Left bundle branch area pacing in patients with transthyretin cardiac amyloidosis: a case series

Figures

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  Figure 1. Patient 1—left bundle branch area pacing in wild-type transthyretin cardiac amyloidosis: electrocardiography and imaging insights before and after pacing. (A) Pre-pacemaker electrocardiography indicating a first-degree atrioventricular block with a complete left bundle branch block and a QRS duration of 142 ms. (B-1) Magnetic resonance imaging cine image showing left ventricular hypertrophy. (B-2) Late gadolinium enhancement magnetic resonance imaging image revealing significant endocardial enhancement indicative of diffuse fibrosis. (C) Subsequent electrocardiography showed progression to a third-degree atrioventricular block with a right bundle branch block-escape rhythm. (D) Post-pacemaker electrocardiography after left bundle branch area pacing demonstrating a reduced QRS duration to 114 ms with a V6 R-wave peak time of 71 ms and a right bundle branch block morphology at unipolar 1 V/0.4 ms. V6RWPT, V6 R-wave peak time.

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  Figure 2. Patient 2—left bundle branch area pacing in hereditary transthyretin cardiac amyloidosis: an integrative pacing and imaging approach. (A-1) Magnetic resonance imaging cine image showing significant atrial septal hypertrophy with a septal thickness of 23 mm, indicating severe cardiac structural remodelling. (A-2) Magnetic resonance imaging demonstrating diffuse late gadolinium enhancement throughout the myocardium, consistent with extensive fibrosis typical of amyloid infiltration. (B) Continuous unipolar pacing electrocardiography tracing showing the transition of QRS morphology during left bundle branch area pacing. Note the progressive posterior shift of the notch and eventual development of an rSr’ pattern indicative of right bundle branch block. (C-1) Pre-implantation 12-lead electrocardiography demonstrating a wide QRS complex with a duration of 172 ms, characteristic of a complete left bundle branch block. (C-2) Intraoperative electrocardiography during threshold testing at unipolar 10 V/0.4 ms showing a V6 R-wave peak time of 90 ms and a V1 R-wave peak time of 122 ms, suggestive of non-selective left bundle branch pacing. (C-3) Intraoperative electrocardiography during…

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  Figure 3. Patient 3—integrative diagnostic and therapeutic imaging in hereditary transthyretin cardiac amyloidosis. (A) Pre-pacemaker electrocardiography showing a complete atrioventricular block with a left bundle branch block escape rhythm, characterized by a QRS duration of 165 ms. (B-1) Cardiac magnetic resonance imaging cine image shows non-uniform hypertrophy of the ventricular septum, with substantial thickening at the base and mid-portion (23 mm) and no hypertrophy at the apical side (10 mm). (B-2) Cardiac magnetic resonance imaging late gadolinium enhancement image showing strong enhancement in the hypertrophied regions of the septum, indicative of amyloid deposition, with less enhancement in the apical region. (C) Fluoroscopic right anterior oblique view during left bundle branch area pacing highlighting areas with high pacing thresholds (enclosed by ellipses) unsuitable for lead placement, necessitating alternative site selection. (D) Post-pacemaker electrocardiography during left bundle branch area pacing at bipolar 3.5 V/0.4 ms showing anodal capture with a QRS duration of 124 ms and a deep S wave in the V6 lead, suggesting successful left bundle branch area pacing. However,…