Morning report ECG Elias B Hanna, MD LSU New Orleans, Cardiology

What is the diagnosis?

Narrow complex tachycardia QRS<120 ms =SVT QRS width

Narrow complex tachycardia QRS<120 ms =SVT QRS width Irregularly irregular 1.Afib 2.MAT (P waves of ≥3 different morphologies)

Regular or regularly irregular Narrow complex tachycardia QRS<120 ms =SVT QRS width Irregularly irregular 1.Afib 2.MAT (P waves of ≥3 different morphologies)

Regular or regularly irregular 1.AVNRT 2.AVRT 3.Atrial tachycardia 4.Atrial flutter Beside sinus tachy Narrow complex tachycardia QRS<120 ms =SVT QRS width Irregularly irregular 1.Afib 2.MAT (P waves of ≥3 different morphologies)

Dual AV node pathways and AVNRT Some individuals have dual AV node pathways (up to 20% of individuals). Normally, conduction spreads through the fast pathway and gets blocked in the slow pathway. However, after a PAC, the electrical activity cannot spread through the fast pathway (which is still in a refractory period), but can get conducted through the slow pathway which then conducts both down to the ventricle and up to the atrium, through the recovered “fast pathway”, thus creating a tachycardia with retrograde P waves

AV node Accessory pathway Accessory pathway AVRT (after PAC or PVC) Similar process happens in case of accessory pathway that is conducting retrogradely. We have 2 pathways that create a reentrant circuit after a PAC or PVC.

Retrograde P wave Pseudo-r’ in V1 + Pseudo S in inf leads Arrows point to the retrograde P that is superimposed on ST segment and looks as a notch on ST segment

ECG of the previous pt in sinus rhythm after adenosine. Note the difference (no “pseudo-r’ “ or “pseudo S”)

Regular or regularly irregular Look for P waves Assess RP interval Short RP (<1/2 RR) -AVNRT -AVRT - Atrial tachycardia Long RP (>1/2 RR) -Atrial tachycardia -Atypical AVNRT Sawtooth P, esp. rate~150 -Atrial flutter Narrow complex tachycardia QRS<120 ms =SVT QRS width Irregularly irregular 1.Afib 2.MAT (P waves of ≥3 different morphologies)