The pain in left arm or hand while walking or exercising is a sign of poor blood supply to the heart. As you have already stated that your ecg is not good and you are a heart patient, you should investigate further by doing an angiography to ascertain the state of coronary blood flow. If there is any serious block in the coronaries then you need to undergo treatments like angioplasty. Do not neglect and keep in contact with your physician.
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