Q What causes fast heartbeat in infants?
In some physiological conditions like crying, exercising or any vigorous activity the heart beats faster in infants. But, if at rest, the heartbeats are fast, then the causes are pathological like- dehydration, any lung disease, heart disease etc. It is an emergency condition and you can notice by the sudden paleness or bluishness of the skin, fainting of the baby etc. In such a case, you must visit your paediatrician as early as possible to get the accurate curative and preventive measures.