Living with a pacemaker: patient-reported outcome of a pacemaker system

Living with a pacemaker: patient-reported outcome of a pacemaker system Background: The aim of this study was to assess among pacemaker patients their overall satisfaction with the pacemaker system, pain, soreness/discomfort, cosmetic results, restrictions due to impaired movement of the shoulder/arm/chest, related sleep disturbances, and concern about possible device malfunction. Methods: The seven-item questionnaire was mailed to patients from a single center who had a pacemaker implant or replacement between 2006 and 2016. A higher score indicated worse outcome on a visual analog scale (VAS) of 0–100 mm. Results: The response rate was 75.5% and 342 questionniares were analyzed. Median age of respondents was 77. 6 years and 57.0% were males. In total, 65 complications requiring surgery (10 pocket corrections (2.9%), 5 in females) occurred during a median follow-up of 5.6 years.The distribution of the primary outcome had a median score of 5 while the 75th percentile was 13. Cosmetic appearance was significantly associated with reoperation (but not other variables). Overall scores for men and women were 5 vs. 6, respectively, which achieved significance (p = 0.042). Median ratings of pain, soreness/discomfort, cosmetic appearance, range of motion, sleep, and concern about device malfunction were all ≤5. Females reported worse outcomes for all questions, except for cosmetic results and concern about malfunction. Conclusions: The vast majority of patients report excellent overall satisfaction with the pacemaker system, and are not affected by pain, soreness/discomfort, or concern about device malfunction. They also reported favourable outcomes with respect to cosmetic results, shoulder movement, and sleep. However, some patients underwent a surgical correction of the pacemaker pocket. Keywords: Arrhythmia, Complication, Experience, Pacemaker, Pocket Background A transvenous pacemaker system consists of one (VVI A permanent pacemaker is indicated in patients with brady- or AAI) or two leads (DDD) fixated in the right side of cardia, i.e. second- or third-degree atrioventricular block, the heart; a CRT devices adds a special lead on the left significant sinus node dysfunction, tachycardia-bradycardia side. The lead(s) is plugged into a pacemaker device syndrome, bundle branch block with a history of syncope, (50 × 50 mm and 5-7 mm thick and weight 20-30 g), and, in specific circumstances, in various disease states, which is inserted beneath the collarbone, typically on according to guidelines [1]. In symptomatic patients with the left side. Perioperative complications can occur dur- heart failure, with an ejection fraction ≤40% and bundle ing vascular access (pneumothorax, arterial puncture, branch block despite optimal medical therapy, cardiac resyn- and nerve plexus injury) and during lead fixation in the chronization therapy (CRT) is indicated [1]. The implant- myocardial wall (perforation, tricuspid valve damage, ation incidence in Western Europe is 938 bradycardia and sustained arrhythmias) [3, 4]. Postoperative and pacemakers and 140 CRT devices per million annually [2]. long-term complications requiring surgical revision in- clude infections, lead malfunction due to oversensing or * Correspondence: peter.magnusson@regiongavleborg.se mechanical failure, technical device failure, and discom- Cardiology Research Unit, Department of Medicine, Karolinska Institutet, fort with the device system [5]. In many countries, these Karolinska University Hospital/Solna, SE-171 76 Stockholm, Sweden 2 complications are reported in a national register e.g. the Centre for Research and Development, Uppsala University/Region Gävleborg, Gävle, Sweden © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 2 of 7 Swedish Pacemaker Registry and the Danish Pacemaker was sent 6 weeks later and a final reminder another 6– Register [6, 7]. In a validation study of the latter registry, 8 weeks thereafter. A phone call preceded the last re- 9.5% of cardiac implantable device patients were affected minder. In addition, a phone call was made to patients who by complications after half a year [8]. However, the returned incomplete questionnaires. patient-reported experience, specifically with regard to the pacemaker system, is not completely understood [9]. The questionnaire Furhermore, generic questionnaires on health-related The questionnaire consisted of seven questions, to be quality of life lack disease specificity [10]. Therefore we answered on a 100 mm visual analog scale (VAS) with developed a questionnaire to assess overall satisfaction wording and pictures at each end (see example Fig. 1). A with the pacemaker system (primary outcome), and to higher score indicates worse outcome. assess secondary outcomes of pain, soreness/discomfort, The questions appear below with the words at either cosmetic results, restrictions of movement impairment extreme on the VAS shown in parentheses. of the shoulder/arm/chest, sleep disturbances related to the pacemaker generator, and concern about device mal- 1. How satisfied are you overall with your function. We aimed to address these research questions pacemaker? (Very satisfied, Very dissatisfied). in a cross-sectional cohort study in an unselected popu- 2. How much pain related to your pacemaker do you lation of pacemaker patients with various duration since experience? (No pain, Considerable pain). first implantation. 3. How much are you bothered by sorenesss/ discomfort from the pacemaker? (No soreness/ Methods discomfort, Considerable soreness/discomfort). Setting 4. How do you feel about the cosmetic appearance of The records of all patients ≥18 years who recieved an your pacemaker? (Very Good, Very bad). initial pacemaker or a replacement pacemaker at Gävle 5. Do you experience any restrictions of movement Hospital, Region Gävleborg between December 2006 of shoulder/arm/chest related to your pacemaker? and December 2016 were extracted from the electronical (No restriction of movement, Considerable system Provisio™. restriction of movement). We excluded patients with a history of primary a CRT 6. How would you rate any sleep disturbances implant and/or an implantable defibrillator. We used related to your pacemaker generator? (No sleep search codes FPE00, FPE10, FPE20, and FPE40 accord- disturbance, Considerable sleep disturbance). ing to the International Code of Disease and Classifica- 7. How much concern do you feel that your tion [11], which have not changed during the study pacemaker will stop working or malfunction? period. (No concern, Always concerned). Data collection and power analysis The questionnaire was developed by the authors and The search yielded 2950 patients. A power analysis was face validity was addressed by input from physicians and performed using Monte-Carlo simulations from a hypo- nurses involved in the follow-up of pacemaker patients. thetical outcome of the primary outcome: log-normal dis- Laypeople were consulted to assure that the form was tribution, truncated at 10 mm with a log-scale mean score clearly understood and easy to follow. As generic of 1.6 and a log-scale standard deviation of 1. The simula- quality-of-life instruments could not capture the specific tions showed that 400 patients would under the described patient-reported outcomes this paper aimed to address circumstances be sufficient to estimate the median VAS and as no suitable disease-specific instrument could be score of with an expected 95% confidence interval width found in the literature, we developed a new question- of 7 mm, as estimated from BCa non-parametric boot- naire based on clinical experience. This new question- strapping. This was deemed to be a sufficient precision. naire has not been evaluated with regards to reliability To compensate for non-responses, one fifth of the or validity, which we recognize as a limitation. patients (590 out of 2950) were randomly selected using a computer script written in R and manually entered into the daily updated census register to ensure that we included only living patients [12]. After removal of du- plicates, the final sample consisted of 453 patients, who were mailed the questionnaire. In early January of 2017, the questionnaire was sent by Fig. 1 Question 1 in the questionnaire. A higher score indicates regular mail together with information about the study, an worse outcome informed consent form, and a return envelope. A reminder Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 3 of 7 Other variables including benzodiazepines (n = 28; 7.3%), acetaminophen In addition to the questionnaire, we asked patients to fill (paracetamol) (n = 18; 5.3%), selective serotonin reuptake in their current medications, which were categorized as inhibitors (n = 18; 5.3%), opioids (n = 8; 2.3%), and corti- follows: sleeping pills (zolpidem, propiomazin) including costeroids (n = 4; 1.2%). More than half of the patients other benzodiazepines, acetaminophen (paracetamol), (59.4%) were overweight (body mass index [BMI] > 25) selective serotonin reuptake inhibitors, opioids, and cor- at the time they completed the questionnaire. Median ticosteroids. Complications were defined as those requir- BMI was 26.0 kg/m (IQR 24.6–29.3) and only 3.3% ing surgery involving the pacemaker system, i.e. opening reported BMI < 20 kg/m . Patient characteristics are of the pacemaker pocket. Information on complications summarized in Table 1. was obtained from medical records and registry data. Analysis of non-response Statistics The response rate of the questionnaire was 75.5%. Rea- Numeric data were described as frequencies, percent- sons for non-response were as follows: dementia (n =10), ages, medians (interquartile range [IQR]), means (stand- no registered postal address/emigration (n = 6), or un- ard deviation [SD]), and percentiles. All VAS-scores on known (n =95). Fisher’s exact test revealed no stastically the questionnaire were reported in millimeters (mm). significant difference in response rate with regard to sex; Tests of differences in VAS results between subgroups 78.0% among males returned the questionnaire and were performed using the Mann-Whitney U-test. Asso- females 72.4% (p = 0.188). Non-responders were signifi- ciations between continuous variables were assessed cantly older than responders (median age: 82.4 years vs using Spearman’s correlation coefficient. Possible differ- 77.6 years, p =0.018). ences in proportion of response rates between males and females were tested using Fisher’s exact test. The choice Table 1 Characteristics of 342 pacemaker patients of using non-parametric statistics was made based on Variable n non-normality of all measured variables, as seen from Number of patients 342 graphically examination of data. All statistical tests were Median age (years) 77.6 (IQR 70.4–84.2) two-sided with a significance level of 0.05. The database Males 195 (57.0%) in Excel 2010 (Microsoft Corporation, Redmond, WA) Pacemaker type was imported for analyses using R(R Core Team, 2015). DDD 262 (76.6%) Ethics VVI 51 (14.9%) The Regional Ethical Committee in Uppsala approved AAI 7 (2%) the study (protocol number 2016/478). CRT-P 22 (6.4%) Number of procedures Results 1 229 (67.0%) A total of 342 questionniares were analyzed. Ages ranged from 30 to 100 years, with a median age of 2 67 (19.6%) 77.6 years (interquartile range [IQR]: 70–84) and the 3 29 (8.5%) mean age was 75.9 years (standard deviation [SD] 12.0). 4 15 (4.4%) There were more males (n = 195; 57.0%) than females (n 5 1 (0.3%) = 147; 43%). Patients had DDD (76.6%), single-chamber 6 1 (0.3%) (17.0%), or CRT (6.4%) pacemakers. During the median Complications requiring reintervention time since primary pacemaker implant of 5.6 years (mean 6.5 years, SD 5.1), 65 complications requiring sur- Lead malfunction 40 (11.7%) gical intervention occurred, mainly lead-related malfunc- Pocket correction 10 (2.9%) tion or perforation. One patient had two complications. Perforation 5 (1.5%) Notably, 10 patients (2.9%), of whom 5 were females, Extraction 9 (2.6%) underwent pacemaker pocket revision, i.e. a correction. Exploration unipolar lead 1 (0.3%) Median time since last device surgery was 4.3 years (IQR Body-mass index (kg/m ) 1.73–8.1 years). In our study, over a median time since primary implant of 5.6 years, patients underwent device < 20 11 (3.3%) replacement either before battery depletion (n =104, 20–25 119 (35.7%) 30.4%) or due to complications (n = 51, 14.9%). The 25–30 130 (39%) pharmacological regimens that could influence the pa- > 30 73 (21.9%) tient’s pacemaker experience were mainly sleeping pills Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 4 of 7 Primary outcome from 8 (pain)to 16(cosmetic results) and the 95th As for the ratings of each seven questions, the distri- percentile ranged from 38 (pain)to 54(movement), see bution of the primary outcome overall satisfaction Tables 2 and 3. Statistically significant differences be- was heavily skewed to the right (Fig. 2). Median score tween males and females were found for all questions, was 5 while the 75th percentile was 13 and the 95th except for cosmetic results and concern about device percentile 44.9. malfunction. Reoperation was significantly associated Men and women had similar median scores (5 vs. 6, withworse outcome for cosmetic results, but not for the respectively) but the Mann-Whitney U test revealed stat- other variables. istical significance (p = 0.042) driven by differences in the higher percentiles (75th percentile:15.5 vs 11.5; 95th Correlations percentile: 54.2 vs 30.3). Patients who underwent reoper- None of the seven outcome scores correlated signifi- ation did not report a significantly different outcome in cantly to patient age at the time of evaluation (Spear- overall satisfaction compared to those who did not man’s rho ranging between 0.00 and 0.16, all p-values undergo a revision (p = 0.14). ≥0.355), time since the first implantation (Spearman’s rho between - 0.09 and − 0.01, all p > 0.12) or BMI Secondary outcomes (Spearman’s rho between - 0.10 and 0.00, all p > 0.48). Median ratings of pain, soreness/discomfort, cosmetic However, a longer time since last pacemaker surgery was results, movement, sleep, and concern about device significantly correlated to better outcomes for all ques- malfunction were all ≤5. The 75th percentiles ranged tions (overall satisfaction rho = − 0.26, p < 0.001; pain 0 20406080 100 0 20406080 Overall satisfaction (mm) Pain (mm) 0 20406080 100 0 20 40 60 80 100 Soreness/discomfort (mm) Cosmetic (mm) 0 20406080 100 0 20 40 60 80 100 Movement (mm) Sleep (mm) 0 20406080 100 Concern malfunction (mm) Fig. 2 Histogram of frequency and outcome of pacemaker-patient reporting on a 100 mm scale. A higher score indicates worse outcome Frequency Frequency Frequency Frequency 0 100 250 0 100 250 0 100 250 0 100 250 Frequency Frequency Frequency 0 100 250 0 100 250 0 100 250 Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 5 of 7 Table 2 Percentile distribution and mean values (standard Females more often report pain, soreness/discomfort, and deviations) of responses on VAS-scale (mm) sleep disturbances Question 5% 25% 50% 75% 95% Mean(SD) We found statistically significant differences in reported overall satisfaction, pain soreness/discomfort and sleep Overall satisfaction 0 2 5 13 44.9 10.3 (14.1) between the sexes, where females more frequently re- Pain 0 1 3 8 38 8.3 (13.1) ported worse outcome than males. Since females are Soreness/discomfort 0 2 4 14 62 13 (19.5) generally smaller,the device may more readily impede Cosmetic results 0 2 5 15.8 50.9 12.4 (17.9) arm movement. Interestingly, there were few patients Movement 0 1 4 10 53.9 10.3 (17.8) who reported cosmetic problems and there was no dif- Sleep 0 2 4 9 44.8 9.2 (14.8) ference between males and females in the assessment of cosmetic results. Although the study population was Concern about malfunction 0 2 4 13 52.9 11.7 (18.4) 57% men, among the patients who underwent surgical revision to correct pacemaker position in the pocket, rho = − 0.21, p < 0.001; Soreness/discomfort rho = − 0.16, 50% were women (n = 5). p = 0.01; cosmetic rho = − 0.16, p = 0.01; movement rho = − 0.22, p = 0.01; sleep rho = − 0.19, p = 0.01; concern Age, BMI, reoperation malfunction rho = − 0.09, p = 0.04). Interestingly, neither age nor BMI seemed to affect the patient-reported outcomes for our survey. The fact that re-operation was not associated with worse outcome is Discussion reassuring, but it still must be remembered that surgical Pacemaker implantation typically results in lifelong ther- revision increases the risk of infection and may require apy. From a healthcare perspective, complications related lead extraction. From the perspective of each individual to pacemaker implantation may require surgical interven- patient, it is important to take every measure to avoid tions as well as extra follow-up visits, either in-clinic or reoperation due to complications and consider the opti- remotely by using home-monitoring. Notably, 10 patients mal technique for pacemaker and lead placement at the complained about the device position and underwent sur- initial implantation [17, 18]. gical intervention to reposition the pacemaker. Clinicians may hesitate before making the decision to surgically cor- Future perspectives rect the pacemaker pocket, because it increases the risk of This study provides insights into the perceptions of infection and lead damage, which may necessitate lead pacemaker patients about their device therapy. Despite extractions that involve serious risks and expense [13–16]. the increasing proportion of home-monitoring devices, which have improved patient safety and clinical logistics, it is still important to evaluate outcomes from a holistic Most patients report overall satisfaction and pacemaker-patient-centric viewpoint. The creation In the present study, the vast majority claimed very high of the pocket during the initial implantation is crucial. overall satisfaction and further analyses of secondary There is an ongoing trial designed to address whether outcomes confirmed this. Nevertheless, a non-neglible intramuscular implantation is superior to a subcutane- proportion of the patients reported complaints which ous pocket for initial pacemaker placement [19]. did not result in surgical revisions because they were not The introduction of a new leadless pacemaker (Micra™) addressed clinically. It is not clear from our study why may eliminate problems due to the pocket and leads. some patient complaints were not identified during their However, this device has limited availability, few indica- follow-up. tions, and may be cost prohibitive [20, 21]. Rechargeable Table 3 Median and interquartile range (IQR) with regard to sex and reoperation (p-value using Mann-Whitney U-test) Question Females, median (IQR) Males, median (IQR) p-value No reop, median (IQR) Reoperation, median (IQR) p-value Overall satisfaction 6 (3–15.5) 5 (2–11.5) 0.042 6 (2–14) 4 (2–11) 0.142 Pain 4 (2–11) 3 (1–7) 0.025 3 (2–9) 3 (1–8) 0.612 Soreness/discomfort 6 (2–20) 4 (1–11) 0.002 4 (2–14) 5 (2–15) 0.568 Cosmetic results 5 (2–17) 4 (2–14) 0.201 4 (2–13) 7 (2–21) 0.043 Movement 4 (2–13) 3 (1–8) 0.079 4 (1–10) 3 (1–8) 0.958 Sleep 5 (2–11.5) 3 (1–7) 0.009 4 (2–8) 3 (1–9) 0.595 Concern about malfunction 5 (2–13.5) 4 (1–12) 0.12 5 (2–13) 3 (2–11) 0.253 Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 6 of 7 pacemakers seem to offer the theoretical advantages of Ethics approval and consent to participate The study was approved by the Regional Ethical committee in Uppsala (Dnr reducing device replacements, but there are no recharge- 2015/060). All patients gave their written consent to participate in the study. able devices currently on the market. Competing interests The authors declare that they have no competing interests. Strengths and weaknesses This study evaluates pacemaker therapy from the patient perspective, going beyond data in registries in order to ad- Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in published dress patient attitudes without the potential bias that maps and institutional affiliations. could be introduced by interviewing patients during clinical follow-up. Many of our respondents were elderly Received: 21 June 2017 Accepted: 24 May 2018 and some suffered cognitive impairments and were not able to follow instructions, even though the questionnaire References was short and straightforward. Nonresponders tended to 1. Brignole M, Auricchio A, Baron-Esquivias G, Bordachar P, Boriani G, be older than respondents, but males and females partici- Breithardt OA, Cleland J, et al. 2013 ESC guidelines on cardiac pacing and cardiac resynchronization therapy: the task force on cardiac pacing and pated in the study to the same extent.In order to over- resynchronization therapy of the European Society of Cardiology (ESC). come the limitations of a cross-sectional study design, Developed in collaboration with the European heart rhythm association repeated outcome assessments at predefined follow-up (EHRA). Europace. 2013;15:1070–118. 2. www.eucomed.org/medical-technology/facts-figures periods are required. Psychological coping strategies, like 3. Ellenbogen KA, Hellkamp AS, Wilkoff BL, Camunas JL, Love JC, Hadjis TA, adaptation, were not addressed. Finally, we would like to Lee KL, et al. Complications arising after implantation of DDD pacemakers: point out that multiple statistical tests were performed in the MOST experience. Am J Cardiol. 2003;92:740–1. 4. Udo EO, Zuithoff NP, van Hemel NM, de Cock CC, Hendriks T, Doevendans our study, but no correction for mass significance has PA, Moons KG. Incidence and predictors of short- and long-term been made, which means that caution is warranted when complications in pacemaker therapy: the FOLLOWPACE study. Heart interpreting individual tests. An alternative approach Rhythm. 2012;9:728–35. 5. Eberhardt F, Bode F, Bonnemeier H, Boguschewski F, Schlei M, Peters W, would have to perform such corrections to reduce the risk Wiegand UK. Long term complications in single and dual chamber pacing of statistical type 1-errors, but at the cost of an increased are influenced by surgical experience and patient morbidity. Heart. 2005;91: risk of type 2-errors. 500–6. 6. Gadler F, Valzania C, Linde C. Current use of implantable electrical devices in Sweden: data from the Swedish pacemaker and implantable cardioverter- Conclusion defibrillator registry. Europace. 2015;17:69–77. The vast majority of pacemaker patients report excellent 7. https://ssl.icddata.dk/download/Danish_Pacemaker_and_ICD_Register_ Annual_Report_2015b.pdf overall satisfaction with their pacemaker system, includ- 8. Kirkfeldt RE, Johansen JB, Nohr EA, Jorgensen OD, Nielsen JC. Complications ing the absence of pain, no soreness/discomfort, accept- after cardiac implantable electronic device implantations: an analysis of a able cosmetic results, good shoulder movement, sound complete, nationwide cohort in Denmark. Eur Heart J. 2014;35:1186–94. 9. Udo EO, van Hemel NM, Zuithoff NP, Nijboer H, Taks W, Doevendans PA, sleep, and no concerns about device malfunction. In Moons KG. Long term quality-of-life in patients with bradycardia pacemaker 2.9% of the study population, a surgical procedure was implantation. Int J Cardiol. 2013;168:2159–63. need to correct device placement. Females report worse 10. Stofmeel MA, Post MW, Kelder JC, Grobbee DE, van Hemel NM. Quality-of- life of pacemaker patients: a reappraisal of current instruments. Pacing Clin overall satisfaction, pain, soreness/discomfort, and more Electrophysiol. 2000;23:946–52. sleep problems related to the pacemaker. 11. World Health Organization . International Classification of Diseases (ICD)". Retrieved 2017. Abbreviations 12. Statistics Sweden Database. Official population statistics. 2015. www.scb.se/ BMI: body mass index; CRT: cardiac resynchronization therapy; BE0101 IQR: interquartile range; SD: standard deviation; VAS: visual analog scale 13. Buch E, Boyle NG, Belott PH. Pacemaker and defibrillator lead extraction. Circulation. 2011;123:378–80. Acknowledgements 14. Johansen JB, Jorgensen OD, Moller M, Arnsbo P, Mortensen PT, Nielsen JC, The authors acknowledge editing by Jo Ann LeQuang of LeQ Medical who et al. Infection after pacemaker implantation: infection rates and risk factors reviewed the manuscript for American English use. Thanks to Julia Fahlstedt associated with infection in a population-based cohort study of 46299 and Therese Martinell for administrative support. consecutive patients. Eur Heart J. 2011;32:991–8. 15. Kirkfeldt RE, Johansen JB, Nohr EA, Moller M, Arnsbo P, Nielsen JC, et al. Risk Funding factors for lead complications in cardiac pacing: a population-based cohort Region Gävleborg funded this research project. study of 28,860 Danish patients. Heart Rhythm. 2011;8:1622–8. 16. Tobin K, Stewart J, Westveer D, Frumin H. Acute complications of Availability of data and materials permanent pacemaker implantation: their financial implication and relation The datasets used and analysed during the current study are available from to volume and operator experience. Am J Cardiol. 2000;85:774–6. the corresponding author on reasonable request. 17. Rajappan K. Permanent pacemaker implantation technique: part I: arrhythmias. Heart. 2009;95:259–64. Authors’ contributions 18. Rajappan K. Permanent pacemaker implantation technique: part II. Heart. PM: project idea, design, data collection and analysis, major writing of the 2009;95:334–42. manuscript, project management. PL: design with regard to statistical issues, 19. Magnusson P, Wennström L, Kastberg R, Liv P. Placement of cardiac data collection and analysis, critical revision of the manuscript. Both authors PacemaKEr trial (POCKET) – rationale and design: a randomized controlled approved the manuscript for submission. trial. Heart Int. 2017;12(1):e8–e11. Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 7 of 7 20. Reynolds DW, Duray GZ, Omar R, Soejima K, Neuzil P, Zhang S, Narasimhan C, et al. A leadless Intracardiac Transcatheter pacing system. N Engl J Med. 2016;374(6):533–41. 21. Duray GZ, Ritter P, El-Chami M, Narasimhan C, Omar R, Tolosana JM, Zhang S, et al. Micra Transcatheter pacing study group. Long-term performance of a transcatheter pacing system: 12-month results from the Micra Transcatheter pacing study. Heart Rhythm. 2017;14(5):702–9. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png BMC Cardiovascular Disorders Springer Journals

Living with a pacemaker: patient-reported outcome of a pacemaker system

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Abstract

Background: The aim of this study was to assess among pacemaker patients their overall satisfaction with the pacemaker system, pain, soreness/discomfort, cosmetic results, restrictions due to impaired movement of the shoulder/arm/chest, related sleep disturbances, and concern about possible device malfunction. Methods: The seven-item questionnaire was mailed to patients from a single center who had a pacemaker implant or replacement between 2006 and 2016. A higher score indicated worse outcome on a visual analog scale (VAS) of 0–100 mm. Results: The response rate was 75.5% and 342 questionniares were analyzed. Median age of respondents was 77. 6 years and 57.0% were males. In total, 65 complications requiring surgery (10 pocket corrections (2.9%), 5 in females) occurred during a median follow-up of 5.6 years.The distribution of the primary outcome had a median score of 5 while the 75th percentile was 13. Cosmetic appearance was significantly associated with reoperation (but not other variables). Overall scores for men and women were 5 vs. 6, respectively, which achieved significance (p = 0.042). Median ratings of pain, soreness/discomfort, cosmetic appearance, range of motion, sleep, and concern about device malfunction were all ≤5. Females reported worse outcomes for all questions, except for cosmetic results and concern about malfunction. Conclusions: The vast majority of patients report excellent overall satisfaction with the pacemaker system, and are not affected by pain, soreness/discomfort, or concern about device malfunction. They also reported favourable outcomes with respect to cosmetic results, shoulder movement, and sleep. However, some patients underwent a surgical correction of the pacemaker pocket. Keywords: Arrhythmia, Complication, Experience, Pacemaker, Pocket Background A transvenous pacemaker system consists of one (VVI A permanent pacemaker is indicated in patients with brady- or AAI) or two leads (DDD) fixated in the right side of cardia, i.e. second- or third-degree atrioventricular block, the heart; a CRT devices adds a special lead on the left significant sinus node dysfunction, tachycardia-bradycardia side. The lead(s) is plugged into a pacemaker device syndrome, bundle branch block with a history of syncope, (50 × 50 mm and 5-7 mm thick and weight 20-30 g), and, in specific circumstances, in various disease states, which is inserted beneath the collarbone, typically on according to guidelines [1]. In symptomatic patients with the left side. Perioperative complications can occur dur- heart failure, with an ejection fraction ≤40% and bundle ing vascular access (pneumothorax, arterial puncture, branch block despite optimal medical therapy, cardiac resyn- and nerve plexus injury) and during lead fixation in the chronization therapy (CRT) is indicated [1]. The implant- myocardial wall (perforation, tricuspid valve damage, ation incidence in Western Europe is 938 bradycardia and sustained arrhythmias) [3, 4]. Postoperative and pacemakers and 140 CRT devices per million annually [2]. long-term complications requiring surgical revision in- clude infections, lead malfunction due to oversensing or * Correspondence: peter.magnusson@regiongavleborg.se mechanical failure, technical device failure, and discom- Cardiology Research Unit, Department of Medicine, Karolinska Institutet, fort with the device system [5]. In many countries, these Karolinska University Hospital/Solna, SE-171 76 Stockholm, Sweden 2 complications are reported in a national register e.g. the Centre for Research and Development, Uppsala University/Region Gävleborg, Gävle, Sweden © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 2 of 7 Swedish Pacemaker Registry and the Danish Pacemaker was sent 6 weeks later and a final reminder another 6– Register [6, 7]. In a validation study of the latter registry, 8 weeks thereafter. A phone call preceded the last re- 9.5% of cardiac implantable device patients were affected minder. In addition, a phone call was made to patients who by complications after half a year [8]. However, the returned incomplete questionnaires. patient-reported experience, specifically with regard to the pacemaker system, is not completely understood [9]. The questionnaire Furhermore, generic questionnaires on health-related The questionnaire consisted of seven questions, to be quality of life lack disease specificity [10]. Therefore we answered on a 100 mm visual analog scale (VAS) with developed a questionnaire to assess overall satisfaction wording and pictures at each end (see example Fig. 1). A with the pacemaker system (primary outcome), and to higher score indicates worse outcome. assess secondary outcomes of pain, soreness/discomfort, The questions appear below with the words at either cosmetic results, restrictions of movement impairment extreme on the VAS shown in parentheses. of the shoulder/arm/chest, sleep disturbances related to the pacemaker generator, and concern about device mal- 1. How satisfied are you overall with your function. We aimed to address these research questions pacemaker? (Very satisfied, Very dissatisfied). in a cross-sectional cohort study in an unselected popu- 2. How much pain related to your pacemaker do you lation of pacemaker patients with various duration since experience? (No pain, Considerable pain). first implantation. 3. How much are you bothered by sorenesss/ discomfort from the pacemaker? (No soreness/ Methods discomfort, Considerable soreness/discomfort). Setting 4. How do you feel about the cosmetic appearance of The records of all patients ≥18 years who recieved an your pacemaker? (Very Good, Very bad). initial pacemaker or a replacement pacemaker at Gävle 5. Do you experience any restrictions of movement Hospital, Region Gävleborg between December 2006 of shoulder/arm/chest related to your pacemaker? and December 2016 were extracted from the electronical (No restriction of movement, Considerable system Provisio™. restriction of movement). We excluded patients with a history of primary a CRT 6. How would you rate any sleep disturbances implant and/or an implantable defibrillator. We used related to your pacemaker generator? (No sleep search codes FPE00, FPE10, FPE20, and FPE40 accord- disturbance, Considerable sleep disturbance). ing to the International Code of Disease and Classifica- 7. How much concern do you feel that your tion [11], which have not changed during the study pacemaker will stop working or malfunction? period. (No concern, Always concerned). Data collection and power analysis The questionnaire was developed by the authors and The search yielded 2950 patients. A power analysis was face validity was addressed by input from physicians and performed using Monte-Carlo simulations from a hypo- nurses involved in the follow-up of pacemaker patients. thetical outcome of the primary outcome: log-normal dis- Laypeople were consulted to assure that the form was tribution, truncated at 10 mm with a log-scale mean score clearly understood and easy to follow. As generic of 1.6 and a log-scale standard deviation of 1. The simula- quality-of-life instruments could not capture the specific tions showed that 400 patients would under the described patient-reported outcomes this paper aimed to address circumstances be sufficient to estimate the median VAS and as no suitable disease-specific instrument could be score of with an expected 95% confidence interval width found in the literature, we developed a new question- of 7 mm, as estimated from BCa non-parametric boot- naire based on clinical experience. This new question- strapping. This was deemed to be a sufficient precision. naire has not been evaluated with regards to reliability To compensate for non-responses, one fifth of the or validity, which we recognize as a limitation. patients (590 out of 2950) were randomly selected using a computer script written in R and manually entered into the daily updated census register to ensure that we included only living patients [12]. After removal of du- plicates, the final sample consisted of 453 patients, who were mailed the questionnaire. In early January of 2017, the questionnaire was sent by Fig. 1 Question 1 in the questionnaire. A higher score indicates regular mail together with information about the study, an worse outcome informed consent form, and a return envelope. A reminder Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 3 of 7 Other variables including benzodiazepines (n = 28; 7.3%), acetaminophen In addition to the questionnaire, we asked patients to fill (paracetamol) (n = 18; 5.3%), selective serotonin reuptake in their current medications, which were categorized as inhibitors (n = 18; 5.3%), opioids (n = 8; 2.3%), and corti- follows: sleeping pills (zolpidem, propiomazin) including costeroids (n = 4; 1.2%). More than half of the patients other benzodiazepines, acetaminophen (paracetamol), (59.4%) were overweight (body mass index [BMI] > 25) selective serotonin reuptake inhibitors, opioids, and cor- at the time they completed the questionnaire. Median ticosteroids. Complications were defined as those requir- BMI was 26.0 kg/m (IQR 24.6–29.3) and only 3.3% ing surgery involving the pacemaker system, i.e. opening reported BMI < 20 kg/m . Patient characteristics are of the pacemaker pocket. Information on complications summarized in Table 1. was obtained from medical records and registry data. Analysis of non-response Statistics The response rate of the questionnaire was 75.5%. Rea- Numeric data were described as frequencies, percent- sons for non-response were as follows: dementia (n =10), ages, medians (interquartile range [IQR]), means (stand- no registered postal address/emigration (n = 6), or un- ard deviation [SD]), and percentiles. All VAS-scores on known (n =95). Fisher’s exact test revealed no stastically the questionnaire were reported in millimeters (mm). significant difference in response rate with regard to sex; Tests of differences in VAS results between subgroups 78.0% among males returned the questionnaire and were performed using the Mann-Whitney U-test. Asso- females 72.4% (p = 0.188). Non-responders were signifi- ciations between continuous variables were assessed cantly older than responders (median age: 82.4 years vs using Spearman’s correlation coefficient. Possible differ- 77.6 years, p =0.018). ences in proportion of response rates between males and females were tested using Fisher’s exact test. The choice Table 1 Characteristics of 342 pacemaker patients of using non-parametric statistics was made based on Variable n non-normality of all measured variables, as seen from Number of patients 342 graphically examination of data. All statistical tests were Median age (years) 77.6 (IQR 70.4–84.2) two-sided with a significance level of 0.05. The database Males 195 (57.0%) in Excel 2010 (Microsoft Corporation, Redmond, WA) Pacemaker type was imported for analyses using R(R Core Team, 2015). DDD 262 (76.6%) Ethics VVI 51 (14.9%) The Regional Ethical Committee in Uppsala approved AAI 7 (2%) the study (protocol number 2016/478). CRT-P 22 (6.4%) Number of procedures Results 1 229 (67.0%) A total of 342 questionniares were analyzed. Ages ranged from 30 to 100 years, with a median age of 2 67 (19.6%) 77.6 years (interquartile range [IQR]: 70–84) and the 3 29 (8.5%) mean age was 75.9 years (standard deviation [SD] 12.0). 4 15 (4.4%) There were more males (n = 195; 57.0%) than females (n 5 1 (0.3%) = 147; 43%). Patients had DDD (76.6%), single-chamber 6 1 (0.3%) (17.0%), or CRT (6.4%) pacemakers. During the median Complications requiring reintervention time since primary pacemaker implant of 5.6 years (mean 6.5 years, SD 5.1), 65 complications requiring sur- Lead malfunction 40 (11.7%) gical intervention occurred, mainly lead-related malfunc- Pocket correction 10 (2.9%) tion or perforation. One patient had two complications. Perforation 5 (1.5%) Notably, 10 patients (2.9%), of whom 5 were females, Extraction 9 (2.6%) underwent pacemaker pocket revision, i.e. a correction. Exploration unipolar lead 1 (0.3%) Median time since last device surgery was 4.3 years (IQR Body-mass index (kg/m ) 1.73–8.1 years). In our study, over a median time since primary implant of 5.6 years, patients underwent device < 20 11 (3.3%) replacement either before battery depletion (n =104, 20–25 119 (35.7%) 30.4%) or due to complications (n = 51, 14.9%). The 25–30 130 (39%) pharmacological regimens that could influence the pa- > 30 73 (21.9%) tient’s pacemaker experience were mainly sleeping pills Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 4 of 7 Primary outcome from 8 (pain)to 16(cosmetic results) and the 95th As for the ratings of each seven questions, the distri- percentile ranged from 38 (pain)to 54(movement), see bution of the primary outcome overall satisfaction Tables 2 and 3. Statistically significant differences be- was heavily skewed to the right (Fig. 2). Median score tween males and females were found for all questions, was 5 while the 75th percentile was 13 and the 95th except for cosmetic results and concern about device percentile 44.9. malfunction. Reoperation was significantly associated Men and women had similar median scores (5 vs. 6, withworse outcome for cosmetic results, but not for the respectively) but the Mann-Whitney U test revealed stat- other variables. istical significance (p = 0.042) driven by differences in the higher percentiles (75th percentile:15.5 vs 11.5; 95th Correlations percentile: 54.2 vs 30.3). Patients who underwent reoper- None of the seven outcome scores correlated signifi- ation did not report a significantly different outcome in cantly to patient age at the time of evaluation (Spear- overall satisfaction compared to those who did not man’s rho ranging between 0.00 and 0.16, all p-values undergo a revision (p = 0.14). ≥0.355), time since the first implantation (Spearman’s rho between - 0.09 and − 0.01, all p > 0.12) or BMI Secondary outcomes (Spearman’s rho between - 0.10 and 0.00, all p > 0.48). Median ratings of pain, soreness/discomfort, cosmetic However, a longer time since last pacemaker surgery was results, movement, sleep, and concern about device significantly correlated to better outcomes for all ques- malfunction were all ≤5. The 75th percentiles ranged tions (overall satisfaction rho = − 0.26, p < 0.001; pain 0 20406080 100 0 20406080 Overall satisfaction (mm) Pain (mm) 0 20406080 100 0 20 40 60 80 100 Soreness/discomfort (mm) Cosmetic (mm) 0 20406080 100 0 20 40 60 80 100 Movement (mm) Sleep (mm) 0 20406080 100 Concern malfunction (mm) Fig. 2 Histogram of frequency and outcome of pacemaker-patient reporting on a 100 mm scale. A higher score indicates worse outcome Frequency Frequency Frequency Frequency 0 100 250 0 100 250 0 100 250 0 100 250 Frequency Frequency Frequency 0 100 250 0 100 250 0 100 250 Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 5 of 7 Table 2 Percentile distribution and mean values (standard Females more often report pain, soreness/discomfort, and deviations) of responses on VAS-scale (mm) sleep disturbances Question 5% 25% 50% 75% 95% Mean(SD) We found statistically significant differences in reported overall satisfaction, pain soreness/discomfort and sleep Overall satisfaction 0 2 5 13 44.9 10.3 (14.1) between the sexes, where females more frequently re- Pain 0 1 3 8 38 8.3 (13.1) ported worse outcome than males. Since females are Soreness/discomfort 0 2 4 14 62 13 (19.5) generally smaller,the device may more readily impede Cosmetic results 0 2 5 15.8 50.9 12.4 (17.9) arm movement. Interestingly, there were few patients Movement 0 1 4 10 53.9 10.3 (17.8) who reported cosmetic problems and there was no dif- Sleep 0 2 4 9 44.8 9.2 (14.8) ference between males and females in the assessment of cosmetic results. Although the study population was Concern about malfunction 0 2 4 13 52.9 11.7 (18.4) 57% men, among the patients who underwent surgical revision to correct pacemaker position in the pocket, rho = − 0.21, p < 0.001; Soreness/discomfort rho = − 0.16, 50% were women (n = 5). p = 0.01; cosmetic rho = − 0.16, p = 0.01; movement rho = − 0.22, p = 0.01; sleep rho = − 0.19, p = 0.01; concern Age, BMI, reoperation malfunction rho = − 0.09, p = 0.04). Interestingly, neither age nor BMI seemed to affect the patient-reported outcomes for our survey. The fact that re-operation was not associated with worse outcome is Discussion reassuring, but it still must be remembered that surgical Pacemaker implantation typically results in lifelong ther- revision increases the risk of infection and may require apy. From a healthcare perspective, complications related lead extraction. From the perspective of each individual to pacemaker implantation may require surgical interven- patient, it is important to take every measure to avoid tions as well as extra follow-up visits, either in-clinic or reoperation due to complications and consider the opti- remotely by using home-monitoring. Notably, 10 patients mal technique for pacemaker and lead placement at the complained about the device position and underwent sur- initial implantation [17, 18]. gical intervention to reposition the pacemaker. Clinicians may hesitate before making the decision to surgically cor- Future perspectives rect the pacemaker pocket, because it increases the risk of This study provides insights into the perceptions of infection and lead damage, which may necessitate lead pacemaker patients about their device therapy. Despite extractions that involve serious risks and expense [13–16]. the increasing proportion of home-monitoring devices, which have improved patient safety and clinical logistics, it is still important to evaluate outcomes from a holistic Most patients report overall satisfaction and pacemaker-patient-centric viewpoint. The creation In the present study, the vast majority claimed very high of the pocket during the initial implantation is crucial. overall satisfaction and further analyses of secondary There is an ongoing trial designed to address whether outcomes confirmed this. Nevertheless, a non-neglible intramuscular implantation is superior to a subcutane- proportion of the patients reported complaints which ous pocket for initial pacemaker placement [19]. did not result in surgical revisions because they were not The introduction of a new leadless pacemaker (Micra™) addressed clinically. It is not clear from our study why may eliminate problems due to the pocket and leads. some patient complaints were not identified during their However, this device has limited availability, few indica- follow-up. tions, and may be cost prohibitive [20, 21]. Rechargeable Table 3 Median and interquartile range (IQR) with regard to sex and reoperation (p-value using Mann-Whitney U-test) Question Females, median (IQR) Males, median (IQR) p-value No reop, median (IQR) Reoperation, median (IQR) p-value Overall satisfaction 6 (3–15.5) 5 (2–11.5) 0.042 6 (2–14) 4 (2–11) 0.142 Pain 4 (2–11) 3 (1–7) 0.025 3 (2–9) 3 (1–8) 0.612 Soreness/discomfort 6 (2–20) 4 (1–11) 0.002 4 (2–14) 5 (2–15) 0.568 Cosmetic results 5 (2–17) 4 (2–14) 0.201 4 (2–13) 7 (2–21) 0.043 Movement 4 (2–13) 3 (1–8) 0.079 4 (1–10) 3 (1–8) 0.958 Sleep 5 (2–11.5) 3 (1–7) 0.009 4 (2–8) 3 (1–9) 0.595 Concern about malfunction 5 (2–13.5) 4 (1–12) 0.12 5 (2–13) 3 (2–11) 0.253 Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 6 of 7 pacemakers seem to offer the theoretical advantages of Ethics approval and consent to participate The study was approved by the Regional Ethical committee in Uppsala (Dnr reducing device replacements, but there are no recharge- 2015/060). All patients gave their written consent to participate in the study. able devices currently on the market. Competing interests The authors declare that they have no competing interests. Strengths and weaknesses This study evaluates pacemaker therapy from the patient perspective, going beyond data in registries in order to ad- Publisher’sNote Springer Nature remains neutral with regard to jurisdictional claims in published dress patient attitudes without the potential bias that maps and institutional affiliations. could be introduced by interviewing patients during clinical follow-up. Many of our respondents were elderly Received: 21 June 2017 Accepted: 24 May 2018 and some suffered cognitive impairments and were not able to follow instructions, even though the questionnaire References was short and straightforward. Nonresponders tended to 1. Brignole M, Auricchio A, Baron-Esquivias G, Bordachar P, Boriani G, be older than respondents, but males and females partici- Breithardt OA, Cleland J, et al. 2013 ESC guidelines on cardiac pacing and cardiac resynchronization therapy: the task force on cardiac pacing and pated in the study to the same extent.In order to over- resynchronization therapy of the European Society of Cardiology (ESC). come the limitations of a cross-sectional study design, Developed in collaboration with the European heart rhythm association repeated outcome assessments at predefined follow-up (EHRA). Europace. 2013;15:1070–118. 2. www.eucomed.org/medical-technology/facts-figures periods are required. Psychological coping strategies, like 3. Ellenbogen KA, Hellkamp AS, Wilkoff BL, Camunas JL, Love JC, Hadjis TA, adaptation, were not addressed. Finally, we would like to Lee KL, et al. Complications arising after implantation of DDD pacemakers: point out that multiple statistical tests were performed in the MOST experience. Am J Cardiol. 2003;92:740–1. 4. Udo EO, Zuithoff NP, van Hemel NM, de Cock CC, Hendriks T, Doevendans our study, but no correction for mass significance has PA, Moons KG. Incidence and predictors of short- and long-term been made, which means that caution is warranted when complications in pacemaker therapy: the FOLLOWPACE study. Heart interpreting individual tests. An alternative approach Rhythm. 2012;9:728–35. 5. Eberhardt F, Bode F, Bonnemeier H, Boguschewski F, Schlei M, Peters W, would have to perform such corrections to reduce the risk Wiegand UK. Long term complications in single and dual chamber pacing of statistical type 1-errors, but at the cost of an increased are influenced by surgical experience and patient morbidity. Heart. 2005;91: risk of type 2-errors. 500–6. 6. Gadler F, Valzania C, Linde C. Current use of implantable electrical devices in Sweden: data from the Swedish pacemaker and implantable cardioverter- Conclusion defibrillator registry. Europace. 2015;17:69–77. The vast majority of pacemaker patients report excellent 7. https://ssl.icddata.dk/download/Danish_Pacemaker_and_ICD_Register_ Annual_Report_2015b.pdf overall satisfaction with their pacemaker system, includ- 8. Kirkfeldt RE, Johansen JB, Nohr EA, Jorgensen OD, Nielsen JC. Complications ing the absence of pain, no soreness/discomfort, accept- after cardiac implantable electronic device implantations: an analysis of a able cosmetic results, good shoulder movement, sound complete, nationwide cohort in Denmark. Eur Heart J. 2014;35:1186–94. 9. Udo EO, van Hemel NM, Zuithoff NP, Nijboer H, Taks W, Doevendans PA, sleep, and no concerns about device malfunction. In Moons KG. Long term quality-of-life in patients with bradycardia pacemaker 2.9% of the study population, a surgical procedure was implantation. Int J Cardiol. 2013;168:2159–63. need to correct device placement. Females report worse 10. Stofmeel MA, Post MW, Kelder JC, Grobbee DE, van Hemel NM. Quality-of- life of pacemaker patients: a reappraisal of current instruments. Pacing Clin overall satisfaction, pain, soreness/discomfort, and more Electrophysiol. 2000;23:946–52. sleep problems related to the pacemaker. 11. World Health Organization . International Classification of Diseases (ICD)". Retrieved 2017. Abbreviations 12. Statistics Sweden Database. Official population statistics. 2015. www.scb.se/ BMI: body mass index; CRT: cardiac resynchronization therapy; BE0101 IQR: interquartile range; SD: standard deviation; VAS: visual analog scale 13. Buch E, Boyle NG, Belott PH. Pacemaker and defibrillator lead extraction. Circulation. 2011;123:378–80. Acknowledgements 14. Johansen JB, Jorgensen OD, Moller M, Arnsbo P, Mortensen PT, Nielsen JC, The authors acknowledge editing by Jo Ann LeQuang of LeQ Medical who et al. Infection after pacemaker implantation: infection rates and risk factors reviewed the manuscript for American English use. Thanks to Julia Fahlstedt associated with infection in a population-based cohort study of 46299 and Therese Martinell for administrative support. consecutive patients. Eur Heart J. 2011;32:991–8. 15. Kirkfeldt RE, Johansen JB, Nohr EA, Moller M, Arnsbo P, Nielsen JC, et al. Risk Funding factors for lead complications in cardiac pacing: a population-based cohort Region Gävleborg funded this research project. study of 28,860 Danish patients. Heart Rhythm. 2011;8:1622–8. 16. Tobin K, Stewart J, Westveer D, Frumin H. Acute complications of Availability of data and materials permanent pacemaker implantation: their financial implication and relation The datasets used and analysed during the current study are available from to volume and operator experience. Am J Cardiol. 2000;85:774–6. the corresponding author on reasonable request. 17. Rajappan K. Permanent pacemaker implantation technique: part I: arrhythmias. Heart. 2009;95:259–64. Authors’ contributions 18. Rajappan K. Permanent pacemaker implantation technique: part II. Heart. PM: project idea, design, data collection and analysis, major writing of the 2009;95:334–42. manuscript, project management. PL: design with regard to statistical issues, 19. Magnusson P, Wennström L, Kastberg R, Liv P. Placement of cardiac data collection and analysis, critical revision of the manuscript. Both authors PacemaKEr trial (POCKET) – rationale and design: a randomized controlled approved the manuscript for submission. trial. Heart Int. 2017;12(1):e8–e11. Magnusson and Liv BMC Cardiovascular Disorders (2018) 18:110 Page 7 of 7 20. Reynolds DW, Duray GZ, Omar R, Soejima K, Neuzil P, Zhang S, Narasimhan C, et al. A leadless Intracardiac Transcatheter pacing system. N Engl J Med. 2016;374(6):533–41. 21. Duray GZ, Ritter P, El-Chami M, Narasimhan C, Omar R, Tolosana JM, Zhang S, et al. Micra Transcatheter pacing study group. Long-term performance of a transcatheter pacing system: 12-month results from the Micra Transcatheter pacing study. Heart Rhythm. 2017;14(5):702–9.

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BMC Cardiovascular DisordersSpringer Journals

Published: Jun 4, 2018

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