Could persistency of current of injury forecast successful active-fixation pacing lead implantation?

Presence of adequate current of injury (COI) was recognized as a sign of favorable pacemaker lead outcome. Little is known regarding the value of its dynamic behavior. We sought to test whether persistency of COI could predict active-fixation pacing lead performance.

COI was monitored up to 10min after right ventricular (RV) pacing electrode fixation. COI persistency was defined as the percentage of COI magnitude relative to its initial measurement. An unacceptable pacing threshold (≥1.0V in acute evaluation or ≥2.0V over 2-year follow-up) with or without lead dislodgement was considered as lead failure.

Lead implantation was attempted for 217 times in 174 patients (age 66.3±7.8years, 78 female). Acute lead failures occurred 43 times. Independent predictors of acute lead failure were RV enlargement (odds ratio [OR] 1.23, 95% confidential interval [CI] 1.11-2.04, P=0.033), absence of COI (OR 3.13, 95%CI 2.08-9.09, P=0.027), and COI persistency at 5min (OR 0.32, 95%CI 0.20-0.69, P=0.001) and 10min (OR 0.41, 95%CI 0.13-0.77, P=0.001). The optimal cutoffs were COI_5min persistency ≥50% (sensitivity 81.4%; specificity 81.9%) and COI_10min persistency ≥20% (sensitivity 86%; specificity 88.6%). There were 12 lead failures during 24.0±6.4months of follow-up. Patients with COI_5min persistency ≥50% had higher event-free survival compared to those with COI_5min persistency <50% (hazard ratio 3.54, 95% CI 1.04-12.06, P=0.043).

COI persistency appears to be a valuable indicator for both acute and long-term outcome of active-fixation pacemaker leads. A precipitous decline in COI may require more attention to make sure of the lead performance.