It is a good question. What you describe is probably anxiety, but I would discuss some diagnostics with a neurologist to make sure it is not a variation of petit mal seizure.
If it was a Cardiac issue, you'd be in the ER. The symptoms you described are all on the panic symptom list. People get these symptoms in different ways or fasion. Sometimes more physical, than emotional or vice versa. The main thing is, you seem to be dealing with these frightening symptoms since you say you are not experiencing fear or panic. The panic/fear symptoms come as a result of what you are making of the symptoms. They are not life threatening, nor will they significantly interfer with your daily activities. Ask your doctor about giving you a few Xanax's to relieve these outbreaks for times the symptoms become almost unbearable. And because of your age, you might want to get some circulatory tests done, just for reassurance's sake. Good luck!
I'm not a Dr., but it sounds like panic due to your worries about your medical conditions. I would get checked out of course, but here's my experience with anxiety and my slow road to recovery.
I tried Lexapro and had really bad side effects. I did not stay on it very long as the side effects scared the heck out of me. I also took and am taking 1MG Xanax XR per day for anxiety.
My goal is to get control of my panic and anxiety so that it does not rule my life.
I went to see a counselor and Psychiatrist. My Psychiatrist just kept prescribign medications for anxiety, my counselor actually helped me talk things out and get to some of the issue that may be causing my anxiety. Along with the in office therapy, she suggested I read the book called "Don't Panic" by R. Reid Wilson, PH.D. The book teaches you how to deal with and ultimately face your anxiety and panic attacks head on. The techniques including daily relaxation, positive talk during anxious times and relaxation at the time of anxiety. It builds on providing the ability and skills to invite panic head on and deal with it. The theory is that if you avoid it, it will always come back. If you face your fears and deal with them adaquately, then panic subsides. The book has worked really well for me. I am going to try next week to taper off the XANAX and slowly go back to a medicine free existence.
I am not a DR. and cannot recommend this in place of medications. I just choose to try to conquer my fear of panic with out drugs. I highly recommend this book which you can purchase for about $9.00. I has helped me a great deal. I think it could help you, too as it addresses issues like yours as well. People with Physical problems are very likely to develop anxiety. The book give you good coping skills and helps you understand, confront and conquer your anxiety. ]
Hope this helps.