Hello and thank you for using HCM.I carefully read your question and I understand your concern. I will try to explain you something and give you my opinion. This heart racing has to do with a rhythm issue. There are some electrical impulses that generates from a part of the heart different from normal sinus rhythm.They can cause a premature heart contaction that we call extra sistolic beats or different arythmia like atrial fibrillation. This rhythm heart issues can cause heart palpitation, flattering sensation or heart racing. You might experience anxiety, nausea, difficulties in breathing deeply, chest discomfort, sweats. There are different causes of this rhythm issue like simple stress , coffee and alcohol consumption. Also pathologys like anemia, hyperthyroidism or ischemic heart disease might be other causes. So , if I was your treating doctor I will recommend some examination like an electrocardiogram, a cardiac echo to evaluate heart function and walls and the most important one holter rhythm monitoring to see what happens with your rhythm during day and night. After all this we can better understand what we are dealling whith and how to treat the problem. Hope I was helpful.Wish you good health Best regards.