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[Perception threshold of angina and transient myocardial ischemia in ambulatory electrocardiography]
S Scardi1, C Pandullo, A Di Lenarda
1Centro Cardiovascolare, Ospedale Maggiore, Trieste.
Insights
A prolonged angina perception threshold during exercise testing can identify patients with stable coronary artery disease at risk for silent myocardial ischemia. However, silent ischemia itself does not appear to negatively impact long-term prognosis.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Tools
Background:
- Stable coronary artery disease (CAD) patients often experience silent myocardial ischemia.
- Identifying patients at risk for silent ischemia during daily life is crucial for management.
- Current methods for detecting silent ischemia can be complex and invasive.
Purpose of the Study:
- To evaluate the predictive value of angina perception threshold (APT) in identifying patients with stable CAD at risk of silent myocardial ischemia.
- To determine if APT can serve as a simple, non-invasive marker for ambulatory ischemia.
- To assess the prognostic significance of silent ischemia identified by APT.
Main Methods:
- Seventy-one patients with documented CAD underwent symptom-limited exercise testing and ambulatory Holter monitoring.
- Angina perception threshold was defined as the time from ST-segment depression onset to angina onset during exercise.
- Patients were categorized into two groups based on APT (>60 seconds vs. <60 seconds).
Main Results:
- A prolonged APT (>60 seconds) was the strongest predictor of ambulatory ischemia, particularly painless episodes.
- Patients with a prolonged APT experienced significantly longer durations of silent ischemic time.
- Demographic, clinical, and angiographic factors did not influence APT.
Conclusions:
- Angina perception threshold during exercise testing is a valuable and simple tool for identifying stable CAD patients at risk for silent ischemia.
- Silent myocardial ischemia, as identified by APT, did not demonstrate an adverse prognostic value in this cohort over a 2-year follow-up.
Aim Of The Study:
We studied the predictive value of prolonged angina perception threshold in identifying patients with stable coronary artery disease at risk of silent myocardial ischemia during daily life.
Methods And Results:
71 patients with documented coronary artery disease (previous myocardial infarction or stenotic lesion > 60% at angiography) underwent a symptom-limited exercise test and out-of-hospital Holter monitoring after drug withdrawal. A second exercise test was performed before disconnecting the dynamic EKG in order to validate the ST-depression recorded during ambulatory monitoring. 23 patients (32.4%) (Group A) had angina perception threshold > 60 sec after onset of ischemia (ST > 1 mm), while in 48 (67.7%) the delay in the perception of angina was shorter than 60 sec (Group B). The demographic, clinical and angiographic variables did not influence the angina perception threshold; however, this parameter was the most powerful predictor of ambulatory ischemia among the two groups (4.8 vs 2.8 p < 0.02), and in particular of the painless episodes (3.8 vs 1.8 p < 0.002). Moreover, the silent ischemic time was longer in patients of group A (4362 vs 1774 sec p < 0.017). Finally, the event-free survival was similar in the two groups of patients during the 2 years of follow-up (cardiac death 1 vs 3, nonfatal myocardial infarction 1 vs 1, aorto-coronary bypass 2 vs 7, PTCA 2 vs 2, unstable angina 0 vs 2), total events 6 vs 15 p = ns.
Conclusions:
These results demonstrate that the patients at risk for silent ischemia during ambulatory monitoring may be identified simply by evaluating their angina perception threshold during exercise test; however, silent ischemia does not have an adverse prognostic value.