Assessment of ventricular mechanical synchronization after left bundle branch pacing using 2‐D speckle tracking echocardiography

FIGURE 1. LBBP lead location confirmed by fluoroscopy and post‐implant 2D echocardiography. Fluoroscopic imaging when the pacing lead was placed in the left bundle branch area which was beneath the left side of the ventricular septum in orthotopic view, the right anterior oblique 30° view and the left anterior oblique 40° view, A‐C. Contrast injection through the sheath in the left anterior oblique 35° view, D. F, Enlarged picture of, E, to show the pacing lead tip under the left endocardium of the septum. The arrow indicates the location of the pacing lead tip with a high density. LBBP, left bundle branch pacing; LV, left ventrium; RV, right ventrium; VS, ventricular septum

FIGURE 2. Twelve‐lead ECG after LBBP, RVAP, and RVSP. QRS duration of LBBP post‐implantation was much shorter than that of RVAP and RVSP. We can get narrower ORS waves by programing the AVD in order to fuse right and left ventricular depolarization after pacing. AVD, atrium ventricular delay; ECG, electrocardiogram; LBBP, left bundle branch pacing; RVAP, right ventricular apical pacing; RVSP, right ventricular septal pacing; RVP, right ventricle pacing

FIGURE 3. 2‐D speckle‐tracking echocardiography was used to get the time‐systolic strain curve of the 18 segments. We calculate the maximum time difference of the 18‐segment systolic time to peak 2‐D strains (2‐D‐TD). Maximum 2‐D‐TD between ventricle segments in the RVP group was larger than those in the LBBP group. The TD to PSS of the six segments of the apex four‐chamber view, apex three‐chamber view, and apex two‐chamber view were larger in the RVP group than those in the LBBP group. LBBP, left bundle branch pacing; RVP, right ventricular pacing

FIGURE 4. The 18‐segment time to peak left ventricular systolic strain curves exhibiting a bull's eye pattern were used to determine left ventricular synchronization status. During selective LBBP, the range of 18‐segment time to peak left ventricular systolic strain was 310 to 330 ms, and the left ventricle showed uniform gray levels, which represents good left ventricular synchronization status. During RVP, the range of 18‐segment time to peak left ventricular systolic strain was 330 ms to 495 ms, and the left ventricle showed larger gray‐scale differences, which represents worse left ventricular synchronization status compared with LBBP. 2‐D‐TD, time difference of systolic time to peak 2‐D strains; LBBP, left branch bundle pacing; PSS, peak systolic strain; RVP, right ventricular pacing

FIGURE 5. An 86 years old male patient with left anterior fascicular block and I0 II0 AVB accepted LBBP using a 3830‐pacing lead. After LBB pacing, the left anterior fascicular block still existed (Figure 5A). 2‐D speckle‐tracking echocardiography was used to get the time‐systolic strain curve of the 18 segments after operation (Figure 5B); 2D‐TDmax of the 18‐segment systolic time to peak systolic strain was 152 ms (Figure 5B), which has no statistical difference compared with that of RVP group (148.62 ± 43.67). AVB, atrioventricular block; LBBP, left bundle branch pacing; RVP, right ventricular pacing