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Editors: Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; Stock, M. ChristineTitle: Cli nical Anest hesia, 6t h Edit ion

Copyright 2009 Lippincott Williams & Wilkins

> Back of Book > Appendix - Electrocardiography

AppendixElectrocardiography

James R. Zaidan

Paul G. Barash

Electrocardiogram

Lead PlacementELECTRODE

POSITIVE NEGATIVE

BIPOLAR LEADS

I LA RA

II LL RA

III LL LA

AUGMENTED UNIPOLAR

avr RA LA, LL

avl LA RA, LL

avf LL RA, LA

PRECORDIAL

V1 4 ICSRSB

V2 4 ICSLSB

V3 Midway between V 2 and V 4

V4 5 ICSMCL

V5 5 ICSAAL

V6 5 ICSMAL

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THREE-LEAD SYSTEMS

FootnoteWe wish to thank Dr. Malcom S. Thaler for graciously permitting reproduction of electrocardiographic tracingsfrom his book, The Only EKG Book You'll Ever Need (Philadelphia, JB Lippincott, 1988).

The Normal Elect rocardiogramCar diac Cycle

In this section the electrocardiogram (ECG) complex is divided into the atrial (PR interval) and ventricular (QTinterval) components.

BIPOLAR LEAD SYSTEM ELECTRODE PLACEMENT ECG LEADa ADVANTAGE

II RA Rclavicle

LA L10th rib (midclavicular line)

LL Ground

II (II) Dysrhythmias

MCL 1 RA Ground

LA LclavicleLL V1

III (V1) Dysrhythmias and conduction defects

CS 5 RA RclavicleLA V5

LL Ground

I (V5) Precordial ischemia

CB 5 RA RscapulaLA V5

LL Ground

I (V5) Precordial ischemia and dysrhythmias

ECG, electrocardiogram; MCL, modified central lead; CB, central back; CS, central subclavian.aSelected lead on monitor: ( ) = simulated E CG lead.



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Ashman Beat s

Rate: Variable.

Rhythm: Irregular.

PR interval: P wave may be present if supraventricular premature beat.

QT interval: QRS prolonged (>0.12 second) and altered, revealing bundle-branch pattern, most commonly rightbundle. ST segment abnormal.

Note: Ashman beats are often confused with ventricular premature contractions. Ashman beats, usually seenwith atrial fibrillation, have no compensatory pause and are a benign ECG finding, requiring no treatment.

Atrial Fibrillation

Rate: Variable (approximately 150 to 200 beats/min).

Rhythm: Irregular.

PR interval: No P wave, and PR interval not discernible.

QT interval: QRS normal.

Note: Must be differentiated from atrial flutter: (1) absence of flutter waves and presence of fibrillatory line,and (2) flutter usually associated with higher ventricular rates (>150 beats/min). Loss of atrial contractionreduces cardiac output (10 to 20%). Mural atrial thrombi may develop. Considered controlled if ventricular rate

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Rate: Rapid, atrial usually regular (250 to 350 beats/min); ventricular usually regular (0.20 second) and constant.

QT interval: Normal.

Note: Usually clinically insignificant; may be early harbinger of drug toxicity.

At r iovent r icular Block (Second-Degr ee), Mobi t z Type I/Wenckebach



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Block

Rate: 60 to 100 beats/min.

Rhythm: Atrial regular; ventricular irregular.

PR interval: P wave normal; PR interval progressively lengthens with each cycle until QRS complex is dropped(dropped beat). PR interval following the dropped beat is shorter than normal.

QT interval: QRS complex normal but dropped periodically.

Note: Commonly seen (1) in trained athletes and (2) with drug toxicity.

At r iovent r icular Block (Second-Degr ee), Mobit z Type II

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Rate:

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Rate:

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Rate: Variable.

Rhythm: Atrial regular; ventricular regular; ventricular rate faster than atrial rate; no relationship between Pwave and QRS complex.

PR interval: Variable because atria and ventricles beat independently.

QT interval: QRS morphology depends on location of ventricular pacemaker. ST segment and T wave abnormal.

Note: Digitalis toxicity can present as atrioventricular dissociation.

Bundl e-Br anch BlockLeft



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Rate: 0.12 second); incomplete LBBB.

(QRS = 0.10 to 0.12 second); Lead V 1 negative rS complex; I, aVL, V 6 wide R wave without Q or S component. ST

segment and T-wave defection opposite direction of the R wave.

Note: LBBB does not occur in healthy patients and usually indicates serious heart disease with a poorerprognosis. In patients with LBBB, insertion of a pulmonary artery catheter may lead to complete heart block.

Bundle-Branch BlockRight



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Rate: 0.12 second); incomplete RBBB (QRS = 0.10 to0.12 second). Varying patterns of QRS complex; rSR (V 1); RS, wide R with M pattern. ST segment and T wave

opposite direction of the R wave.

Note: In the presence of RBBB, Q waves may be seen with a myocardial infarction.

Electrolyte Disturbances

Digit ali s Ef f ect

Ca2+ Ca2+ K + K +

Rate

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Rate:

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vasospasm (Prinzmetal) ST segment elevation.

Note: Intraoperative ischemia is usually seen in the presence of normal vital signs (e.g., 20% of preinductionvalues).

Coronary Artery DiseaseMyocardial Infarction

Subendocar dial Myocardi al Inf arct ion Persistent ST segment depression and/or T-wave inversion in the absence of Q wave. Usually requires additionallaboratory data (e.g., isoenzymes) to confirm diagnosis.

Tr ansmural Myocardial Inf arct ion Q waves seen on ECG useful in confirming diagnosis. Associated with poorer prognosis and more significanthemodynamic impairment; dysrhythmias frequently complicate course.

Paroxysmal At r ial Tachycardia


Rhythm: Regular.

PR interval: Difficult to distinguish because of tachycardia obscuring P wave. P wave may precede, be included

ANATOMIC SITE LEADS ECG CHANGES CORONARY ARTERY

Inferior II, III, aVF Q, ST, T Right

Lateral I, aVL, V 5V6 Q, ST, T Left circumflex

Anterior I, aVL, V 1V4 Q, ST, T Left

Anteroseptal V1V4 Q, ST, T Left anterior descending

ECG, electrocardiogram.



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in, or follow QRS complex.

QT interval: Normal, but ST segment and T wave may be difficult to distinguish.

Note: Therapy depends on degree of hemodynamic compromise. In contrast to management of paroxysmal atrialtachycardia (PAT) in awake patients, synchronized cardioversion rather than pharmacologic treatment ispreferred in hemodynamically unstable anesthetized patients.

Premature Atrial Contraction

Rate:

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Rate: Usually 0.12 second); ST segment cannot be evaluated (e.g., ischemia); T wave oppositedirection of QRS with compensatory pause ( A). Bigeminy: every other beat a premature ventricular contraction(PVC) (B); trigeminy: every third beat a PVC. R-on-T occurs when PVC falls in the T wave and can lead toventricular tachycardia or fibrillation.

Note: If compensatory pause is not seen following an ectopic beat, the complex is most likely supraventricular inorigin.

Sinus Tachycar dia



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Rhythm: Regular.

PR interval: Normal; P wave may be difficult to see.

QT interval: Normal.

Note: Should be differentiated from PAT. With PAT, carotid massage terminates dysrhythmia. Sinus tachycardiamay respond to vagal maneuvers but reappears as soon as vagal stimulus is removed.

Tor sades De Point es


Rhythm: No atrial component seen; ventricular rhythm regular or irregular.

PR interval: P wave buried in QRS complex.

QT interval: QRS complexes usually wide and with phasic variation twisting around a central axis (a fewcomplexes point upward then a few point downward). ST segments and T waves difficult to discern.

Note: Type of ventricular tachycardia associated with prolonged QT interval. Seen with electrolyte disturbances(e.g., hypokalemia, hypocalcemia, and hypomagnesemia) and bradycardia. Administering standardantidysrhythmics (e.g., lidocaine, procainamide) may worsen torsades de pointes. Treatment includes increasingheart rate pharmacologically or by pacing.

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Vent ri cular Fibri llat ion

Rate: Absent.

Rhythm: None.

PR interval: Absent.

QT interval: Absent.

Note: Pseudoventricular fibrillation may be the result of a monitor malfunction (e.g., ECG lead disconnect).Always check for carotid pulse before instituting therapy.

Ventricular Tachycardia


Rhythm: No atrial component seen; ventricular rhythm irregular or regular.

PR interval: Absent; retrograde P wave may be seen in QRS complex.

QT interval: Wide, bizarre QRS complex. ST segment and T wave difficult to determine.

Note: In the presence of hemodynamic compromise, immediate DC synchronized cardioversion is required. If thepatient is stable, with short bursts of ventricular tachycardia, pharmacologic management is preferred. Shouldbe differentiated from supraventricular tachycardia with aberrancy (SVT-A). Compensatory pause andatrioventricular dissociation suggest a PVC. P waves and SR (V1) and slowing to vagal stimulus suggest SVT-A.

Wolf f -Parkinson-Whit e Syndrome



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Rate:

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Generic Defibrillator Code (NBG): NASPE/BPEG

Example of A Stepwise Approach to the Perioperative Treatment of thePatient with A Cardiac Rhythm Management Device (CRMD)

A = atrium A = atrium I = inhibited R = rate modulation A = atrium

V = ventricle V = ventricle T = triggered V = ventricle

D = dual (A + V) D = dual (A + V) D = dual (T + I) D = dual (A + V)

aNBG: N refers to North American Society of Pacing and E lectrophysiology (NASPE), now called the Heart Rhythm Society (HRS); B r efers to British

Pacing and Electrophysiology Group (BPEG); and G r efers to generic.

From Practice advisory for perioperative management of patients with cardiac rhythm management devices: Pacemakers and implantable

cardioverter-defibrillators. A report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with

Cardiac Rhythm Management Devices. Anesthesiology 2005; 103: 186, with permission.

POSITION I, SHOCK

CHAMBER(S)

POSITION II, ANTITACHYCARDIA

PACING CHAMBER(S)

POSITION III, TACHYCARDIA

DETECTIONPOSITION IV,a ANTIBRADYCARDIA

PACING CHAMBER(S)

O = none O = none E = electrogram O = none

A = atrium A = atrium H = hemodynamic A = atrium

V = ventricle V = ventricle V = ventricle

D = dual (A + V) D = dual (A + V) D = dual (A + V)

NASPE, North American Society of Pacing and Electrophysiology; BPEG, British Pacing and Electrophysiology Group.aFor robust identification, position IV is expanded into its complete NBG code. For example, a biventricular pacingdefibrillator with ventricular

shock and antitachycardia pacing functionality would be identified as VVE-DDDRV, assuming that the pacing section was programmed DDDRV.

Currently, no hemodynamic sensors have been approved for tachycardia detection (position III).

From Practice advisory for perioperative management of patients with cardiac rhythm management devices: Pacemakers and implanta ble



P.1587

PERIOPERATIVE PERIOD PATIENT/CRMD CONDITION INTERVENTION

Pr eoperative evaluation Patient has CRMD Focused history

Focused physical examination

Determine CRMD type (pacemaker, ICD,

CRT)Manufacturer's CRMD identification card

Chest x-ray studies (no data available)

Supplemental resources a

Determine whether patient is CRMD-

dependent for pacing functionVerbal history

Bradyarrhythmia symptoms

Atrioventricular node ablation

No spontaneous ventricular activity b

Determine CRMD function Comprehensive CRMD evaluation C

Determine whether pacing pulses are present and create

paced beats



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Preoperative preparation EMI unlikely during procedure If EMI unlikely, special precautions are not needed

EMI likely: CRMD is pacemaker Reprogram to asynchronous mode when indicated

Suspend rate-adaptive functions d

EMI likely: CRMD is ICD Suspend antitachyarrhythmia functions

If patient is dependent on pacing function, after pacingfunctions as above

EMI likely: all CRMD Use bipolar cautery; ultrasonic scalpel

Temporary pacing and external cardioversiondefibrillation

available

Intraoperative physiologic changes likely

(e.g., bradycardia, ischemia)Plan for possible adverse CRMDpatient interaction

Intraoperative management Monitoring Electrocardiographic monitoring per ASA standard

Peripheral pulse monitoring

Electrocautery interference CT/CRPno current through PG/leads

Avoid proximity of CT to PG/leads

Short bursts at lowest possible energy

Use bipolar cautery; ultrasonic scalpel

Radiofrequency catheter ablation Avoid contact of radiofrequency catheter with PG/leads

Radiofrequency current path far away from PG/leads

Discuss these concerns with operator

Lithotripsy Do not focus lithotripsy beam near PG

R wave triggers lithotripsy? Disable atrial pacing e

MRI Generally contraindicated

If required, consult ordering physician, cardiologist,

radiologists, and manufacturer

RT PG/leads must be outside of RT field

Possible surgical relocation of PG

Verify PG function during/after RT course

ECT Consult with ordering physician, patient's cardiologist, a

CRMD service, or CRMD manufacturer

Emergency defibrillation

cardioversion

ICD: magnet disabled Terminate all EMI sources

Remove magnet to re-enable therapiesObserve for appropriate therapies

ICD: programming disabled Programming to re-enable therapies or proceed directly with

external cardioversiondefibrillation

ICD: either of above Minimize current flow through PG/leads

PP as far as possible from PG

PP perpendicular to major axis PG/leads



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Treatment of Pacemaker Failure

Pacemaker Tracings Atrial Pacing

To extent possible, PP in anteriorposterior location

Regardless of CRMD type Use clinically appropriate cardioversion/defibrillation energy

Postoperative management Immediate postoperative period Monitor cardiac R&R continuously

Backup pacing and cardioversion/defibrillation capability

Postoperative interrogation and

restoration of CRMD functionInterrogation to assess function

Setting appropriate? f

Is CRMD an ICD?g

Use cardiology/pacemakerICD service if needed

ICD, internal cardioverterdefibrillator; CRT, cardiac resynchronization therapy; EMI, electromagnetic interference; ASA, American Society of

Anesthesiologists; CT, cautery tool; CRP, current return pad; PG, pulse generator; MRI, magnetic resonance imaging; RT, radiation therapy; ECT,

electroconvulsive therapy; PP, external cardioversiondefibrillation pads or paddles; R&R, rhythm and rate.aManufacturer's databases, pacemaker clinic records, cardiology consultation. bWith cardiac rhythm management device (CRMD) programmed WI at lowest programmable rate. CIdeally, CRMD function assessed by interrogation, with function altered by reprogramming if required. dMost times this will be necessary; when in doubt, assume so. eAtrial pacing spikes may be interpreted by the lithotriptor as R waves, possibly inciting the lithotriptor to deliver a shock during a vulnerable

period in the heart.f If necessary, reprogram appr opriate setting. gRestore all antitachycardia therapies.

From Practice advisory for perioperative management of patients with cardiac rhythm management devices: Pacemakers and implanta ble



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RATE POSSIBLE RESPONSE

Adequate to maintain blood

pressure

1. Oxygen, airway control

2. Place magnet over pacemaker3. Atropine if sinus bradycardia

Severe bradycardia and

hypotension1. Oxygen, airway control

2. Place magnet over pacemaker

3. Other types of pacing if magnet does not activate the pacemaker (transcutaneous, esophageal, or

transvenous)

4. Atropine if sinus bradycardia

5. Isoproterenol to increase ventricular rate

No escape rhythm 1. Cardiopulmonary resuscitation

2. Place magnet over pacemaker

3. Other types of pacing if magnet does not activate the pacemaker (transcutaneous, esophageal, or

transvenous)

4. Isoproterenol to increase ventricular rate

From Zaidan JR: Pacemakers, Cardiac, Vascular and Thoracic Anesthesia. Edited by Youngberg JA, Lake CL, Roizen MF et al. New Yo rk, Churchill

Livingstone, 2000, with permission.



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Atrial pacing as demonstrated in this f igure is used when the atrial impulse can proceed through theatrioventricular (AV) node. 1 Examples are sinus bradycardia and junctional rhythms associated with clinicallysignificant decreases in blood pressure.

Vent r icular Pacing

In this tracing ventricular pacing is evident by absence of atrial wave (P wave) and pacemaker spike precedingQRS complex. Ventricular pacing is employed in the presence of bradycardia secondary to AV block or atrialfibrillation.

Dual-Chamber Pacing

The dual-chamber (DDD) pacemaker (generator), one of the most commonly used, paces and senses both atrium

and ventricle. In the first four beats, the P waves were not followed by a QRS complex within the programmedPR interval. Therefore, a ventricular pacing spike and a ventricular paced beat occurred. In the last four beats(after the arrow in the figure), atrial activity proceeded through the AV node in the allotted amount of time;therefore, ventricular pacing was inhibited.

At ri al Elect r ogr am



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The atrial electrogram (AEG) is useful in differentiating various atrial dysrhythmias. The AEG is obtained from anintra-cardiac or esophageal lead if P waves are not clearly seen on the surface ECG. In this trace, the V lead

does not have obvious P waves; however, the AEG reveals large P waves ( arrows ) that precede each QRScomplex. Locate the QRS on the AEG by matching the R wave on the surface ECG to the AEG. The surface andAEG must be simultaneously recorded.

Guidelines for Using the Electrocautery

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1. Electromagnet interference created by an electrocautery can cause a number of problems with pacemaker or ICD function including, but not

limited to, reprogramming, inhibition, noise reversion mode, electrical reset, myocardial burns, increase in threshold, rate increment

changes in rate adaptive pacemakers, and inappropriate sensing and charging in ICDs. 2, 3

2. When positioning the return plate of the electrocautery:

a. Ensure it is located so the pacemaker or ICD is not between this return plate and the active electrode.

b. Ensure the plane described by the return plate and the active electrode of the electrocautery is perpendicular to a plane described by

the pacemaker or ICD and the pa cemaker's electrodes.

3. Use the smallest current required to cut or coagulate.

4. Use the electrocautery in short bursts.

5. Avoid using the electrocautery within 6 inches of the device or leads.

6. Consider using the bipolar electrocautery or the ultrasonic scalpel 4, 5 to minimize interference with pacemaker or IC D function.

7. Activating the electrocautery in the area of the pacemaker or ICD, even if the active electrode is not touching the patient, will cause

interference. 6

8. Do not use the electrocautery when an ICD is programmed to sense and deliver therapy.

9. Convert the ICD to no response either by programming or by using the magnet, depending on the manufacturer of the ICD, so the device will

not deliver therapy secondary to misinterpretation of signals from the electrocautery as a dysr hythmia. These maneuvers will not change



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Additional Issues for Patients with Implanted Cardioverter Defibrillators

References

1. Epstein AE, DiMarco JP, Ellenbogen KA et al: ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities. A report of the American College of Cardiology/American Heart AssociationTask Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 GuidelineUpdate for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices). Circulation 2008; 117: e350

2. Levine P: Evaluation and management of pacing system malfunctions, Cardiac Pacing and ICDs, 4thedition. Edited by Ellenbogen KA, Ward MA. Boston, Blackwell Publishing, 2005

3. Atlee JL, Bernstein AD: Cardiac rhythm management devices (part II): Perioperative management.Anesthesiology 2001; 95: 1492

4. Nandalan SP, Vanner RG: Use of the harmonic scapel in a patient with a permanent pacemaker.Anaesthesia 2001; 94: 710

5. Ozeren M, Dogan OV, Duzgun C et al: Use of an ultrasonic scalpel in the open-heart reoperation of a

the program of a pacemaker that is incorporated into an ICD.

10. If desired, convert a pacemaker that does not have an ICD to the asynchronous mode so it is not inhibited by the electrocautery.

11. A magnet will not change bradycardia-related pacing parameters in the ICD.

12. ICDs must be programmed to respond to a magnet.

ICD, implanted cardioverter defibrillator.

1. All ICDs have pacemakers incorporated into the circuitry.

2. Preoperative assessments should include those procedures that are standard for patients with heart disease.

3. Obtain a cardiology consult to help assess the patient, interrogate the ICD, program the device to no response, and program the device to

respond to the magnet.

4. There is no particular anesthetic technique that is clearly right or wrong for a patient who has an ICD.

5. Apply patches for external defibrillation when the ICD is programmed to no response. Ensure these external patches are as far away as

possible from the device and, if possible, not in the same plane as the device and electrodes.

6. Monitor as required for patient care. If monitoring with a pulmonary arterial catheter, discuss the issues of dislodgment of the ICD

electrodes with the patient and cardiologist. Document in the chart your discussions and the logic supporting the necessity for a p ulmonary

arterial catheter. Maintain sterile technique, and consider administering antibiotics just before inserting central lines.

7. Continue antidysrhythmic agents until the time of surgery. Discuss with the cardiologist the necessity of administering an additional dose of

an antidysrhythmic agent if the patient experiences an intraoperative dysrhythmia.

8. Intraoperative dysrhythmias:a. If the patient has a dysrhythmia, rule out and treat the usual intraoperative causes to prevent a recurrence.

b. If the dysrhythmia continues and a magnet has been used to create the no-response mode, remove the magnet from the ICD and allow

the ICD to charge and deliver a resp onse.

c. If the ICD has been programmed to the no-response mode, then either quickly reprogram the ICD to deliver a response or proceed

directly to external defibrillation.

d. If external defibrillation or cardioversion is required, apply the defibrillator paddles in an anterior-posterior position, if possible, and

deliver the shock at a level sufficient to terminate the dysrhythmia.

e. External pacing might be required if the pacemaker/ICD is damaged with the shock.

9. Monitor the patient's ECG and be prepared to deliver an external defibrillation when transporting the patient to and from the operating

room.

10. Interrogate and reprogram the ICD when the patient has entered the postoperative care unit.

ICD, implanted cardioverter defibrillator; ECG, electrocardiogram.



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patient with pacemaker. Eur J Cardiothorac Surg 2002; 21: 761

6. Stevenson WG, Chaitman BR, Ellenbogen KA et al, for the Subcommittee on Electrocardiography andArrhythmias of the American Heart Association Council on Clinical Cardiology, in collaboration with theHeart Rhythm Society: Clinical assessment and management of patient with implanted cardioverter-defibrillators presenting to nonelectrophysiologists. Circulation 2004; 110: 3866


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