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Late potentials and ventricular enlargement after myocardial infarction. A new role for high-resolution
A G Zaman1, J L Morris, J H Smyllie
1Department of Cardiology, General Infirmary, Leeds, UK.
Insights
Early detection of late potentials after myocardial infarction predicts ventricular enlargement. These findings in the first week post-infarction may indicate cell slippage and serve as an early warning for developing ventricular dilatation.
Area of Science:
- Cardiology
- Electrophysiology
- Myocardial Infarction Research
Background:
- Arrhythmias frequently occur in patients with ventricular enlargement following myocardial infarction.
- Ventricular dilatation post-myocardial infarction is a significant clinical concern.
Purpose of the Study:
- To investigate the relationship between ventricular dilatation and the emergence of late potentials after myocardial infarction.
- To determine if early detection of late potentials can predict subsequent ventricular enlargement.
Main Methods:
- Prospective study involving 52 patients with first anterior myocardial infarction.
- Echocardiograms and signal-averaged ECGs recorded on days 1, 3, 7, and 42.
- Analysis of late potentials and end-diastolic volume index changes.
Main Results:
- Late potentials were detected in 29% of patients on admission, peaking at 42% by day 7, and decreasing to 13% by day 42.
- Early late potentials (admission, day 3, day 7) correlated with increased end-diastolic volume index, indicating ventricular dilatation.
- No association was found between late potentials on day 42 and ventricular dilatation, highlighting the transient nature of early predictors.
Conclusions:
- Late potentials identified within the first week post-myocardial infarction are associated with subsequent ventricular dilatation.
- These early-phase late potentials may represent a cellular mechanism (cell slippage) preceding gross ventricular enlargement.
- Early detection of late potentials shows promise as a predictive marker for ventricular dilatation after myocardial infarction.
Background:
Arrhythmias are common in patients who have developed ventricular enlargement after myocardial infarction.
Methods And Results:
A prospective study was undertaken to assess the relation between ventricular dilatation and the development of late potentials after myocardial infarction. Echocardiograms and signal-averaged ECGs were recorded on days 1,3,7, and 42 in 52 patients with a first anterior myocardial infarction. Twenty-nine percent of patients were late potential-positive on their initial signal-averaged ECG recorded on the day of admission. The incidence of late potentials rose during the next week to a peak of 42% at day 7, declining to 13% by day 42. The presence of late potentials on the day of admission was associated with an increase in end-diastolic volume index of 16.1 +/- 6.0 mL/m2 (mean +/- SEM), compared with a decreased of 4.7 +/- 2.7 mL/m2 among late potential-negative patients (P < .006). Qualitatively similar results were evident for late potentials on day 3 and day 7. By contrast, there was no association between late potentials on day 42 and ventricular dilatation. Marked dynamic changes in late potentials were evident during the first week. Patients with persistent late potentials (n = 9) on all three recordings in the first week showed a marked increase in end-diastolic volume index of 21.3 +/- 8.1 mL/m2 (P < .005 in comparison with patients who were persistently negative [n = 20]). Patients demonstrating dynamic positivity (n = 15) not present on all three recordings in the first week showed no significant increase in end-diastolic volume index.
Conclusion:
It is concluded that late potentials during the first week after infarction are associated with subsequent ventricular dilatation. These early-phase late potentials may be a manifestation of cell slippage. They arise before gross topographical enlargement and may serve as a predictor of ventricular dilatation.