Pulse weakens for several beats (10 to 20) concurrent with chest pain / spasm

[ednitram]

Since I was about twenty I have had occasional chest pain probably averaging about twice per year, I am now fifty four years old. It usually occurs when I am inactive; often waking me from sleep. When it occurs it feels like a spasm a bit like you get in calf muscles when they have been overworked. This happened to me today; it woke me and it felt like my chest was being pushed in or constricted from the sides of the chest wall. Today it was accompanied by a slightly nauseous feeling. Usually it lasts from about five minutes to about twenty minutes. I have called an ambulance on one occasion but by the time they reached me the feeling had subsided and they detected nothing abnormal on my ECG (EKG?). Today when I had the feeling I tried to take my pulse to see if I could provide more symptoms to aid diagnosis. I am quite good at taking my pulse because I do it every now and again when I exercise, etc. I noticed that my pulse seemed to be coming in waves in as much as it would be normal and strong for a while but every now and again it would seem to weaken to the point that I could hardly feel it or even not feel it at all. I suppose that in my anxious state, I might have been losing concentration and just imagining this attenuation of the strength in the pulse but I don't think so. My pulse was weakening for durations of perhaps ten to twenty beats or so but was not speeding up or slowing down nor missing individual beats.
I am now wondering if the periods of weakened pulse might be starving the heart of oxygen thus causing the cramping feeling.
In the recent past (only the last couple of years and not since approximately the age of twenty as in the case of the symptoms I have been describing) I have noticed that my resting pulse sometimes increases to around 100 beats even though my usual resting pulse is about seventy or eighty. I don't think the two are related but I thought I'd mention it in case it was important.
I have been worried about this for nigh on thirty five years and have never been able to get to the bottom of it; any advice would be appreciated.