All ECG 143
1. Junctional rhythm
2. Left bundle branch block
3. SVT with aberrancy
Not all ECG tracings are clear cut and textbook quality. This ECG is a bit vague in a couple of ways. There is some baseline artifact making it difficult to see if there is truly P wave activity. There are some QRS complexes toward the beginning of the tracing where a P wave can be imagined; however, these are not consistent. The first four QRS complexes are very regular, but then the fifth has a longer RR interval. The rhythm is likely junctional, but it is not completely clear.
Then the QRS rate increases suddenly toward the end of the tracing. Note that the QRS morphology remains the same as far as we can tell. This fact alone gives the diagnosis of SVT with aberrancy and not ventricular tachycardia. Click the Ventricular Tachycardia topic review below to see how to distinguish VT from SVT with aberrancy.