EMS was called for a young adult male who had collapsed at home.
He had been walking through the kitchen when he complained of some chest discomfort, appeared to perhaps have trouble breathing, and then had a syncopal episode.
He had a PMHx history of trisomy 21, sleep apnea, DM type 2, and right-sided CHF due to his sleep apnea. His family also told medics that he had some congenital heart problems — a ventricular septal defect had been repaired in childhood, but he currently had an un-repaired bicuspid aortic valve, with aortic stenosis.
He was conscious by the time EMS arrived. Vital signs and exam were unremarkable.
EMS obtained a series of ECGs.
What do the ECGs show?
The first ECG shows ST segment elevation (STE) in aVR, as well as in V1. ST depression is seen in most of the inferior and lateral leads. The second ECG also shows these features, as well as a right bundle branch block.
On arrival to the ED another ECG was obtained.
Given his risk factors (including diabetes and obesity), cardiology took the patient immediately for angiography, but found no significant coronary disease. His ECG improved without any specific therapy.
His aortic stenosis, on the other hand, was found to have significantly progressed, and was likely the reason for his syncope. He underwent a surgical replacement of his bicuspid aortic valve, with good results.
Were you expecting a left-main coronary occlusion?
The STE in aVR pattern that we see here is widely understood to be practically diagnostic of an acute occlusion of the left main coronary artery. However, this pattern can be seen in many clinical scenarios (e.g., anemia, sepsis, tachycardia). In fact, a recent study found that, in patients with a pulmonary embolism, STE in aVR predicted cardiovascular collapse.
As Vince explained last year, the pattern of STE in aVR, with depression elsewhere, simply reflects a widespread ischemia in the heart, and such ischemia can have many causes. Aortic stenosis likely produces this pattern thorough a few mechanisms:
- Stenosis causes increased pressure in the left ventricle.
- That pressure causes hypertrophy of the LV.
- The pressure & hypertrophy reduce subendocardial blood flow
- Tachycardia reduces diastolic filling time
- Severe aortic stenosis reduces coronary artery flow
This isn’t just theoretical as patients with severe aortic stenosis have elevated troponin at baseline. Not good. This combination of stressors can even provoke a VF arrest in otherwise healthy-seeming people with aortic stenosis.
Don’t get carried away with aVR ST elevation. Look for provoking causes!