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1 Temporary Pacemakers Karim Rafaat, MD. 12/052 Temporary pacemakers Objectives Objectives Explain the situations when temporary pacemakers are indicated.

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Presentation on theme: "1 Temporary Pacemakers Karim Rafaat, MD. 12/052 Temporary pacemakers Objectives Objectives Explain the situations when temporary pacemakers are indicated."— Presentation transcript:

1 1 Temporary Pacemakers Karim Rafaat, MD

2 12/052 Temporary pacemakers Objectives Objectives Explain the situations when temporary pacemakers are indicated. Explain the situations when temporary pacemakers are indicated. Describe the principles of pacing. Describe the principles of pacing. Illustrate normal and abnormal pacemaker behavior. Illustrate normal and abnormal pacemaker behavior. Discuss the steps to be taken in troubleshooting a temporary pacemaker. Discuss the steps to be taken in troubleshooting a temporary pacemaker.

3 12/053 Indications for Temporary Pacing Bradyarrhythmias Bradyarrhythmias AV conduction block AV conduction block Congenital complete heart block (CHB)- normal or abnormal heart structure Congenital complete heart block (CHB)- normal or abnormal heart structure L-Transposition (corrected transposition) L-Transposition (corrected transposition) Bundle of His long; AV node anterior Bundle of His long; AV node anterior Prone to CHB Prone to CHB Trauma- surgical or other Trauma- surgical or other Slow sinus or junctional rhythm Slow sinus or junctional rhythm Suppression of ectopy Suppression of ectopy Permanent pacer malfunction Permanent pacer malfunction Drugs, electrolyte imbalances Drugs, electrolyte imbalances Sick Sinus Syndrome Sick Sinus Syndrome Secondary to pronounced atrial stretch Secondary to pronounced atrial stretch Old TGA s/p Senning or Mustard procedure Old TGA s/p Senning or Mustard procedure

4 12/054 Indications for Temporary Pacing Sick Sinus Syndrome Sick Sinus Syndrome

5 12/055 Principles of Pacing Electrical concepts Electrical concepts Electrical circuit Electrical circuit Pacemaker to patient, patient to pacemaker Pacemaker to patient, patient to pacemaker Ampere – a unit of electrical current delivered to stimulate a cardiac contraction Ampere – a unit of electrical current delivered to stimulate a cardiac contraction Milliamperes (mA) Milliamperes (mA) Voltage – a unit of electrical pressure causing the current of electrons to flow Voltage – a unit of electrical pressure causing the current of electrons to flow Millivolts (mV) Millivolts (mV) Resistance- the opposition to the flow of electrical current Resistance- the opposition to the flow of electrical current

6 12/056 Principles of Pacing Temporary pacing types Temporary pacing types Transcutaneous Transcutaneous Emergency use with external pacing/defib unit Emergency use with external pacing/defib unit Transvenous Transvenous Emergency use with external pacemaker Emergency use with external pacemaker Epicardial Epicardial Wires sutured to right atrium & right ventricle Wires sutured to right atrium & right ventricle Atrial wires exit on the right of the sternum Atrial wires exit on the right of the sternum Ventricular wires exit on the left of the sternum Ventricular wires exit on the left of the sternum

7 12/057 Principles of Pacing Wiring systems Wiring systems Unipolar Unipolar One wire on the heart One wire on the heart Subcutaneous “ ground wire ” Subcutaneous “ ground wire ” Bipolar Bipolar Two wires on the heart Two wires on the heart One positive, one negative One positive, one negative

8 12/058 Principles of Pacing Modes of Pacing Modes of Pacing Atrial pacing Atrial pacing Intact AV conduction system required Intact AV conduction system required Ventricular pacing Ventricular pacing Loss of atrial kick Loss of atrial kick Discordant ventricular contractions Discordant ventricular contractions Sustains cardiac output Sustains cardiac output Atrial/Ventricular pacing Atrial/Ventricular pacing Natural pacing Natural pacing Atrial-ventricular synchrony Atrial-ventricular synchrony

9 12/059 Principles of Pacing 3-letter NBG Pacemaker Code 3-letter NBG Pacemaker Code First letter: Chamber Paced First letter: Chamber Paced V- Ventricle V- Ventricle A- Atrium A- Atrium D- Dual (A & V) D- Dual (A & V) O- None O- None

10 12/0510 Principles of Pacing 3-letter NBG Pacemaker Code 3-letter NBG Pacemaker Code Second letter: Chamber Sensed Second letter: Chamber Sensed V- Ventricle V- Ventricle A- Atrium A- Atrium D- Dual (A & V) D- Dual (A & V) O- None O- None

11 12/0511 Principles of Pacing 3-letter NBG Pacemaker Code 3-letter NBG Pacemaker Code Third letter: Sensed Response Third letter: Sensed Response T- Triggers Pacing T- Triggers Pacing I- Inhibits Pacing I- Inhibits Pacing D- Dual D- Dual O- None O- None

12 12/0512 Principles of Pacing Commonly used modes: Commonly used modes: AAI - atrial demand pacing AAI - atrial demand pacing VVI - ventricular demand pacing VVI - ventricular demand pacing DDD – atrial/ventricular demand pacing, senses & paces both chambers DDD – atrial/ventricular demand pacing, senses & paces both chambers AOO - atrial asynchronous pacing AOO - atrial asynchronous pacing DOO – atrial/ventricular asynchronous pacing DOO – atrial/ventricular asynchronous pacing

13 12/0513 Principles of Pacing Atrial and ventricular output Atrial and ventricular output Milliamperes (mA) Milliamperes (mA) Typical atrial mA 5 Typical atrial mA 5 Typical ventricular mA 8-10 Typical ventricular mA 8-10 AV Interval AV Interval Milliseconds (msec) Milliseconds (msec) Time from atrial sense/pace to ventricular pace Time from atrial sense/pace to ventricular pace Synonymous with “ PR ” interval Synonymous with “ PR ” interval Atrial and ventricular sensitivity Atrial and ventricular sensitivity Millivolts (mV) Millivolts (mV) Typical atrial: 0.4 mV Typical atrial: 0.4 mV Typical ventricular: 2.0mV Typical ventricular: 2.0mV

14 12/0514 Principles of Pacing (cont.) Atrial/ventricular rate Atrial/ventricular rate Set at physiologic rate for individual patient Set at physiologic rate for individual patient AV Interval, upper rate, & PVARP automatically adjust with set rate changes AV Interval, upper rate, & PVARP automatically adjust with set rate changes Upper rate Upper rate Automatically adjusts to 30 bpm higher than set rate Automatically adjusts to 30 bpm higher than set rate Prevents pacemaker mediated tachycardia from unusually high atrial rates Prevents pacemaker mediated tachycardia from unusually high atrial rates Wenckebach-type rhythm results when atrial rates are sensed faster than the set rate Wenckebach-type rhythm results when atrial rates are sensed faster than the set rate Refractory period Refractory period PVARP: Post Ventricular Atrial Refractory Period PVARP: Post Ventricular Atrial Refractory Period Time after ventricular sensing/pacing when atrial events are ignored Time after ventricular sensing/pacing when atrial events are ignored

15 12/0515 Principles of Pacing Electrical Safety Electrical Safety Microshock Microshock Accidental de-wiring Accidental de-wiring Taping wires Taping wires Securing pacemaker Securing pacemaker Removal of pacing wires Removal of pacing wires Potential myocardial trauma Potential myocardial trauma Bleeding Bleeding –Pericardial effusion/tamponade –Hemothorax Ventricular arrhythmias Ventricular arrhythmias Pacemaker care & cleaning Pacemaker care & cleaning Batteries Batteries Bridging cables Bridging cables Pacemakers Pacemakers

16 12/0516 Pacemaker Medtronic 5388 Dual Chamber (DDD) Medtronic 5388 Dual Chamber (DDD)

17 12/0517 Pacemaker EKG Strips Assessing Paced EKG Strips Assessing Paced EKG Strips Identify intrinsic rhythm and clinical condition Identify intrinsic rhythm and clinical condition Identify pacer spikes Identify pacer spikes Identify activity following pacer spikes Identify activity following pacer spikes Failure to capture Failure to capture Failure to sense Failure to sense EVERY PACER SPIKE SHOULD HAVE A P- WAVE OR QRS COMPLEX FOLLOWING IT. EVERY PACER SPIKE SHOULD HAVE A P- WAVE OR QRS COMPLEX FOLLOWING IT.

18 12/0518 Normal Pacing Atrial Pacing Atrial Pacing Atrial pacing spikes followed by P waves Atrial pacing spikes followed by P waves

19 12/0519 Normal Pacing Ventricular pacing Ventricular pacing Ventricular pacing spikes followed by wide, bizarre QRS complexes Ventricular pacing spikes followed by wide, bizarre QRS complexes

20 12/0520 Normal Pacing A-V Pacing A-V Pacing Atrial & Ventricular pacing spikes followed by atrial & ventricular complexes Atrial & Ventricular pacing spikes followed by atrial & ventricular complexes

21 12/0521 Normal Pacing DDD mode of pacing DDD mode of pacing Ventricle paced at atrial rate Ventricle paced at atrial rate

22 12/0522 Abnormal Pacing Atrial non-capture Atrial non-capture Atrial pacing spikes are not followed by P waves Atrial pacing spikes are not followed by P waves

23 12/0523 Abnormal Pacing Ventricular non-capture Ventricular non-capture Ventricular pacing spikes are not followed by QRS complexes Ventricular pacing spikes are not followed by QRS complexes

24 12/0524 Failure to Capture Causes Causes Insufficient energy delivered by pacer Insufficient energy delivered by pacer Low pacemaker battery Low pacemaker battery Dislodged, loose, fibrotic, or fractured electrode Dislodged, loose, fibrotic, or fractured electrode Electrolyte abnormalities Electrolyte abnormalities Acidosis Acidosis Hypoxemia Hypoxemia Hypokalemia Hypokalemia Danger - poor cardiac output Danger - poor cardiac output

25 12/0525 Failure to Capture Solutions Solutions View rhythm in different leads View rhythm in different leads Change electrodes Change electrodes Check connections Check connections Increase pacer output ( ↑ mA) Increase pacer output ( ↑ mA) Change battery, cables, pacer Change battery, cables, pacer Reverse polarity Reverse polarity

26 12/0526 Reversing polarity Changing polarity Changing polarity Requires bipolar wiring system Requires bipolar wiring system Reverses current flow Reverses current flow Switch wires at pacing wire/bridging cable interface Switch wires at pacing wire/bridging cable interface

27 12/0527 Abnormal Pacing Atrial undersensing Atrial undersensing Atrial pacing spikes occur irregardless of P waves Atrial pacing spikes occur irregardless of P waves Pacemaker is not “ seeing ” intrinsic activity Pacemaker is not “ seeing ” intrinsic activity

28 12/0528 Abnormal Pacing Ventricular undersensing Ventricular undersensing Ventricular pacing spikes occur regardless of QRS complexes Ventricular pacing spikes occur regardless of QRS complexes Pacemaker is not “ seeing ” intrinsic activity Pacemaker is not “ seeing ” intrinsic activity

29 12/0529 Failure to Sense Causes Causes Pacemaker not sensitive enough to patient ’ s intrinsic electrical activity (mV) Pacemaker not sensitive enough to patient ’ s intrinsic electrical activity (mV) Insufficient myocardial voltage Insufficient myocardial voltage Dislodged, loose, fibrotic, or fractured electrode Dislodged, loose, fibrotic, or fractured electrode Electrolyte abnormalities Electrolyte abnormalities Low battery Low battery Malfunction of pacemaker or bridging cable Malfunction of pacemaker or bridging cable

30 12/0530 Failure to Sense Danger – potential (low) for paced ventricular beat to land on T wave Danger – potential (low) for paced ventricular beat to land on T wave

31 12/0531 Failure to Sense Solution Solution View rhythm in different leads View rhythm in different leads Change electrodes Change electrodes Check connections Check connections Increase pacemaker ’ s sensitivity ( ↓ mV) Increase pacemaker ’ s sensitivity ( ↓ mV) Change cables, battery, pacemaker Change cables, battery, pacemaker Reverse polarity Reverse polarity Check electrolytes Check electrolytes Unipolar pacing with subcutaneous “ ground wire ” Unipolar pacing with subcutaneous “ ground wire ”

32 12/0532 Oversensing Pacing does not occur when intrinsic rhythm is inadequate Pacing does not occur when intrinsic rhythm is inadequate

33 12/0533 Oversensing Causes Causes Pacemaker inhibited due to sensing of “ P ” waves & “ QRS ” complexes that do not exist Pacemaker inhibited due to sensing of “ P ” waves & “ QRS ” complexes that do not exist Pacemaker too sensitive Pacemaker too sensitive Possible wire fracture, loose contact Possible wire fracture, loose contact Pacemaker failure Pacemaker failure Danger - heart block, asystole Danger - heart block, asystole

34 12/0534 Oversensing Solution Solution View rhythm in different leads View rhythm in different leads Change electrodes Change electrodes Check connections Check connections Decrease pacemaker sensitivity ( ↑ mV) Decrease pacemaker sensitivity ( ↑ mV) Change cables, battery, pacemaker Change cables, battery, pacemaker Reverse polarity Reverse polarity Check electrolytes Check electrolytes Unipolar pacing with subcutaneous “ ground wire ” Unipolar pacing with subcutaneous “ ground wire ”

35 12/0535 Competition Assessment Assessment Pacemaker & patient ’ s intrinsic rate are similar Pacemaker & patient ’ s intrinsic rate are similar Unrelated pacer spikes to P wave, QRS complex Unrelated pacer spikes to P wave, QRS complex Fusion beats Fusion beats

36 12/0536 Competition Causes Causes Asynchronous pacing Asynchronous pacing Failure to sense Failure to sense Mechanical failure: wires, bridging cables, pacemaker Mechanical failure: wires, bridging cables, pacemaker Loose connections Loose connections Danger Danger Impaired cardiac output Impaired cardiac output Potential (low) for paced ventricular beat to land on T wave Potential (low) for paced ventricular beat to land on T wave

37 12/0537 Competition Solution Solution Assess underlying rhythm Assess underlying rhythm Slowly turn pacer rate down Slowly turn pacer rate down Troubleshoot as for failure to sense Troubleshoot as for failure to sense Increase pacemaker sensitivity ( ↓ mV) Increase pacemaker sensitivity ( ↓ mV) Increase pacemaker rate Increase pacemaker rate

38 12/0538 Assessing Underlying Rhythm Carefully assess underlying rhythm Carefully assess underlying rhythm Right way: slowly decrease pacemaker rate Right way: slowly decrease pacemaker rate

39 12/0539 Assessing Underlying Rhythm Assessing Underlying Rhythm Assessing Underlying Rhythm Wrong way:pause pacer or unplug cables Wrong way:pause pacer or unplug cables

40 12/0540 Wenckebach Assessment Assessment Appears similar to 2 nd degree heart block Appears similar to 2 nd degree heart block Occurs with intrinsic tachycardia Occurs with intrinsic tachycardia

41 12/0541 Wenckebach Causes Causes DDD mode safety feature DDD mode safety feature Prevents rapid ventricular pacing impulse in response to rapid atrial rate Prevents rapid ventricular pacing impulse in response to rapid atrial rate Sinus tachycardia Sinus tachycardia Atrial fibrillation, flutter Atrial fibrillation, flutter Prevents pacer-mediated tachycardia Prevents pacer-mediated tachycardia Upper rate limit may be inappropriate Upper rate limit may be inappropriate

42 12/0542 Wenckebach Solution Solution Treat cause of tachycardia Treat cause of tachycardia Fever: Cooling Fever: Cooling Atrial tachycardia: Anti-arrhythmic Atrial tachycardia: Anti-arrhythmic Pain: Analgesic Pain: Analgesic Hypovolemia: Fluid bolus Hypovolemia: Fluid bolus Adjust pacemaker upper rate limit as appropriate Adjust pacemaker upper rate limit as appropriate

43 12/0543 Threshold testing Stimulation threshold Stimulation threshold Definition: Minimum current necessary to capture & stimulate the heart Definition: Minimum current necessary to capture & stimulate the heart Testing Testing Set pacer rate 10 ppm faster than patient ’ s HR Set pacer rate 10 ppm faster than patient ’ s HR Decrease mA until capture is lost Decrease mA until capture is lost Increase output until capture is regained (threshold capture) Increase output until capture is regained (threshold capture) Output setting to be 2x ’ s threshold capture Output setting to be 2x ’ s threshold capture –Example: Set output at 10mA if capture was regained at 5mA

44 12/0544 Performing an AEG Purpose: Determine existence & location of P waves Purpose: Determine existence & location of P waves Direct EKG from atrial pacing wires Direct EKG from atrial pacing wires Bedside EKG from monitor Bedside EKG from monitor Full EKG Full EKG Atrial pacing pins to RA & LA EKG lead- wires Atrial pacing pins to RA & LA EKG lead- wires

45 12/0545 Interpreting an AEG

46 12/0546 Sensitivity Threshold Definition: Minimum level of intrinsic electric activity generated by the heart detectable by the pacemaker Definition: Minimum level of intrinsic electric activity generated by the heart detectable by the pacemaker

47 12/0547 Sensitivity Threshold Testing Testing Testing Set pacer rate 10 ppm slower than patient ’ s HR Set pacer rate 10 ppm slower than patient ’ s HR Increase sensitivity to chamber being tested to minimum level (0.4mV) Increase sensitivity to chamber being tested to minimum level (0.4mV) Decrease sensitivity of the pacer ( ↑ mV) to the chamber being tested until pacer stops sensing patient (orange light stops flashing) Decrease sensitivity of the pacer ( ↑ mV) to the chamber being tested until pacer stops sensing patient (orange light stops flashing) Increase sensitivity of the pacer ( ↓ mV) until the pacer senses the patient (orange light begins flashing). This is the threshold for sensitivity. Increase sensitivity of the pacer ( ↓ mV) until the pacer senses the patient (orange light begins flashing). This is the threshold for sensitivity. Set the sensitivity at ½ the threshold value. Set the sensitivity at ½ the threshold value. Example: Set sensitivity at 1mV if the threshold was 2mV Example: Set sensitivity at 1mV if the threshold was 2mV

48 12/0548 Factors Affecting Stimulation Thresholds

49 12/0549 Practice Strip#1

50 12/0550 Practice Strip #2

51 12/0551 Practice Strip #3

52 12/0552 Practice Strip #4

53 12/0553 Practice Strip #5

54 12/0554 Practice Strip #6

55 12/0555 Practice Strip #7

56 12/0556 Practice Strip #8

57 12/0557 Practice Strip #9

58 12/0558 Answers Mode of pacing, rhythm/problem, solution 1. AAI: normal atrial pacing 2. Sinus rhythm: no pacing; possible back-up setting AAI, VVI, DDD 3. DDD: failure to sense ventricle; increase ventricular mA 4. VVI: ventricular pacing 5. DDD: failure to capture atria or ventricle; increase atrial & ventricular mA 6. DDD: normal atrial & ventricular pacing 7. DDD: normal atrial sensing, ventricular pacing 8. DDD: failure to capture atria; increase atrial mA 9. DDD: oversensing; decrease ventricular sensitivity

59 12/0559 References Conover, M. Understanding Electrocardiography, (6th Ed.). Mosby Year Book; Conover, M. Understanding Electrocardiography, (6th Ed.). Mosby Year Book; Hazinski, M. F. Nursing Care of the Critically Ill Child, (2nd Ed.). Mosby Year Book; Hazinski, M. F. Nursing Care of the Critically Ill Child, (2nd Ed.). Mosby Year Book; Heger, J., Niemann, J., Criley, J. M. Cardiology for the House Officer, (2nd Ed.). Heger, J., Niemann, J., Criley, J. M. Cardiology for the House Officer, (2nd Ed.). Williams and Wilkins; Williams and Wilkins; Intermedics Inc. Guide to DDD Pacing, Intermedics Inc. Guide to DDD Pacing, Moses, H. W., Schneider, J., Miller, B., Taylor, G. A Practical Guide to Moses, H. W., Schneider, J., Miller, B., Taylor, G. A Practical Guide to Cardiac Pacing, (3rd Ed.). Boston: Little, Brown, and Co.; Cardiac Pacing, (3rd Ed.). Boston: Little, Brown, and Co.; Merva, J. A. Temporary pacemakers. RN. May, Merva, J. A. Temporary pacemakers. RN. May, 1992.


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