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Abolition of exercise induced positive U-wave after coronary angioplasty: clinical implication
N H Hayat1, H Salman, M A Daimee
1Cardiac Catheterization Laboratories, Chest Diseases Hospital, Faculty of Medicine, Kuwait University, PO Box 24923, 13110, Safat, Kuwait.
Insights
Exercise-induced positive U-waves are infrequent but specific markers of coronary artery stenosis. These ECG changes resolved after angioplasty, indicating potential for detecting restenosis.
Area of Science:
- Cardiology
- Diagnostic Electrocardiography
- Interventional Cardiology
Background:
- Negative U-waves on ECG correlate with myocardial ischemia in the left anterior descending artery territory.
- The diagnostic value of positive U-waves in localizing coronary artery disease requires further investigation.
Purpose of the Study:
- To prospectively evaluate the course of exercise-induced positive U-waves before and after percutaneous transluminal coronary angioplasty (PTCA).
Main Methods:
- Prospective study of 20 patients with exercise-induced positive U-waves out of 730 referred for chest pain.
- Patients underwent angiography and PTCA for significant coronary artery stenosis (>70%).
- Exercise tests were repeated post-PTCA, monitoring for U-waves, ST depression, and clinical endpoints.
Main Results:
- Significant stenosis was found in the circumflex (55%) and right coronary arteries (45%).
- Post-PTCA, coronary artery stenosis decreased significantly (90% to 13%).
- Exercise-induced U-waves and ST depression resolved in all patients after angioplasty, with improved effort tolerance.
Conclusions:
- Exercise-induced positive U-waves are rare but specific indicators of significant single-vessel coronary artery stenosis (circumflex or right).
- This ECG finding may be useful in detecting restenosis after angioplasty.
Objective:
We prospectively studied the course of exercise induced positive U-wave before and after percutaneous transluminal coronary angioplasty (angioplasty).
Background:
Negative U-wave in ECG is known to be associated with the myocardial ischemia in the territory of the left anterior descending artery. Positive U-wave needs further evaluation to prove its diagnostic value in localization of coronary artery disease.
Method:
Twenty patients demonstrated exercise induced positive U-wave from a cohort of 730 patients referred because of chest pain. Exercise was carried to > or =90% of target heart rate. They underwent angiography and subsequent angioplasty for stenosis of 70% or greater. The exercise test was repeated post angioplasty. Careful screening for clinical endpoints and presence of ST segment depression and positive U-wave was done during exercise and the first 3 min of the recovery phase.
Results:
Fifteen patients had isolated exercise induced U-wave and five had additional ST segment depression of > or =1 mm. Significant stenosis (>70% diameter reduction) of the circumflex artery was seen in 11 (55%) and of the right coronary artery in 9 (45%) patients. Coronary artery stenosis was reduced from 90+/-2% to 13+/-1% (mean+/-S.D.) P<0.001. On repeat of the exercise test U-wave and ST depression disappeared in all 20 individuals. Effort tolerance was improved after angioplasty for a mean duration of 3 min and 38 s, P<0.001.
Conclusion:
Exercise induced positive U-wave is an infrequent but specific marker of significant single coronary (circumflex or right) artery stenosis. It may lend itself to the detection of restenosis.