Hi Thanks for posting your query. Fluttering of heart ( palpitations) can occurs due to many reasons like Pain , fear, anxiety, fever etc . These conditions increase the heart rate which is a normal response. There are other conditions like heart problems, thyroid problems, low blood pressure, adrenal problems which can cause palpitations. But since she has been tested by specialist it s very unlikely of these conditions to be present. So palpitations could be just a response to nausea. Now nausea could be due to stress of delivery, hormonal changes post delivery , acidity or indigestion. These are simple conditions which shall subside on its own . She can take ondansetron tablets for nausea and avoid spicy and non veg food. If nausea persists for more than 3 days kindly get a liver function test. Hope this information was useful to you. Any clarification feel free to ask.