<s>[INST] I get these weird heart palpitations every once in a while where it literally feels like my heart is beating in my throat for a few seconds.  I get really light headed, scares me.  and then within a few seconds it just goes away.  what could this be? [/INST] hello,I have gone through your query.Thanks for using HCM.you should get ECG at the time of palpitation.You may be getting recurent SVT.you should get echocardiogram done to rule out Mitral valve prolapse.My best wishes,Dr.Rajesh Teli,MD. </s>