Wellens Type B: Lead Distribution and T-Wave Inversion Depth
Lead Distribution in Wellens Type B
Wellens Type B is characterized by deep, symmetrical T-wave inversions that typically involve leads V2-V4, not just V2-V3, and can extend even further across the precordial leads. 1, 2
- The classic description includes deep T-wave inversions in V2-V4, though the pattern may be limited to V2-V3 in some cases 1
- T-wave inversions can extend beyond V4 to involve V5 and even V6 in more extensive LAD territory involvement 2
- The key distinguishing feature from Type A is the presence of deeply inverted (rather than biphasic) T-waves 3
Minimum Depth of T-Wave Inversion Required
Deep T-wave inversions in Wellens syndrome are typically ≥2 mm in depth, which is the threshold that strongly suggests critical proximal LAD stenosis. 4, 5
- T-wave inversions ≥2 mm in two or more adjacent precordial leads are rarely observed in healthy individuals but are common in patients with critical coronary stenosis 4, 5
- The American College of Cardiology emphasizes that marked (≥2 mm) symmetrical precordial T-wave inversions strongly suggest acute ischemia from critical LAD stenosis 5
- While some sources describe "deep" inversions without specifying exact measurements, the ≥2 mm threshold is the clinically significant cutoff used in guidelines 4
Critical Clinical Context
This ECG pattern represents a pre-infarction stage requiring urgent coronary angiography, as 75% of patients will develop extensive anterior MI within weeks if not treated. 1, 3
- Wellens syndrome occurs during a pain-free period in patients with recent intermittent angina, making it easy to miss if the ECG pattern is not recognized 3
- The pattern correlates with 95-99% occlusion of the proximal LAD artery with collateral circulation 3
- Patients often have normal or minimally elevated cardiac biomarkers at presentation, which can falsely reassure clinicians 3, 6
Important Diagnostic Pitfalls
- Do not perform stress testing in patients with suspected Wellens syndrome, as this can precipitate complete LAD occlusion and massive anterior MI 3
- The T-wave pattern may evolve—Type A (biphasic) can progress to Type B (deeply inverted) or vice versa, particularly after reperfusion 3
- Similar patterns can occur in inferior leads (with RCA or LCx stenosis) or posterior leads, so the principle extends beyond just anterior precordial leads 7
Management Algorithm
- Immediate cardiology consultation for urgent coronary angiography with percutaneous coronary intervention 1, 2
- Antiplatelet therapy and anticoagulation (therapeutic enoxaparin or heparin) while awaiting catheterization 3
- Continuous cardiac monitoring and serial troponins, though normal biomarkers do not exclude the diagnosis 3, 6
- Avoid provocative testing or discharge from the emergency department even if pain-free with normal biomarkers 3