Computerized interpretation of the electrocardiogram (ECG) began in the 1950s when conversion of its analog signal to digital form became available. Since then, automatic computer interpretations of the ECG have become routine, even at the point of care, by the addition of interpretive algorithms to portable ECG carts. Now, more than 100 million computerized ECG interpretations are recorded yearly in the United States. These interpretations have contributed to medical care by reducing physician reading time and accurately interpreting most normal ECGs.