac issue related to your symptoms. Other possible causes to consider would be anxiety, an electrolyte imbalance, etc. Coming to this point, I recommend consulting with your attending physician for a physical exam and some tests: - a resting ECG and cardiac enzymes - an exercise cardiac stress test - a chest X ray study - complete blood count for anemia - blood electrolytes for any possible imbalances. Hope I have answered your query. Let me know if I can assist you further.