Relationship between the change in pacing threshold and the myocardial injury

To investigate the effects of general conditions and past medical history of patients on the short-term pacing threshold after the implantation of active electrodes of a cardiac pacemaker, and to understand whether the application of active electrodes will cause muscle injury and the severity of the injury.

A total of 156 patients who were treated with a cardiac pacemaker and implanted with single or double active electrodes in Cardiovascular Department of Central Hospital of Jiangjin District were enrolled, including 96 patients treated with a single active electrode and 60 patients treated with double active electrodes. Their clinical data were collected. During operation, the short-term atrial and ventricular pacing thresholds were monitored and recorded after the implantation of the active fixed electrode lead.

Multivariate Logistic regression analysis showed that female sex, age, smoking, drinking, coronary heart disease, diabetes mellitus and hyperlipidemia had effects on pacing thresholds in a short-term to some extent after the implantation of active fixed electrode lead of cardiac pacemaker. The levels of myocardial enzymes, myoglobin (MYO), creatine kinase (CK), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTNI), in patients were gradually increased after the implantation of active fixed electrode lead and reached the peak at 24 h, which were higher than those before operation (p < 0.05). The levels were decreased at 72 h with statistically significant differences.

Female sex, age, smoking, drinking, coronary heart disease, diabetes mellitus and hyperlipidemia are independent influencing factors of pacing thresholds in a short term after the implantation of active fixed electrode lead of cardiac pacemaker. The implantation of active electrodes can raise the myocardial enzyme indexes compared with those before operation, but will fall to the preoperative levels or normal, near normal levels at 72 h after operation. The implantation of active electrodes is safe and feasible for myocardial tissues.