Influence of different percentages and positions of right ventricular pacing detected by color Doppler ultrasound on heart function in elderly patients

XING Yu-wei; ZHENG Min; SUN Su-li

doi:10.3969/j.issn.1674-4055.2017.01.20

Abstract：Objective To detect the influence of different percentages and positions of right ventricular pacing on heart function detected with color Doppler ultrasound in elderly patients.Methods The patients implanted dual-chamber pacemakers (n=64) were chosen from the Department of Ultrasound of the First Affiliated Hospital of Harbin Medical University from Jan. 2014 to Jan. 2015, and then divided, according to the percentages of right ventricular pacing, into group A (≥50%) and group B (<50%, eachn=32), and group A was divided further into subgroup A1 (right ventricular outflow tract septum pacing) and subgroup A2 (right ventricular apex pacing, each n=16). The patients’ clinical data was retrospectively analyzed, and left ventricular ejection fraction (LVEF), left ventricular end-diastolic inner diameter (LVEDd) and left atrial diameter (LAD) were compared between group A and group B, and between subgroup A1 and subgroup A2 after the operation for 1 y. The myocardial strain rates of all segments of left ventricular septum and all layers of medium segment of left ventricular septum were detected and compared by using color Doppler ultrasound and x-strain software after the operation for 1 y.Results There were 18 male cases and 14 female cases (average age=78.5±5.1) in group A, and 22 male cases and 10 female cases (average age=77.1±4.9) in group B. There were 16 cases (average age=78.8±5.4) in subgroup A1 and 16 cases (average age=78.0±5.1) in subgroup A2. The difference in LVEF, LVEDd and LAD had no statistical significance between group A and group B (P>0.05) before the operation. After the operation for 1 y, LVEF decreased and LAD increased (P<0.05), and LVEDd had no significant changes (P>0.05) in group A. LVEF, LVEDd and LAD had no significant changes (P>0.05) in group B. LVEF was lower in group A than that in group B (P<0.05), and difference in LVEDd and LAD had no statistical significance between 2 groups (P>0.05) after the operation for 1 y. The difference in LVEF, LVEDd and LAD had no statistical significance between subgroup A1 and subgroup A2 (P>0.05) before the operation. After the operation for 1 y, LVEF, LVEDd and LAD had no significant changes in subgroup A1 (P>0.05), and LVEF decreased and LVEDd and LAD increases in subgroup A2 (P<0.05). LVEF was higher and LVEDd and LAD were lower in subgroup A1 than those in subgroup A2 (P<0.05) after the operation for 1 y. The myocardial strain rates of left ventricular septal basal segment and medium segment at systole, early diastole and late diastole were higher in subgroup A1 than those in subgroup A2 (P<0.05) after the operation for 1 y. The myocardial strain rates of 3 layers of medium segment of left ventricular septum at systole, early diastole and late diastole were higher in subgroup A1 than those in subgroup A2 (P<0.05).Conclusion Compared with right ventricular apex pacing, right ventricular outflow tract septum pacing is more stable and has less influence on left ventricular systolic and diastolic functions in elderly patients implanted pacemakers.