Brief Answer:
Angina

Detailed Answer:
Hello

Thanks for the query

If she has undergone angioplasty and stenting recently then it is possible that the chest discomfort and shortness of the breath is due to the blockage of the stent. I strongly recommend you to approach the ER immediately for an EKG without further delay.
I also suggest the following

1. Do not consume anything until you reach the ER
2. Keep calm, avoid anxiety
3. Avoid physical activity like climbing stairs, driving, etc

I hope I was of help, if you have any further queries please get back to me

I wish your mother good health and a speedy recovery

Regards

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Brief Answer:
Angina

Detailed Answer:
Hello

Thanks for the reply

If the angiography was fine then the possible cause for the fluctuating heart beat and chest discomfort are arrhythmias.
Here is what I suggest

1. Watch for triggers of chest pain and discomfort, for example while eating or while brushing teeth, etc
2. If the EKG was normal then I strongly suggest you to get an ECHO done. If the ECHO is showing Mitral or aortic stenosis then it is more likely to be arrhytmias
3. To be for sure, she has to undergo something called as 24 hour holter monitoring, where a small EKG machine is attached to her chest for 24 hours. EKG will be taken through out the day
4. The other possible reason for chest discomfort is acute gastritis, especially if she is on Aspirin

I hope I was of help, if you have any further queries please get back to me

Regards

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