ECG of the week 7th December 2022 – Interpretation:
There is a regular narrow complex tachycardia (QRS < 120ms, rate ~160) with no obvious visible P waves (including retrograde) consistent with a supraventricular tachycardia. There is some diffuse nonspecific ST depression that may be due to rate related ischaemia. Underlying causes of SVT include AVNRT or AVRT for this rate. Junctional tachycardias present with a rate <100 usually. In the most common form of AVNRT (slow-Fast), P waves are often buried in QRS complexes and not visible.
Trial of modified Valsalva manoeuvre in this patient after 1L of crystalloid rehydration was unsuccessful at reverting to sinus rhythm. 6mg of adenosine IV was administered with the patient reverting to sinus rhythm uneventfully.