PACEMAKERS AND ICDS INDICATIONS, FUNCTION AND TROUBLESHOOTING

Transcription

1 PACEMAKERS AND ICDS INDICATIONS, FUNCTION AND TROUBLESHOOTING Tanja Sloan R.N., PA-C St. Vincent Healthcare Cardiac and Vascular Nursing Conference 2014

2 Disclosures I have no disclosures

3 Historical Perspective Electrical cardiac pacing for the management of brady-arrhythmias was first described in 1952 Permanent transvenous pacing devices were first implanted in the early 1960 s First ICD was implanted in 1980

4 Normal conduction system of the heart

5 Indications For Permanent Pacing Third degree AV block associated with: Symptomatic bradycardia Symptomatic bradycardia secondary to drugs required for dysrhythmia management Asystole > 3 seconds or escape rate < 40 After catheter ablation of the AV node Post-op AV block not expected to resolve Neuromuscular disease with AV block

6 Indications For Permanent Pacing Symptomatic bradycardia from second degree AV block Bifascicular or trifascicular block with intermittent third degree or type II second degree block Sinus node dysfunction with symptomatic bradycardia Recurrent syncope caused by carotid sinus stimulation

7 Indications For Permanent Pacing Post myocardial infarction with: Persistent second degree AV block with bilateral bundle branch block or third degree AV block Transient second or third degree AV block and bundle branch block Symptomatic, persistent second or third degree AV block

8 Miscellaneous Pacemaker Indications Hypertrophic obstructive cardiomyopathy Dilated cardiomyopathy Cardiac transplantation Termination and prevention of tachyarrhythmias Congenital heart disease in children and adolescents

9 Indications for Implantable Cardiac Defibrillator Placement Class I 1.Cardiac Arrest Due to VT or VF Not due to transient or reversible cause 2.Spontaneous sustained VT With structural heart disease 3.Syncope of undetermined origin with: Inducible sustained VT or VF that has clinical relevance and/or hemodynamic significance Class II 1.Sustained VT Normal or near-normal LVEF 2.Unexplained Syncope with: Significant LV dysfunction and NICM

10 Pacing types Temporary Permanent BiVentricular

11 Pacemaker Components Pulse Generator Electronic Circuitry Lead system ICD + High power

12 Pulse Generator Lithium-iodine cell is the current standard battery Advantages: Long life 6 to 10 years Output voltage decreases gradually with time making sudden battery failure unlikely

13 Lead Systems Endocardial leads which are inserted using a subclavian vein approach Actively fixed to the endocardium using screws or tines Unipolar or bipolar leads

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15 Pacemaker Functions Stimulate cardiac depolarization Sense intrinsic cardiac function Respond to increased metabolic demand by providing rate responsive pacing Provide diagnostic information stored by the pacemaker

16 ICD Therapies Brady pacing Antitachycardia pacing Cardioversion (1 to 40J) Defibrillation (up to 40J)

17 ICD Therapy ICD Therapy Low Power (Pacing Therapies) Anti-tachycardia Pacing (ATP) Bradyarrhythmia Pacing High Power (Shock Therapies) Cardioversion Defibrillation

18 Pacing Function: Asynchronous/Fixed Rate Does not synchronize with intrinsic HR Used safely in pts with no intrinsic ventricular activity If pt has ventricular activity, it may compete with pt s own conduction system VT may result (R-on-T phenomenon)

19 Pacing Function: Synchronous/Demand Contains two circuits * One forms impulses * One acts as a sensor When activated by an R wave, sensing circuit either triggers or inhibits the pacing circuit Called Triggered or Inhibited pacers Most frequently used pacer Eliminates competition Energy sparing

20 Pacing Function Atrial pacing: Stimulation of right atrium produces spike on EKG preceding P wave

21 Pacing Function Ventricle pacing : Stimulation of RT or LT ventricle produce a spic on ECG preceding QRS complex

22 Pacing Function AV pacing: Direct stimulation of right atrium and either ventricles to mimic normal heart conduction

23 Sensing Function Sensing: Ability of the pacemaker to see intrinsic cardiac activity when it occurs. Two types: Demand: pacing stimulation delivered only if the heart rate falls below the preset limit. Fixed: no ability to sense. constantly delivers the preset stimulus at preset rate. Triggered: delivers stimuli in response to (sensing) cardiac event.

24 Capture Function Capture: Ability of the pacemaker to generate a response from the heart (contraction) after electrical stimulation.

25 Capture Function Electrical capture: Indicated by P or QRS following and corresponding to a pacemaker spike. Mechanical capture: Palpable pulse corresponding to the electrical event.

26 Troubleshooting Define the problem Identify the cause of the problem Correct the problem Verify the solution

27 Pacemaker complications Pacemaker complications are divided into: Implant related complications Lead related complications Pacemaker malfunction

28 Implanted related complications 1. Procedure related/acute Subclavian puncture Traumatic pneumothorax Hemothorax, air embolism AV fistula Thoracic duct injury Brachial plexus injury

29 Implanted related 2. Hematoma formation at pulse generator 3. Thrombus formation/embolism/av thrombus Asymptomatic due to collaterals 4. Lead perforation/cardiac tamponade rising threshold, diaphragmatic stimulation, friction rub, hypotension 5. SVT/VT during implantation

30 Pacemaker Infections Pacemaker insertion is a surgical procedure: 1% risk for bacteremia 2% risk for wound or pocket infection Usually occur soon after pacer insertion Presence of a foreign body complicates management Most common S. Aureus/Epidermis Lead vegetations Local inflammation, fever, +BC

31 Lead related complications 1. Lead dislodgement A>V 2. Lead fracture Usually occurs adjacent to PM near venous site If fracture of bipolar lead occurs, may be possible to reprogram to unipolor configuration 3. Loss of integrity of insulation Manufacturing defects/wear & tear Crush injury

32 Lead related complications 4. Exit block Abnormality at myocardial-electrode interface 5. Diaphragmatic or pectoral muscle pacing Dislodgement, insulation defects, common with unipolar leads

33 Pacemaker Failure A. Early: electrode displacement/breakage B. Failure > 6 months Premature battery depletion Faulty pulse generator

34 Pacemaker Malfunction Generally Be Assigned To Five Categories: Undersensing Oversensing Noncapture No output Pseudomalfunction

35 Undersensing may be caused by: Inappropriately programmed sensitivity Lead dislodgment Lead failure Insulation break; conductor fracture Lead maturation Change in the native signal

36 Undersensing Pacer fails to detect an intrinsic rhythm Paces unnecessarily Patient may feel extra beats If an unneeded pacer spike falls in the latter portion of T wave, dangerous tachyarrhythmias or V fib may occur TX: Increase sensitivity of pacer

37 Undersensing An intrinsic depolarization that is present, yet not seen or sensed by the pacemaker

38 Oversensing may be caused by: Lead failure Poor connection at connector block Exposure to interference

39 Oversensing Pacer interprets noncardiac electrical signals as originating in the heart Detects extraneous signals such as those produced by electrical equipment or the activity of skeletal muscles (tensing, flexing of chest muscles, EMI) Inhibits itself from pacing as it would a true heart beat

40 Oversensing On ECG: pauses longer than the normal pacing interval are present Often, electrical artifact is seen Deprived of pacing, the patient suffers CO, feels dizzy/light-headed Most often due to sensitivity being programmed too high TX: Reduce sensitivity

41 Oversensing The sensing of an inappropriate signal Can be physiologic or nonphysiologic

42 Noncapture Pacer s electrical stimulus (pacing) fails to depolarize (capture) the heart There is no failure to pace Pacing is simply unsuccessful at stimulating a contraction ECG shows pacer spikes but no cardiac response CO occurs TX: threshold/output strength or duration

43 Noncapture No evidence of depolarization after pacing artifact

44 Noncapture

45 Noncapture can be caused by: Lead dislodgment Low output Lead maturation Poor connection at connector block Lead failure

46 Less common causes of noncapture Twiddler s syndrome Electrolyte abnormalities Myocardial infarction Drug therapy Battery depletion

47 Output failure Output failure occurs when a paced stimulus is not generated in a situation where expected. Results in decreased or absent pacemaker function. Very rare, usually a malfunctioning device.

48 Output failure

49 Pseudomalfunction Pseudomalfunctions are defined as: Unusual Unexpected Eccentric ECG findings that appear to result from pacemaker malfunction but that represent normal pacemaker function

50 Pseudomalfunctions May Be Classified Under The Following Categories: Rate AV interval/refractory periods Mode

51 Rate Changes May Occur Due To Normal Device Operation: Magnet operation Timing variations A-A versus V-V timing Upper rate behavior Pseudo-Wenckebach; 2:1 block Electrical reset Battery depletion PMT intervention Rate response

52 Magnet operation Magnet application causes asynchronous pacing at a designated magnet rate

53 Pacemaker Mediated Tachycardia (PMT) A rapid paced rhythm that can occur with atrial tracking pacemakers

54 PMT Retrograde conduction Tracking fast atrial rates (physiologic or nonphysiologic)

55 Retrograde Conduction May Be Caused By: Loss of A-V synchrony due to: Loss of sensing/capture Myopotential sensing Premature ventricular contraction (PVC) Magnet application

56 Pacemaker troubleshooting

57 Common problems with ICDs Common: Recalled device issues of varying severity SVTs causing inappropriate shocks Less common: Oversensing (electromagnetic interference, myopotentials) causing inappropriate shocks Lead failure causing inappropriate shocks, pacing problems or sensing problems

58 ICD with repeated shocks Place magnet over ICD Place external defibrillator pads and telemetry Initiate ACLS or critical care management as appropriate OK to do CPR or external defibrillation before magnet is placed

59 Case Study 1 67 year old male presents to the emergency room 12 hours after insertion of a pacemaker complaining of left sided chest pain and shortness of breath PR96, RR 33, BP 125/85, Oxygen saturation 88% RA CXR as shown

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61 Pneumothorax Occurs during cannulation of the subclavian vien Incidence -?? Cardiologist dependent Treatment: Asymptomatic or small observation Symptomatic or large tube thoracostomy

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63 Case Study 2 72 year old male presents to the emergency room after a fall, tripped over a bath mat, no LOC Shortened and rotated left leg Past history pacemaker, hypertension Nurse does an routine pre-op CXR and EKG

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65 Septal Perforation Usually identified at the time of pacer insertion but leads can displace after insertion Can occur with transvenous pacer insertion Keys diagnosis are a RBBB pattern on EKG and a pacer lead displaced to the apex of the heart on CXR

66 Septal Perforation Management: Pacer wire has to be removed but not emergently Small VSD which heals spontaneously

67 Case Study 83 year old female underwent PPM implantation several hours ago Patient is doing well, VS are stable

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