LAUSR

Background Right ventricular pacing can cause pacing-induced ventricular dysfunction (PIVD) correctable with biventricular pacing (BiVP). Factors associated with PIVD are poorly understood. Methods We reviewed children receiving epicardial dual-chamber pacemakers for complete heart block (CHB) after congenital heart disease (CHD) surgery. PIVD was defined as% fractional shortening <15% improving after BiVP. Results Between 2005 and 2014, 47 children <2 years developed CHB after CHD surgery. All had biventricular hearts and underwent epicardial dual chamber pacemaker implantation. Nine of the 47 (19%) developed PIVD. PIVD occurred in 0/10 with ventricular septal defect (VSD), 0/6 with tetralogy of Fallot, 2/6 with double outlet right ventricle, 2/6 with transposition and VSD, 3/9 with atrioventricular canal defect, 1/2 with mitral valve replacement; 1/3 with congenitally corrected TGA repair; and 0/3 with atrioventricular canal plus tetralogy of Fallot and 0/1 with subaortic membrane. QRS duration (QRSD) was 84–170 (median 135 ms) in the non PIVD group and 100–168 (median 124) ms in the PIVD group. Percentage fractional shortening (%FS) while paced was 16–46, median 30% in the non-PIVD group and 6–15 (median 11%) in the PIVD group.%FS post upgrade to BiVP (with an epicardial LV lead) in the 9 patients with PIVD was 23–33 (median 29%). Conclusions PIVD occurred in certain CHD but not others. Prolonged QRSD was not associated with PIVD. The predilection for RV pacing to result in PIVD in certain types of CHD needs further study.