ECG Changes Following LAD Stent Placement
Yes, LAD stent placement can cause significant 12-lead ECG changes, particularly ST-segment elevation during the acute procedure and evolving repolarization abnormalities afterward, with the most critical concern being new ST-segment changes that may indicate acute stent thrombosis requiring emergent intervention.
Acute Procedural ECG Changes
During LAD stent placement, transient ST-segment elevation in anterolateral leads is expected as the procedure itself causes temporary vessel occlusion during balloon inflation and stent deployment 1. These changes should resolve once flow is restored. The case series demonstrates ST-segment elevation in anterolateral leads with reciprocal ST-depression in inferior leads during acute LAD occlusion, which normalized after successful stenting 1.
Post-Procedural Baseline ECG Alterations
After successful LAD stenting, the baseline ECG may show persistent abnormalities:
- T-wave changes in precordial leads V2-V4 are common and may persist, particularly if there was any myocardial injury during the procedure 1
- Q-waves may develop if there was periprocedural myocardial infarction 1
- Non-specific ST-T wave abnormalities can persist as part of the post-intervention baseline 1
Approximately 63% of patients have baseline ST-segment deviations of ≥1 mm on monitoring for various reasons including prior infarction, which is relevant for LAD stent patients 1.
Critical Warning: Stent Thrombosis ECG Changes
The most dangerous ECG change is recurrent ST-segment elevation indicating acute stent thrombosis, which occurred in 0.42-0.91% of cases and requires immediate catheterization 2. The case report demonstrates this clearly: a patient developed recurrent ST-segment elevation in anterior leads on day 8 post-procedure due to acute stent thrombosis at the LAD ostium 1.
Wellens' Syndrome Pattern
Biphasic or deeply inverted T-waves in V2-V4 after chest pain resolution indicate critical proximal LAD stenosis or in-stent restenosis and warrant emergent catheterization 3. This pattern can recur with stent restenosis, which occurs in 26.1% of ostial LAD stents 4.
Monitoring Recommendations
Obtain a 12-lead ECG immediately post-procedure, in the recovery room, and on postoperative days 1 and 2, as this strategy has the highest sensitivity for detecting complications 1. This approach detected 88% of ischemic changes in the first postoperative evaluation 1.
Key Monitoring Principles:
- Set ST-segment alarm parameters 1-2 mm above and below the patient's new post-stent baseline, not the isoelectric line 1
- Evaluate ST-segment changes with the patient supine, as positional changes can cause false alarms 1
- Mark electrode positions with indelible ink to ensure consistent lead placement, as even 1 cm variation in precordial leads can alter waveforms 1
Common Pitfalls to Avoid
Do not dismiss new ST-segment elevation as "baseline changes" in LAD stent patients—this represents stent thrombosis until proven otherwise and requires emergent angiography 1. The mortality risk is substantial if intervention is delayed.
Avoid using torso-placed monitoring electrodes for diagnostic comparison with standard 12-lead ECGs, as these cannot be considered equivalent and may show false-positive or false-negative infarction patterns 1, 5. Always use standard limb and precordial positions for diagnostic ECGs 1, 5.
Restenosis Considerations
Proximal LAD stents have higher restenosis rates (26.1%) compared to other vessels 4, 6. Drug-eluting stents reduce restenosis risk (HR 0.39) and mortality (HR 0.58) specifically in proximal LAD lesions compared to bare metal stents 6. Clinical restenosis may present with recurrent Wellens' syndrome ECG pattern 3.