PSVT

A 50 years old female came to the emergency with chief complaints of acute onset palpitation since last one hour of duration. There was no history of dyspnoea, chest pain, giddiness. Patient was a known case of diabetes mellitus since last 10 years and hypothyroidism  since last 7 years. During admission patient blood pressure was 126/70 mmhg. ECG of  the patient is shown below.

ECG during episode of tachycardia (Click  on the image to enlarge it)

ECG is showing narrow QRS complex (QRS duration in the ecg is less than 120 msec), regular tachycardia at rate around 190 beats per minutes, no visibble P wave seen anywhere, no significant ST-T wave changes are seen so the ecg is suggestive of narrow complex regular Short RP( P wave not seen, it mean P wave are most likely merged in the QRS complex, so RP interval(from the start of QRS complex to the start of P wave) is very small or < 70 msec, tachycardia. 

Differential is first most likely Atrioventricular nodal reentrant tachycardia (AVNRT), second AVRT, third atrial tachycardia.Patient was given injection adenosine, following which she achieved normal sinus rhythm. 

ECG after giving injection adenosine is shown below (Click on the image to enlarge it)

ECG is showing  normal sinus rhythm at 100 beats per minute, normal axis, PR interval 120 msec, no ST-T wave changes seen.

Patient underwent Electrophysiology study which showed dual Atrioventricular nodal physiology suggestive of AVNRT. Patient underwent successful slow pathway ablation.

Let's discuss how to approach in a patient with narrow QRS complex, regular tachycardia.

Thank you.