Author + information
- Andrew Aboyme,
- Ammar Al Akshar,
- Abhigyan Mukherjee,
- Joanna Rock and
- John Kassotis
Ventriculo-atrial (VA) conduction can occur with ventricular pacing. This can lead to pacemaker (PM) syndrome which occurs because of AV dyssynchrony. In this setting, echo beats can manifest that make electrocardiography (ECG) interpretation difficult.
A 71 year old man presented with dyspnea. He was implanted with a PM due to sick sinus syndrome. Serial ECGs showed ventricular paced complexes with intermittent conducting and non-conducting P waves.
Heart block with intermittent ventricular capture was considered as the initial diagnosis. Upon further inspection however, retrograde conduction is suggested given the QRS complexes followed by narrow P waves with a superior axis (F1). Subsequent prolongation of the R-P interval also infers that there is decremental VA conduction. This is likely the mechanism that sets up for the echo beats, manifesting as the intermittent narrow QRS complexes. With each retrograde conduction, the impulse turns around within the AV junction finding the anterograde pathway refractory. However, as each retrograde conduction is delayed, eventually an impulse will find the anterograde pathway recovered from its refractory period resulting in an echo beat (F2).
Echo beats can obscure ECG interpretation during ventricular pacing. A thoughtful approach on the mechanism is needed to arrive to the right diagnosis. Recognition of VA conduction is important as future changes may be needed to avoid PM syndrome.
Posters Hall_Hall A
Monday, March 30, 2020, 9:45 a.m.-10:30 a.m.
Session Title: FIT Clinical Decision Making: Arrhythmias and Clinical EP 7
Abstract Category: Arrhythmias and Clinical EP
Presentation Number: 1437-313
- 2020 American College of Cardiology Foundation