Temporary pacemaker toufiqur rahman
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This document discusses temporary pacemakers. It explains that temporary pacemakers are indicated for bradyarrhythmias, conduction blocks, and permanent pacemaker malfunctions. It describes the principles of pacing, including electrical concepts, pacing types, wiring systems, modes of pacing, and parameters like output and sensitivity. It illustrates normal pacemaker behavior and various abnormalities including failure to capture, failure to sense, oversensing, competition, and Wenckebach behavior. It discusses evaluating underlying rhythm, assessing pacemaker strips, and troubleshooting issues like changing settings, electrodes, batteries, or reversing polarity.
Temporary pacemaker toufiqur rahman
- 1. Temporary Pacemaker Dr. Md.Toufiqur Rahman MBBS, FCPS, MD, FACC, FESC, FRCPE, FSCAI, FAPSC, FAPSIC, FAHA, FCCP, FRCPG Associate Professor of Cardiology National Institute of Cardiovascular Diseases(NICVD), Sher-e-Bangla Nagar, Dhaka-1207 Consultant, Medinova, Malibagh branch Honorary Consultant, Apollo Hospitals, Dhaka and STS Life Care Centre, Dhanmondi drtoufiq19711@yahoo.com CRT 2014 Washington DC, USA
- 2. 2 Temporary pacemakers âĸ Objectives â Explain the situations when temporary pacemakers are indicated. â Describe the principles of pacing. â Illustrate normal and abnormal pacemaker behavior. â Discuss the steps to be taken in troubleshooting a temporary pacemaker.
- 3. 4/07 3 Indications for Temporary Pacing âĸ Bradyarrhythmias âĸ AV conduction block â Congenital complete heart block (CHB)- normal or abnormal heart structure â L-Transposition (corrected transposition) âĸ Bundle of His long; AV node anterior âĸ Prone to CHB â Trauma- surgical or other âĸ Slow sinus or junctional rhythm âĸ Suppression of ectopy âĸ Permanent pacer malfunction âĸ Drugs, electrolyte imbalances âĸ Sick Sinus Syndrome â Secondary to pronounced atrial stretch â Old TGA s/p Senning or Mustard procedure
- 4. 4/07 4 Indications for Temporary Pacing âĸ Sick Sinus Syndrome
- 5. 4/07 5 Principles of Pacing âĸ Electrical concepts â Electrical circuit âĸ Pacemaker to patient, patient to pacemaker â Current- the flow of electrons in a completed circuit âĸ Measured in milliamperes (mA) â Voltage â a unit of electrical pressure or force causing electrons to move through a circuit âĸ Measured in millivolts (mV) â Impedance- the resistance to the flow of current
- 6. 4/07 6 Principles of Pacing âĸ Temporary pacing types â Transcutaneous âĸ Emergency use with external pacing/defib unit â Transvenous âĸ Emergency use with external pacemaker â Epicardial âĸ Wires sutured to right atrium & right ventricle âĸ Atrial wires exit on the right of the sternum âĸ Ventricular wires exit on the left of the sternum
- 7. 4/07 7 Principles of Pacing âĸ Wiring systems â Unipolar âĸ One electrode on the heart (-) âĸ Signals return through body fluid and tissue to the pacemaker (+) â Bipolar âĸ Two electrodes on the heart (- & +) âĸ Signals return to the ring electrode (+) above the lead (- ) tip
- 8. 4/07 8 Principles of Pacing âĸ Modes of Pacing â Atrial pacing âĸ Intact AV conduction system required â Ventricular pacing âĸ Loss of atrial kick âĸ Discordant ventricular contractions âĸ Sustains cardiac output â Atrial/Ventricular pacing âĸ Natural pacing âĸ Atrial-ventricular synchrony
- 9. 4/07 9 Principles of Pacing âĸ 3-letter NBG Pacemaker Code â First letter: Chamber Paced âĸ V- Ventricle âĸ A- Atrium âĸ D- Dual (A & V) âĸ O- None
- 10. 4/07 10 Principles of Pacing âĸ 3-letter NBG Pacemaker Code â Second letter: Chamber Sensed âĸ V- Ventricle âĸ A- Atrium âĸ D- Dual (A & V) âĸ O- None
- 11. 4/07 11 Principles of Pacing âĸ 3-letter NBG Pacemaker Code â Third letter: Sensed Response âĸ T- Triggers Pacing âĸ I- Inhibits Pacing âĸ D- Dual âĸ O- None
- 12. 4/07 12 Principles of Pacing âĸ Commonly used modes: â AAI - atrial demand pacing â VVI - ventricular demand pacing â DDD â atrial/ventricular demand pacing, senses & paces both chambers; trigger or inhibit â AOO - atrial asynchronous pacing
- 13. 4/07 13 Principles of Pacing âĸ Atrial and ventricular output â Milliamperes (mA) âĸ Typical atrial mA 5 âĸ Typical ventricular mA 8-10 âĸ AV Interval â Milliseconds (msec) âĸ Time from atrial sense/pace to ventricular pace âĸ Synonymous with âPRâ interval âĸ Atrial and ventricular sensitivity â Millivolts (mV) âĸ Typical atrial: 0.4 mV âĸ Typical ventricular: 2.0mV
- 14. 4/07 14 Principles of Pacing (cont.) âĸ Atrial/ventricular rate â Set at physiologic rate for individual patient â AV Interval, upper rate, & PVARP automatically adjust with set rate changes âĸ Upper rate â Automatically adjusts to 30 bpm higher than set rate â Prevents pacemaker mediated tachycardia from unusually high atrial rates â Wenckebach-type rhythm results when atrial rates are sensed faster than the set rate âĸ Refractory period â PVARP: Post Ventricular Atrial Refractory Period âĸ Time after ventricular sensing/pacing when atrial events are ignored
- 15. 4/07 15 Principles of Pacing âĸ Electrical Safety â Microshock â Accidental de-wiring âĸ Taping wires âĸ Securing pacemaker âĸ Removal of pacing wires â Potential myocardial trauma âĸ Bleeding â Pericardial effusion/tamponade â Hemothorax âĸ Ventricular arrhythmias âĸ Pacemaker care & cleaning â Batteries â Bridging cables â Pacemakers
- 16. 4/07 16 Pacemaker âĸ Medtronic 5388 Dual Chamber (DDD)
- 17. 4/07 17 Pacemaker EKG Strips âĸ Assessing Paced EKG Strips â Identify intrinsic rhythm and clinical condition â Identify pacer spikes â Identify activity following pacer spikes â Failure to capture â Failure to sense âĸ EVERY PACER SPIKE SHOULD HAVE A P-WAVE OR QRS COMPLEX FOLLOWING IT.
- 18. 4/07 18 Normal Pacing âĸ Atrial Pacing â Atrial pacing spikes followed by P waves
- 19. 4/07 19 Normal Pacing âĸ Ventricular pacing â Ventricular pacing spikes followed by wide, bizarre QRS complexes
- 20. 4/07 20 Normal Pacing âĸ A-V Pacing â Atrial & Ventricular pacing spikes followed by atrial & ventricular complexes
- 21. 4/07 21 Normal Pacing âĸ DDD mode of pacing â Ventricle paced at atrial rate
- 22. 4/07 22 Abnormal Pacing âĸ Atrial non-capture â Atrial pacing spikes are not followed by P waves
- 23. 4/07 23 Abnormal Pacing âĸ Ventricular non-capture â Ventricular pacing spikes are not followed by QRS complexes
- 24. 4/07 24 Failure to Capture âĸ Causes â Insufficient energy delivered by pacer â Low pacemaker battery â Dislodged, loose, fibrotic, or fractured electrode â Electrolyte abnormalities âĸ Acidosis âĸ Hypoxemia âĸ Hypokalemia âĸ Danger - poor cardiac output
- 25. 4/07 25 Failure to Capture âĸ Solutions â View rhythm in different leads â Change electrodes â Check connections â Increase pacer output (âmA) â Change battery, cables, pacer â Reverse polarity
- 26. 4/07 26 Reversing polarity âĸ Changing polarity â Requires bipolar wiring system â Reverses current flow â Switch wires at pacing wire/bridging cable interface â Skin âgroundâ wire
- 27. 4/07 27 Abnormal Pacing âĸ Atrial undersensing â Atrial pacing spikes occur irregardless of P waves â Pacemaker is not âseeingâ intrinsic activity
- 28. 4/07 28 Abnormal Pacing âĸ Ventricular undersensing â Ventricular pacing spikes occur regardless of QRS complexes â Pacemaker is not âseeingâ intrinsic activity
- 29. 4/07 29 Failure to Sense âĸ Causes â Pacemaker not sensitive enough to patientâs intrinsic electrical activity (mV) â Insufficient myocardial voltage â Dislodged, loose, fibrotic, or fractured electrode â Electrolyte abnormalities â Low battery â Malfunction of pacemaker or bridging cable
- 30. 4/07 30 Failure to Sense âĸ Danger â potential (low) for paced ventricular beat to land on T wave
- 31. 4/07 31 Failure to Sense âĸ Solution â View rhythm in different leads â Change electrodes â Check connections â Increase pacemakerâs sensitivity (âmV) â Change cables, battery, pacemaker â Reverse polarity â Check electrolytes â Unipolar pacing with subcutaneous âground wireâ
- 32. 4/07 32 Oversensing âĸ Pacing does not occur when intrinsic rhythm is inadequate
- 33. 4/07 33 Oversensing âĸ Causes â Pacemaker inhibited due to sensing of âPâ waves & âQRSâ complexes that do not exist â Pacemaker too sensitive â Possible wire fracture, loose contact â Pacemaker failure âĸ Danger - heart block, asystole
- 34. 4/07 34 Oversensing âĸ Solution â View rhythm in different leads â Change electrodes â Check connections â Decrease pacemaker sensitivity (âmV) â Change cables, battery, pacemaker â Reverse polarity â Check electrolytes â Unipolar pacing with subcutaneous âground wireâ
- 35. 4/07 35 Competition âĸ Assessment â Pacemaker & patientâs intrinsic rate are similar â Unrelated pacer spikes to P wave, QRS complex â Fusion beats
- 36. 4/07 36 Competition âĸ Causes â Asynchronous pacing â Failure to sense â Mechanical failure: wires, bridging cables, pacemaker â Loose connections âĸ Danger â Impaired cardiac output â Potential (low) for paced ventricular beat to land on T wave
- 37. 4/07 37 Competition âĸ Solution â Assess underlying rhythm âĸ Slowly turn pacer rate down â Troubleshoot as for failure to sense â Increase pacemaker sensitivity (âmV) â Increase pacemaker rate
- 38. 4/07 38 Assessing Underlying Rhythm âĸ Carefully assess underlying rhythm â Right way: slowly decrease pacemaker rate
- 39. 4/07 39 Assessing Underlying Rhythm âĸ Assessing Underlying Rhythm â Wrong way: pause pacer or unplug cables
- 40. 4/07 40 Wenckebach âĸ Assessment â Appears similar to 2nd degree heart block â Occurs with intrinsic tachycardia
- 41. 4/07 41 Wenckebach âĸ Causes â DDD mode safety feature â Prevents rapid ventricular pacing impulse in response to rapid atrial rate âĸ Sinus tachycardia âĸ Atrial fibrillation, flutter âĸ Prevents pacer-mediated tachycardia âĸ Upper rate limit may be inappropriate
- 42. 4/07 42 Wenckebach âĸ Solution â Treat cause of tachycardia âĸ Fever: Cooling âĸ Atrial tachycardia: Anti-arrhythmic âĸ Pain: Analgesic âĸ Hypovolemia: Fluid bolus â Adjust pacemaker upper rate limit as appropriate
- 43. 4/07 43 Threshold testing âĸ Stimulation threshold â Definition: Minimum current necessary to capture & stimulate the heart â Testing âĸ Set pacer rate 10 ppm faster than patientâs HR âĸ Decrease mA until capture is lost âĸ Increase output until capture is regained (threshold capture) âĸ Output setting to be 2xâs threshold capture â Example: Set output at 10mA if capture was regained at 5mA
- 44. 4/07 44 Performing an AEG âĸ Purpose: Determine existence & location of P waves âĸ Direct EKG from atrial pacing wires â Bedside EKG from monitor â Full EKG âĸ Atrial pacing pins to RA & LA EKG lead-wires
- 45. 4/07 45 Interpreting an AEG
- 46. 4/07 46 Sensitivity Threshold âĸ Definition: Minimum level of intrinsic electric activity generated by the heart detectable by the pacemaker
- 47. 4/07 47 Sensitivity Threshold Testing âĸ Testing â Set pacer rate 10 ppm slower than patientâs HR â Increase sensitivity to chamber being tested to minimum level (0.4mV) â Decrease sensitivity of the pacer (âmV) to the chamber being tested until pacer stops sensing patient (orange light stops flashing) â Increase sensitivity of the pacer (âmV) until the pacer senses the patient (orange light begins flashing). This is the threshold for sensitivity. â Set the sensitivity at ÂŊ the threshold value. âĸ Example: Set sensitivity at 1mV if the threshold was 2mV
- 48. 4/07 48 Factors Affecting Stimulation Thresholds
- 49. Thank Youdrtoufiq19711@yahoo.com Asia Pacific Congress of Hypertension, 2014, February Cebu city, Phillipines Seminar on Management of Hypertension, Gulshan, Dhaka