Just i want to know how is her feeding, activity and weight gain and urine output. If these are in normal range nothing to worry. If child is getting sweating while taking feeds, or not able to take breast feeds continuously or weight gain is not appropraite and urine output is decreased then the heart murmur
may be significant and you should consult the doctor. If loose motions are still going give oral rehydrating solutions sips by sips to prevent dehydration
and continue breastfeeding
and consult your doctor for specific treatment.