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ECG shows sinus Tachycardia
it may be due to nervousness
during examination, and every ECG needs to be corelated to clinical parameters.
The Right bundle branch is conduction abnormality if it is old and there silently no treatment is required and there is nothing to worry about.
Left atrial enlargement can be suspected if thre is some thing which needs work up a 2 D Echocardiography
gives exact size of all chambers of heart.
You Treating is best person to judge what is best for you.
If he says every thing fine it must be have faith.