Hello and thank you for ussing HCM. I carefully read your question and I understand your concern. I will try give you my opinion and advise. This flattering sensations on the heart has to do with some rhythm issues. It might be a simple sinusal tachycardia, meaning that your heart is beating over 100 beats for minute. It might be a different kind of arrhythmia like atrial fibrillation, meaning that your rhythm is not normal bur the heart runs in a chaotic way. Or this flattering sensations might be what we call extra-sistolic beats that are some premature heart contractions, during normal heart rhythm. All this rhythm issues gives the feeling like a fluttering sensation, might cause anxiety and insomnia (sleeping problem). There are different factors that might cause this rhythm issues. Simple emotional stress, excessive coffee consumption, alcohol usage. So it is mandatory to avoid them. Also different pathology s like anemia, thyroid gland problems or ischemic heart disease might be other causes. In your case, with angiogram we have excluded significant ischemia. So, i would say that you have nothing to worry if it happen once a wile. This has been a stressed period for you and it may soon pass. But if they continue and interfere in your daily live i will recommend a holter rhythm monitoring to better evaluate the kind of this rhythm issues, what they really are. Hope I was helpful. Best regards.