The definition varies according to the context. In what context was the term used?
In this context, there is a particular pattern that can be seen on the EKG that is referred to as "strain." There are many different possible causes of the strain pattern on the EKG. One of the possible causes is poor blood supply to the heart, and this is the cause that is most concerning in a person that is about to have elective surgery. Other causes of a strain pattern include high blood pressure, ventricular hypertrophy, valvular disease, or congestive heart failure. Certain lung diseases can also cause right heart strain on the EKG. Regarding the possibility of a heart attack, there are some heart attacks that can occur without causing any symptoms, called silent heart attacks. As the ability to detect previous heart attacks have improved, it has been found that about ¼ of heart attacks are silent. Therefore, it is not that unusual for a person to discover that they have had a heart attack despite having never had symptoms.
Treatment would depend upon the nature and extent of the artery disease that is leading to the poor blood supply, but may include medicines, such as aspirin, beta-blockers, or nitrates, or may require procedures to open up or bypass more severe artery disease. Hypertrophy is treated by treating the underlying condition that is causing the hypertrophy, but may include lowering blood pressure or treating the lung disease. Treatment of valve disease depends upon which valve is involved and the nature of the valve dysfunction, but may require ACE inhibitors or surgery.