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GRAND ROUNDS

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GRAND ROUNDS Gord McNeil A proposed new format for rounds..... Outline: PART 1: Pacemakers Indications for pacemakers. Generic pacer code. Complications of pacers. – PowerPoint PPT presentation

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Title: GRAND ROUNDS


1
GRAND ROUNDS
  • Gord McNeil

2
A proposed new format for rounds.....
3
Outline
  • PART 1 Pacemakers
  • Indications for pacemakers.
  • Generic pacer code.
  • Complications of pacers.
  • Use of the magnet.
  • Miscellaneous information about pacers.

4
Outline
  • PART 2 Methadone
  • Guest speaker Richard Phillips from Opiate
    Dependency Clinic.

5
Pacemaker indications
  • 1) 3rd degree AV block
  • 2) Symptomatic bradycardia from 2nd degree AV
    block regardless of type or site of block
  • 3) Chronic bifascular or trifascicular block with
    intermittent 3rd or 2nd degree AV block.
  • 4) Sick sinus syndrome
  • 5) Recurrent syncope from carotid sinus.
    (Guidelines from the Joint Task force of the
    American Heart Association and the American
    College of Cardiology)

6
Temporary transvenous pacemaker
  • Patients that ONLY need pacemaker, should have 6
    Fr central line inserted.
  • Open 8.5F and 6F kits, but insert 6F catheter.
  • Patients will 8.5F catheter can be used
    emergently, but switched to 6F ASAP.
  • Complications of 8.5F catheter leakage of
    blood, inotropes, air, death.

7
Pacemaker code
8
Permanent pacer complications
  • Majority of pacemaker complications occur within
    1- 12 weeks implantation.
  • (7- 15 in the first year, then 6 per year.)
  • Clinically almost always present with recurrence
    of symptomatic bradyarrhythmia.

9
Categories of pacemaker failure
  • 1) Failure to sense properly.
  • Undersense
  • Oversense
  • 2) Failure to pace properly.
  • Output failure
  • Capture failure

10
Under sensing Failure to sense properly
  • The pacer will ignore any intrinsic rhythm and
    pace at a fixed rate.
  • Example A pacer spike occurring between the end
    of the QRS complex and the T wave.

11
Undersensing
  • Pacemaker does not see the intrinsic beat, and
    therefore does not respond appropriately.

Scheduled pace delivered
Intrinsic beat not sensed
12
Undersensing Failure to sense properly
  • Caused by
  • Lead displacement.
  • AMI.
  • Myocardial perforation.
  • Electrolyte abnormality severe enough to widen
    the QRS and delay its upstroke.
  • Lead or pacer failure (fibrosis, fracture, etc.)
  • No magnet needed - call EPS.

13
Oversensing Failure to sense properly
  • Pacemaker detects electrical complexes
    incorrectly as QRS complexes.
  • Results in inhibition of pacemaker function and
    therefore usually underlying bradycardia.

14
Oversensing
Pacemaker senses T wave as QRS and doesnt fire
Pacemaker working properly
15
Oversensing
  • Caused by
  • Far field and crosstalk.
  • Electromagnetic interference.
  • Lead fracture.
  • Can result in a pacemaker-mediated tachycardia.

16
Failure to pace
  • Failure of pacer output
  • Lead failure.
  • Generator failure.
  • Other
  • Failure of pacer capture.
  • Lead failure

17
Failure of pacer output
  • Suspect failure of output if HR is below the
    pacer rate and no pacer activity is noted on the
    EKG.

18
Causes of failure of output
  • Lead failure
  • Lead fracture.
  • Loose lead to generator
  • Generator failure
  • Very rare -lithium battery.
  • Oversensing.

19
Failure to capture
  • Inability of an appropriately discharged pacing
    spike to depolarize tissue.
  • Causes
  • Lead displacement.
  • AMI.
  • Myocardial perforation.
  • Lead or pacer failure(fibrosis, fracture, fails.)
  • Inappropriate programming.

20
Other pacemaker problems
  • Case 77 year old female with acute dyspnea and
    fluttering in chest for 4 hours. No c/p, cough
    or fever. Pacemaker placed 1 month ago for 3rd
    degree block.

21
  • .

22
Magnet applied in PMT
23
Pacemaker mediated tachycardia
  • Retrograde conduction of impulses from the
    ventricle is sensed by the pacer as atrial
    tachycardia and a continuous circuit is formed.
  • Occur in patients with dual chamber pacemakers.
  • Initiated by a PVC with retrograde atrial
    conduction occurs.

24
Management of PMT
  • The rate of this tachycardia will not exceed the
    maximum tracking rate of the pacemaker and is
    therefore unlikely to result in instability
    (although it can cause ischemia is susceptible
    patients).
  • Magnet will temporarily slow rate
  • (leave it on if it works).
  • Reprogrammed by EPS cardiologist.

25
Runaway pacemaker
  • Extremely rare now only in older pacers.
  • Usually present with extreme rapid tachycardia at
    rates from 130 up to 400 beats/min.
  • Disconnect pacer generator by severing pacer
    lead.

26
Runaway pacemaker vs. Pacemaker mediated
tachycardia
  • Runaway Pacemaker
  • Heart rate 130 400 beats per minute
  • Rarely a change with magnet application.
    (although can try)
  • Surgical management sever lead
  • PMT
  • Heart rate less than 130/min
  • Will temporarily stop with magnet application
  • Medical management - pacemaker reprogramming

27
Pacemaker syndrome
  • Typically occurs in a patient with VVI pacing who
    develops symptoms as a result of loss of AV
    synchrony.
  • Most common presenting complaints are vague
    symptoms of SOB, dizziness, fatigue, orthopneaa
    and confusion. Also palpitations pulsations or
    fullness in neck or abdomen.

28
Pacemaker syndrome
  • Complaints related not only to loss of atrial
    kick, but also to complex alterations in
    autonomic function, effects of atrial loading on
    atrial receptors and bioreceptors that alter
    vagal tone.
  • 20 of patients get a mild form in the 1st month
    and adapt. 1/3 of these have severe symptoms.

29
Pacemaker syndrome
  • Clinically diagnosis looking for cannon waves
    combined with ECG that shows retrograde
    conduction during ventricular pacing.
  • Dx of exclusion.
  • Tx with dual chamber pacemaker.

30

Pacemaker Syndrome
31
Cardiac perforation
  • Less than 1 of insertions.
  • Consider if
  • new RBBB
  • Hiccups or intercostal movements
  • pericardial friction rub
  • pericarditis, effusion, tamponade.

32
Magnets
33
Magnet
  • Indications for use
  • 1) Pacemaker mediated tachycardia.
  • 2) Oversensing.
  • 3) Repeatedly inappropriate firing of AICD.
  • 4) Suspect failure to capture.
  • 5) Suspect failure to generate output.

34
Use of magnet
  • Used when the intrinsic rhythm is rapid enough to
    totally inhibit pacemaker function, but there is
    suspicion that pacemaker malfunction is causing
    the patients symptoms.
  • Magnet application then allows pacing to occur
    and pacing rate and the presence of capture can
    be determined.

35
Magnet
  • It is important to remember that there is no way,
    including the use of a magnet, to disable
    pacemaker output.
  • Rarely removal of the magnet can result in
    endless loop tachycardia secondary to retrograde
    conduction of the last asynchronous ventricular
    impulse into the atrium, usually solve by
    reapplying the magnet.

36
Approach to the patient with possible pacemaker
malfunction
  • 1) ECG/ rhythm strip and compare to pulse.
  • 2) Get pacemaker card from pt date of
    implantation, pacer rate, contact person.
  • 3) CXR PA and LAT to assess lead placement
    and continuity.
  • 4) Apply magnet prn.
  • 5) Call pacemaker nurse prn.

37
(No Transcript)
38
AMI and paced EKG
  • Use same Sgarbossa criteria as in LBBB and
    therefore a paced EKG that does not meet the
    above criteria can not exclude AMI.

39
  • Figure 13 page 440 of clinics - rbbb

40
Lead displacement
  • Characteristically, a left bundle branch pattern
    is seen.
  • A right bundle branch is usually abnormal and
    suggests a lead displacement.
  • Exception is cardiac resynchronization therapy
  • biventricular pacer for CHF therefore RBBB is not
    abnormal. CXR to check the number of leads.

41
Pacemakers in cardiac arrest
  • Electrical defibrillation is is safe (paddles
    placed at least 10 cm from the implant.
  • Immediate return of pacing (capture) may not
    occur after defibrillation secondary to increased
    pacing threshold of ischemia and not due to pacer
    malfunction.
  • Use TC pacer not TV pacer.
  • CXR post chest compressions.

42
  • Case 62 yr old male with previous pacer inserted
    with chest pain and collapsed and found
    pulseless. AED applied and no shock advised.
    Rhythm with EMS arrive is v fib. Why no shock
    advised from AED?

43
  • AED units can recognize pacemaker spikes as a
    non-shockable rhythm.

44
Fever and pacemaker
  • If a patient with a pacemaker presents with a
    fever of unclear etiology, pacemaker lead
    infection and endocarditis must be considered.
  • If suspect pocket infection - do not aspirate
    unless under fluoroscopy. Tx is removal of
    pacemaker and IV vancomycin.

45
Clot and pacemaker
  • Thrombophelbitsis and clot -30-50 with 33
    having complete obstruction.
  • Only 0.5-3.5 of these will have symptoms.Treat
    with heparin and coumadin as per usual.
  • Do not treat with LMWH for first 6 weeks post
    insertion.

46
  • Case 69 yr old female riding motorbike, hits
    tree and is transported by STARS for isolated
    femur fracture. On take off HR goes to 170 beats
    per min. Why?

47
  • New rate modulated sensing pacemaker
  • Controls heart rate according to vibrations (it
    assumes it is related to physical activity).
  • Treatment - take out of helicopter or apply
    magnet.

48
Conclusions
  • 6 Fr catheter for pacemaker insertion in ED.
  • Pacemaker complications usually in first 12 weeks
    of insertion.Think of cardiac perforation.
  • Magnet for PMT, AICD firing, oversensing.
  • EPS available for consult.
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