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[Dynamic signal-averaged ECG during spontaneous stenocardia attacks in patients with ischemic heart disease]
Insights
Transient myocardial ischemia during angina episodes did not create new substrate for late potentials in coronary heart disease patients. Existing late potentials persisted, with no significant changes in signal-averaged ECG parameters observed.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Electrophysiology
Background:
- Signal-averaged electrocardiography (SAECG) assesses electrical activity.
- Late potentials (LPs) on SAECG may indicate arrhythmogenic substrates.
- Coronary heart disease (CHD) can cause myocardial ischemia and arrhythmias.
Observation:
- Studied 19 CHD patients during spontaneous anginal episodes.
- Assessed signal-averaged ECG and late potentials.
- Monitored changes before, during, and after anginal events.
Findings:
- Baseline LPs present in 45% of patients persisted throughout anginal episodes.
- No new LPs emerged during transient myocardial ischemia.
- Minor, non-significant trends observed in QRS duration and LP amplitude during ischemia.
Implications:
- Transient ischemia during angina does not appear to generate substrate for new LPs.
- SAECG may not be sensitive to acute ischemic changes causing LPs.
- Further research needed to understand LP dynamics in ischemic heart disease.
Abstract:
The dynamics of signal-averaged ECG and late potentials was studied in 19 patients with coronary heart disease during spontaneous anginal episodes. Baseline late potentials were observed in 9 (45%) patients, they remaining in all during and after anginal episodes. The occurrence of new late potentials was recorded in none of them. There were no significant differences in some parameters of signal-averaged ECG before, during, and after an anginal episode, though the duration of low-amplitude signals tended to increase at the end of the QRS complex and the mean square amplitude of late 40 msec of QRS complex decreased during transient myocardial ischemia. The differences did not achieve their statistical significance. It was concluded that transient myocardial ischemia during spontaneous anginal episodes failed to lead to the appearance of a substrate for the occurrence of late potentials.