This ECG was recorded from a 44-year old female after she had complained to her GP about occasional light-headedness. Is there anything to be concerned about here?
Dr Dave Richley, Associate Lecturer, Newcastle University
This ECG was recorded from a 44-year old female after she had complained to her GP about occasional light-headedness. Is there anything to be concerned about here?
Dr Dave Richley, Associate Lecturer, Newcastle University
Sinus rhythm with 2:1 heart block, right bundle branch block and borderline left axis deviation.
2 to 1 atrioventricular block with Right bundle branch block and left axis deviation – bifascicular block involving the left anterior fascicle.
There is also an element of ventriculophasic sinus arrhythmia, causing the p-wave following the conducted r-wave to have a slightly shorter p-p interval.
This is a class 1 pacing indication, although echocardiogram should precede pacing to evaluate potential benefit from His bundle or CRT pacing due to the expected high pacing burden.
There is also sinus tachycardia (hence normal ventricular rate), displaying increased sympathetic tone by the autonomic nervous system to compensate for reduced cardiac output.
As Zoe and Scott have observed, this ECG shows right bundle branch block and 2:1 AV block. 2:1 block is often not recognised because the non-conducted P wave frequently falls on or just after the T wave of the preceding beat, in which case it may be missed or mistaken for a U wave. In fact, the computer-generated report for this ECG failed to mention the 2:1 block, providing evidence, should it be needed, that computer-generated ECG reports are not necessarily to be trusted. This is important in this case because right bundle branch block alone is not an indication for pacing but, as Scott points out, 2:1 block is.
This ECG also, as Zoe states, shows a borderline left axis deviation (-30 degrees). This is not normally considered sufficient for a diagnosis of left anterior fascicular block, which usually produces an axis of between -45 and -60 degrees.
Additionally, as Scott describes, there is sinus tachycardia with ventriculophasic sinus arrhythmia, a phenomenon that is frequently observed in 2:1 and complete heart block and in which the PP intervals that enclose a QRS are shorter than the PP intervals that don’t.
Any questions or further comments?