Related Experiment Videos
[The influence of myocardial ischemia on the electrocardiogram under stress]
A Fuglewicz1, W Banasiak, M Pieróg
1Klinika Chorób Wewnetrznych Wojskowego Szpitala Klinicznego we Wrocławiu.
Insights
Ventricular late potentials (LP) indicate substrate for arrhythmias in coronary artery disease (CAD). Signal-averaged ECG (SAECG) helps stratify risk in post-myocardial infarction (MI) patients, though frequency domain analysis needs standardization.
Area of Science:
- Cardiology
- Electrophysiology
Context:
- Ventricular late potentials (LP) are linked to ventricular reentrant tachyarrhythmias in ischemic heart disease (CAD).
- Myocardial infarction (MI) can cause conduction delays and refractoriness dispersion, creating substrate for reentry.
- LP prevalence is higher in CAD patients post-MI, particularly those with prior ventricular tachycardia or cardiac arrest.
Purpose:
- To investigate the role of LP in CAD, especially after MI.
- To assess the influence of acute ischemia on LP and SAECG parameters.
- To evaluate SAECG as a risk stratification tool for ventricular tachycardia in CAD patients.
Summary:
- LP are found in 18-53% of CAD patients and 63-92% in selected post-MI groups.
- Acute ischemia minimally affects LP in non-MI CAD patients and slightly increases them in post-MI patients, without significant SAECG time-domain changes.
- Correlations between LP during ischemia and LV function/MI characteristics are inconsistent, requiring further study.
- Time-domain SAECG is accepted for risk stratification, but frequency-domain parameters lack standardization and clear clinical utility.
Impact:
- Highlights LP's role in identifying arrhythmia substrate in CAD.
- Identifies SAECG as a valuable, albeit imperfect, risk stratification tool for ventricular tachycardia post-MI.
- Underscores the need for further research into frequency-domain SAECG standardization and clinical application.
Abstract:
Ventricular late potentials (LP) seem to reflect mixed, anatomic and electrophysiologic substrate for ventricular reentrant tachyarrhythmias. Ischemic events can perform areas of delay and dispersion of conduction and refractoriness in patients with ischaemic heart disease (CAD), especially after myocardial infarction (MI). These electrophysiological disturbances can induce the reentry phenomenon. LP are present in 18-53% patients with CAD, but in selected groups of patients after MI with ventricular tachycardia or/and cardiac arrest in the past, LP are registered in 63-92% objects. The influence of acute ischemia provoked by the effort and pharmacological stress testing isn't significant in groups with CAD without MI. Occurrence of LP increase in a small grade only in post-MI patients but differences of time domain parameters of signal-averaged ECG (SAECG) are not statistically significant. There are no correlations between LP incidence during ischemia and left ventricle wall motion disturbances, ejection fraction, localisation of MI, date of MI and number of occluded coronary vessels in the greater part of investigations, but the results are divergent and the matter has to be studied. Time domain SAECG is one of admitted methods of risk stratification of incidence of sustained ventricular tachycardia in patients with CAD, but the parameters of frequency domain SAECG still are not standardized, so its clinical usefulness isn't clear.