On paper, masturbation can not cause a heart attack. Masturbation and any other sexual activity will cause a rise in your blood pressure, but this is never a cause for concern. Any sexual activity is the equivalent of mild forms of exercise like brisk walking, climbing a flight of stairs, slow jogging, etc.; if you have been cleared to do any of these activities, then you can also indulge in masturbation or other sexual activities without any concern.