Explain this ECG in the context of active chest pain, slightly elevated troponin without a delta, RCA culprit, and previous with LBBB

A 60-something yo female presented w/ exertional chest pain for 3 days. She had a recent positive stress test about one week ago. Pain was 8/10 and constant. She has been experiencing progressively worsening exertional dyspnea and chest tightness mostly when climbing up flights of stairs since early September.  She underwent exercise echocardiogram in mid October where she exercised for nearly 7 minutes on the standard Bruce protocol and had typical anginal pain and shortness of breath.  Baseline echocardiogram showed moderate LV systolic dysfunction with no wall motion abnormalities. Over the last 1 week, her exertional chest pain became worse both in intensity and triggering threshold. She has been having waxing and waning pain even at rest over the last 24 horus.  Pain is described as dull and pressure-like over the retrosternal area radiating to her neck with associated tingling of the left hand.  It is rated 8/10 in severity.  She has associated shortness of breath.Time zero, with painSinus rhythm with normal narrow QRST-wave inversion that looks like Wellens ' waves in V1-V3 (the distribution is a bit unusual).  But the patient has active chest pain.  Is it Wellens ' syndrome?If so, one would expect that the chest pain is diminishing or gone& that the culprit would be the LAD.Time 17 minutesNot much differentOne month earlierThis is Left Bundle Branch Block (LBBB) without any sign of ischemia.It turns ...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs