I would seriously consider taking a Beta blocker like Atenolol .. it will help block adrenaline and epinephrine from over stimulation of your heart. it will also help keep your heart rhythm steady and lower blood pressure.

I used to get bad panic attacks and heart rate would jump up to 140 bpm just laying in bed.. also my heart would skip beats and flutter.
years back after having surgery they would not release me from the hospital cause my resting heart rate would not go any lower then 110.. they did EKG and found a heart murmur.

anyhow, I started taking 25mg a Atenolol (a few years back).. and that did the trick. no side effects either. my blood pressure is now 120/70 and my resting heart rate is 68 and I no longer get any skipped beats or heart murmurs. and it helps with anxiety as well.

worth looking into