Conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch (LBB) pacing (LBBP), as a physiological pacing strategy, can achieve interventricular and/or intra-left ventricular mechanical synchronization by delivering physiological or nearly physiological ventricular activation. And many studies have verifed clinical efficacy of CSP that it can significantly relieve dyssynchrony of ventricular contraction, improve cardiac function and reduce the risk of heart failure as compared to right ventricular pacing. However, CSP has some shortcomings which limit its widespread application to some extent. As for HBP, although it can achieve optimal physiological ventricular synchronization, the problems of relatively high pacing threshold, low R-wave amplitude, the long-term performance, and inability to correct infra-Hisian atrioventricular block and intraventricular block in some patients have always been concerns. Nevertheless, LBBP is likely free of the restrictions mentioned above. On the contrary, LBBP can capture the left conduction system by directly stimulating the proximal LBB distal to the site of conduction block, thereby achieving rapid and physiological LV activation with a lower and stable pacing threshold and higher R-wave amplitude. However, as a newly emerged physiologic pacing technology, LBBP is currently in the exploratory stage and there are some phenomena to be interpreted, such as the evolution of pacing QRS morphology during the lead penetration into the interventricular septum. Therefore, the aim of this study is to assess the morphological evolution and electrophysiological characteristics of various pacing QRS patterns observed as the lead penetrates the interventricular septum from right to left.
Study Type
OBSERVATIONAL
Enrollment
50
In the procedure of left bundle branch pacing, various QRS morphologies are observed as penetrating the lead into the interventricular septum.
General Hospital of Northern Theater Command
Shenyang, Liaoning, China
RECRUITINGLeft ventricular activation time (LVAT)
Left ventricular activation time (LVAT) is defined as the interval from the onset of the pacing stimulus to the peak of the R wave in lead V5/6, which reflects the lateral precordial myocardium depolarization time.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
Right ventricular activation time (RVAT)
Right ventricular activation time (RVAT) is defined as the interval from the onset of the pacing stimulus to the peak potential recorded by the atrial electrode temporarily placed in the right ventricle, which reflects delayed right ventricular activation.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
Paced QRS morphology
Paced QRS morphology during lead penetration through the interventricular septum mainly includes left bundle branch block, intraventricular block and right bundle branch block.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
Stimulus-QRSend duration (s-QRSend)
Stimulus-QRSend duration (s-QRSend) is the time from the onset of the pacing stimulus to the end of QRS complex.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
The late-R wave duration and amplitude in lead V1 (r´dur、r´amp)
The late-R wave duration in lead V1 indicates delayed right ventricular excitation.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
The S wave duration and amplitude in lead V6 (Sdur、Samp)
The S wave duration in lead V6 indicates delayed right ventricular excitation.
Time frame: Continuous uninterrupted monitoring during the lead penetration into the interventricular septum.
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