Welcome to Health Care Magic, Thanks for writing to us,
I am Dr.Ahmad Bilal, I have read your question, I understand your concern and will try to help you in the best possible way.
There is no way other than a massive heart attack
which dilates the heart so much that it gets enlarged within 3--4 days.
Usually it is problem with the X-rays.
X-rays are never good in predicting enlarged heart
, heart size in an X-ray may look changed depending upon.
1) position of the patient when X-ray was taken,
Standing, lying , sitting cause different heart size in Xray.
2) Inspiration expiration also make heart size look changed.
And there are many other factors due to which X-ray can not be relied upon for heart enlargement.
I would suggest you to meet your Doctor, and discuss if you need an echocardiography
Only Echo can predict well about the heart size,
I would suggest you not to worry about random X-ray finding but do discuss other confirmatory options with your doctor.
I Hope this answers your question, if your have more queries feel free to ask,I will be pleased to alleviate your concerns.Wish you the best of health.