best cardiac doctors in bangalore An LV (left ventricular) clot in an echo is a blood clot tha An LV (left ventricular) clot in an echo is a blood clot that forms inside the heart's main pumping chamber, and it's often a complication of a heart attack. Echocardiography (echo) is the main diagnostic tool used to see it, though contrast-enhanced echo can improve accuracy. Diagnosis depends on seeing a distinct mass within the ventricle.