Pacemaker complication: Difference between revisions
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==Background== | ==Background== | ||
*All [[ICD]]s are also pacemakers (i.e. have pacing functionality), but not all pacemakers are ICDs (i.e. do not have shocking functionality) | |||
===Nomenclature=== | ===Nomenclature=== | ||
[[File:paced.gif|thumb|Paced rhythm with characteristic wide LBBB and pacer spikes]] | [[File:paced.gif|thumb|Paced rhythm with characteristic wide LBBB and pacer spikes]] | ||
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! I || II || III || IV || V | ! I || II || III || IV || V | ||
|- | |- | ||
|+Generic code for | |+Generic code for pacing modes<ref>Bernstein AD. et al. The revised NASPE/BPEG generic code for antibradycardia, adaptive-rate, and multisite pacing. North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group. Pacing Clin Electrophysiol 2002 Feb; 25(2) 260-4. lmid:11916002</ref> | ||
| Chamber(s) paced || Chamber(s) sensed || Response to sensing || Rate modulation || Multisite pacing | | Chamber(s) paced || Chamber(s) sensed || Response to sensing || Rate modulation || Multisite pacing | ||
|- | |- | ||
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*Cardiac Resynchronization Therapy- Conduction delay (>150msec with mortality benefit) in chronic systolic heart failure further decreases EF, increases remodeling and increased MR. | *Cardiac Resynchronization Therapy- Conduction delay (>150msec with mortality benefit) in chronic systolic heart failure further decreases EF, increases remodeling and increased MR. | ||
*Neurocardiogenic Syncope and Carotid Sinus Syndrome | *Neurocardiogenic Syncope and Carotid Sinus Syndrome | ||
===Lead Location=== | |||
*Atrial | |||
**Right Atrial Appendage | |||
**Lateral RA wall | |||
*Right Ventricle | |||
**Apex | |||
**Septum | |||
*Left Ventricle (most commonly placed for cardiomyopathy or CHF) | |||
**Coronary veins along external LV wall via coronary sinus | |||
**Rarely, externally placed electrode during open surgical procedure | |||
===Additional Pacemaker Functions=== | |||
*Can record rhythm strips of AF, VT, and VF episodes for later review | |||
*Keeps track of % of paced vs intrinsic beats | |||
*Keeps a rate histogram, as well as % of time spent in AF | |||
===Methods to Identify Manufacturer=== | ===Methods to Identify Manufacturer=== | ||
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====Problems with pocket==== | ====Problems with pocket==== | ||
*Infection | *Infection | ||
**Most commonly | **Most commonly S. aureus or S. epidermidis | ||
**2% local wound infection; 1% sepsis/bacteremia | **2% local wound infection; 1% sepsis/bacteremia | ||
*Hematoma | *Hematoma | ||
**Typically occurs shortly after placement | **Typically occurs shortly after placement | ||
====Problems with leads==== | ====Problems with leads==== | ||
* | *Dislodgment | ||
* | *Perforation (most commonly at RV apex) | ||
* | *Infection can cause severe sepsis | ||
* | *Tricuspid regurgitation | ||
* | *Coiling (ie: [[Twiddler's Syndrome]]) [[File:Twiddler Syndrome.png|thumb|Twiddler Syndrome after large pocket and defibrillator wires coiled around the generator]] | ||
===Failure to Capture=== | ===Failure to Capture=== | ||
*Delivery of pacing stimulus without depolarization | *Delivery of pacing stimulus without depolarization | ||
*Functional- myocardium | **Functional - refractory myocardium, desensitized local tissue around the lead | ||
* | **Medical - drugs, myocardial disease, electrolytes | ||
* | **Technical - insufficient device output, lead dislodgment, fracture, insulation defect, ventricular wall perforation | ||
*Battery of End of Life (EOL) | |||
===Failure to Pace=== | ===Failure to Pace=== | ||
*Failure to deliver a stimulus to the heart | *Failure to deliver a stimulus to the heart | ||
*Oversensing - most common cause: retrograde P’s, T’s, skeletal muscle myopotentials, | **Oversensing - most common cause: retrograde P’s, T’s, skeletal muscle myopotentials, | ||
*Crosstalk - type of oversensing where the ventricular lead senses atrial pacing stimulus, and ventilator output inhibited | **Crosstalk - type of oversensing where the ventricular lead senses atrial pacing stimulus, and ventilator output inhibited | ||
===Failure to Sense=== | ===Failure to Sense=== | ||
* | *Normal function: a sensed myocardial depolarization greater than the programmed threshold causes inhibition of pacing | ||
* | *Failure to sense results in a paced beat on top of an intrinsic beat (as the device is "unaware" of the intrinsic beat") | ||
*Voltages of patient's intrinsic QRS complex is too low to be detected | **Voltages of patient's intrinsic QRS complex is too low to be detected | ||
*New intrinsic arrhythmia, AMI, electrolyte abnormalities, lead separation, battery depletion | **New intrinsic arrhythmia (AF has a smaller depolarization than sinus beat), AMI, electrolyte abnormalities, lead separation, battery depletion | ||
===Runaway Pacing=== | ===Runaway Pacing=== | ||
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*Potentially life-threatening as it can cause V-Fib or (paradoxically) bradycardia due to failure to capture | *Potentially life-threatening as it can cause V-Fib or (paradoxically) bradycardia due to failure to capture | ||
===Pacemaker Mediated | ===Pacemaker Mediated Tachycardia=== | ||
*Also known as Endless Loop Tachycardia | *Also known as Endless Loop Tachycardia | ||
*Formation of a re-entrant circuit causing inappropriate tachycardia | *Formation of a re-entrant circuit causing inappropriate tachycardia | ||
**Most commonly: paced ventricular beat -> retrograde AV node conduction -> intrinsic P wave -> device reacts to intrinsic P wave by looking for intrinsic QRS, but since AV node is now refractory it delivers a paced beat at the programmed P-R interval (typically ~200-250ms), starting the process anew | |||
*Tachycardia does not exceed programmed upper limit rate on pacemaker | *Tachycardia does not exceed programmed upper limit rate on pacemaker | ||
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*[[Troponin]] | *[[Troponin]] | ||
*Interrogation | *Interrogation | ||
**Each company has on-call representatives who will come interrogate a device 24/7 (phone numbers above) | |||
**Most cath labs will have machines capable of interrogating each brand | |||
===Expected ECG Patterns=== | ===Expected ECG Patterns=== | ||
*Absence of pacer artifact indicates intrinsic depolarization | *Absence of pacer artifact indicates intrinsic depolarization | ||
**With newer pacemakers, pacer spikes may not appear on some or all paced beats, depending on EKG machine | |||
*Pacing artifacts preceding depolarizations indicate successful pacing and capture | *Pacing artifacts preceding depolarizations indicate successful pacing and capture | ||
*Leads in RV apex produce LBBB pattern with appropriate discordance | *Leads in RV apex produce LBBB pattern with appropriate discordance | ||
*New RBBB pattern may indicate lead in LV | *New RBBB pattern may indicate lead in LV | ||
*Simultaneous | * Bi-ventricular devices can produce paced QRS complexes that are either narrow or wide and bizarre, depending on device programming | ||
*Simultaneous depolarization of ventricles produces dominant R wave in V1 | |||
===Plain Film Findings=== | ===Plain Film Findings=== | ||
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*Pacemaker Mediated Tachycardia | *Pacemaker Mediated Tachycardia | ||
**Break with [[adenosine]] or magnet.<ref>EB Medicine- Sept 2014- Managing Pacemaker-Related Complications and Malfunctions in the Emergency Department </ref> | **Break with [[adenosine]] or magnet.<ref>EB Medicine- Sept 2014- Managing Pacemaker-Related Complications and Malfunctions in the Emergency Department </ref> | ||
***Magnet placement will stop the sensing of the retrograde-conducted P waves driving PMT; this will immediately terminate the rhythm. | |||
***Recurrence of PMT after earlier termination means that the pacemaker settings need to be changed | |||
**Consider chest wall stimulation techniques<ref>Barold SS, Falkoff MD, Ong LS, Heinle RA. Pacemaker endless loop tachycardia: termination by simple techniques other than magnet application. Am J Med. 1988;85(6):817-22.</ref> - transcutaneous pacing, isometric muscular exercise, precordial thump | **Consider chest wall stimulation techniques<ref>Barold SS, Falkoff MD, Ong LS, Heinle RA. Pacemaker endless loop tachycardia: termination by simple techniques other than magnet application. Am J Med. 1988;85(6):817-22.</ref> - transcutaneous pacing, isometric muscular exercise, precordial thump | ||
* | *Electrophysiology or cardiology consult is often needed | ||
*Contact a device representative for a full interrogation | |||
==Disposition== | ==Disposition== | ||
*Resolved Pacemaker-mediated Tachycardia without recurrence - discharge | |||
*Infection - admission with [[MRSA]] coverage antibiotics, consult to cardiology, with likely replacement of pacemaker after 4-6 weeks of IV antibiotics | *Infection - admission with [[MRSA]] coverage antibiotics, consult to cardiology, with likely replacement of pacemaker after 4-6 weeks of IV antibiotics | ||
*Pacing/sensing/capture issue - likely admit | |||
==See Also== | ==See Also== | ||
*[[Medical device complications]] | *[[Medical device complications]] | ||
*[[In-Training Exam Review]] | *[[In-Training Exam Review]] | ||
*[[Implantable Cardioverter-Defibrillator complication]] | |||
==References== | ==References== |
Revision as of 17:18, 11 March 2021
Background
- All ICDs are also pacemakers (i.e. have pacing functionality), but not all pacemakers are ICDs (i.e. do not have shocking functionality)
Nomenclature
I | II | III | IV | V |
---|---|---|---|---|
Chamber(s) paced | Chamber(s) sensed | Response to sensing | Rate modulation | Multisite pacing |
O = None | O = None | O = None | O = None | O = None |
A = Atrium | A = Atrium | T = Triggered | R = Rate modulation | A = Atrium |
V = Ventricle | V = Ventricle | I = Inhibited | V = Ventricle | |
D = Dual (A+V) | D = Dual (A+V) | D = Dual (T+I) | D = Dual (A+V) |
Indications
- Sinus Node Dysfunction-sinus bradycardia/arrest, sinoatrial block, chronotropic incompetence, a-fib.
- Acquired AV block- 3rd degree block and 2nd degree type II
- Chronic Bifascicular or Trifascicular block
- After Acute MI-high mortality with persistent AV block post MI
- Cardiac Resynchronization Therapy- Conduction delay (>150msec with mortality benefit) in chronic systolic heart failure further decreases EF, increases remodeling and increased MR.
- Neurocardiogenic Syncope and Carotid Sinus Syndrome
Lead Location
- Atrial
- Right Atrial Appendage
- Lateral RA wall
- Right Ventricle
- Apex
- Septum
- Left Ventricle (most commonly placed for cardiomyopathy or CHF)
- Coronary veins along external LV wall via coronary sinus
- Rarely, externally placed electrode during open surgical procedure
Additional Pacemaker Functions
- Can record rhythm strips of AF, VT, and VF episodes for later review
- Keeps track of % of paced vs intrinsic beats
- Keeps a rate histogram, as well as % of time spent in AF
Methods to Identify Manufacturer
- Patient most often has a pocket card indicating manufacturer
- Manufacturer Hotline has patient database
- Medtronic Inc. (1-800-328-2518)
- St. Jude Medical Inc. (recently acquired by Abbott, Inc.) (1-800-722-3774)
- Boston Scientific Inc. (1-800-227-3422)
- Magnet mode - with placement of a magnet over the device, the mode changes to asynchronous (i.e. DOO or VOO). Each brand has slightly different rates
- Medtronic Inc.: 85 bpm; 65 bpm when battery is ready for replacement
- St. Jude Medical Inc.: 98.6 bpm; 86.3 bpm when battery is ready for replacement
- Boston Scientific Inc.: 100 bpm; 85 bpm when battery is ready for replacement
- Manufacturer code on pulse generator is visible on Chest Xray
Electromagnetic Interference
- Nonmedical
- Cell phones: do not interact with device
- Airport security: may trigger alarm, no alteration of activity
- Medical Sources
- MRI: mostly safe, consult cards on device specific recs
- Cardioversion: Use AP pads >8cm from device to minimize adverse effects
- Unipolar Cautery - can cause sensing and pacing malfunction as well as reprogramming
Differential Diagnosis
Pacemaker Malfunction
Problems with pocket
- Infection
- Most commonly S. aureus or S. epidermidis
- 2% local wound infection; 1% sepsis/bacteremia
- Hematoma
- Typically occurs shortly after placement
Problems with leads
- Dislodgment
- Perforation (most commonly at RV apex)
- Infection can cause severe sepsis
- Tricuspid regurgitation
- Coiling (ie: Twiddler's Syndrome)
Failure to Capture
- Delivery of pacing stimulus without depolarization
- Functional - refractory myocardium, desensitized local tissue around the lead
- Medical - drugs, myocardial disease, electrolytes
- Technical - insufficient device output, lead dislodgment, fracture, insulation defect, ventricular wall perforation
- Battery of End of Life (EOL)
Failure to Pace
- Failure to deliver a stimulus to the heart
- Oversensing - most common cause: retrograde P’s, T’s, skeletal muscle myopotentials,
- Crosstalk - type of oversensing where the ventricular lead senses atrial pacing stimulus, and ventilator output inhibited
Failure to Sense
- Normal function: a sensed myocardial depolarization greater than the programmed threshold causes inhibition of pacing
- Failure to sense results in a paced beat on top of an intrinsic beat (as the device is "unaware" of the intrinsic beat")
- Voltages of patient's intrinsic QRS complex is too low to be detected
- New intrinsic arrhythmia (AF has a smaller depolarization than sinus beat), AMI, electrolyte abnormalities, lead separation, battery depletion
Runaway Pacing
- Physiologic electrical activity (T waves, muscle potentials)
- External electromagnetic interference
- Signals generated by interaction of different portions of the pacing system
- Potentially life-threatening as it can cause V-Fib or (paradoxically) bradycardia due to failure to capture
Pacemaker Mediated Tachycardia
- Also known as Endless Loop Tachycardia
- Formation of a re-entrant circuit causing inappropriate tachycardia
- Most commonly: paced ventricular beat -> retrograde AV node conduction -> intrinsic P wave -> device reacts to intrinsic P wave by looking for intrinsic QRS, but since AV node is now refractory it delivers a paced beat at the programmed P-R interval (typically ~200-250ms), starting the process anew
- Tachycardia does not exceed programmed upper limit rate on pacemaker
Evaluation
Work-Up
- BMP and Mg
- CXR
- ECG
- Troponin
- Interrogation
- Each company has on-call representatives who will come interrogate a device 24/7 (phone numbers above)
- Most cath labs will have machines capable of interrogating each brand
Expected ECG Patterns
- Absence of pacer artifact indicates intrinsic depolarization
- With newer pacemakers, pacer spikes may not appear on some or all paced beats, depending on EKG machine
- Pacing artifacts preceding depolarizations indicate successful pacing and capture
- Leads in RV apex produce LBBB pattern with appropriate discordance
- New RBBB pattern may indicate lead in LV
- Bi-ventricular devices can produce paced QRS complexes that are either narrow or wide and bizarre, depending on device programming
- Simultaneous depolarization of ventricles produces dominant R wave in V1
Plain Film Findings
- Obtain PA/Lateral Films to confirm pulse generator, manufacturer, lead placement/number/integrity
- R atrial lead J shaped(tip medially on AP) entering right atrial appendage
- RV leads point downward with tip between left spine and cardiac apex--lateral XR shows inferior and anterior
- Coronary sinus lead- courses posteriorly on lateral XR
- Extra leads may be appropriately abandoned and capped
- ICD component appears as thickened shock coil
Management
- Pacemaker Mediated Tachycardia
- Break with adenosine or magnet.[2]
- Magnet placement will stop the sensing of the retrograde-conducted P waves driving PMT; this will immediately terminate the rhythm.
- Recurrence of PMT after earlier termination means that the pacemaker settings need to be changed
- Consider chest wall stimulation techniques[3] - transcutaneous pacing, isometric muscular exercise, precordial thump
- Break with adenosine or magnet.[2]
- Electrophysiology or cardiology consult is often needed
- Contact a device representative for a full interrogation
Disposition
- Resolved Pacemaker-mediated Tachycardia without recurrence - discharge
- Infection - admission with MRSA coverage antibiotics, consult to cardiology, with likely replacement of pacemaker after 4-6 weeks of IV antibiotics
- Pacing/sensing/capture issue - likely admit
See Also
- Medical device complications
- In-Training Exam Review
- Implantable Cardioverter-Defibrillator complication
References
- ↑ Bernstein AD. et al. The revised NASPE/BPEG generic code for antibradycardia, adaptive-rate, and multisite pacing. North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group. Pacing Clin Electrophysiol 2002 Feb; 25(2) 260-4. lmid:11916002
- ↑ EB Medicine- Sept 2014- Managing Pacemaker-Related Complications and Malfunctions in the Emergency Department
- ↑ Barold SS, Falkoff MD, Ong LS, Heinle RA. Pacemaker endless loop tachycardia: termination by simple techniques other than magnet application. Am J Med. 1988;85(6):817-22.