Contents

Search

cardiac pacemaker

Classification: Pacemaker nomenclature. A series of 3-5 letters in the following order denotes pacemaker function. 1) chamber paced 2) chamber sensed 3) mode of response 4) programmable functions 5) special anti-tachyarrhythmia functions The following letters are used in pacemaker nomenclature. (NBG code) V ventricle A atrium D double 0 none T triggered, if senses P wave, triggers ventricular activity I inhibited P programmable rate M multi-programmable C communication B bursts N normal rate competition S scanning E external A active anti-tachycardia fixation Unipolar pacemakers (older) produce larger pacing spikes than bipolar pacemakers. Programmable functions include increased heart rate during activity by using a feedback loop, based on sensors that measure body vibration or respiratory rate. Indications: 1) *symptomatic bradycardia a) not due to pharmaceutical agents that can be safely discontinued b) not due to transient ischemia c) sick sinus syndrome is the most common indication - dual chamber pacemaker [NGC (NICE)] 2) asymptomatic patients with type 2 second degree AV block* 3) 3rd degree AV block* 4) *asymptomatic patients with significant pauses (> 3 seconds in sinus rhythm or persistent heart rate <= 40/min [1] - *conduction abnormalities likely to progress to complete heart block [1] 5) alternating bundle branch block 6) *atrial fibrillation with pauses of > 5 seconds * in patients with heart block following myocardial infarction, delay insertion of a permanent pacemaker for several days to determine if heart block is transient or permanent [1] Procedure: - comprehensive geriatric assessment in older patients undergoing pacemaker implantation may identify disability associated with mortality & nursing home admission [12] Special laboratory: - electrocardiogram - QRS complex & ST segment & T waves are discordant in patients with ventricular pacing or left bundle branch block (upward QRS complex associated with downward ST segment & T wave & downward QRS complex associated with upward ST segment & T wave) - if ST segment depression is concordant with QRS complex, ischemia should be suspected - if ST segment elevation is excessively discordant with QRS complex, ischemia should be suspected [14] - in patients with ventricular pacing or left bundle branch block, ST segment depression >= 1 mm concordant with the QRS complex defines cardiac ischemia - Sgarbossa criteria for myocardial ischemia in patients with ventricular pacing or left bundle branch block: - >= l lead with >= 1 mm of concordant ST segment depression, or - >= l lead of V1 to V3 with >= 1 mm of concordant ST-segment depression, or - >= 1lead any where with >= 1 mm ST segment elevation, with proportionally discordant ST segment elevation ((>= 25% of depth of previous S-wave) [14] Complications: 1) infection a) most originate in subcutaneous pocket created for generator box - do NOT aspirate pacemaker pocket; it may seed a sterile pocket leading to infection b) pacemaker protrusion through the skin indicates that the entire pacemaker system is infected even in the absence of signs & symptoms of infection [1] c) etiologic agents a) coagulase-negative Staphylococcus b) Staphylococcus aureus d) management: 1] blood cultures [1] 2] removal of the generator box 3] systemic antibiotics for 2 weeks 4] epicardial & transvenous wires a] should also be removed if possible b] if not, 6 weeks of antibiotics therapy 2) upper extremity deep vein thrombosis (10%) Notes: - DDD pacers - upper & lower limits - heart rate above upper limit results in 2:1 block by the pacemaker - common electromagnetic devices may interfere with operation of pacemakers - these include Apple iPhone 12, Apple AirPods Pro & their wireless charging case, Microsoft Surface Pen, & Apple Pencil 2nd generation [13] - hand-held metal detectors used for security screening probably do not affect pacemaker or ICD function [3,4] - handheld electric drills may interfere with pacemakers [9] - leadless pacemakers described [6] - first leadless pacemaker FDA-approved April 2016 [8] - cybersecurity fix announced regarding vulnerability of pacemakers to hacking [10] - His-bundle pacing appears to be more physiologic & more likely to prevent heart failure & death than right ventricular pacing (25% vs 32%) [11]; however, it is associated with more complications

Related

cardiac device infection implantable cardioverter defibrillator (ICD) indications for permanent cardiac pacemaker pacemaker syndrome

Specific

cardiac resynchronization therapy transvenous pacemaker

General

cardiovascular implantable electronic device (CIED)

Figures/Diagrams

EKG: MAT, pacemaker

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2012, 2015, 2018.
  2. Zaidan JR et al Practice Advisory for the Perioperative Management of Patients with Cardiac Rhythm Management Devices: Pacemakers and Implantable Cardioverter-Defibrillators: A Report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Cardiac Rhythm Management Devices. Developed by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Cardiac Rhythm Management Devices: Anesthesiology: Volume 103(1) July 2005 pp 186-198 NGC guideline withdrawn 12/2010 http://www.anesthesiology.org/pt/re/anes/fulltext.00000542-200507000-00027.htm
  3. Kolb CK et al. Do airport metal detectors interfere with implantable pacemakers or cardioverter-defibrillators? J Am Coll Cardiol 2003 Jun 4; 41:2054-9. PMID: 12798581 - Jilek C et al Safety of Screening Procedures With Hand-Held Metal Detectors Among Patients With Implanted Cardiac Rhythm Devices A Cross-sectional Analysis Annals of Internal Medicine November 1, 2011. 155(9):587-592 http://www.annals.org/content/155/9/587.abstract
  4. Jilek C et al. Safety of screening procedures with hand-held metal detectors among patients with implanted cardiac rhythm devices: A cross-sectional analysis. Ann Intern Med 2011 Nov 1; 155:587. PMID: 22041947
  5. Baddour LM et al Update on cardiovascular implantable electronic device infections and their management: A scientific statement from the American Heart Association. Circulation 2010 Jan 26; 121:458. PMID: 20048212
  6. Reddy VY, Exner DV, Cantillon DJ et al Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker. N Engl J Med. August 30, 2015 PMID: 26321198 http://www.nejm.org/doi/full/10.1056/NEJMoa1507192 - Reynolds D, Duray GZ, Omar R et al. A leadless intracardiac transcatheter pacing system. N Engl J Med 2015 Nov 9 PMID: 26551877 http://www.nejm.org/doi/full/10.1056/NEJMoa1511643
  7. Epstein AE, DiMarco JP, Ellenbogen KA et al ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation. 2008 May 27;117(21):e350-408 PMID: 18483207
  8. FDA News Release. April 6, 2016 FDA approves first leadless pacemaker to treat heart rhythm disorders. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm494417.htm
  9. Stunder D, Seckler T, Joosten S et al In Vivo Study of Electromagnetic Interference With Pacemakers Caused by Everyday Electric and Magnetic Fields. Circulation. 2017;135:907-909. February 27, 2017 PMID: 28242642 http://circ.ahajournals.org/content/135/9/907
  10. FDA Safety Alert. 08/29/2017 Implantable Cardiac Pacemakers by Abbott (formerly St. Jude Medical): Safety Communication - Firmware Update to Address Cybersecurity Vulnerabilities. https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm573854.htm
  11. Abdelrahman M, Subzposh FA, Beer D et al. Clinical outcomes of His bundle pacing compared to right ventricular pacing. J Am Coll Cardiol 2018 Mar 10; PMID: 29535066
  12. Schoenenberger AW, Russi I, Berte B et al. Evaluation of comprehensive geriatric assessment in older patients undergoing pacemaker implantation. BMC Geriatr. 2020;20(1):287. Published 2020 Aug 12 PMID: 32787787 PMCID: PMC7424674 Free PMC article
  13. Fery C et al. Magnetic field measurements of portable electronic devices: The risk inside pockets for patients with cardiovascular implantable devices. Circ Arrhythm Electrophysiol 2022 Mar; 15:e010646 PMID: 35227069 https://www.ahajournals.org/doi/10.1161/CIRCEP.121.010646
  14. NEJM Knowledge+ - Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996 Sep;19(9):1370-9. PMID: 8880802 Review. - Meyers HP, Limkakeng AT Jr, Jaffa EJ et al Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study. Am Heart J. 2015 Dec;170(6):1255-64. PMID: 26678648