To the editor: The reader of the Chinese Medical Journal read with great enthusiasm an interesting and exciting case report and a review of the literature “Reversible ischemia on treadmill exercise in left main coronary artery vasospasm” by Hung et al1 who describe two patients who are referred for coronary angiography due to positive treadmill exercise testing and diagnosed of left main coronary artery (LMCA) vasospasm. They offered a successful medical treatment composed of a calcium channel blocker with follow-up based on treadmill exercise testing for both patients. Our clinic is also enduringly engaged among research concerning LMCA disease diagnosis via treadmill exercise testing and hereby we aim to focus on increasing the sensitivity and specificity of the treadmill exercise testing by incorporating not only lead aVR but also lead V1 during the interpretation of exercise testing when particularly used for LMCA disease follow up.
Diagnosis and follow-up of LMCA disease is crucial and use of ST-segment elevation in leads aVR and V1 during exercise testing for prediction of left main disease is previously reported.2 It is widely accepted that exercise electrocardiography has limited role in localizing ischemic territory.3 However for localizing ischemia due to LMCA disease, specificity of the treadmill exercise testing may significantly be increased from 49% to 82% without a major sacrifice of sensitivity when ST-segment elevation in leads aVR and V1 is taken together into account during the interpretation of the test result.2 In the recent case report published in the Chinese Medical Journal, the authors have excellent discussion of the exercise test results of both patients concerning ST-segment elevation in lead aVR however they have not commented on the ST-segment elevation in lead V1 which can be seen during the peak exercise of both patients in Figure 1B, and Figure 2B of the recent report.1 As the authors excellently offered treadmill exercise testing in order to monitor the success of the medical treatment in both patients, one can assume that increasing the predictive value of information gained from exercise testing of such high risk patients may increase quality of patient care. Thus, it may be advisable to focus on both aVR and V1 during the interpretation of treadmill exercise test results in such LMCA disease patients during follow-up.
1. Hung MY, Chang NC, Hung MJ. Reversible ischemia on treadmill exercise in left main coronary artery vasospasm. Chin Med J 2011; 124: 4364-4367.
2. Tuna Katircibaşi M, Tolga Koçum H, Tekin A, Erol T, Tekin G, Baltali M, et al. Exercise-induced ST-segment elevation in leads aVR and V1 for the prediction of left main disease. Int J Cardiol 2008; 128: 240-243.
3. Dunn RF, Freedman B, Bailey IK, Uren RF, Kelly DT. Localization of coronary artery disease with exercise electrocardiography: correlation with thallium-201 myocardial perfusion scanning. Am J Cardiol 1981; 48: 837-843.