Abstract 2433: Effects of Selective Site Pacing on the Hemodynamics and Functional Recovery in Patients Requiring Permanent Right Ventricular Pacing (International Standard RCT Number: 67629267)
Aim This single-centre randomized trial assessed whether RVOT compared to RVA pacing is more beneficial in terms of hemodynamic and functional capacity at the medium to long-term follow-up.
Methods Fifty patients were randomized to either RVA (n=25) or RVOT (n=25) pacing. Baseline and 6 month follow-up investigations included: EKG, NYHA class, Minnesota living with Heart failure score (MLWHF), Short Form-36 health survey (SF-36), echocardiogram, and a cardiopulmonary exercise test. The primary endpoint was PVO2. Secondary endpoints were: NYHA class, MLWHF and SF-36 scores, LVEF, and dyssynchrony criteria. The investigators were blinded, on follow-up, to the RV lead position. The primary analyses were as per intention to treat while secondary analyses were as per protocol basis.
Results There were no significant differences in changes in PVO2 levels between the study arms. In contrast, NYHA class improved to a greater extent in the RVOT arm (0.84) as compared with RVA arm (0.38), P=0.04. MLWHF scores improved significantly in the RVOT arm (32±19) compared with the RVA arm (21±22), P=0.041. In addition, SF-36 health survey indicated better scores in RVOT patients in the following areas: (1) Physical Function, 36.6±28.0 (RVOT) versus 11.2±26.0 (RVA), P= 0.005. (2) Role Limitation due to Emotional Problem scores, 43.3±9.7 (RVOT) versus 4.5±11.6 (RVA arm), P=0.016. (3) Vitality Energy Fatigue scores 26.3±27.0 (RVOT) versus 7.2±24.0 (RVA), P=0.024. QRSd prolongations were not significantly different between the groups. Echocardiogram data analysis revealed that the CARE-HF echo dyssynchrony criteria were met in 4 patients (2 in each arm) at the baseline and 11 patients on the FU (6 RVA and 5 RVOT). There were no significant differences in the changes of the following between the two study arms: LVEDD, EF, APE, APE-PPE, and LVOT-VTI. Three patients had hospital admission with heart failure; all were in the RVA arm, P=0.13.
Conclusion At 6 months, RVOT pacing was not superior to RVA in terms of PVO2. In contrast, RVOT pacing offered a more significant improvement in health-related quality of life scores, a feature that was strongly related to the superiority in NYHA class scores. Both RVA and RVOT pacing comparably worsened the echocardiogram parameters.