Circulatory block is a medical condition caused by a CLOT in the circulatory system. A CLOT is a mass of blood cells and proteins that form when the blood thickens and clumps together. The CLOT can block the flow of blood, leading to circulatory block. Symptoms of this condition include chest pain, shortness of breath, and dizziness. Treatment for circulatory block typically involves medications to dissolve the CLOT or surgery to remove it.