AACN Advanced Critical Care:
DEPARTMENTS: ECG Challenges
Kimberly Scheibly is Outreach Coordinator, Marin Sanitary Service, 824 Appleberry Dr, San Rafael, CA 94903 (email@example.com).
A 57-year-old white man complained of increased shortness of breath with moderate exercise that would lead to left arm numbness and tingling if exercise continued for more than 5 minutes. A few days before presenting at the office of his primary care physician, he reported daily symptoms with minimal exertion that were relieved with rest. His primary care doctor ordered an in-office electrocardiogram (ECG), which was reported to be normal and showed no change from his last ECG in 2002. On the basis of this information, the doctor referred the patient for a cardiac treadmill test.
Two days later, the patient arrived for his stress test. His medical history was significant for mild to moderate hypertension treated with Lotensin HTC (benazepril/hydrochlorthiazide), smoking a half pack per day for 20 years and then quitting in 2007, and drinking 2 to 4 glasses of wine per week. Family history was significant for coronary artery disease, hypertension, and diabetes. Physical examination was unremarkable, and the patient reported that he had not been symptomatic since seeing his primary doctor. The patient was prepared for the test and connected to the cardiac monitoring equipment. As per protocol, a 12-lead ECG was performed. The cardiology resident read the ECG and gave approval for the staff to start the test; however, the attending immediately returned and canceled the test because of the diagnosis of Wellens syndrome. The patient was sent to the cardiac catheterization laboratory, where he underwent percutaneous coronary intervention, and a 90% proximal lesion was revealed. The patient received a stent in the affected vessel and was discharged symptom-free after 2 days.
T-wave inversion, though known to be associated with myocardial ischemia, is also known to be a normal variant in many individuals.1 For this reason, it is often not given much notice by the bedside nurse if the patient is not complaining of overt chest pain. However, 2 ECG patterns have been described, which deserve prompt medical attention even when no chest pain is reported at the time of the ECG recording. In 1982, Wellens and colleagues2 gave evidence of T-wave changes in the anterior leads that are predictive of a critical narrowing of the proximal left anterior descending (LAD) artery.3 In the original study, 75% of those who did not receive surgical intervention died from anterior wall myocardial infarction soon after admission to the hospital.2 In both studies, the culprit lesion was in the proximal portion of the LAD, and the degree of occlusion ranged from 50% to complete blockage.2,3
The 2 T-wave patterns identified in the anterior leads are (1) symmetric and deeply inverted T waves (75% of cases) and (2) biphasic T waves (25% of cases). Most often, this occurs in leads V2 and V3, although it can also occur in leads V1, V4, V5, and V6.
It is evident that the patient in the case report (Figure 1) has T-wave inversion in the anterior leads, most prominently in leads V2-V3 as identified by Wellens et al.2,3 The T waves in leads I, II, III, and aVF (augmented vector foot) as well as leads V5 and V6 are all upright, and there is no evidence of ST-segment elevation or depression. Assuming that there was no change between the ECG taken at the time of symptoms and the ECG from 2002, the ECG in Figure 2 is shown for comparison. The T waves are all upright, except for aVR (augmented vector right), which is normal. Because of this finding, the primary care physician had no reason to suspect Wellens syndrome and was correctly trying to assess for risk of exercise-induced angina and ischemia.
Cardiac stress testing should be avoided in patients exhibiting signs of Wellens syndrome because of the high risk of developing a critical LAD stenosis, which can lead to anterior wall myocardial infarction and death.4–7 Had this patient undergone the treadmill stress test, chances are great that he would have suffered severe consequences and even death. As clinicians, we must be able to identify simple, yet easy-to-dismiss, ECG changes. In the case of Wellens syndrome, looking for deep, symmetric T-wave inversion or biphasic T waves in the anterior leads should signal an alert to get these patients to an cardiac catheterization laboratory for immediate percutaneous coronary intervention.2–7
1. Channer K, Morris F ABC of clinical electrocardiography: myocardial ischaemia. BMJ. 2002 324: 1023–1026.
2. de Zwaan C, Bar FW, Wellens HJ Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction. Am Heart J. 1982 103: 730–736.
3. de Zwaan C, Bär FW, Janssen JH, et al. Angiographic and clinical characteristics of patients with unstable angina showing an ECG pattern indicating critical narrowing of the proximal LAD coronary artery. Am Heart J. 1989 117(3): 657–665.
4. Sobnosky S, Kohli R, Bleibel S Wellens' syndrome. Intern J Cardiol. 2006 3: 1.
5. Tatli E, Aktoz M Wellens' syndrome: the electrocardiographic finding that is seen as unimportant. Cardiol J. 2009 16(1): 73–75.
© 2011 American Association of Critical–Care Nurses