A cardiac monitoring system for monitoring a plurality of patients including a plurality of patient-worn units and one or more office units. A patient unit detects a patient's EKG and analyzes the EKG in real time (during the patient's R-R interval). It provides morphology analysis, heart rate data, ST segment analysis, symptomatic and asymptomatic event recordings, and the counting of ectopic runs. The analyzed data is sent over a standard voice-grade telephone line or other suitable communication channel to an office which prepares a patient report for a physician. In addition, the office unit provides an interactive scheme by which various alarm and recording criteria are established for a particular patient at the time of hook-up. Also, the office unit automatically communicates with the physician under predetermined emergency circumstances so that a patient can get medical attention with a minimun time delay.