Pacemaker

Imp PPT on PACEMAKER

1. Pacemaker Prepared by , Asso Prof.Mr.Vijayreddy Vandali Med Surg Nursing Dept.

2. DEFINITION A pacemaker is a battery operated generator that initiates & controls electrical stimulation of the heart via an electrode that is usually in direct contact with the myocardium.

3. PACING METHODS Temporary Pacing:- The pulse generator is external & the pacing electrode is inserted by transvenous, transthroracic, transesophageal, or transctaneous route either at the bedside or under fluoroscopy.

4. CONTD……. The transvenous route, which is preferred in emergency situations, requires a hard tipped or balloon- tipped pacing lead to be guided into the right heart & into contact with the endocardium.

5. Temporary transvenous pacing wire in right ventricle inserted through antecubital vein.

6. Transvenous installation of a permanent pacemaker. For dual-chamber pacing, a separate pacing wire would be in the Antrim.

7. CONTD……. The transthroracic route is most invasive requiring attachment of an epicardial pacing lead during open heart surgery. In infants needing emergency ventricular pacing, the transesophageal route is favored. Both transcutaneous & transesophageal pacing are preferable in the presence of coagulation abnormalities or venous access difficulties.

8. PERMANENT PACING

9. PERMANENT PACING In an operating room, the pulse generator- a small hermetically sealed, lithium battery weighing from 30 to 130 gm- is placed into a small tunnel burrowed within the subcutaneous tissue below the right clavicle (less frequently the left clavicle). The pacing electrode is inserted via a transvenous route(most common) or directly applied to the epicardial surface by thoracotomy.

10. PACEMAKER CLASSIFICATION The Inter Society Commission For Heart Disease (ICHD) established a code to create uniform descriptions of pacemaker function. 1 st Letter:- indicates which chamber is paced: V :- Ventricles A :- Atrium D :- Dual (Both atrium and ventricle)

11. 2 nd Letter Indicates which chamber is sensed V :- Ventricles A :- Atrium D :- Dual (Both atrium & ventricle) O :- No sensing.

12. 3 rd Letter Indicates the mode (how the pacemaker responds to intrinsic heart pulses) : I :- Inhibited response. T :- Trigger response. D :- Dual response – inhibited for some sensed impulses & trigger for others. R :- Reverse – pacer is activated to send out impulses during fast intrinsic heart rates instead of slow. O :- No response to sensed impulses.

13. 4 TH LETTER Indicates programmable function: P :- Programmable (rate/ output). M ;- Multiprogrammable (3 or more functions). C :- Multiprogrammable with telemetry. O :- None.

14. 5 TH LETTER Indicates special tachycardia function : B :- Bursts. N :- Normal rate competition. S :- Scanning. E :- External

15. Examples of temporary pulse generators. (A, B) Single-chamber pulse generators. (C, D) Dual-chamber pulse generators.

16. PACEMAKER FUNCTION The cardiac cycle normally begins with the clients own beat. The pacemaker’s sensor senses whether the intrinsic beat has occurred, if not, the pacer sends out an impulse to begin myocardial depolarization through a pulse generator.

17. CONTD….. The impulse generator is said to “Capture” the myocardium & there by maintain heart rhythm.

18. PACING LEADS

19. PACING LEADS Unipolar Pacemaker:- Lead has only one electrode that contacts the heart at its tip (+) pole. The power source is the (-) pole. Patient serves as the grounding source. Patient’s body fluids provide the return pathway for the electrical signal Electromagnetic interference occurs more often in Unipolar leads

20. BIPOLAR LEADS If bipolar, there are two wires to the heart or one wire with two electrodes at its tip. Provides a built-in ground lead Circuit is completed within the heart Provides more contact with the endocardium; needs lower current to Pace Less chance for cautery Interference.

21. Bipolar pacing system.

22. PACING MODES

23. PACING MODES There are essentially five pacemaker modes involving “single chamber pacing,” either Atrial or ventricular, & “dual chamber pacing”, both Atrial & ventricular.

24. 1) FIXED RATE (AOO, VOO, DOO) In fixed rate pacing, the heart is stimulated at a continuous preset rate independent of it’s intrinsic electrical activity (non sensing). The major disadvantages is that competition between the paced beats & the patients intrinsic rhythm may occur, potentiating ventricular tachycardia & fibrillation.

25. 2) NONCOMPETITIVE (DEMAND) PACING (VVI, VVT, AAI, AAT) The demand pacemaker avoids competitive beating by sensing the electrical signals from the chamber it is pacing (either Atrial or ventricular). Demand pacing is either “inhibited” or “triggered”.

26. CONTD….. If the spontaneous P wave or QRS complex fails to occur, the pacemaker discharges at its preset delay interval. In triggered demand pacing, the sensing of spontaneous Atrial or ventricular activity results in generation of an output pulse by the pacemaker.

27. CONTD….. The pacemaker “fires” into the P wave or QRS but dose not stimulate depolarization because of myocardial refractoriness at this time. If no intrinsic depolarization's occurs, the pacemaker will fire at it’s preset delay interval.

28. A) ATRIAL DEMAND PACING The atrium is paced & the ventricle is allowed to be depolarized via conduction of the paced Atrial impulse through the normal pathway of the A-V Node & the His- Purkinje conduction system. Atrial demand pacing is useful in symptomatic sinus bradycardia of any kind (provided A-V conduction is intact)

29. B) VENTRICULAR DEMAND PACING Patients with episodic A-V Block may benefit from ventricular demand pacing. When spontaneous ventricular depolarization's fall below the preset pacemaker rate, paced ventricular depolarization's ensure. Disadvantage is the loss of Atrial ventricular synchrony & the Atrial kick.

30. 3) SYNCHRONOUS PACING (VAT, VDD) Synchronous pacing was the first mode developed to offer dual chamber pacing. Sensing occurs in both atrium & ventricle. When a P wave is sensed, a ventricular output pulse is triggered after a preset ateroventricular interval. If a spontaneous QRS complex is sensed, the paced output is inhibited, thus preventing competitive pacing in the ventricle.

31. 4) ATRIOVENTRICULAR(AV) SEQUENTIAL PACING (DVI) In this mode sensing occurs only in the ventricle while pacing occurs sequentially in the atrium & after a preset A V interval, in the ventricle. If spontaneous ventricular depolarization follows quickly enough after the paced Atrial beat, inhibition of the ventricular output pulse occurs.

32. DVI PACING

33. 5) UNIVERSAL ATRIOVENTRICULAR PACING (DDD) If spontaneous Atrial activity does not take place within the preset time limit, Atrial pacing triggered. Any sensed intrinsic Atrial activity inhibits the paced Atrial pulse. if ventricular depolarization in response to a spontaneous or paced Atrial beat does not occurs within a preset interval, a ventricular stimulus is issued by the pacemaker.

34. CONTD….. Intrinsic ventricular activity occurring with in the preset time interval inhibits the paced ventricular stimulus. This pacing is indicated in Atrial Brady arrhythmia with or without abnormal AV conduction or in normal sinus node function with AV block.

35. BENEFITS OF DDD MODE It allows the Atrial kick(increasing cardiac output by 30 %). It adjust heart rate to meet the metabolic demands of the body (only if sinus node function is normal).

36. ECG

37. COMPLICATIONS Thrmobhlebitis Arrhythmias Pneumothorax Myocardial perforation Diaphragmatic stimulation

38. HEALTH EDUCATION WOUND CARE PACEMAKER MANAGEMENT ACTIVITY LEVELS MEDICATIONS IDENTIFICATION FOLLOW UP CARE

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