Woken up by slow heart rate but pounding really really hard! But slow!

Can anyone relate? I woke up last night with a slow pounding heart! Never happened ever before! Really scared me! It would not go back to normal for ages! Very scary! Then I had really bad chest pain which was like really ba acid reflux! So I related it all to a carton of cranberry juice I necked before bed! Please reply x

Slow pounding heartrate was very common for me, especially on waking up.

It would last from 5 minutes to several hours.