Current knowledge of upgrade procedure
HBP has been thought to be associated with several limitations, such as
higher capture thresholds, especially in the setting of BBB or
infranodal block; lower R-wave amplitudes; and increased risk for lead
revisions from late threshold increase. Indeed, as abovementioned,
survival prognosis of HBP application was still unclear due to lacking
randomized evidence. Thus, HBP has not been widely generalized in
clinical practice and is a class IIa indication in the latest guidelines
for the management of bradyarrhythmia [15]. In our study, we found
that the distal HBP and LBBP were helpful for the better capture
thresholds and R-wave. The distal HBP and LBBP pacing, fixed in the
septal myocardium, could provide ideal capture thresholds, high R-wave
amplitudes. The key point for successful pacing is bypass conduction
blocks area of distal his bundle or proximal left bundle. We were able
to achieve distal HBP /LBBP in 34 of 36 patients with infranodal AV
block in this study, which proved the possibility to achieve high
success rates of physiologic pacing in patients dependent to ventricular
pacing. The long-term effects of his-purkinje pacing on the septal
contractile stress need to be further evaluated.