The Year in Cardiovascularmedicine 2020: Arrhythmias

Harry J.G.M. Crijns; Frits Prinzen; Pier D. Lambiase; Prashanthan Sanders; Josep Brugada

Disclosures

Eur Heart J. 2021;42(5):499-507. 

In This Article

Resynchronization Therapy, Including his Bundle, Septal, and Left Bundle Pacing

The year 2020 saw an exponential increase in interest for His bundle (HBP) and left bundle branch area pacing (LBBAP) in cardiac resynchronization therapy (CRT). The number of implants in the USA of the most commonly used lead (Medtronic 3830), showed an increase from 2000 in 2016 to 10 000 in 2018. The number of HBP related publications increased from 5 in 2014 to 75 in 2018.[41] Worldwide sales of the 3830 lead increased nine-fold between 2014 and 2018. The Twitter '#dontdisthehis' attracted almost 1200 users within 2.5 years.[42] The increased interest in HBP is likely due to the availability of better guiding catheters and the evidence that HBP is also suitable for CRT. In 2020, a few studies indicated that HBP may be equal or superior to conventional biventricular pacing (BVP) with regard to acute hemodynamic improvement, reverse remodeling and clinical outcome.[43–45]

In 2020, LBBAP was only 3 years old but attracted already considerable interest. For LBBAP, the 3830 lead is introduced transvenously and subsequently screwed through the interventricular septum until the tip of the lead is (almost) at the left ventricular (LV) endocardium (Figure 3). Compared to HBP, LBBAP lead implantation is easier and pacing thresholds are lower.[46] Some investigators aim at capturing the left bundle branch itself,[45] but others are less critical and accept any 'LV septal' lead position.[44] In 2020, a number of small single and multicenter studies appeared. Hou et al.[46] performed a study in 56 patients with bradyarrhythmias and LVEF >55%. These authors found that permanent LBBAP is safe and feasible. A better maintenance of synchrony of contraction, determined using SPECT MPI phase analysis, was observed when the left bundle branch was captured. Three studies comprising a total of 116 patients with LBBAP, 49 with HBP, and 75 with BVP consistently showed a larger reduction in QRS-complex (QRS) duration in combination with a larger increase in LV ejection fraction.[45,47,48]

Figure 3.

Schematic representation (upper right) and X-ray and computed tomography images (lower right) of positioning the pacing lead at the left side of the septum. Left panels show the electrocardiogram (ECG) during intrinsic rhythm of a patient with atrial fibrillation that received a pacemaker. Middle row of ECGs shows signals when pacing the lead at its initial position at the right of the septum and right row shows signals during pacing at final position. Note almost normalization of signals, QRS duration, and QRS area during LBB pacing.

Salden et al.[44] compared the acute hemodynamic and electrophysiological effects of 'LV septum pacing' with that of BVP and HBP. The three pacing modes were comparable with regards to increase in LVdP/dtmax, whilst HBP and LV septum pacing tended to provide better electrical resynchronization. An important finding was also that similar effects were observed when pacing the LV septum at the basal, equatorial and apical part of the septum. To show feasibility, safety (including lead extraction) and clinical effectiveness of these new pacing modalities, randomized studies are required comparing LBBP with HBP and BVP. A prospective randomized study is currently performed in China.[49]

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