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Prevalence, resolution, and determinants of late potentials in patients with unstable angina and left ventricular
1Second Department of Internal Medicine, Kansai Medical University, Japan.
Insights
Late potentials, detected via signal-averaged ECG, were observed in unstable angina patients with prolonged wall motion abnormalities. These potentials resolved as heart function improved, suggesting ischemia causes late potentials.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Late potentials on signal-averaged ECG (SAECG) are linked to ventricular arrhythmias.
- The association between late potentials and myocardial ischemia, particularly prolonged wall motion abnormalities, remains unclear.
Purpose of the Study:
- To investigate the presence and resolution of late potentials in unstable angina patients with reversible, prolonged left ventricular wall motion abnormalities.
Main Methods:
- Prospective evaluation of 37 unstable angina patients.
- Signal-averaged ECG (SAECG) and echocardiograms recorded during acute phase and before discharge.
- Analysis of correlation between late potentials, wall motion abnormalities, and clinical factors.
Main Results:
- Late potentials were identified in 16% of patients initially, resolving before discharge.
- Patients with initial late potentials showed more frequent normalization of inferior wall motion abnormalities (p < 0.05).
- Multivessel disease was also more common in patients with initial late potentials (p < 0.05).
Conclusions:
- Late potentials can occur in patients with reversible, prolonged left ventricular wall motion abnormalities.
- Resolution of late potentials correlated with improved wall motion abnormalities.
- Myocardial ischemia causing prolonged wall motion abnormalities is a potential mechanism for late potential generation.
Abstract:
Although transient myocardial ischemia such as exercise-induced ischemia has not been reported to be associated with the occurrence of late potentials, the association of late potentials with more profound ischemic damage, which is represented by reversible but prolonged left ventricular wall motion abnormalities, has not been demonstrated. We prospectively evaluated 37 unstable angina patients who had reversible but prolonged wall motion abnormalities after resolution of chest pain and electrocardiogram (ECG) changes. Signal-averaged ECG (SAECG) and echocardiogram were recorded during the acute phase and before hospital discharge. Late potentials were present in 6 (16 percent) patients on the initial SAECG recording and resolved in all 6 patients on the second recording before hospital discharge. Normalization of inferior left ventricular wall motion abnormality and multivessel disease were observed more frequently in patients with late potentials on the initial recording than in patients without (p < 0.05 and p < 0.05, respectively). In conclusion, late potentials were observed in patients who had reversible but prolonged wall motion abnormalities; these late potentials were resolved with improvement of left ventricular wall motion abnormalities. These results suggest that myocardial ischemia with prolonged wall motion abnormalities is a possible mechanism of the occurrence of late potentials.