Electrocardiograms are read by many health professionals, but it is critical that they be interpreted and understood by cardiologists. A four-hour session of the cardiology board exam is devoted to interpreting ECGs, and they are featured extensively in the anaesthesiology and critical care boards as well. In November 1993, the American College of Cardiology (ACC) begins recertification exams for its members. The ability to interpret ECGs is seen as being so crucial that the ACC has begun to offer review courses on the subject. This text consists of 200, high quality, three channel electrocardiograms, ranging from simple to complex, accompanied by a complete narrative history and usual interpretations. Readers can make their own diagnoses before turning the page to read the answer.