A 48-year-old man with no significant medical history was hospitalized for substernal chest pressure radiating to his left arm. The chest pain was severe and was associated with nausea, vomiting, and diaphoresis. Physical examination was unremarkable, including a cardiac exam. At the outlying facility, serial electrocardiograms (EKG) revealed increasing amplitude of T waves and then an episode of transient unresponsiveness for 40 seconds, associated with a heart rate of 20 beats/min. The initial troponin level was 0.095 ng/mL (reference range, 0 to 0.034 ng/mL). He continued to experience severe chest pain. He was given IV morphine with modest pain relief. The second troponin level was further elevated at 0.11 ng/mL. A CT angiogram of the chest showed coronary calcifications of the left anterior descending (LAD) artery and no evidence of pulmonary embolism. Transthoracic echocardiography revealed borderline reduced left ventricular systolic function with distal anterior and apical wall hypokinesis.
The patient was then transferred to our facility for emergent cardiology consultation and possible coronary angiography. Repeat EKGs were obtained from the time of departure from the outlying facility to the time of coronary angiography in succession (Figure 1). The troponin level peaked at 26.6 ng/mL during this time. A diffuse proximal LAD coronary artery plaque rupture with subsequent thrombus was found on coronary angiography (Figure 2). Percutaneous coronary intervention (PCI) in the form of balloon angioplasty and stent placement was performed to alleviate the occlusion in the LAD and restore flow.
The diagnosis is de Winter's phenomenon from a LAD artery distribution myocardial infarction. The hyperacute T waves with ST depression in the anterior EKG leads in a patient with symptoms suggesting acute coronary syndrome (ACS) should prompt the diagnosis of de Winter T waves. Absence of ST elevation in the precordial leads is required to make the diagnosis. ST-segment elevation (0.5 to 1 mm) in the augmented vector right has been frequently reported in these patients. The pattern involves tall, prominent, symmetric T waves in the precordial leads and upsloping ST-segment depression greater than 1 mm at the J-point in precordial leads.
De Winter phenomenon was first described in the New England Journal of Medicine in 2008 in a series of patients who had presented with hyperacute T waves and ST depression in the anterior EKG leads and were subsequently found to have acute LAD occlusions. Another case series, published in Heart in 2009, found similar EKG findings in 2% of ACS patients requiring emergent PCI to the LAD. De Winter EKG pattern in this study was found to be more prevalent in younger males with a higher incidence of hyperlipidemia compared to patients with a classic ST-elevation myocardial infarction (STEMI). Based on multiple clinical reports, de Winter pattern has been proposed to be a “STEMI equivalent.” In the presence of ACS symptoms, patients with de Winter pattern should be treated with emergent reperfusion therapy.
Similar changes in repolarization can be seen in other conditions such as hyperkalemia. However, T waves in patients with hyperkalemia tend to be narrow and peaked. Tachycardia has also been reported to be associated with up-sloping ST-segment depression.
As prompt diagnosis and management of ACS are critical, recognition of potential STEMI in EKG patterns is of paramount importance. De Winter phenomenon is a relatively newly discovered EKG pattern that has been associated with acute LAD occlusion, and there is a need for education of clinicians, including first responders, to promptly recognize this high-risk condition.
- In patients presenting with symptoms of ACS, an EKG demonstrating ST-segment depression with tall, symmetrical T waves in the precordial leads (de Winter phenomenon) could signify a proximal LAD artery occlusion.
- Clinical suspicion along with a de Winter EKG pattern should prompt triage of patients for immediate reperfusion therapy, even when laboratory results are within the normal range.