ISCHEMIC STROKE SECONDARY PREVENTION IN SPECIAL SITUATIONS in cardiac conditions related to valve problem patient needs to be on long term anticoagulation. this is required when there is irregular heart rhythm in condition called atrial fibrillation and also in prosthetic valve replacements.these drugs require careful monitoring of clotting parameter called as prothrombin time if the person doed not have valvular heart disease but still has atrial fibrillation newer drugs like DABIGATRAN, RIVROXIBAN may be given.the davantage of the above mentioned drug is it doesnot require monitoring of clotting parameters