Case Report: Left bundle branch pacing in an amyloid light-chain cardiac amyloidosis patient with atrioventricular block

Figures

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  Figure 1. Holter monitoring of the patient. Holter monitoring in December 2020 (A) revealed an intermittent sinus pause and AVB. Holter monitoring after the first syncope episode in April 2022 (B,C) indicated an intermittent third-degree AVB with (B) and without (C) ventricular escapes. ECG without third-degree AVB (D) showed first-degree AVB, and the morphology of the QRS complex showed an RBBB pattern.

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  Figure 2. Permanent dual-chamber pacemaker implantation. Before the implantation procedure, the intrinsic ECG (A) showed first-degree AVB, RBBB, and LAFB (a sweep speed of 25 mm/s). Paced QRS morphology in the right ventricular septum (B) showed a “w” pattern with a notch at the nadir of the QRS in lead V1 (a sweep speed of 100 mm/s). With the lead screwed into the interventricular septum, the terminal R-wave of the paced QRS appeared in lead V1 (marked with a black arrow) (C) (a sweep speed of 100 mm/s). The left bundle branch potential (marked with a black arrow) was recorded from a Model 3830 lead tip (D) (unipolar, a sweep speed of 100 mm/s), and the left bundle branch potential to V6RWPT in the intrinsic rhythm was 58.33 ms. (E) Pacing at high voltage (5 V @ 0.4 ms) with the stimulus to V6RWPT of 78.28 ms (a sweep speed of 100 mm/s). (F) Pacing at low voltage (0.5 V @ 0.4 ms) with the stimulus to V6RWPT of 78.28 ms and a V6–V1 inter-peak interval of 41.67 ms (a sweep speed of 100 mm/s). (G,H) Positions of the pacing leads.

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  Figure 3. One-year follow-up visit. The intrinsic rhythm (A) was a sinus rhythm with first-degree AVB. The stimulus to V6RWPT (78 ms) was stable at high (5.0 V @ 0.4 ms) (B) and low (1.0 V @ 0.4 ms) (C) output voltages when the left bundle branch was captured.

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  Figure 4. Trends in the RA lead (A,C,E) and LBBP lead (B,D,F) threshold, sensing, and impedance. RA, right atrium; LBB, left bundle branch.