The following ECG (ECG 1) was recorded in a 25-year-old patient in ICU who was alert and conscious with a blood pressure of 100/50 mmHg.
What rhythm is demonstrated?
Give the reasons for your answer.
(the college has not released their ECGs; the image above was appropriated from LITFL without any explicit permission but in the spirit of FOAM)
The ECG is consistent with a diagnosis of SVT with aberrant conduction for the following reasons:
There are no capture or fusion beats
There is no concordance in the chest leads
The QRS complexes are relatively narrow (under 160ms)
The patient’s age makes the diagnosis of an atrial origin more likely
This image comes from the LITFL page on distinguishing VT from SVT with aberrancy. As such, it is well suited to this SAQ. The reason for wanting to know the difference is that potentially a patient in VT will become very unstable if AV-nodal blockers like adenosine are given.
From "the ECG made easy", by Hampton (2003), and ECGs shamelessly stolen from Life in The Fastlane without any sort of permission, but in the non-commercial spirit of free education
One may turn to the ARC guidelines for management of supraventricular tachycardias (guideline 11.9), which suggests (Class A evidence) that in a stable patient, vagal manoeuvres ought to be tried and then adenosine may be used unless contraindications exist. An unstable patient may also have a trial of adenosine while a defibrillator is being acquired, or while the chest is being shaved etc.....
As their reference for this set of guidelines, the ARC quote the ACC's statement.