Cavitation was first directly related to mechanical heart valves in the mid 1980s after a series of valve failures observed with the Edwards-Duromedics valve. The damages observed indicated that cavitation could be responsible. Later, several in vitro studies visualized the bubble formation and collapse of cavitation at mechanical heart valves. It was suggested that cavitation could also cause damage to the formed elements of blood and thereby enhance the risk of thromboembolic complications seen in mechanical heart valve patients. Therefore, an applicable technique for in vivo detection of cavitation is required. This article reviews techniques developed for in vivo detection of cavitation and suggests focus for future studies.