ABSTRACT
PURPOSE: Distinguishing between left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) is challenging. This study aimed to compare the echocardiographic distance from the pacing lead tip to the left ventricular (LV) septal endocardium between patients who underwent LBBP and those who underwent LVSP successfully. METHODS: Fifty-nine consecutive patients (age 71.9 ± 12.0 years, 35.6% male) with traditional indications for permanent cardiac pacing were included (LBBP group, n = 46; LVSP group, n = 13). Unipolar pacing from the final pacing sites generated narrow QRS complexes with a right bundle branch block pattern in all patients. After the procedure, a physician blinded to the group allocation performed echocardiographic measurements of the distance between the lead tip and the LV septal endocardium. RESULTS: The mean paced QRS duration was comparable between the LBBP group and the LVSP group (105.3 ± 15.6 ms vs. 109.2 ± 9.6 ms, P = 0.287). In the LBBP group, the interval from the left bundle branch potential to QRS onset was 28.7 ± 9.0 ms. During diastole, the mean distance between the lead tip and the LV septal endocardium was 0.6 ± 0.9 mm in the LBBP group and 3.0 ± 1.6 mm in the LVSP group (P < 0.001). During systole, the distance was 1.5 ± 1.4 mm in the LBBP group and 4.3 ± 2.6 mm in the LVSP group (P < 0.001). CONCLUSIONS: The landing zone of the lead tip was closer to the LV septal endocardium in the patients who underwent LBBP. There is a need for real-time intraprocedural monitoring of the distance between the lead tip and the LV septal endocardium when performing LBBP.
Subject(s)
Bundle of His , Cardiac Pacing, Artificial , Humans , Male , Middle Aged , Aged , Aged, 80 and over , Female , Cardiac Pacing, Artificial/methods , Endocardium/diagnostic imaging , Electrocardiography/methods , Heart Conduction SystemABSTRACT
Breast cancer patients with bone,liver and lung metastases tend to have a poor prognosis.According to Paget's "seed and soil" theory,metastatic cancer cell "seeds" must fall on congenial target organ "soil".Studies have shown that myeloid-derived suppressor cells(MDSCs)can be recruited at the site of breast cancer metastasis in advance and play a role in the metastasis of breast cancer cells.This paper reviews the biological characteristics of MDSCs,the roles of MDSCs in peripheral circulation,prometastatic niche,and metastatic site during breast cancer metastasis,as well as the research progress of MDSCs-targeted treatment of breast cancer metastasis.
