title: Multiple leadless pacemakers implanted in the right ventricle of swine.
abstract: OBJECTIVE
  The miniaturized leadless pacemaker has recently emerged as a bradycardia therapy in humans, and many patients may need at least two pacemakers in their lifetime. Thus, the present study assessed the effect of two leadless pacemakers in the right ventricle (RV) on cardiac function in a swine model.
  
  
  RESULTS
  Fourteen mini pigs were chronically studied. Each animal received two sequential leadless pacemakers in the RV with 1 month between two separate implantations. All animals were then followed for 6 months. Cardiac function was assessed with echocardiography at baseline, the second implantation, and the end of the 6-month follow-up. A necropsy at the end of the study was performed to measure the length of the fibrous tissue covering the devices and assess tricuspid valve integrity. Four animals died during the surgical procedure, and one animal died of infection during the follow-up period. In the remaining nine animals, there were no significant changes in left ventricular ejection fraction, aortic time integral, cardiac output, and left ventricular size from baseline to the end of the study. The mean length of fibrous tissue covering Micra devices was 14.3 ± 7.8 mm. No tricuspid valve injury was observed.
  
  
  CONCLUSIONS
  Multiple leadless pacemakers implanted in the RV do not appear to impact cardiac function. Therefore, it appears safe to implant multiple leadless pacemakers in the same heart.
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
authors.forename: Keping
authors.initials: K
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Dai
authors.affiliation: Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Laboratory of Pre-Clinical Research and Evaluation for Cardiovascular Implant Materials of Animal Experimental Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Tingyu
authors.initials: T
authors.lastname: Lan
authors.affiliation: Department of Echocardiography, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Jinping
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Laboratory of Pre-Clinical Research and Evaluation for Cardiovascular Implant Materials of Animal Experimental Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Laboratory of Pre-Clinical Research and Evaluation for Cardiovascular Implant Materials of Animal Experimental Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Baojie
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Cardiac Rhythm and Heart Failure, Medtronic plc, Mounds View, MN 55112, USA.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Cardiac Rhythm and Heart Failure, Medtronic plc, Mounds View, MN 55112, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bonner
authors.affiliation: State Key Laboratory of Cardiovascular Disease, Arrhythmia Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China zsfuwai@vip.163.com.
authors.forename: Shu
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002302:Cardiac Output; D004452:Echocardiography; D004567:Electrodes, Implanted; D004867:Equipment Design; D006352:Heart Ventricles / Q000601:surgery*; D023421:Models, Animal; D009206:Myocardium / Q000473:pathology*; D010138:Pacemaker, Artificial; D013552:Swine / Q000601:surgery
keywords: Cardiac output; Delivery catheter; Leadless pacing; Pacemaker; Transcatheter pacing system