Had Myocardial Infarction, Angiogram Shows Buildup, Felt Chest Pressure. Common?

Ok I don t know how to ask this, but I have had, according to my doctors, 2 myocardial infarctions. My angiograms showed some buildup, but not enough for a stent . A couple years ago, I had an episode where ir felt as if someone had reached into my chest and squeezed my heart and wouldn t let go and I had to fight it. It wouldn t start agin. It lasted a half minute or so. I spent five days in the hospital and the doctors didn t find any evidence of a heart attack . Is this common and I was told it isn t life threatening, but it is certainly unnerving. Additionally, at the time of the attack I was doing light housework and nothing very strenuous. Can I do anything to prevent another episode and is caffeine a contributing factor to it?