Preva-AS 75 Tablet is used for the prevention of heart attack and stroke. A heart attack occurs when a blood clot blocks the blood flow to the heart. This blockage of arteries is most often an accumulation of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries). Signs of a heart attack include chest pain, upper body pain, sweating, nausea, fatigue and trouble breathing