[Ideal current of injury and R-wave sensingvalues for identifying optimized placement of right ventricular...

To define the ideal COI and R-wave sensing values for optimized placement of right ventricular active-fixation pacing leads.

Three hundred and six patients underwent right ventricular active-fixation lead implantation in our department from January 2013 to December 2014 were enrolled in this prospective pilot cohort study. According to the times needed for successful implantation, patients were divided into group SP (success poisoning after single procedure, n=229) and group MP (success poisoning after multiple procedures, n=77). Current of injury (COI) was characterized as the magnitude of ST-segment elevation. Pacing parameters were measured up to 10 minutes after lead fixation.

(1) COI at 1 minute (COI1, (9.34±2.44)mV vs. (3.19±1.36)mV, P<0.001) and 10 minutes (COI10, (4.99±2.04)mV vs. (1.91±0.62)mV, P<0.001) after lead fixation was significantly higher in SP group compared to MP group. R-wave sensing measured at 10 minutes after lead fixation (R10 min) was also significantly higher in SP group than in MP group ((14.2±4.5)mV vs. (5.4±0.7)mV, P<0.001). Pacing threshold measured at 10 minutes after lead fixation was significantly lower ((0.65±0.18)V vs. (1.90±0.40)V, P<0.001) in SP group than in MP group. (2) The optimized placement of pacing lead was related with COI1(OR=0.247, 95%CI 0.098-0.623, P=0.003) and R10 min(OR=0.081, 95%CI 0.015-0.428, P=0.003). (3) The cut-off value of COI1 was 4.77 mV(sensibility 0.97, specificity 0.95), the cut-off value of R10 min was 7.25 mV (sensibility 0.96, specificity 1.00) for optimized lead fixation. After 3 months follow up, pacing threshold was (0.68±0.19)V, R-wave sensing was (12.1±3.6)mV, and pacing impedance was (543±107)Ω for right ventricular active-fixation pacing leads.

COI1>4.77 mV and R10 min>7.25 mV are the ideal parameters for identifying optimized placement of right ventricular active-fixation pacing leads.