When it comes to heart, nothing should be ignored. From your description, it seems that you are inviting a bigger problem (though not so recent) in your life. There can be many cases where you may feel such palpitations. Many diseases like Arrhythmias , Sinus Tachycardia , mitral valve prolapses, PVCs. I am not trying to frighten you, but make you aware of the situation.

Arrhythmias shows the symptoms of disorder of regular rhythmic beating of heart. And this can occur in a healthy heart and be of minimal consequence. And if this is the case, it indicates the serious problem and lead to heart disease, stroke or even a sudden cardiac death.

Sinus tachycardia is a disease where a person has a heart beat rate above 100. This is generally found in many people. Not so serious, but worth noting.

Having a blocked artery is something really very serious issue. You cannot take that lightly, and I seem your doctor is doing the same. There is nothing to feel confused. You are really in a big problem if you are having any artery blockage. This is quite good that your doctors are moving fast in your case, otherwise sometimes it happens to be exactly opposite, they usually tends to be so slow that we really feel very angry on them. I had got a similar experience in my medical checkup at Elite health medical centre at Los Angeles. They really gave a very good amount of attention to my health problems. I got these entire tests you described in same chronological order. But everything was just as fine as it could possibly be. I was found to be having a problem in the atrial valve, which is taken care of now. But the overall experience I have with all these test was quite satisfying. You can get some very good information on advanced diagnostic test of heart disease from www.elitehealth.com/advanced_diagnostic_testing.php.