I have had similar heart palpitations to these, they feel like little heart attacks. During the years of 1998 and 2000 I documented the heart attacks as they occured, and the total count exceeded two hundred and fifty (250) by the time the year 2000 marker had hit. I still have them occasionally, and the paralysis effect caused has nearly cost me my life on several occasions. I had a small hole in my heart when I was born that healed and mended itself during my first week alive. The doctors observed and monitored my condition for the first 15 years of my life. Everything seemed to look normal. One day I just felt this shocking clench to the left of the middle of my chest, the room spun, and I felt my heart skip several beats, and then make up for it with extreme counter measures (the chest clenching contraction). This condition is a connective tissue disorder, I have also seen these symptoms attributed to Marfan's Syndrome. Treatment and monitoring of this condition cannot be effectively administered in hospital environments under a limited scope timeframe. Be careful, wearing a heart-monitor watch to record your status is highly advised, so that when you're having one of the heart fluxuations you can record your body's electricity measurements. In social situations, specificly romantic interludes, it is a good idea to tell your partner about your heart condition-- because explaining to your signifigant other that you're having a heart attack while in the act can be rather embaressing. On the subject of driving, it is usually a good idea to make sure there is someone in the car capable of grabbing the wheel should a serious symptom develop. I had these when I was 17.