If ecg and echo are normal then your heart condition is probably good. Fast heart beats ( palpitation ) can be due to anemia or increased blood pressure also. Once check your hemoglobin and bp also. It can also be due to anxiety and stress. Try yoga and meditation . It can also be a sign of dehydration. Drink plenty of water. Endoscopy shows signs of GERD , take antacids for that. Tab pantoprazole 40mg twice daiky 30 mins before food for 14 days.

You may be having duodenal ulcer and that is why you are having palpitations, you will require immediate treatment with antacids otherwise your duodenal ulcer may worsen and cause bleeding

Go for 2D Echo test of heart to know any conduction defect or reason for I crease heart rate

Consult gastroenterologist