Assessment of silent and symptomatic ischemia in daily activity by an ambulatory ventricular function monitor
1Department of Radiology & Nuclear Medicine, Kyoto University School of Medicine, Japan.
Insights
Ambulatory monitoring of left ventricular function and ECG in coronary artery disease (CAD) patients revealed transient ejection fraction decreases, often preceding symptoms. This combined approach effectively identifies silent and symptomatic ischemia severity.
Area of Science:
- Cardiology
- Medical Monitoring
- Diagnostic Technology
Background:
- Coronary artery disease (CAD) poses significant risks, necessitating accurate assessment of cardiac function and ischemia.
- Traditional monitoring methods may not capture transient functional changes during daily activities.
- Evaluating left ventricular (LV) function alongside electrocardiogram (ECG) provides a comprehensive view of cardiac health.
Purpose of the Study:
- To assess sequential changes in left ventricular function and ECG in patients with CAD during daily activities.
- To evaluate the utility of combined ambulatory LV function and ECG monitoring for detecting ischemia.
- To differentiate between symptomatic and asymptomatic ischemic events.
Main Methods:
- Utilized an ambulatory ventricular function monitor and modified V5 ECG in 39 CAD patients.
- Monitored beat-to-beat LV time activity curves and ECG data for up to 6 hours during daily activities.
- Correlated transient ejection fraction (EF) decreases with ST segment changes and patient-reported symptoms.
Main Results:
- Recorded 36 episodes of transient EF decrease (6-18%) in 16 patients, with 12 symptomatic and 24 asymptomatic.
- ST segment changes occurred in both symptomatic (6/12) and asymptomatic (5/24) episodes.
- In symptomatic episodes, EF drop preceded symptoms by 30-90 seconds; 11/14 significant ST depressions were linked to EF decrease.
Conclusions:
- Combined ambulatory LV function and ECG monitoring is a promising tool for assessing ischemia in CAD.
- This method can determine the incidence and severity of both silent and symptomatic ischemic events.
- Early detection of functional changes preceding symptoms aids in risk stratification and management.
Abstract:
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.
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