Impact of moderate exercise workload on predicted optimal AV and VV delays determined by an intracardiac electrogram-based method for optimizing cardiac resynchronization therapy.

AIMS

Aim of this study is to evaluate reproducibility, consistency and the impact of moderate exercise workload on optimized PV and VV delays as determined by the IEGM-based QuickOpt™ method (St. Jude Medical), that was shown to produce hemodynamic performance similar to that obtained by echo-guided aortic VTI maximization.

METHODS

Sixty patients with CRT-ICD (65 ± 9 years, 12% female, LVEF 28 ± 9%, 48% CAD and 52% DCM) were enrolled. IEGM-based PV/VV optimization was conducted six times: twice at rest, twice immediately after a 6-min walk test and twice following a 3-min recovery period. Timing cycle delays were programmed in accordance with the optimization results. Follow-up was performed after 1 year.

RESULTS

Although significant difference in heart rate was reached [68 ± 9 bpm (REST) vs. 79 ± 12 (6MWT), p < 0.001], differences were not observed between IEGM-based optimized PV/VV delays: PV(opt) = 128 ± 14 ms (REST) versus 130 ± 17 ms (6MWT) versus 129 ± 16 ms (RECOV); VV(opt) = 15 ± 24 ms (REST) versus 15 ± 22 ms (6MWT) versus 16 ± 24 ms (RECOV). During 1-year follow-up PV(opt) and VV(opt) remained stable (ΔPV(opt) = 10 ± 10 ms, ΔVV(opt) = 9 ± 11 ms).

CONCLUSION

Optimized IEGM-based timing cycle delays are independent of moderate exercise status within a particular patient but varied between patients. This supports the use of PV/VV optimization in each CRT patient.