Ayahuasca can cause some cardio instability, very rarely is this more than just a passing event. I also experience some strange sensations sometimes when using these substances.
Have you ever experienced heart pain before? These medicines can really mess with one's mind. Where you imagine heart pain to be and where heart pain actually occurs may not even be the same place. Heart pain is generally right in the center of your chest, not to one side as is commonly preconceived.
I have experienced myself and read more than one trip report where people have perceived cardiac pain and feared death. Then on accepting that they may die and that they are powerless to do anything about it have instantly had a lessening of the symptoms and enjoyed the rest of their experience. I am not saying that what you experienced was imaginary, just that it is common and may not have been a real representation of what was happening with you physically. Panic is common when you first use these medicines, I have experienced that too. Fighting the medicine's effect can cause anxiety. I think, from what you have written, you may have experienced that to a greater extent.
Every single experience with these medicines is unique. Even to the person taking them. It is never the same twice. Do not try to compare your experience to others. For people who do it more often it becomes difficult to compare their own experiences with their own.
All that said DMT is contraindicated with people with serious heart conditions as it can be quite a workout for it, but no more than any other moderately strenuous exercise. A checkup is definitely worth it if you are concerned. But I would not worry unduly.
People say they are not scared of dying, but when the moment comes and you think "this is it, I am going to die right now" fear is much harder to control than previously imagined. The reality of the experience is much harsher than the preconception. It's funny how much we really know ourselves when faced with situations out of the ordinary.
I wish you the best in your healing time and hope you reconcile your experience well. Do take the time to think about and integrate what you experienced, don't just try and forget about it. Even harsh experiences like you had are great teachers if we take the time to truly examine what we were thinking and why.
Wishing you warmest light.
The nearest we ever come to knowing truth is when we are witness to paradox.