LBBAP in patients with normal intrinsic QRS duration: Electrical and mechanical characteristics

FIGURE 1. A flow diagram of data collection [Color figure can be viewed at wileyonlinelibrary.com] Abbreviations: AVVTI, aortic valvular velocity time integral; IVMD, interventricular mechanical delay; LBBAP+, patients with left bundle branch potential; LBBAP−, patients without left bundle branch potential; LVAT, activation time of left ventricle; LVEF, ejection fraction of left ventricle; LVEDD, left ventricular end‐diastolic diameter; LVESD, left ventricular end‐systolic diameter; LVPSD, peak systolic dispersion of left ventricle; LVPSS, left ventricular peak systolic strain; PASP, pulmonary artery systolic pressure; QRSd, QRS duration

FIGURE 2. The comparation between the intrinsic status and the paced status Abbreviations: LBBAP+, patients with left bundle branch potential; LBBAP−, patients without left bundle branch potential; LVAT, activation time of left ventricle; LVPSD, peak systolic dispersion of left ventricle; LVPSS, left ventricular peak systolic strain

FIGURE 3. The distribution of QRS morphology in lead V1 and the distribution of the polarity in the lead II, III, and AVF. BASE = normal intrinsic QRS condition; LBBAP+ = patients with left bundle branch potential; LBBAP− = patients without left bundle branch potential. A, BASE group has four types of QRS morphology in lead V1, including five qR, 10 QS, 54 rS, and one rSR’. There are two types of QRS morphology in lead V1 in LBBAP, LBBAP+, and LBBAP− group in unipolar 10 V pacing, including 51 qR and 19 rSR’ in LBBAP, 36 qR and 16 rSR’ in LBBAP+ and 15 qR and 3 rSR’ in LBBAP−. B, Intrinsic lead II, III, and AVF polarity includes II+III+AVF+ 37, II‐III‐AVF‐ 7, II+III‐AVF+ 16, and II+III‐AVF‐ 10. Lead II, III, and AVF polarity in LBBAP+ in unipolar 10 V pacing includes II+III+AVF+ 18, II‐III‐AVF‐ 14, II+III‐ AVF+ 10, and II+III‐AVF‐ 10. Lead II, III, and AVF polarity in LBBAP− in unipolar 10 V pacing includes II+III+AVF+ 7, II‐III‐AVF‐ 2, II+III‐ AVF+ 7, and II+III‐AVF‐

FIGURE 4. The R‐wave transition in precordial leads in LBBAP+ and LBBAP−. BASE = normal intrinsic QRS condition; LBBAP+ = patients with left bundle branch potential; LBBAP− = patients without left bundle branch potential

FIGURE 5. The electrocardiographic and echocardiographic manifestations in intrinsic and LBBAP status. Figure shows electrocardiogram (ECG) and two‐dimensional speckle tracking echocardiography (the bull's eye plots and the left ventricular longitudinal strain curve) before and after LBBAP. Group A shows one LBBAP+ patient suffered from atrial fibrillation with a slow ventricular rate. A1 is ECG in intrinsic status, the QRS duration is 106 ms; A2 is echocardiography in intrinsic status, LVPSD is 54 ms, LVPSS is −20%. A3 is ECG in LBBAP status, the QRS duration is 118 ms; A4 is echocardiography in LBBAP status, LVPSD is 42 ms, LVPSS is −18.2%. Group B shows one LBBAP− patient suffered from atrial fibrillation with a third‐degreeatrioventricular block. B1 is ECG in intrinsic status, the QRS duration is 84 ms; B2 is echocardiography in intrinsic status, LVPSD is 32 ms, LVPSS is −17%. B3 is ECG in LBBAP status, the QRS duration is 118 ms; B4 is echocardiography in LBBAP status, LVPSD is 35 ms, LVPSS is ECG 16.8% Abbreviations: LBBAP, left bundle branch area pacing; LBBAP+, patients with left bundle branch potential; LBBAP−, patients without left bundle branch potential; LVPSD, peak systolic…

FIGURE 6. The lead parameters in LBBAP+ and LBBAP− Abbreviations: LBBAP+, patients with left bundle branch potential; LBBAP−, patients without left bundle branch potential. *compared with LBBAP+, P < .05

FIGURE 7. LBBAP lead perforation in one LBBAP+ patient. A, LBBAP+ patient with third degree atrioventricular block had asymptomatic lead perforation 6 months after the operation. Her intrinsic QRSd was 90 ms, and intrinsic LVAT was 44 ms. The patient had a LBB injury current. The unipolar 10 V paced QRSd was 112 ms. The unipolar paced QRSd at threshold was 126 ms. The unipolar paced LVAT was unchanged and was 54 ms. Her unipolar impedance immediately after the operation was 518 Ω and dropped to 306 Ω after 6 months. Her unipolar threshold immediately after the operation was 0.4 V @ 0.4 ms and cannot be measured after 6 months. The bipolar impedance immediately after the operation was 608 Ω and decreased to 489 Ω after 6 months. The bipolar threshold abnormally increased from 0.4 V @ 0.4 ms to 2.25 V @ 1 ms after 6 months. The red star shows the interventricular septum. The red arrow shows the tip of the LBBAP lead. A, The tip of the LBBAP lead is in the left ventricular endocardium 7 days after the operation. B, The tip of the lead enters the left ventricular cavity 6 months after the operation [Color figure can be viewed at wileyonlinelibrary.com] Abbreviations: LBBAP+, patients with left…