Case Presentation CornerAbnormal vasodilator stress electrocardiogram with normal myocardial perfusion: Clinical decision-making and review of literature
Introduction
The presence of ST segment depressions during stress testing is a marker of myocardial ischemia. The sensitivity of diagnostic ischemic ECG changes during exercise stress testing is reported to be 67%.1 However, the presence of these ECG changes during vasodilator stress testing is less common (3%-27% prevalence) with a 24% sensitivity and 91% specificity.2,3 Significance of ST segment depression during vasodilator stress test has been under debate for long. Studies have suggested that during vasodilator stress, ischemic ECG changes in the presence of abnormal myocardial imaging are associated with high specificity and predictive accuracy for multivessel coronary artery disease (CAD). However, diagnostic accuracy of ischemic ECG changes during vasodilator stress in the setting of normal myocardial perfusion imaging (MPI) has been less frequently described. We present two cases of abnormal vasodilator stress ECG with normal myocardial perfusion and no transient ischemic dilatation (TID) who were subsequently found to have significant left main coronary artery disease and severe right coronary artery in-stent restenosis, respectively.
Section snippets
Case 1
A 69-year-old woman was evaluated by cardiology service for peri-operative cardiovascular risk stratification after sustaining a displaced right patellar fracture due to a mechanical fall. She had history of uncontrolled diabetes mellitus, hypertension, and peptic ulcer disease. Her medications included insulin, metformin, amlodipine, enalapril, and pantoprazole. On presentation, she had no cardiopulmonary symptoms, and her cardiovascular examination was unremarkable. Baseline electrocardiogram
Discussion
Significance of ST segment depression during vasodilator stress has been well established. Investigators who examined ST segment depression in the setting of abnormal perfusion have found such patients to have more extensive CAD and a worse prognosis than those without ST segment depression across different vasodilator agents.2,4, 5, 6, 7, 8 A recent study by Doukky et al showed that development of ST segment depression during Regadenoson myocardial perfusion imaging (MPI) was an independent
Conclusion
The prognostic utility of ischemic ECG changes with normal MPI has been guarded. However, accumulating amount of literature has suggested that those changes should not be disregarded and can predict worse outcomes. As we recommend that ST depression of 0.5 to 0.9 mm occurring during vasodilator stress be reported and considered as an equivocal finding. Referral for additional anatomical testing with CACs and/or CCTA, or performance of hybrid imaging when available, can further re-stratify
Disclosures
Kameel Kassab, Ahmed Al-Ogaili, Saurabh Malhotra—Pfizer Inc.: Speakers Bureau and Akcea Therapeutics: Advisory Board.
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