I am sure most of this has already been said but...
do you notice its worse day or 2 after injection or better day before injection?
have u tried less often injection?
whats your Estrogen like? over 28-30 BMI? estrogen can affect anxiety/heart palpatations..
its possible when u lay down puts pressure on a certain part of your heart esp if overweight(even slightly) and causes ur heart to pound harder.. from my understanding its like temp carditis that causes similar issue.
have you worn a monitor during an episode?
lots of DRs suck or prefer not to say "maybe this" as not 100% and than it may affect your insurance/anxiety etc. esp if borderline and not super obvious... heck i had a DR miss a broken bone had !!
as for it being testosterone directly that is idopathic i wonder if its connected to DHEA and other minor steroids/precursers... or perhaps because its un natural to have test high all day and night and causes calcium/electrolyte issues/imbalance.. ie making your body think its dehydrated essentially. i know when im dehydrated i get similar thing with pounding heart get woken up in the night...
i know its been 7 years but even flu can mess with heart... and now adays with covid covid infection gives ~25% of people pericardial infraction which is kinda scary.. usually resolves apparently but of course fluid around the heart isnt ideal.. so if get sick every year with a fever could make it worse.
can try magnesium vitamin E omega q10 D... but be aware sometimes too much magnesium out of balance can cause pounding heart so possible can make it worse. also worth staying hydrated taking digestive enzymes (that allow u to absorb vitamin D and others) probiotics... also perhaps trying to lower sugar before bed/supper aswell as tottaly if possible esp bad carbs/sugar and try and get more proteins... also getting 2-3 hrs a week of cardio may help if it is infact anxiety based...
here is a good article lays out how test is good AND BAD for the heart.. mentions calcium channels etc..
Testosterone, cardiomyopathies, and heart failure: a narrative review. I would guess pharmokenetics is why some folks notice differences in different esters/injection frequency or sub vs IM vs excipient carriers etc as perhaps more drastic changes on homostasis in calcium channels or because directly affect heart cells causes some of the issues observed.
also curious if u drink more than 1 cup of coffee per day and or take nicotine or on ADD medication. while it may seem impossible 1 cup of coffee causes the issues many hours later its def possible.
I think its weird that its often overlooked about test levels... test levels are tested early am to see PEAK levels... ie 700 for a few hrs and down to 3-400 for the rest of the time.. yet for some reason folks target the PEAK level and keep it at the HIGHEST LEVEL during the day of a healthy individual.. when if want to be more "natural" should stay well below "normal peak" for majority of the time... ie shoot for "normal" levels of a guy at 3 pm not 8 am vs upper level of high test individual. likely why frequent injections work better for some vs having ultra high test for 2-3 days a week...
since im on a rant, also remember most if not all test clinics are pill mills. wether u agree or not they are there for $$.. and obv better they make people feel more customers they get...which is fine if u want legal steroids. but if looking for health and longevity such clinics may not be the best. all these clinics that give 25 yo test when already have levels around 500 test levels obv are not out for health but certainly make people dependant and feel awesome just like oxy clinics..