Journal: HeartRhythm Case Reports
Article Title: A case of inappropriate pacing due to intermittent His bundle capture and the post–atrial pacing ventricular blanking period of managed ventricular pacing
doi: 10.1016/j.hrcr.2022.06.001
Figure Lengend Snippet: a: The endocardial electrogram (EGM) during an inappropriate back-up. Inappropriate back-up pacing necessarily followed serial narrow waveforms. The interval of back-up pacing in this case corresponded to the interval of managed ventricular pacing (MVP). Subsequent back-up pacing did not occur because of right ventricular (RV) pacing after a wide waveform that occurred within 1300 ms. b: Intracardiac conduction of the wide waveforms. Wide waveforms corresponded to the left bundle branch block–type morphology of the QRS complex on the 12-lead electrocardiogram and were presumed to represent septal pacing. The conduction interval between the RV septum and the His bundle was about 40 ms because the interval of the leads with narrow waveforms, which represented the conduction interval between the His bundle and the myocardium, was 50 ms. c: Intracardiac conduction of the narrow waveforms. The narrow waveforms were presumed to represent His bundle capture; therefore, the conduction interval between the His bundle and the myocardium was 50 ms, as described. Ap = HBP pacing; HB = His bundle; HBP = His bundle pacing; LAF = left anterior fascicle; LPF = left posterior fascicle; RBB = right bundle branch; Vp = RV pacing; Vs = RV sensing.
Article Snippet: A unipolar electrogram (EGM) was recorded from the lead tip and displayed on an electrophysiology recording system (Bard; Boston Scientific, Lowell, MA) and a Medtronic pacing system analyzer (model 2290).
Techniques: Blocking Assay