Objective To assess the effects of RA-URIS dual chamber sequential pacing on left ventricular remodelling and cardiac function in SSS or AVB patients with chronic heart dysfunction.

Methods 32 patients with SSS or AVB associated chronic heart dysfunction were divided two groups RA-URIS pacing group (13 cases) and RA-RVA pacing group (19 cases). The parameters including left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF) and 6 min walk test (6-MWT) were compared between two groups in pre-pacing and in follow up 24 months after pacing.

Results There were no difference on LVEF, LVMI and 6-MWT between two groups before pacemaker implanted. But after 24 months for pacing therapy in RA-URIS group, there was significant increase in LVEF (48.3±10.1 vs 40.7±8.4, p<0.05), 6MWT (386±69 vs 330±78, p<0.05) and decrease in LVMI (102.5±16.3 vs 120.1±18.5, p<0.05) Meanwhile, LVEF, 6-MWT (48.3±10.1 vs 43.7±5.5, 386±69 vs 329±91, p<0.05) were increased and LVMI (102.5±16.3 vs 113.6±17.4, p<0.05) were decreased significantly in RA-URIS group compared with those of RA-RVA group in 24 months follow up.

Conclusion The results showed that RA-URIS pacing may reverse left ventricular remodelling in patients with chronic heart dysfunction as well as improving life quality.