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Cardiology > Electrophysiology Procedures
Pacemaker Failure
Article Last Updated: Mar 23, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 11  
Author: Chakri Yarlagadda, MD, FACC, Consulting Staff, Section of Cardiology, St Elizabeth Hospital
Chakri Yarlagadda is a member of the following medical societies: American College of Cardiology, American College of Chest Physicians, American College of Physicians, American Medical Association, and American Society of Echocardiography
Coauthor(s):
Atef S Labib, MD, PAC, FACC, FACP, Chief, Section of Cardiology, St Elizabeth Hospital; Clinical Associate Professor, Department of Medicine, Northeastern Ohio Universities College of Medicine
Editors: Hanumant Deshmukh, MD †, Former Chief of Cardiology, Veterans Affairs Medical Center; Former Associate Professor, Department of Medicine, Rosalind Franklin University of Medicine and Science; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Brian Olshansky, MD, Professor of Medicine, Department of Internal Medicine, University of Iowa Hospitals; Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital; John Paul Mounsey, BSc, BM, BCh, PhD, MRCP, Associate Professor, Department of Medicine, Cardiovascular Division, University of Virginia
Author and Editor Disclosure
Synonyms and related keywords:
pacemaker malfunction, pacing system malfunction, heart pacing malfunction, pacemaker complication, pacemaker syndrome, pacemaker-mediated tachycardia, twiddler's syndrome, cardiac pacing, heart pacing, broken pacemaker, failed pacemaker, malfunctioning pacemaker, runaway pacemaker
Background
The number of pacemaker implants is growing because of newer indications. Knowledge of different modes, timing cycles, and event markers, as well as newer algorithms, is necessary for accurate diagnosis of pacing system malfunction.
Pathophysiology
Although true pulse generator failure is very rare, pacing system malfunction occurs occasionally. Pacing system malfunction can be due to malfunction of lead, electrode-tissue interface, or pulse generator. Most of these malfunctions can be corrected by simple reprogramming of the device. The majority of malfunctions in fact are due to normal programmed pacemaker function. Thorough understanding of the cause of malfunction is extremely important for accurate diagnosis and management.
Frequency
United States
Actual incidence of pacemaker malfunction is unknown.
Mortality/Morbidity
Overall morbidity and mortality depend on the underlying cause of malfunction as well as the patient's dependency on the pacemaker. Most pacing system malfunctions are benign, although conditions such as cross-talk inhibition or runaway pacemaker can be life threatening.
History
Clinical symptoms of pacemaker malfunction are variable and include syncope, dizziness, palpitations, and slow or fast heart rate. Extracardiac stimulation or hiccough may be present. Obtain as much information as possible regarding the pulse generator, leads, and programmed values. Information on indication for pacemaker implant, special programming features particular to that model or patient, and knowledge of any manufacturer recalls or alerts on pacing systems may provide clues to underlying malfunction.
Physical
Look for the following signs in patients with pacing system malfunction:
- Pocket stimulation
- Erosion of packet
- Diaphragmatic stimulation
- Cannon A waves during atrioventricular (AV) dyssynchrony
- Bradycardia
- Tachycardia
- Hypotension
Causes
Causes of pacing system malfunction can be classified into the following groups:
- Undersensing (see Image 1, Image 2): Causes of undersensing include the following:
- Improper lead position
- Improper programming
- Lead maturation or dislodgement (see Image 3)
- Lead insulation break
- Loose connection at connector block
- Incompatible connector
- Battery depletion
- Magnet application
- Electromagnetic interference (EMI)
- Reed switch malfunction
- Dry (air) pocket in unipolar pacers
- Circuit failure
- Change in signal morphology or amplitude of intrinsic event
- Partial open circuit
- Post defibrillation or cardioversion
- Electrolyte abnormality such as hyperkalemia
- Oversensing: Causes of oversensing include the following:
- EMI
- Improper programming
- Myopotential
- Cross talk: Electrical event in one chamber is sensed by another chamber, which results in inappropriate inhibition of pacing artifact in the second chamber.
- Cross talk is more common in unipolar system than in bipolar systems.
- Cross talk can occur in the pulse generator circuit itself.
- Causes of cross talk include atrial lead dislodgement into the ventricle, ventricular lead dislodgement into the atrium, high atrial output current, high ventricular sensitivity, and short ventricular blanking period.
- Loss of capture (noncapture [see Image 4, Image 5]): Causes of loss of capture include the following:
- Dry (air) pocket in unipolar pacer
- Circuit failure
- Impending battery depletion
- Inadequate programmed output with higher threshold
- Insulation break
- Partial conductor coil fracture
- Lead maturation, dislodgement, or perforation
- Poor or incompatible connection at connector block
- Conditions that increase the capture threshold, such as metabolic and electrolyte abnormalities, medications, and myocardial infarction
- Loss of output (no pacer artifact and no QRS): Causes of loss of output include the following:
- Dry (air) pocket in unipolar pacer
- Circuit failure
- Impending battery depletion
- Inadequate programmed output with higher threshold
- Insulation break
- Partial conductor coil fracture
- Lead maturation, dislodgement, or perforation
- Poor or incompatible connection at connector block
- Conditions that increase the capture threshold, such as metabolic and electrolyte abnormalities, medications, and myocardial infarction
- Failure to output: Causes of failure to output include the following:
- Cross-talk inhibition due to oversensing
- Total battery depletion
- Conductor coil fracture
- Lead fracture
- Loose set-screw
- Incompatible lead or header
- Open circuit
- Internal insulation break in bipolar lead
- Myopotential inhibition or far-field sensing
- Inappropriate rate: Causes of inappropriate rate include the following:
- Battery depletion
- Oversensing
- Runaway pacemaker
- Undersensing
- Pacer reset
- Inappropriate lead position: Causes of inappropriate position include the following:
- Left ventricle (LV) position of transvenous lead through atrial septal defect (ASD), patent foramen ovale (PFO), or interventricular septal perforation or inadvertent position through arterial system
- Coronary sinus or gastric vein position instead of right ventricle (RV)
- Left atrial position of atrial lead through ASD or PFO
- Inappropriate mode: Causes of inappropriate mode include the following:
- Magnet application
- Battery depletion
- Power on reset
- Noise reversion
- Extracardiac stimulation: Causes of extracardiac stimulation include the following:
- Phrenic nerve stimulation from atrial lead or dislodged ventricular lead
- Diaphragmatic stimulation from RV lead perforation or high output
- Pocket stimulation from insulation break or upside down pacer in pocket
- True pulse generator failure: Causes of true pulse generator failure include the following:
- Battery depletion
- Direct trauma
- Circuit or component failure
- EMI because of cardioversion, defibrillation, electrocautery, lithotripsy, radiofrequency ablation, MRI, electroconvulsive therapy, therapeutic radiation, or lightening
- Pacemaker-mediated tachycardia (PMT): PMT (see Image 6) is observed in dual-chamber pacemakers with DDD, VDD, and DDDR modes.
- The classic form of PMT is endless-loop tachycardia (ELT), although any condition associated with inappropriate rapid pacing rate, such as sensor-driven tachycardia, myopotential tracking, EMI, atrial arrhythmias, or runaway pacemaker, can fall into this category.
- Usually, ELT is initiated by a premature ventricular beat. The atrial channel senses the retrograde atrial activation from the premature ventricular contraction (PVC), and the ventricular channel paces the ventricle after the programmed AV delay, which again is sensed by the atrial channel after retrograde ventriculoatrial (VA) conduction and results in ELT.
- Conditions that result in AV dissociation, such as atrial noncapture, atrial oversensing, atrial undersensing, long AV interval, and magnet application and removal, can initiate ELT.
- Long postventricular atrial refractory period (PVARP), short AV delay, and post-PVC PVARP extension may prevent PMT.
- Termination of PMT (see Image 7): Magnet application results in loss of sensing and termination of the tachycardia, PVARP extension, withholding ventricular channel output.
- Pacemaker syndrome (PS): PS usually is observed with ventricular pacing (eg, usually VOO, VVI, VVIR modes and sometimes VDD mode) because of atrial contraction against the closed AV valves during ventricular pacing.
- PS can occur in any other pacing modes where AV dyssynchrony occurs.
- The reported incidence of PS varies from 5-20%, depending on the severity of symptoms.
- Most common symptoms include pulsation and fullness in neck, dizziness, palpitations, and near syncope.
- Treatment involves upgrading the pacemaker to a dual-chamber pacing system.
- Twiddler syndrome: Patient manipulation of the pulse generator within the pocket results in coiling of the lead, lead dislodgement, or rotation and/or reversal of the anterior and posterior surfaces of the pulse generator.
- Treatment includes uncoiling the lead, new lead implant, and repositioning of the pulse generator.
- Educate patients not to manipulate the pacing system.
Sudden Cardiac Death
Syncope
Other Problems to be Considered
In pseudomalfunction of the pacemaker, although an apparent pacing system malfunction is suggested clinically, the apparent malfunction is a normal programmed pacer function. Examples of pseudomalfunction include the following: - Functional undersense with magnet application
- Functional oversense with short ventricular blanking period
- Inappropriate rate with rate hysteresis, rate-drop response, rate smoothing, rate-responsive mode, programmed rest/sleep rate, and mode switch
- Inappropriate mode with magnet application and mode switch
Lab Studies
- Creatine kinase (CK) and isoenzymes - Elevated in myocardial injury and cardiac trauma
- Coagulation panel - Required to prevent bleeding complications during invasive procedures
- Electrolytes - To exclude electrolyte abnormalities that may affect pacing thresholds
- Drug levels - For drugs, such as digoxin and antiarrhythmics (particularly flecainide), that may alter pacing thresholds
Imaging Studies
- Chest radiography: Overpenetrated film helps to evaluate lead position, fracture, and the set-screws. Specific markers on pulse generator are useful for identification.
- Echocardiogram: It has limited use in the diagnosis of pacing system malfunction. Inappropriate lead position (ie, left ventricle, left atrium, or pericardial space), pericardia effusion/tamponade, or lead fracture may be observed on 2-dimensional echocardiogram.
Other Tests
- Pacemaker interrogation - Evaluation of thresholds, lead impedance, and battery voltage, as well as review of histograms, mode switch episodes, and stored electrograms
- Magnet application - After magnet application, pacemaker goes to asynchronous pacing mode at a programmed rate, which is unique to that model. This is helpful in diagnosis of loss of capture and battery depletion.
- 12-lead electrocardiogram - This simple bedside test is useful to diagnose undersensing, oversensing, and capture loss. Holter or event monitoring may be useful to diagnose intermittent dysfunction.
- Telemetry monitoring - It is useful in early recognition of loss of sensing and capture from lead dislodgement in immediate post-implant period.
- Holter monitoring - This simple test is helpful in the diagnosis of atrial and ventricular arrhythmias and abnormal sensing or capture.
- Transtelephonic monitoring - Periodic transtelephonic monitoring is very useful in early recognition of battery depletion based on the magnet rate, which is unique to each pacemaker model.
Procedures
- Fluoroscopy is useful to evaluate lead fracture, especially during provocative maneuvers.
Medical Care
Medical therapy has a limited role in pacemaker malfunction. Correction of electrolyte and metabolic abnormalities and pulse generator reprogramming is all that is needed in most cases. Based on pacing malfunction, reprogram the following:
- Increase pacing output during loss of capture.
- Decrease atrial pacing output during cross-talk inhibition.
- Decrease ventricular sensitivity during cross-talk inhibition.
- Decrease ventricular sensitivity during myopotential oversensing.
- Temporarily program to unipolar during outer conductor failure.
- Increase the ventricular blanking period during cross talk.
- Activate ventricular safety pacing during cross talk.
- Avoid EMI, such as using digital cellular phone close to pulse generator.
- Avoid pulse generator manipulation.
- Magnet application terminates PMT.
- PVARP extension, short AV delay, and increasing ventricular sensitivity prevent PMT.
Surgical Care
- Exploration of pacemaker pocket, lead, connectors, and set-screws
- Repair, reposition, extraction, or replacement of lead
- Removal of air from dry-pocket
- Upgrading single chamber to dual chamber generator in pacemaker syndrome
- Tightening of loose set-screws
- Replacement of pulse generator
Consultations
- Cardiologist - To reprogram the pacemaker to prevent, eliminate, or minimize the pacing system malfunction
- Cardiovascular surgeon - If thoracotomy is needed
Activity
To minimize risk of lead dislodgement, advise patient not to raise ipsilateral arm over and above the shoulder for approximately 2 weeks after lead implant.
Medical therapy has a limited role in pacemaker malfunction. In case of abnormal thresholds, correct electrolyte abnormalities (eg, hypokalemia, hyperkalemia, or hypomagnesemia) and adjust medication dose as needed.
Further Inpatient Care
- Device interrogation
- Chest radiograph for lead position and any complications such as pneumothorax
- Wound care after pulse generator change or lead implant
Further Outpatient Care
- Most cases require only follow-up device interrogation and chest radiograph.
Complications
- Complications during pulse generator change and lead insertion or extraction include the following:
- Vascular injury
- Venous thrombosis
- Cardiac tamponade
- Hemothorax
- Pneumothorax
- Perforation of heart
- Avulsion of RV
- Bleeding
- Infection
Prognosis
- Prognosis depends on the underlying cause of pacemaker failure.
- Most of the pacing system malfunctions are benign and can be corrected with appropriate reprogramming.
Patient Education
- Patient education needed for optimal pacemaker function and early diagnosis of malfunction includes the following:
- Advise patients not to manipulate the pulse generator to prevent twiddler syndrome.
- Advise patients not to operate digital cellular phones close to the pulse generator to avoid inappropriate inhibition from oversensing.
- Advise patients to seek medical attention for any unusual symptoms, such as dizziness, palpitations, and syncope, and for any pain, swelling, or drainage from pacemaker area.
Medical/Legal Pitfalls
- Be aware of the causes of pacemaker pseudomalfunction.
- Be familiar with various programmable functions that are unique to manufacturers.
- Be aware of device recalls and safety alerts.
| Media file 1:
Atrial undersensing. Rhythm strip showing an atrial pacing artifact after the intrinsic P wave. |
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Media type: Rhythm Strip
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| Media file 2:
Ventricular undersensing. Rhythm strip showing ventricular pacing artifacts despite normal underlying ventricular activity. |
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| Media file 3:
Atrial lead dislodgement. Chest radiograph film detail showing dislodged atrial lead with tip in the right ventricular cavity. |
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| Media file 4:
Ventricular noncapture. Rhythm strip showing atrial (P wave) sensing followed by ventricular spike, which failed to capture the ventricle. |
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Media type: Rhythm Strip
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| Media file 5:
Loss of atrial capture. Rhythm strip showing intermittent loss of atrial capture. |
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Media type: Rhythm Strip
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| Media file 6:
Pacemaker-mediated tachycardia. Rhythm strip showing ventricular pacing at 110 beats per minute (programmed maximal track rate). |
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Media type: Rhythm Strip
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| Media file 7:
Termination of pacemaker-mediated tachycardia. Automatic postventricular atrial refractory period (PVARP) extension terminated the PMT. |
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Media type: Rhythm Strip
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| Media file 8:
This is an artifact due to monitor malfunction or loose limb lead connection. An abrupt loss of a portion of the QRS complex followed by a flat line can be observed. If R-R intervals are matched, 2 QRS complexes are missing during the pause. If it is due to a dislodged lead, a pacing artifact with no capture should be observed. |
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Media type: Rhythm Strip
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| Media file 9:
This is a typical example of ventricular oversensing with inhibition of ventricular pacing. In ventricular noncapture, a ventricular pacing artifact should be present after the third P wave. |
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Media type: Rhythm Strip
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- Erickson S, Sweesy M, Forney R. Complications and Corrections in Pacing systems. Pace. 1995;18:999-1004.
- Foldesi C, Hegedus Z, Simon J, et al. [Pacemaker syndrome without a pacemaker]. Orv Hetil. Aug 30 1998;139(35):2081-2. [Medline].
- Goldman DS, Levine PA. Pacemaker-mediated polymorphic ventricular tachycardia. Pacing Clin Electrophysiol. Oct 1998;21(10):1993-5. [Medline].
- Heldman D, Mulvihill D, Nguyen H, et al. True incidence of pacemaker syndrome. Pacing Clin Electrophysiol. Dec 1990;13(12 Pt 2):1742-50. [Medline].
- Levine PA, Love CJ. Pacemaker diagnostics and evaluation of pacing system malfunction. In: Clinical Cardiac Pacing and Defibrillation. 2000. 2nd ed. Philadelphia, Pa: WB Saunders:827-875.
- Mitsui T, Hori M, Suma K. The "pacemaker syndrome". In: Jacobs JE, ed. Proceedings of the Eighth Annual International Conference on Advancement of Medical Biological Engineering. Chicago Association for Advancement of Medical Instrumentation; 1969:29-33.
- Pinski SL, Trohman RG. Interference with cardiac pacing. Cardiol Clin. Feb 2000;18(1):219-39, x. [Medline].
- Sweesy MW, Holland JL. Pseudomalfunction. In: Cardiac Device and Basic EP-Self Assessment. Simpsonville, SC: Cardiac Device Consultants, Inc; 2000:60-86.
- Travill CM, Sutton R. Pacemaker syndrome: an iatrogenic condition. Br Heart J. Aug 1992;68(2):163-6. [Medline].
Pacemaker Failure excerpt Article Last Updated: Mar 23, 2006
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