Thanks for your question on HCM.
In my opinion your mother is having GERD (
gastroesophageal reflux disease).
Her all symptoms like
chest pain, gaseous distention, worsened symptoms on lying down and better on sitting can be seen in GERD.
And her cardiac work up is normal. So no need to worry much for cardiac cause.
So GERD is more likely in her case.
It is due to laxity of gastroesophageal sphincter.
Because of this the acid of the stomach tends to come up in the
esophagus and cause the symptoms.
So ask her to follow these steps for better symptomatic relief.
1. Avoid hot and spicy food.
2. Avoid large meals ,instead take frequent small meals.
3. Avoid
stress and tension.
4. Take good
proton pump inhibitor. Also give ORS (oral rehydration solution).
5. Go for walk after meals.
6. Keep 2-3 pillows under head in bed to prevent reflux.