Assessment of silent and symptomatic ischemia in daily activity by an ambulatory ventricular function monitor

We have assessed the sequential changes in left ventricular function and ECG in 39 patients with coronary artery disease (CAD) using an ambulatory ventricular function monitor. Following radionuclide ventriculography, the instrument detectors were placed over the region of the left ventricle and lung, and beat-to-beat left ventricular time activity curve and modified V5 ECG data were continuously monitored for up to 6 hours (mean 2.5 hours), while the patient performed various daily activities. Thirty-six episodes of transient ejection fraction (EF) decrease (6-18%) were recorded in 16 patients, 12 were symptomatic and 24 asymptomatic. ST segment changes were recorded in 6 of the 12 symptomatic and 5 of the 24 asymptomatic episodes. In 10 of the 12 symptomatic episodes, EF began to drop 30 to 90 seconds before the onset of the symptoms. Of 14 episodes of significant ST segment depression in five patients, 11 were associated with a significant EF decrease. We conclude that the combination of left ventricular function and ECG monitoring is a promising means for determining incidence of silent and symptomatic ischemia and for severity of ischemia in patients with CAD.