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[Coronary heart disease and silent myocardial ischemia]
Y Xu1
1Cardiovascular Institute, CAMS, Beijing.
Insights
Silent myocardial ischemia, often asymptomatic, occurred in over half of coronary heart disease patients. These silent episodes showed distinct physiological changes compared to symptomatic ones, particularly in heart rate and blood pressure.
Area of Science:
- Cardiology
- Ischemic Heart Disease
- Diagnostic Monitoring
Context:
- Coronary heart disease (CHD) patients often experience myocardial ischemia.
- Silent myocardial ischemia (SMI) presents without typical angina symptoms.
- 24-hour Holter monitoring is crucial for detecting transient ischemic events.
Purpose:
- To investigate the characteristics of silent myocardial ischemia in CHD patients.
- To compare physiological parameters during asymptomatic versus symptomatic ischemic episodes.
- To analyze the incidence of SMI in relation to coronary artery disease severity and time of day.
Summary:
- Fifty-one percent of 100 CHD patients exhibited myocardial ischemia via Holter monitoring.
- Of 239 detected ST depression episodes, 67.4% were asymptomatic.
- Both asymptomatic and symptomatic ischemia increased heart rate and rate-pressure product, with symptomatic episodes showing a greater increase.
Impact:
- Silent ischemic episodes are prevalent in CHD and occur more frequently in single-vessel disease.
- SMI episodes peak in the morning (6 a.m. to 12 p.m.).
- Understanding SMI characteristics can refine risk stratification and management strategies for coronary heart disease.
Abstract:
Silent myocardial ischemia was studied in 100 patients with coronary heart disease (CHD), proved by the coronary arteriogram (at least one major coronary artery narrowed by > or = 50%). The study demonstrated that 51 of 100 patients with CHD had episodes of myocardial ischemia by Holter monitoring. In the 51 patients, during daily activities, through 24-hour Holter monitoring, 239 transient episodes of ST depression were detected, 161 of the total were asymptomatic (67.4%). There were no statistically significant differences in the heart rate and the product of heart rate and systolic blood pressure before ST depression between asymptomatic and symptomatic episodes. The heart rate at the time of maximal ST depression during both asymptomatic and symptomatic ischemia increased by 13 and 22 beats/min, respectively, over those before ST depression (P < 0.01); whereas the increase in heart rate during symptomatic ischemia was more significant than during asymptomatic ischemia (P < 0.01). The increase of product of heart rate and systolic blood pressure at the time of maximal ST depression during asymptomatic and symptomatic ischemia were 22.2 and 35.4, respectively, over those before ST depression (P < 0.01). The incidence of silent ischemic episodes in patients with single vessel disease was 81.7% and those with multivessel disease was 61.3% (P < 0.01). The frequency of silent ischemic episodes was maximal (36% of total number of ischemic episodes) between 6 a.m. and 12 a.m. during 24-hour, whereas the incidence of silent ischemic episodes in patients with single vessel disease was similar to that in patients with multivessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)