Pacemaker General Concepts

1. Pacemaker General Concepts Matthew W. Sevensma, DO Metro Heart and Vascular

2. Disclosures BoehringerIngelheim

3. Electrical Stimulation Device 1788

4. External Pacemaker 1952

5. External Pacemaker 1958

6. Implantable Pacemakers 1960-Present

7. Implantable Pacemaker Systems Contain the Following Components: Lead wire(s) Implantable pulse generator (IPG)

9. Implantable Defibrillators

10. Interrogator

11. Leads/ Wires

12. Right Ventricular Lead Placement

13. Symptoms of Bradycardia • Syncope or pre-syncope • Dizziness • Congestive heart failure (edema, SOB) • Mental confusion • Palpitations • Shortness of breath • Exercise intolerance

14. Sinus Arrhythmia

15. Sinus Node Dysfunction –Sinus Arrest 2.8-second arrest • Failure of sinus node discharge resulting in the absence of atrial depolarization and periods of ventricular asystole • Rate = 75 bpm • PR interval = 180 ms (.18 seconds) • 2.8-second arrest

16. Sinus Node Dysfunction – Bradycardia-Tachycardia (Brady-Tachy) Syndrome • Intermittent episodes of slow and fast rates from the SA node or atria • Rate during bradycardia = 43 bpm • Rate during tachycardia = 130 bpm

17. Max Quick Slow Heart Rate Unstable Rest Start Activity Stop Activity Time Chronotropic Incompetence

18. AV Block • First-degree AV block • Second-degree AV block • Mobitz types I and II • Third-degree AV block • Bifascicular and trifascicular block

19. First-Degree AV Block 340 ms • AV conduction is delayed, and the PR interval is prolonged (>200 ms or .2 seconds) • Rate = 79 bpm • PR interval = 340 ms (.34 seconds)

20. Second-Degree Type I AV Block – Mobitz I (Wenckebach) 200 360 400 ms ms ms NoQRS • Progressive prolongation of the PR interval until a ventricular beat is dropped • Ventricular rate = irregular • Atrial rate = 90 bpm • PR interval = progressively longer until a P-wave fails to conduct

21. Second-Degree Type II AV Block – Mobitz II P P QRS • Regularly dropped ventricular beats • 2:1 block (2 P waves to 1 QRS complex) • Ventricular rate = 60 bpm • Atrial rate = 110 bpm

22. Third-Degree AV Block • No impulse conduction from the atria to the ventricles • Ventricular rate = 37 bpm • Atrial rate = 130 bpm • PR interval = variable

23. Neurocardiogenic Syncope • Carotid Sinus Syndrome (CSS) • Vasovagal Syncope (VVS)

24. Hypersensitive Carotid Sinus Syndrome (CSS) • Extreme reflex response to carotid sinus stimulation • Results in bradycardia and/or vasodilation • Can be induced by: • Tight collar • Shaving • Head turning • Exercise • Other activities that stimulate the carotid sinus

25. Mechanisms of Neurocardiogenic Syncope • Cardioinhibitory • Initiated by inappropriate drop in heart rate • Vasodepressor • Symptomatic decrease in systolic blood pressure due to vasodilation • Mixed • Includes components of cardioinhibitory and vasodepressor

26. “Other” Indications • Pacing after Cardiac Transplantation • Pacing for AV Block Associated with Acute MI • Pacing in Children, Adolescents, and Patients with Congenital Heart Disease • Pacing for Hypertrophic Obstructive Cardiomyopathy • Pacing for Idiopathic Dilated Cardiomyopathy • Prevention and Termination of Tachyarrhythmias by Pacing • Pacemakers that Automatically Detect and Pace to Terminate Tachycardias • Pacing Recommendations to Prevent Tachycardia Gregoratos G. et al. ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices: a Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2002;106:2145-2161.

27. CRT and ICD Based Therapies

28. What do these devises do? • All ICD/ CRTs are pacemakers too • CRT= Bi-V≠ Dual Chamber • Not all CRTs have defibrillator capabilities (CRT-D) • ICD/CRT may have pacing algorithms to decrease the likelihood of A-fib • ICD/CRT-D may have antitachycardia pacing algorithms • ICD/CRT-D can have the defibrillator functions suspended with a magnet, if this function is enabled

29. ICD Trials Medicare Reimbursement are Based On • CABG-Patch • MADIT • MUSTT • MADIT II • SCD-HeFT • Low implant risk even with testing

30. ICDs for Primary Prevention SCD • EF≤ 35% (Ischemic or non-ischemic etiology) • NYHA Class II-IV CHF • No reversible cause (thyroid, coronary) • Persistent CM 3mo post medical therapy if non-ischemic or revascularization • Persistent CM 1mo post MI if no revascularization with medical therapy • No life-limiting concomitant illness

31. “Other” ICD Indications • Secondary prevention • HCM • Brugada Syndrome • Prolonged QT Syndrome

32. Cardiac Resynchronization Therapy

33. Sinus node AV node Conduction block Intraventricular Conduction Delay Issue– delayed ventricular activation • Delayed lateral wall contraction • Disorganized ventricular contraction • Decreased pumping efficiency

34. Sinus node AV node Conduction block Stimulation therapy Resynchronization Mechanism of action– ventricular resynchronization • Intraventricular Activation • Organized ventricular activation sequence • Coordinated septal and free-wall contraction • Improved pumping efficiency

35. Cardiac Resynchronization Therapy Patient Indications CRT device: • Moderate to severe HF (NYHA Class III/IV) patients • Symptomatic despite optimal, medical therapy • QRS  120 msec • LVEF  35% CRT plus ICD: • Same as above with medical therapy and/or revascularization

36. CRT Improves Quality of Life & Functional Capacity in Moderate to Severe Heart Failure QoL Score (MLWHF) Avg. Change Improve.  NYHA Class Proportion Changing 1 or more Classes Not Reported Data sources: MIRACLE: Circulation 2003;107:1985-90 MUSTIC SR: NEJM 2001;344:873-80 MIRACLE ICD:JAMA 2003;289:2685-94 Contak CD: J Am Coll Cardiol 2003;2003;42:1454-59  Control CRT