Long-term follow-up of medically treated patients with coronary artery disease--II. Unstable angina pectoris, asymptomatic periods, and sudden unexpected cardiac events.

In order to clarify the incidence of unstable angina (UA), the rate of mutual transition to other forms of ischemic heart disease, and the short term prognosis of asymptomatic patients, we followed prospectively 421 medically treated patients after through assessment of coronary artery disease for an average of 43 months. Three hundred and two episodes of UA had occurred in 139 patients. Of these 14 patients experienced major cardiac events. Sixteen patients had sudden cardiac events with no prior UA. Two hundred and sixty-six patients had no episodes of UA nor cardiac events; of these, 97 patients were followed for more than 49 months. Those with both effort and rest UA had a much more higher incidence of unstable episodes and a higher average age than those with effort UA alone and those with rest UA alone. The average transition rate to the cardiac events by month of patients with UA, by markovian analysis, was higher than those of the asymptomatic or stable angina patient groups. When background factors are taken account, these transition rates might help the physicians in determining the treatment of patients with ischemic heart disease at a specific stage of state.