It started about a year ago. It feels like my lower chest/upper abdomen when I will get a sudden empty/sinking spasm that will jolt me almost like a hiccup. Only lasts for about a heartbeat. Completely random but seems to happen more often when sitting. Went to the doctor and was hooked up to an holtor monitor. Test came back normal. Thinking it was related to anxiety, doctor prescribes me citalopram to see if it goes away but I still have them. It could be days before I have one, or sometimes it will be day after day. Cardiologist did a ultrasound and said that it could possibly be Left ventricular noncompaction but very doubtful. I am due for an MRI on my heart soon to check for this. My question is regarding that maybe it's not heart related, such as gerd or vagus nerve? Just wondering if anyone else has had this problem. It's a very scary feeling and certainly anxiety does not help with this. Any feedback would be welcome. Thanks!