Related Experiment Videos
Pacing-induced ST segment deviation in patients with unstable angina: clinical, angiographic, and hemodynamic
K M Hussain1, L Gould, E V Pomerantsev
1Department of Medicine, New York Methodist Hospital, Brooklyn, USA.
Insights
Unstable angina patients with ST depression show more triple-vessel disease, while those with ST elevation have higher risks of intracoronary thrombi. These distinct patterns aid in evaluating unstable angina for interventions.
Area of Science:
- Cardiology
- Internal Medicine
- Medical Diagnostics
Background:
- Unstable angina presents diverse electrocardiographic (ECG) findings, including ST segment depression, ST segment elevation, or no deviation despite chest pain.
- Understanding the clinical, arteriographic, and hemodynamic differences associated with these ECG presentations is crucial for patient management.
Purpose of the Study:
- To compare clinical, coronary arteriographic, and hemodynamic characteristics of unstable angina patients based on their ECG response during pacing.
- To differentiate patient groups experiencing ST depression, ST elevation, or no ST deviation during atrial pacing.
Main Methods:
- Low-dose digital subtraction ventriculography was performed in 33 unstable angina patients before and after abrupt cessation of atrial pacing.
- Coronary arteriography was conducted selectively.
- Patients were categorized based on ST segment changes (depression, elevation, or none) during pacing.
Main Results:
- ST segment depression occurred in 52% of patients, ST elevation in 18%, and no deviation in 30%.
- ST depression was linked to higher rates of hypertension, prior myocardial infarction, and triple-vessel disease.
- ST elevation was associated with a higher frequency of intracoronary thrombi.
- Left ventricular (LV) regional function worsened with ST depression, while ST elevation led to decreased ejection fraction and increased diastolic stress.
Conclusions:
- Distinct clinical and arteriographic profiles exist for unstable angina patients with ST depression versus ST elevation during pacing.
- The presence of intracoronary thrombi is more frequent in patients with ST elevation.
- These findings necessitate consideration in the diagnostic and therapeutic evaluation of unstable angina.
Abstract:
To assess the clinical, coronary arteriographic, and hemodynamic differences between the unstable angina patients manifesting ST segment depression and those showing ST segment elevation as well as those demonstrating chest pain only without ST segment deviation during pacing, low-dose digital subtraction ventriculography was performed in 33 patients before and after abrupt cessation of atrial pacing during selective coronary arteriography. Transient ST segment depression during pacing was observed in 17 patients (52%), whereas 6 patients (18%) showed ST segment elevation; however, 10 patients (30%) did not manifest any ST segment deviation in spite of typical chest pain. Hypertension and a history of myocardial infarction were observed in a significantly higher (P < 0.05) proportion of patients with ST segment depression than in those with ST elevation. Patients who manifested ST segment depression during pacing had a higher incidence of triple-vessel disease (65 vs 17%; P < .05) as compared with the patients with ST segment elevation. Indirect evidence of intracoronary thrombi (complicated lesion, abrupt occlusion, and intraluminal filling defect) was noticed in a higher frequency (P < 0.05) in the group of patients with ST elevation during pacing. In patients with ST segment depression, no significant changes of global left ventricular (LV) functional parameters were observed. However, the length of the LV severe hypokinetic region was increased significantly (6.2 +/- 3.1 vs 23.5 +/- 6.2%; P < 0.005) during pacing in this group of patients. The shortening of the affected segments of the left ventricle was decreased significantly (52.3 +/- 3.6 vs 38.3 +/- 4.9%; P < 0.05) in these patients during pacing. In the group of patients with ST segment elevation during pacing, decrease in ejection fraction was associated with significant (P < 0.01) increase in midwall equatorial diastolic stress as compared with the patients with pacing-induced ST segment depression as well as patients without ST segment deviation. In the group of patients without ST segment deviation during pacing there was no considerable aggravation of LV global or regional function. This distinction should be taken into consideration in evaluating patients with unstable angina for diagnostic and therapeutic intervention.