Wolff-Parkinson-White syndrome resident survival guide: Difference between revisions

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:❑ Administer until the [[arrhythmia]] is suppressed or until 500 mg has been administered<br>
:❑ Administer until the [[arrhythmia]] is suppressed or until 500 mg has been administered<br>
:❑ Wait 10 minutes or longer to administer new [[dosage]]
:❑ Wait 10 minutes or longer to administer new [[dosage]]
:<span style="font-size:85%;color:red">Contraindications: [[<span style="font-size:85%;color:red">complete heart block</span>]], [[<span style="font-size:85%;color:red">lupus erythematosus</span>]], [[<span style="font-size:85%;color:red">Hypersensitivity|idiosyncratic hypersensitivity</span>]], [[<span style="font-size:85%;color:red">torsades de pointes</span>]]</span><br>
:[[Contraindication|<span style="font-size:85%;color:red">Contraindications:</span>]] [[Third degree AV block|<span style="font-size:85%;color:red">third degree AV block</span>]], [[Systemic lupus erythematosus|<span style="font-size:85%;color:red">lupus erythematosus</span>]], [[Hypersensitivity|<span style="font-size:85%;color:red">idiosyncratic hypersensitivity</span>]], [[Torsades de pointes|<span style="font-size:85%;color:red">torsades de pointes</span>]]<br>
''Or''<br>❑ Administer [[ibutilide]] 1 mg IV [[infusion]] over 10 minutes ([[ACC AHA guidelines classification scheme|Class I, Level of Evidence C]])<ref name="pmid23545139">{{cite journal| author=American College of Cardiology Foundation. American Heart Association. European Society of Cardiology. Heart Rhythm Society. Wann LS, Curtis AB et al.| title=Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. | journal=Circulation | year= 2013 | volume= 127 | issue= 18 | pages= 1916-26 | pmid=23545139 | doi=10.1161/CIR.0b013e318290826d | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23545139  }} </ref><br>
''Or''<br>❑ Administer [[ibutilide]] 1 mg IV [[infusion]] over 10 minutes ([[ACC AHA guidelines classification scheme|Class I, Level of Evidence C]])<ref name="pmid23545139">{{cite journal| author=American College of Cardiology Foundation. American Heart Association. European Society of Cardiology. Heart Rhythm Society. Wann LS, Curtis AB et al.| title=Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. | journal=Circulation | year= 2013 | volume= 127 | issue= 18 | pages= 1916-26 | pmid=23545139 | doi=10.1161/CIR.0b013e318290826d | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23545139  }} </ref><br>
:❑ Repeat the [[dosage]] if the [[tachycardia]] continues <br>
:❑ Repeat the [[dosage]] if the [[tachycardia]] continues <br>
:<span style="font-size:85%;color:red">Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec</span><br>
:<span style="font-size:85%;color:red">[[Contraindication|<span style=color:red">Contraindications:</span>]] [[Hypersensitivity|<span style=color:red">hypersensitivity</span>]] to [[Ibutilide|<span style=color:red">ibutilide</span>]] or any component of the formulation, [[QT interval|<span style=color:red">QTc</span>]] >440 msec</span><br>
''Or''<br>
''Or''<br>
❑ Administer [[flecainide]] 50 mg every 12 hours ([[ACC AHA guidelines classification scheme|Class IIa, Level of Evidence B]])<ref name="pmid23545139">{{cite journal| author=American College of Cardiology Foundation. American Heart Association. European Society of Cardiology. Heart Rhythm Society. Wann LS, Curtis AB et al.| title=Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. | journal=Circulation | year= 2013 | volume= 127 | issue= 18 | pages= 1916-26 | pmid=23545139 | doi=10.1161/CIR.0b013e318290826d | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23545139  }} </ref>
❑ Administer [[flecainide]] 50 mg every 12 hours ([[ACC AHA guidelines classification scheme|Class IIa, Level of Evidence B]])<ref name="pmid23545139">{{cite journal| author=American College of Cardiology Foundation. American Heart Association. European Society of Cardiology. Heart Rhythm Society. Wann LS, Curtis AB et al.| title=Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines. | journal=Circulation | year= 2013 | volume= 127 | issue= 18 | pages= 1916-26 | pmid=23545139 | doi=10.1161/CIR.0b013e318290826d | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23545139  }} </ref>
:❑ Increase 50mg BID every four days until efficacy is achieved <br>
:❑ Increase 50mg BID every four days until efficacy is achieved <br>
:❑ Maximum [[dose]] recommended for [[SVT]] is 300 mg/day<br>
:❑ Maximum [[dose]] recommended for [[SVT]] is 300 mg/day<br>
:<span style="font-size:85%;color:red">Contraindications: pre-existing second- or third-degree AV block, right bundle branch block associated with a left hemiblock unless a pacemaker is present, cardiogenic shock, hypersensitivity to the drug</span><br>
:<span style="font-size:85%;color:red">[[Contraindication|<span style="font-size:85%;color:red">Contraindications:</span>]] pre-existing [[Second degree AV block|<span style="font-size:85%;color:red">second degree AV block</span>]] or [[Third degree AV block|<span style="font-size:85%;color:red">Third degree AV block</span>]] , [[Right bundle brnach block|<span style="font-size:85%;color:red">right bundle branch block</span>]] associated with a left hemiblock unless a [[Artificial pacemaker|<span style="font-size:85%;color:red">pacemaker</span>]] is present, [[Shock|<span style="font-size:85%;color:red">cardiogenic shock</span>]], [[Hypersensitivity|<span style="font-size:85%;color:red">hypersensitivity</span>]] to the drug</span><br>
</div>
</div>
|G01= <div style="float: left; text-align: left; width: 24em; padding:1em;"> <br>
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:❑ Wait 10 minutes or longer to administer new dosage <br>
:❑ Wait 10 minutes or longer to administer new dosage <br>
:❑ [[Dosage]] should be adjusted for the individual patient in case of [[renal impairment]]<br>
:❑ [[Dosage]] should be adjusted for the individual patient in case of [[renal impairment]]<br>
:<span style="font-size:85%;color:red">Contraindications: complete heart block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes</span><br></div>
:<span style="font-size:85%;color:red">Contraindications: [[Third degree AV block|<span style="font-size:85%;color:red">third degree AV block</span>]], [[Systemic lupus erythematosus|<span style="font-size:85%;color:red">lupus erythematosus</span>]], [[Hypersensitivity|<span style="font-size:85%;color:red">idiosyncratic hypersensitivity</span>]], [[Torsades de pointes|<span style="font-size:85%;color:red">torsades de pointes</span>]]</span></div>
| G02= <div style="float: left; text-align: left; width: 24em; padding:1em;"><br>
| G02= <div style="float: left; text-align: left; width: 24em; padding:1em;"><br>


Line 254: Line 254:
:❑ Give until the [[arrhythmia]] is suppressed or until 500 mg has been administered<br>
:❑ Give until the [[arrhythmia]] is suppressed or until 500 mg has been administered<br>
:❑ Wait 10 minutes or longer to administer new [[dosage]]
:❑ Wait 10 minutes or longer to administer new [[dosage]]
:<span style="font-size:85%;color:red">Contraindications: complete heart block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes</span><br>
:<span style="font-size:85%;color:red">Contraindications: [[Third degree AV block|<span style="font-size:85%;color:red">third degree AV block</span>]], [[Systemic lupus erythematosus|<span style="font-size:85%;color:red">lupus erythematosus</span>]], [[Hypersensitivity|<span style="font-size:85%;color:red">idiosyncratic hypersensitivity</span>]], [[Torsades de pointes|<span style="font-size:85%;color:red">torsades de pointes</span>]]</span><br>
''Or''<br>❑ Administer [[ibutilide]] 1 mg IV infusion over 10 minutes ([[ACC AHA guidelines classification scheme|Class I, Level of Evidence B]])<br>
''Or''<br>
❑ Administer [[ibutilide]] 1 mg IV infusion over 10 minutes ([[ACC AHA guidelines classification scheme|Class I, Level of Evidence B]])<br>
:❑ Repeat the [[dosage]] if the [[tachycardia]] continues <br>
:❑ Repeat the [[dosage]] if the [[tachycardia]] continues <br>
:<span style="font-size:85%;color:red">Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec</span><br>
:<span style="font-size:85%;color:red">[[Contraindication|<span style;color:red">Contraindications:</span>]] [[Hypersensitivity|<span style;color:red">hypersensitivity</span>]] to [[Ibutilide|<span style;color:red">ibutilide</span>]] or any component of the formulation, [[QT interval|<span style;color:red">QTc</span>]] >440 msec</span><br>
''Or''<br>
''Or''<br>
❑ Administer [[flecainide]] 50 mg every 12 hours
❑ Administer [[flecainide]] 50 mg every 12 hours
:❑ Increase 50mg BID every four days until efficacy is achieved <br>
:❑ Increase 50mg BID every four days until efficacy is achieved <br>
:❑ Maximum [[dose]] recommended for [[SVT]] is 300 mg/day<br>
:❑ Maximum [[dose]] recommended for [[SVT]] is 300 mg/day<br>
:<span style="font-size:85%;color:red">Contraindications: pre-existing second- or third-degree AV block, right bundle branch block associated with a left hemiblock unless a pacemaker is present, cardiogenic shock, hypersensitivity to the drug</span><br>
:<span style="font-size:85%;color:red">[[Contraindication|<span style="font-size:85%;color:red">Contraindications:</span>]] pre-existing [[Second degree AV block|<span style="font-size:85%;color:red">second degree AV block</span>]] or [[Third degree AV block|<span style="font-size:85%;color:red">Third degree AV block</span>]] , [[Right bundle brnach block|<span style="font-size:85%;color:red">right bundle branch block</span>]] associated with a left hemiblock unless a [[Artificial pacemaker|<span style="font-size:85%;color:red">pacemaker</span>]] is present, [[Shock|<span style="font-size:85%;color:red">cardiogenic shock</span>]], [[Hypersensitivity|<span style="font-size:85%;color:red">hypersensitivity</span>]] to the drug</span><br>
</div>}}
</div>}}
{{familytree/end}}
{{familytree/end}}

Revision as of 15:19, 18 April 2014

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Alonso Alvarado, M.D.; Hilda Mahmoudi M.D., M.P.H.[2]; Alejandro Lemor, M.D. [3]

Wolff-Parkinson-White Syndrome Resident Survival Guide Microchapters
Overview
Causes
FIRE
Diagnosis
Treatment
Initial
Long-term
Do's
Don'ts

Overview

Wolff-Parkinson-White (WPW) syndrome is a condition of pre-excitation of the ventricles of the heart due to the presence of an accessory pathway known as the Bundle of Kent through which the electrical impulses bypass the AV node. The difference between WPW pattern and WPW syndrome is that WPW pattern is characterized by the presence of characteristic ECG findings, such as a short PR interval and a delta wave, whereas WPW syndrome is the occurrence of tachycardia with or without associated symptoms in a subject with existing WPW pattern.[1] The treatment of WPW syndrome is targeted towards the restoration of the sinus rhythm, usually by the administration of either ibutilide or procainamide. The most common type of arrhythmia in WPW syndrome is AV reentrant tachycardia.[2] Atrial fibrillation in a patient with WPW is life threatening and should be managed urgently. Atrial fibrillation in a patient with WPW should be suspected when there is ECG findings suggestive of atrial fibrillation in the context of a heart rate higher than 220 beats per minute.

Causes

Life Threatening Causes

Wolff-Parkinson-White syndrome can be a life-threatening condition and must be treated as such irrespective of the underlying cause.

Common Causes

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.[2][3]
Boxes in salmon color signify that an urgent management is needed.

 
 
 
 
Identify cardinal findings that increase the pretest probability of Wolff-Parkinson-White syndrome

❑ Baseline ECG findings suggestive of WPW pattern (pre-excitation)

Delta wave
❑ Short PR interval

AND
Tachyarrhythmia
ECG findings suggestive of AVRT

❑ Regular rhythm
❑ Rate over 150 bpm
Narrow QRS complex preceded by a P wave (suggestive of orthodrome AVRT)
Wide QRS complex followed by a retrograde P wave (suggestive of antidrome AVRT)

ECG findings suggestive of AF + WPW

❑ Irregularly irregular rhythm
❑ Absent P waves
Heart rate > 220 beats per minute
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Does the patient have any of the following findings that require urgent cardioversion?

❑ Hemodynamic instability

Hypotension
Cold extremities
Peripheral cyanosis
Mottling
Altered mental status

Chest discomfort suggestive of ischemia

Decompensated heart failure
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
 
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Does the patient have a wide irregular rhythm?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
❑ Perform urgent unsynchronized electrical cardioversion
❑ 200-360 Joules monophasic, or
❑ 100-200 Joules biphasic
 
❑ Perform urgent synchronized electrical cardioversion
Narrow regular rhythm: 50-100 Joules
Narrow regular rhythm: 120-200 Joules biphasic or 200 Joules monophasic
Wide irregular rhythm
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 


Complete Diagnostic Approach

A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.[2]

Abbreviations: AF: atrial fibrillation; AVRT: AV reentrant tachycardia; BP: blood pressure; ECG: electrocardiography; HF: heart failure; LVH: left ventricular hypertrophy

 
 
 
 
Characterize the symptoms:

Asymptomatic
Palpitations
Dyspnea
Fatigue
Chest discomfort
Lightheadedness
Polyuria
Characterize the timing of the symptoms:
❑ Onset

❑ First episode
❑ Recurrent

❑ Duration
❑ Frequency
❑ Termination of the episode

❑ Spontaneous
Medication use
❑ Not terminated
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Examine the patient:

Appearance of the patient
❑ Cool and diaphoretic

Vitals
Heart rate

Tachycardia (150-250 beats per minute)
Rhythm
❑ Regular (most of the cases)
❑ Irregularly irregular (suggestive of AF)

Blood pressure

Hypotension
❑ Normal BP

Cardiovascular
❑ Normal heart examination in most cases
Tricuspid regurgitation characterized by a holosystolic murmur heard best along the left lower sternal border (suggestive of Ebstein's anomaly)
S4 (suggestive of LVH)

Respiratory
Rales (suggestive of HF)

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
WPW with AF

Suspect when AF appears with heart rates of 220 to 360.

❑ Irregularly irregular rhythm
❑ Rapid ventricular response (over 220 bpm)
Wide QRS complex

❑ No P wave[4]
 
Orthodromic AVRT

Regular rhythm
Narrow QRS complexes
P wave before QRS

 
Antidromic AVRT

Regular rhythm
Wide QRS complexes
P wave after QRS

 
 

Treatment

Initial Treatment

Shown below is an algorithm summarizing the initial approach to Wolff-Parkinson-White syndrome according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.[2][3]

 
 
 
Does the patient have any of the following findings that require urgent cardioversion?

❑ Hemodynamic instability

Hypotension
Cold extremities
Peripheral cyanosis
Mottling
Altered mental status

Chest discomfort suggestive of ischemia
Decompensated heart failure

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
 
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Direct current cardioversion (Urgent)
Check FIRE for details
 
 
 
What is the type of tachycardia according to the ECG findings?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
WPW+AF
 
Orthodromic AVRT
 
Antidromic AVRT
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Avoid the use of AV node blocking agents such as digoxin, calcium channel blockers, beta blockers and adenosine.

❑ Administer procainamide, 100 mg infusion diluted to 100mg/ml at a rate of 25-50 mg/min every 5 minutes (Class I, Level of Evidence C)[5]

❑ Administer until the arrhythmia is suppressed or until 500 mg has been administered
❑ Wait 10 minutes or longer to administer new dosage
Contraindications: third degree AV block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes

Or
❑ Administer ibutilide 1 mg IV infusion over 10 minutes (Class I, Level of Evidence C)[5]

❑ Repeat the dosage if the tachycardia continues
Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec

Or
❑ Administer flecainide 50 mg every 12 hours (Class IIa, Level of Evidence B)[5]

❑ Increase 50mg BID every four days until efficacy is achieved
❑ Maximum dose recommended for SVT is 300 mg/day
Contraindications: pre-existing second degree AV block or Third degree AV block , right bundle branch block associated with a left hemiblock unless a pacemaker is present, cardiogenic shock, hypersensitivity to the drug
 

❑ Use vagal maneuvers (Class I, Level of Evidence B)

Carotid sinus massage
Valsalva maneuver


If not effective initiate IV AV nodal blocking agent

❑ Administer adenosine 6 mg IV (bolus) (Class I, Level of Evidence A)

❑ If initial dose is not effective, administer a second dose of 12 mg, repeated a second time if required
Contraindications: second- or third-degree A-V block (except in patients with a functioning artificial pacemaker

If not effective

❑ Administer verapamil 5 to 10 mg (0.075 to 0.15 mg/kg body weight) IV boluses of over 2 minutes (Class I, Level of Evidence A)

❑ Give 30% of the dose in case of hepatic impairment
❑ Monitor for prolonged PR interval in case of renal impairment
Contraindications: severe left ventricular dysfunction, hypotension (systolic pressure less than 90 mm Hg) or cardiogenic shock

If not effective

❑ Administer procainamide, 100 mg infusion diluted to 100mg/ml at a rate of 25-50 mg/min every 5 minutes (Class I, Level of Evidence B)

❑ Give until the arrhythmia is suppressed or up to 500 mg
❑ Wait 10 minutes or longer to administer new dosage
Dosage should be adjusted for the individual patient in case of renal impairment
Contraindications: third degree AV block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes
 

Avoid the use of AV node blocking agents such as digoxin, calcium channel blockers, beta blockers and adenosine.

❑ Administer procainamide, 100 mg infusion diluted to 100mg/ml at a rate of 25-50 mg/min every 5 minutes (Class I, Level of Evidence B)

❑ Give until the arrhythmia is suppressed or until 500 mg has been administered
❑ Wait 10 minutes or longer to administer new dosage
Contraindications: third degree AV block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes

Or
❑ Administer ibutilide 1 mg IV infusion over 10 minutes (Class I, Level of Evidence B)

❑ Repeat the dosage if the tachycardia continues
Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec

Or
❑ Administer flecainide 50 mg every 12 hours

❑ Increase 50mg BID every four days until efficacy is achieved
❑ Maximum dose recommended for SVT is 300 mg/day
Contraindications: pre-existing second degree AV block or Third degree AV block , right bundle branch block associated with a left hemiblock unless a pacemaker is present, cardiogenic shock, hypersensitivity to the drug
 
 
 

Long-Term Treatment

Shown below is an algorithm summarizing the long-term treatment of Wolff-Parkinson-White syndrome.[2]

 
 
 
 
 
Does the patient with pre-excitation have symptomatic arrhythmia?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Is the arrhythmia poorly tolerated, OR
is atrial fibrillation with rapid conduction present?
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Do's

Don'ts

References

  1. "Wolff-Parkinson-White Syndrome and Accessory Pathways". Retrieved 1 April 2014.
  2. 2.0 2.1 2.2 2.3 2.4 "ACC/AHA/ESC Guidelines for the Management of Patients With Supraventricular Arrhythmias—Executive Summary". Retrieved 15 August 2013.
  3. 3.0 3.1 "Part 8: Adult Advanced Cardiovascular Life Support". Retrieved 3 April 2014.
  4. Fengler, Brian T.; Brady, William J.; Plautz, Claire U. (2007). "Atrial fibrillation in the Wolff-Parkinson-White syndrome: ECG recognition and treatment in the ED". The American Journal of Emergency Medicine. 25 (5): 576–583. doi:10.1016/j.ajem.2006.10.017. ISSN 0735-6757.
  5. 5.0 5.1 5.2 5.3 American College of Cardiology Foundation. American Heart Association. European Society of Cardiology. Heart Rhythm Society. Wann LS, Curtis AB; et al. (2013). "Management of patients with atrial fibrillation (compilation of 2006 ACCF/AHA/ESC and 2011 ACCF/AHA/HRS recommendations): a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines". Circulation. 127 (18): 1916–26. doi:10.1161/CIR.0b013e318290826d. PMID 23545139.
  6. Garratt, C.; Antoniou, A.; Ward, D.; Camm, AJ. (1989). "Misuse of verapamil in pre-excited atrial fibrillation". Lancet. 1 (8634): 367–9. PMID 2563516. Unknown parameter |month= ignored (help)
  7. Gulamhusein, S.; Ko, P.; Carruthers, SG.; Klein, GJ. (1982). "Acceleration of the ventricular response during atrial fibrillation in the Wolff-Parkinson-White syndrome after verapamil". Circulation. 65 (2): 348–54. PMID 7053894. Unknown parameter |month= ignored (help)
  8. McGovern, B.; Garan, H.; Ruskin, JN. (1986). "Precipitation of cardiac arrest by verapamil in patients with Wolff-Parkinson-White syndrome". Ann Intern Med. 104 (6): 791–4. PMID 3706931. Unknown parameter |month= ignored (help)


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