Puzzling pacing threshold in a patient with cardiac resynchronization therapy device

Song-yun Chu, Jing Zhou, Yan-sheng Ding

Figure 1. Pacing threshold testing during the procedure (A and B) and before the procedure (C). A and B: right ventricular and left ventricular pacing threshold test during the procedure; arrows indicated the loss of capture; C: “satisfactory” biventricular pacing before and after the replacement procedure.