Per Arnsbo

Infection after pacemaker implantation: infection rates and risk factors associated with infection in a population-based cohort study of 46299 consecutive patients

Aims Infection is a serious complication of pacemaker (PM) systems. Although the rate of infection has been debated, the figures are largely unknown. We therefore studied the incidence of PM infection and its associated risk factors in the Danish population. Methods and results Since 1982, all PM implantation and removal procedures performed in Denmark have been prospectively recorded in the Danish Pacemaker Register. All patients (n = 46299) who underwent implantation between 1982 and 2007 were included. The total length of surveillance was 236 888 PM-years. The incidence of infection was calculated according to the total number of PM-years. The incidence of surgical site infection (≤365 days after PM implantation) was compared with later infection in first implant and replacement procedures. Multiple-record and multiple-event-per-subject proportional hazards analyses were used to identify the independent risk factors of PM infection. Surgical site infection occurred in 192 cases after first implantation (incidence rate 4.82/1000 PM-years), and in 133 cases after replacement (12.12/1000 PM-years). Infections occurring more than 365 days after the first implantation occurred in 153 cases (1.02/1000 PM-years), and in 118 cases after replacement (3.26/1000 PM-years). Independent factors associated with an increased risk of PM infection were a greater number of PM operations (including replacements), male sex, younger age, implantation during the earliest part of the study period, and absence of antibiotics (P< 0.001). Conclusion The overall risk of infection after PM implantation was low. A greater number of operations augmented the risk of infection. This should be taken into account when considering revisions of PM systems.

Risk factors for lead complications in cardiac pacing: a population-based cohort study of 28,860 Danish patients.

BACKGROUND Lead complications are the main reason for reoperation after implantation of pacemakers (PM) or cardiac resynchronization therapy (CRT-P) devices. OBJECTIVE This study sought to describe the incidence of lead complications causing reoperation after device implantation and to identify risk factors for lead complications. METHODS A nationwide, population-based, historic cohort study was performed based on data from the Danish Pacemaker Register, which includes all Danish patients who received their first PM or CRT-P device from 1997 to 2008. Follow-up occurred 3 months after implantation. RESULTS The study population consisted of 28,860 patients. The incidence of any lead complication was 3.6%, encompassing right atrial (RA; 2.3%), right ventricular (2.2%), and left ventricular (4.3%) lead complications. The lead complication risk declined during the first part of the study period and remained stable after 2002. Multivariate analysis identified the following significant risk factors: chronic heart failure as indication (adjusted odds ratio (aOR) 3.0; 95% confidence interval [CI] 2.1 to 4.3), implantation in a nonuniversity center (aOR 1.4; 95% CI 1.2 to 1.6), inexperienced operator with <25 implantations (aOR 1.6; 95% CI 1.3 to 2.0), single-lead RA device (aOR 1.4; 95% CI 1.1 to 1.8), dual-chamber pacing device (aOR 1.6; 95% CI 1.4 to 1.9), CRT-P device (aOR 3.3; 95% CI 2.4 to 4.4) and passive-fixation RA lead (aOR 2.2; 95% CI 1.7 to 2.9). CONCLUSION Lead complications causing reoperation remain a clinically important problem in device therapy. Mainly procedure-related factors were identified as independent risk factors for lead complications.

Pneumothorax in cardiac pacing: a population-based cohort study of 28 860 Danish patients

AIM To identify risk factors for pneumothorax treated with a chest tube after cardiac pacing device implantation in a population-based cohort. METHODS AND RESULTS A nationwide cohort study was performed based on data on 28 860 patients from the Danish Pacemaker Register, which included all Danish patients who received their first pacemaker (PM) or cardiac resynchronization device from 1997 to 2008. Multiple logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals for the association between risk factors and pneumothorax treated with a chest tube. The median age was 77 years (25th and 75th percentile: 69-84) and 55% were male (n = 15 785). A total of 190 patients (0.66%) were treated for pneumothorax, which was more often in women [aOR 1.9 (1.4-2.6)], and in patients with age >80 years [aOR 1.4 (1.0-1.9)], a prior history of chronic obstructive pulmonary disease [aOR 3.9 (1.6-9.5)], implantation of a dual-chamber PM [aOR 1.5 (1.0-2.2)], venous access with subclavian vein puncture [aOR 7.8 (4.9-12.5)], venous access with both subclavian vein puncture and cephalic vein cut-down [aOR 5.7 (3.0-10.8)], and implantation in a non-university centre [aOR 2.1 (1.6-2.9)]. CONCLUSION Pneumothorax treated with a chest tube remains a clinically important problem in device therapy. The cephalic vein cut-down technique should be applied whenever possible to avoid this complication.

APPRAISAL OF PACING LEAD PERFORMANCE FROM THE DANISH PACEMAKER REGISTER

The Danish Pacemaker Register was established in January 1982, and the 11 implanting centers in Denmark report to the Register on a continuous basis by use of the European Pacemaker Patient Identification Card proposed by the European Working Group on Cardiac Pacing. As of May 1994, the Register contained data on 18,053 lead implants performed in Denmark, i.e., 1,253 (7%) lead implants before 1982, and all the 16,800 initial lead implants since 1982 on 17,020 generators in 15,366 patients for a total of 12,188 (67,5%) ventricular unipolar, 3,178 (17.6%) ventricular bipolar, 1,316 (7.3%) atrial unipolar, and 1,371 (7.6%) atrial bipolar leads. Preformed J shaped leads were used in 3.5% of the atrial implants and active fixation in < 8%. Lead failure was defined as need for replacement or abandonment of the lead due to pacing or sensing problems with the exception of lead displacement. The 10‐year survival rate for unipolar atrial and ventricular leads was 95.8%± 2.1% (2 standard errors) and 97.1 %± 0.6%, respectively, as compared to a 4‐year survival rate of 91.5%± 4.6% and 91.6%± 1.7% for bipolar atrial and ventricular leads, and an 8‐year survival rate for bipolar ventricular leads of 75.1%± 5.0%. The 5‐year survival rate for the bipolar Medtronic model 4012 lead was 85.8%± 8.1% and 67.4%± 7.3% for the bipolar Siemens model 1010T lead, indicating a poor performance. The Siemens lead models 105T and 1050T seem to be performing like the model 101OT. The 5‐year survival rate for the bipolar Telectronics model 284 lead was 88.4%± 6.2%. The data from the Danish Pacemaker Register confirm the previous reported good survival of unipolar pacing leads irrespective of the chamber paced, and demonstrate that the bipolar Medtronic 4012 lead, the bipolar Telectronics 284 lead, and especially the bipolar Siemens 1010T, 105T, and 1050T models are unreliable leads that need careful monitoring and appropriate replacement.

Management of Spinal Cord Stimulators in Patients with Cardiac Pacemakers

We report a case of spinal cord stimulation (neurostimularion) as treatment for angina pectoris pain in a patient with a demand pacemaker. The precautions to avoid inhibition of the demand pacemaker by the neurostimulator are discussed.

Updated Appraisal of Pacing Lead Performance from the Danish Pacemaker Register: The Reliability of Bipolar Pacing Leads Has Improved

The Danish Pacemaker Register was established in January 1982, and the 12 implanting centers in Denmark report to the Register on a continuous basis by use of the European Pacemaker Patient Identification Card. As of August 1999, the Register contained data on 33,164 bradycardia, endocardial, and epicardial (n = 159) iead implants performed in Denmark on 27,738 generators in 24,180 patients for a total of 17,988 (54.2%) ventricular unipolar, 5,610 (16.9%) ventricular bipolar, 2,056 (6.2%) atrial unipolar, and 7,242 (21.8%) atrial bipolar leads. Lead failure was defined as need for replacement or surgical abandonment of the lead due to pacing or sensing problems with the exception of lead displacement. The 10‐year survival rate for unipolar leads was 97.2 ± 0.4% (± 2 SE) as compared to 79.6 ± 3.2% for bipolar leads (P < 0.001). The Medtronic 4012, the. Telectronics 284, and the Siemens (Pacesetter) 1010T, 105T. and 1050T bipolar lead models were poor performing leads that needed careful monitoring and appropriate replacement. Excluding those five poor performing bipolar leads, the models yielded a 10‐year survival rate of 94.3 ± 2.4% for bipolar leads. The 5‐year survival for all bipolar leads implanted after January IS, 1993 (this was the date that the last of the five poor performing bipolar lead models were implanted in Denmark) was 98.7 ± 0.4% compared with 98.9 ± 0.3% for all unipolar leads implanted after January 18, 1993 and 86.8 ± 1.6% for all bipolar leads implanted on or before January 18, 1993. These results indicate a significant improvement in bipolar lead reliability.

Pregnancy and Cesarean Section in a Patient with a Rate‐Responsive Pacemaker

The function of a rate‐responsive pacemaker was monitored during pregnancy and cesarean section in a woman with complete atrioventricular block. The observations during pregnancy were compared to similar observations obtained in a pregnant normal woman of comparable age, height and weight, and in 12 normal women during elective cesarean section. During pregnancy, the heart rate increased in the normal woman, whereas the pacing rate in the woman with the implanted pacemaker was unchanged. Fetal movement caused an increase in pacing rate in the 37th week of gestation, whereas the heart rate in the normal woman did not respond. During cesarean section the pacing rate was generally within the mean ± 1 SD for normal women.

Supriority of Multiprogrammable to Nonprogrammable VVI Pacing: A Comparative Study with Special Reference to Management of Pacing System Malfunctions

Analysis of pacing system malfunctions was performed in 374 patients at initial implantation or at pulse generator and lead replacement during a period of 55 months. A total of 150 nonprogrammable pacemakers were implanted in 148 patients, while 236 multiprogrammable pacemakers were implanted in 226 patients. The purpose of the analysis was to investigate the occurrence and management of malfunction unrelated to pacemaker/lead failure or lead dislodgement. The nonprogrammable group was followed for 3–53 months (median, 36). Malfunction occurred in 18 patients (12.0%); muscle stimulation in 14; exit block in three; sensing problem in one. Surgical correction was necessary in 14 of 18 cases. The multiprogrammable group was followed for 3–52 months (median, 12). Malfunction occurred in 30 cases (12.7%): muscle stimulation in 22; threshold increase in seven; sensing problem in one: Only seven of these patients required surgical correction as 23 cases were successfully managed by reprogramming alone. Malfunctions occurred during a period of several days to 36 months (median, 2.3 months). The difference in rate of secondary surgical intervention was significant (p < 0.01). Measurements during reoperation in the nonprogrammable group showed that at least 40% of late malfunctions would have been correctable by reprogramming alone. Thus, multiprogrammability is of significant value for noninvasive correction of malfunctions unrelated to pacemaker and lead failures, predominantly muscle stimulation and threshold elevation.