Recruitment of the cardiac conduction system for optimal resynchronization therapy in failing heart

Figures

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  FIGURE 1. The impaired global longitudinal strain of the septal segment of a LBBB patient with preserved LVEF by CMR-feature tracking technique. (A–C) an example from an LBBB patient: A electrocardiogram of the LBBB; B-C AHA segment diagram of 2D long axis GLS, segment eight in septum shows abnormal GLS with a positive value, represented the contradictory motion of septum, red spline; an example from a healthy control patient by (D–F): D electrocardiogram of normal intrinsic rhythm, (E–F): AHA segment diagram of 2D long axis GLS, the same segment in septum shows normal GLS with a negative value, represented as red spline.

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  FIGURE 2. Comparison of LBBP and HBP in electrical and mechanical synchrony in a HF patient with LBBB: (A) Intrinsic rhythm with QRS duration (QRSd) of 169 ms; (B) Selective HBP at left bundle branch block (LBBB) correction threshold of 3 Vat 0.5 ms with QRSd equal to 107 ms. (C) LBBP at 0.5 V at 0.4 ms with QRSd of 127 ms and RV conduction delay pattern. (D) LBBP in DDD mode with SAV delay 110 ms with QRSd reduced to 108 ms. (E) 3-dimensional echocardiogram between selective His bundle pacing (HBP) and left bundle branch pacing (LBBP). Right: intrinsic rhythm; Middle: HBP in VVI mode; Left: LBBP in VVI mode. The upper “bull’s eye” depicts the timing of contraction green areas represent synchronous areas, blue areas contract early and red/yellow areas show late contraction. The lower “bull’s eye” shows the wall excursion with dark/red areas referring to reduced excursion and bright blue areas indicating the largest systolic radial excursion.

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  FIGURE 3. Landmark studies of CSP for CRT.

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  FIGURE 4. LOT-CRT for further correction of LBBB in a patient with myocardium scars. (A) Intrinsic rhythm with LBBB morphology and very wide QRS complex of 216 ms; (B) LBBAP alone at 3v at 0.4 ms in DDD mode with SAV of 120 ms; (C) LOT-CRT at 3.5 Vat 0.4 ms in DDD mode with SAV of 120 m and LBBAP prior to LV pacing of 60 ms. (D) Myocardial scars detected by CMR-late gadolinium enhancement prior to operation: upper LV four-chamber view, the arrow represents the scar in LV lateral wall; lower, short axis view, arrow indicates the septal scar.

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  FIGURE 5. BBBP for correction of RBBD induced by LBBAP in a patient with intrinsic RBBB rhythm. (A) intrinsic rhythm of RBBB pattern with II° AV block and QRSd of 150 ms. (B) left bundle branch pacing by pacing the cathodal tip electrode alone at 0.75v at 0.4 ms with the RV delay pattern. (C), Bilateral bundle branch area pacing (BBBP) with the cathodal tip electrode and the anodal ring electrode at 2.25 v at0.4 ms with QRSd further reduced to 110 ms.