His Bundle Pacing to Reduce Likelihood of Pacing-Induced Cardiomyopathy

A 72-year-old man presented for pacemaker insertion following a syncopal episode with intermittent complete heart block. His baseline electrocardiogram is attached. His echocardiogram revealed mild left ventricular (LV) dysfunction. His-bundle pacing (HBP) was preferred over right ventricular pacing to reduce the likelihood of progression of LV dysfunction given that the patient would end up with a high percentage of ventricular pacing in the setting of existing LV dysfunction. Our final position confirmed capture of 2.40 V at 1.00 ms, an R-wave amplitude of 5.5 mV, and impedance of 871 Ohm. Day 1 post–HBP, routine electrocardiogram confirmed a threshold of 1.25 V at 1.00 ms. Of note, his left bundle branch block (LBBB) has normalised to a QRS width of 120 ms. This example highlights one of the benefits of HBP. By correcting the LBBB there is restoration of physiological biventricular synchrony. Several hypotheses aim to explain this phenomenon, including longitudinal dissociation, virtual pacing polarisation effect, and differential source-sink relationships. By achieving this, particularly in a patient expected to have a high burden of ventricular pacing with baseline LV dysfunction, we expect to reduce the likelihood of pacing-induced cardiomyopathy. In addition, by normalising the LBBB we have reduced the possibility of LBBB-induced cardiomyopathy, a distinct entity in itself.