Marked troponin elevation after implantation of a permanent antibradycardia pacemaker.

INTRODUCTION: Transvenous insertion of endocardial leads for permanent pacing is often accompanied by minor myocardial damage, detected thanks to the high sensitivity of cardiac troponins. It is unknown whether higher troponin levels, commensurate with more severe myocardial damage, can be encountered after implantation procedures. METHODS: Over a 3-year period, 283 patients underwent an implantation of a full antibradycardia pacemaker system (pulse generator plus leads). Patients were required to have normal levels of cardiac troponin I (CTNI) on a venous blood sample taken immediately prior to elective pacemaker insertion. Post implantation CTNI levels were measured in all patients 6 hours after the procedure. Repeated samples were taken if high CTNI levels were found at 6 hours. RESULTS: Elevated CTN-I levels were found in 167 patients (59%, 95% CI: 0.53-0.64), but only 5 of them (1.8%, 95% CI=0.8 to 4.1%) had peak CTN-I levels far exceeding the range of minimal myocardial damage (i.e. CTN-I >1.5 ng/ml). Implantation of the devices was successful in all patients and we did not observe any complications. None had clinical evidence of an acute coronary event before or during the pacemaker implantation procedure and coronary angiography revealed no significant lesions in the coronary arteries. CONCLUSIONS: CTN-I elevations after pacemaker implantation may far exceed levels corresponding to minimal myocardial damage. This should be a matter of concern, especially if an early discharge is planned after pacemaker implantation.

Biochemical evidence of cardiac damage following transvenous implantation of a permanent antibradycardia pacemaker lead.

OBJECTIVES: We tested the hypothesis that transvenous permanent pacemaker lead implantation causes clinically detectable myocardial damage. BACKGROUND: Histological evidence of myocardial damage has been reported after antibradycardia pacemaker lead implantation. METHODS: We studied 30 patients undergoing implantation of a full antibradycardia pacemaker system (pulse generator plus leads) and 10 patients in whom only a generator was implanted. Blood samples for cardiac troponin-I (CTNI), CK-MB mass, and myoglobin measurement were drawn at baseline, at the end of the procedure, and at 2, 6, 12, 24, 48, and 72 hours thereafter. RESULTS: Abnormal CTNI levels were noted only in 24 of the 30 patients undergoing a full system implantation. CTNI levels were already abnormal at the end of the procedure in 16 and became so in all 24 during the next 6 hours. Peak levels were reached within 6 hours in 21 patients and were compatible with "minimal" necrosis (CTNI < 1.5 pg/mL) in 20. Maximum ventricular lead diameter and number of implanted leads were independent predictors of peak CTNI levels. CK-MB mass also increased after the procedure, but exceeded the normal range in only 10 patients. Myoglobin levels increased significantly both in patients undergoing a complete system implantation and in those where only a pulse generator was implanted. CONCLUSIONS: Transvenous insertion of endocardial leads for permanent pacing is accompanied in most patients by "minimal" myocardial damage. In this setting CTNI level kinetics are fast, characterized by early elevation and peak.

Radiation doses to patients and cardiologists from permanent cardiac pacemaker implantation procedures.

BACKGROUND: The purpose of this study was to determine the patient and cardiologist doses during the implantation of permanent cardiac pacemakers under fluoroscopic control. METHODS: For 55 procedures concerning three different types of pacemakers (DDD, VDD, and VVI), the dose-area product (DAP) meter readings and fluoroscopy times were recorded. From these data, the dose to the operating cardiologist was estimated. RESULTS: The median values of DAP and fluoroscopy time for all the procedures monitored were 11.4 Gycm(2) and 6.6 minute, respectively. For the 22 DDD, 21 VDD, and 12 VVI pacemakers implanted, the respective DAP median values were 14.7, 9.9, and 7.3 Gycm(2) and the respective median fluoroscopy times were 8.4, 5, and 2.9 minutes. The median doses to the hands, chest, eyes, and legs of the cardiologist conducting the manipulations were estimated to 0.21, 0.06, 0.03, and 0.11 mGy, respectively, per procedure. CONCLUSIONS: Compared to the existing literature, the median DAP value of this study is almost identical to the 11.2 Gycm(2) reported from a sample of 627 patients in 17 different x-ray rooms, whereas the fluoroscopy times are within the range of values reported by other authors. Concerning the cardiologist exposure, the estimated values indicate that the implantation of pacemakers is a procedure that does not involve a severe risk, especially if it is taken into account that lead aprons and collars are routinely used.