I have a cardiology appt Wednesday. Just had physical...all labs WNL. I am 30 lbs overweight but walk 3-4 days/week. Had an episode on Thursday. Felt fine, getting dressed and blow drying my hairwhen I felt sudden weakness, heart palpitations and lightheadedness. Resting 10 minutes, felt very anxious, went to my PCP hence all the labs, EKG and tests to r/o MI. What could have caused this type episode?