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Identification of anatomically extensive coronary artery disease by the exercise ECG ST segment/heart rate slope
P M Okin1, P Kligfield, O Ameisen
1Department of Medicine, New York Hospital-Cornell Medical Center, NY 10021.
Insights
The ST segment/heart rate (ST/HR) slope effectively identifies three-vessel coronary disease with high sensitivity. A ST/HR slope below 6 makes extensive coronary obstruction unlikely in stable angina patients.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- Stable angina necessitates accurate diagnostic tools for coronary artery disease.
- Exercise electrocardiography (ECG) is a common diagnostic method.
- Identifying multi-vessel coronary disease is crucial for treatment decisions.
Purpose of the Study:
- To evaluate the ST segment/heart rate (ST/HR) slope's ability to detect three-vessel coronary disease.
- To correlate the ST/HR slope with the anatomical extent of coronary disease using Gensini and Duke jeopardy scores.
Main Methods:
- Exercise ECGs from 128 stable angina patients were analyzed.
- Coronary cineangiography findings were used as the gold standard.
- The ST/HR slope was calculated and compared to standard exercise ECG responses and coronary anatomy scores.
Main Results:
- A ST/HR slope ≥ 6 microV/beat/min demonstrated 93% sensitivity for three-vessel coronary disease, significantly outperforming standard tests (50-66% sensitivity).
- The negative predictive value for three-vessel disease with a ST/HR slope < 6 was 94%.
- Patients with ST/HR slopes ≥ 6 exhibited more extensive coronary obstruction (higher Gensini and Duke jeopardy scores) compared to those with lower slopes.
Conclusions:
- A ST/HR slope ≥ 6 is a highly sensitive and specific marker for identifying three-vessel coronary disease.
- This slope also correlates with the anatomical severity of coronary obstruction.
- A ST/HR slope < 6 suggests a lower likelihood of significant multi-vessel coronary disease.
Abstract:
To assess the ability of the ST segment/heart rate (ST/HR) slope to identify three-vessel coronary disease and the relationship between the ST/HR slope and the anatomic extent of disease as determined by the Gensini and Duke jeopardy scores, the exercise ECGs of 128 patients with stable angina were compared with findings at coronary cineangiography. A ST/HR slope greater than or equal to 6 microV/beat/min identified three-vessel coronary disease with a sensitivity of 93% compared with sensitivities of only 50% for early positive standard test responses (p less than 0.001) and 66% for markedly positive standard test responses (p less than 0.01). The negative predictive value of this ST/HR slope partition for three-vessel disease was 94%. Patients with ST/HR slopes greater than or equal to 6 who did not have three-vessel disease had anatomically more extensive obstruction than did patients with lower test values (mean Gensini score 43 +/- 5 vs 22 +/- 3, p less than 0.002 and mean jeopardy score 4.8 +/- 0.4 vs 3.0 +/- 0.3, p less than 0.01). Test performance of the calculated ST/HR slope exceeded that of a simplified index derived by dividing the total change in ST segment depression by the total change in heart rate. These findings demonstrate that a ST/HR slope greater than or equal to 6 is highly sensitive for the identification of three-vessel coronary disease and also identifies patients with anatomically severe obstruction. A ST/HR slope less than 6 makes three-vessel coronary disease or otherwise anatomically extensive coronary obstruction unlikely.