An adult with h/o of HTN came in due to mechanical fall.
Figure 1 - Lead II
Why is the PR interval longer on the left than on the right?
Complex-looking arrhythmias are better interpreted when viewed in full disclosure and numbered.
Figure 2 - Full disclosure
There are bigeminal premature ventricular complexes (PVC) . QRS complexes 1,3,5,7,9,11 are conducted with prolonged PRI's (~280 ms or 0.28 sec). The PRI's of complexes 13 and 14 are shorter (~160 ms or 0.16 sec). The P wave after QRS complex # 12 is not conducted.
The possible explanation as shown in the ladder diagram is PVC with concealed retrograde conduction.
Figure 3 - Ladder diagram
The sinus P wave following the interpolated PVC reaches the AV node during it relative refractory period (induced by concealed retrograde conduction of the PVC) and is conducted with prolonged PRI.
Blocked P wave
The P wave (after complex # 12) reached the AV node during its absolute refractory period (induced by concealed retrograde conduction of the PVC) and failed to conduct.
Reference: Fisch C and Knoebel, 2000, Electrocardiography of Clinical Arrhythmias, Futura Publishing Company Inc, NY
Post a Comment
Note: Only a member of this blog may post a comment.