Longitudinal Echocardiographic Parameters Before and After Pacemaker Placement in Congenital Complete Heart Block
Presented By:
Scott J. Weinreb, MD; Steve B. Ampah, PhD; Oluwatimilehin Okunowo, MPH; Heather Griffis, PhD; Victoria L. Vetter, MD, MPH
Children's Hospital of Philadelphia
weinrebs@chop.eduOverview:
Introduction: Congenital complete heart block (CCHB) is a rare diagnosis, seen in 1:15,000 – 1:20,000 live births, with risk of left ventricular (LV) dysfunction reported in 7-23% of subjects. We investigate serial changes in LV chamber size and systolic function in paced subjects with CCHB by comparing changes in outcome measures before and after pacemaker placement.
Methods: This is a retrospective cohort study of identifiable CCHB subjects at the Children’s Hospital of Philadelphia from 1976-2018, excluding those with AV block identified in association with a known acquired cause and those with structural congenital heart disease. Subjects with echo data available before and after pacemaker implantation are included. LV end diastolic diameter (LVEDD) z-score and LV ejection fraction (EF) are modeled with linear mixed effect regression models, with slopes compared before and after pacemaker placement.
Results: Of 114 subjects with CCHB, 88 underwent pacemaker placement, of whom 52 have echo data available before and after pacemaker placement. The cohort is 60% female and 73% non-Hispanic white. Median age of diagnosis is 0.6 years (IQR, 0.0-3.5 years), age at pacemaker placement 3.4 years (IQR, 0.5-9.0 years), and duration of pacing 10.8 years (IQR, 5.2-13.7 years). A total of 337 echo data points were available for review. LVEDD z-score is estimated to be 1.39 (95% CI, 0.83-1.9) at pacemaker placement, with a significant decrease of -0.08 (95% CI -0.12 to -0.04, p=0.002) per year over the 20 years of follow-up, with mean estimated LVEDD z-score of -0.21 (95% CI, -0.82 to +0.40) at 20 years. Observed changes in LVEDD z-score following pacemaker placement did not vary by baseline demographic or clinical characteristics of interest. From the Loess plot of LVEF, it can be seen that study participants demonstrated slight mean increases in LVEF pre-pacemaker placement, with a mean LVEF of 62% at time of placement. LVEF appears to remain preserved for approximately 5.5 years post-placement; thereafter, there appears to be slight decreases over the remainder of the study period. Regression modeling of LVEF is pending further data collection.
Conclusions: In a cohort of 52 subjects with CCHB, LVEDD z-score decreases significantly following pacemaker placement and mean LVEF appears to remain preserved for 5.5 years post-pacemaker placement, after which it appears to decline. Further analysis will be performed to investigate how this information can inform standard echocardiographic practice in this patient population.
Methods: This is a retrospective cohort study of identifiable CCHB subjects at the Children’s Hospital of Philadelphia from 1976-2018, excluding those with AV block identified in association with a known acquired cause and those with structural congenital heart disease. Subjects with echo data available before and after pacemaker implantation are included. LV end diastolic diameter (LVEDD) z-score and LV ejection fraction (EF) are modeled with linear mixed effect regression models, with slopes compared before and after pacemaker placement.
Results: Of 114 subjects with CCHB, 88 underwent pacemaker placement, of whom 52 have echo data available before and after pacemaker placement. The cohort is 60% female and 73% non-Hispanic white. Median age of diagnosis is 0.6 years (IQR, 0.0-3.5 years), age at pacemaker placement 3.4 years (IQR, 0.5-9.0 years), and duration of pacing 10.8 years (IQR, 5.2-13.7 years). A total of 337 echo data points were available for review. LVEDD z-score is estimated to be 1.39 (95% CI, 0.83-1.9) at pacemaker placement, with a significant decrease of -0.08 (95% CI -0.12 to -0.04, p=0.002) per year over the 20 years of follow-up, with mean estimated LVEDD z-score of -0.21 (95% CI, -0.82 to +0.40) at 20 years. Observed changes in LVEDD z-score following pacemaker placement did not vary by baseline demographic or clinical characteristics of interest. From the Loess plot of LVEF, it can be seen that study participants demonstrated slight mean increases in LVEF pre-pacemaker placement, with a mean LVEF of 62% at time of placement. LVEF appears to remain preserved for approximately 5.5 years post-placement; thereafter, there appears to be slight decreases over the remainder of the study period. Regression modeling of LVEF is pending further data collection.
Conclusions: In a cohort of 52 subjects with CCHB, LVEDD z-score decreases significantly following pacemaker placement and mean LVEF appears to remain preserved for 5.5 years post-pacemaker placement, after which it appears to decline. Further analysis will be performed to investigate how this information can inform standard echocardiographic practice in this patient population.
