Elevated Heart Rate following a GI Episode, reaching Tachycardia range, on 64 year-old woman. No Red Flags of other symptoms. How urgent is a Doctor visit?

TL;DR: My mother has been having elevated heart rate at the number I am concerned about. However, she also has a cough right now, accompanied with possible GI issue from 2 days ago, which she is still recovering from. She exhibit no telltale signs of heart issue otherwise, or at least she claims so. I wish for reassurance and possible non-cardiac-related issue for the elevated heart rate while I wait for a social healthcare appointment.

My mother is 64 years old. She has been quite healthy when it comes to her heart health. Checking from last year said she has mild Cardiomegaly, but with no further action from the doctor or even prescription, I do not see it as anything urgent.

These past few days, I noticed a heightened heart rate. She has 90-110 rate when sitting down, and last night sleeping heart rate was high 80-high 90. Breathing rate during sleep, I counted, is 18-19, possibly 20.

I am not sure when this started, but I do notice that her heart rate has been rather elevated the past few days. I took her blood pressure daily, and up to last week the range was usually explainable with her just going up the stairs etc., but now I am afraid if I had missed something. I do not remember exactly what the HR is, but I wasn't worried, which means that it is fine by my knowledge.

She does not smoke and has no diabetes. But she is slightly overweight in terms of BMI, and has hypertension.

She also has been having trouble sleeping. She wakes up quite often at night, though she said she don't usually feel anything. In fact, recent pattern I notice is that she does not notice that she fell asleep, despite snoring. Her incontinence and her age-induced nocturia does not help.

The thing is, I cannot even be sure of the elevated heart rate is cardiovascular-related. I was starting to worry at Tuesday this week, but her heart rate was still able to go down to 88 shortly after she started lying down. However, on Wednesday, she mentioned she had an episode of vomiting, with blood pressure at normal and heart rate at 120. Wednesday night, she woke up a bit, before claiming pain in the left side of her lower ribcage. This pain is eased with vomiting and afterwards was painful when pressed. She is recovering by Thursday, still feeling slight nausea but can keep the food down. She said she has watery stool now. She also have a mild, infrequent coughing. She has no fever, I think.

She had a Vertigo in Jun 19, and was hospitalized briefly (discharged at Jun 21). She said they take lung and heart test, with both results returning okay. Her breathing rate was 16. The thing is... She does not know what test they took of her. She described the heart test to have a printed results, but with the device only attached to her arm. It sounds like EKG to me, but why just the arm?

Another data point I remember is that by the end of April this year, her "I just woke up" heart rate was at 71. I do not remember usual heart rate, but I do take blood her pressure daily (usually) and the fact that I was not alarmed may have been a good sign. Being a heart failure patient myself at 27, I think I do pay slightly more attention to heart rate.

She is otherwise fine. I checked that she has no edema. She is not nearly active enough to have shortness of breath usually, and it does not change much, except when climbing the stairs. She does not have palpitations, feelings of pressure, or pain, she claimed. She does not have the classic signs of heart failure, is what I am saying. I do not see any emergency to ran her to the ER.

I know some issues, especially GI issues, can raise heart rate. But I cannot help but be worried. Would the increase be this high? She is recovering well, is the elevated HR indeed coming from the recent GI infarction? Should I contact a cardiologist, or is it safe to just monitor her for now in hope it lowers as she recovers even more from her cough and past GI issue? I have my own heart issues, so is this condition a legit concern, or paranoia born from my own condition?

Is this situation a "Monitor and hope she gets better" situation or "Get her checked ASAP" situation? Should I get an urgent Cardiologist, if the social healthcare takes too long.

I hope I could get advice from either knowledge or experience here. I hope I can get some answers to help reassure me, or convince me to try and expedite things. Funding... Is an issue. Again, I am having an ongoing heart issue as well (no CAD at all, but prevailing diagnosis is post-viral myocarditis).

Actually, could whatever caused my myopathy be causing something to her too? If it is indeed viral in nature, could I have been hurting her?