Wide complex tachycardia resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]

Definition

Wide complex tachycardia is characterized by a heart rate more than 100 beats per minute associated with a QRS interval of more than 120 ms. When wide complex tachycardia is present, it is important to determine whether the tachycardia is of a supraventricular or a ventricular origin.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Wide complex tachycardia can be a life-threatening condition and must be treated as such irrespective of the causes.

Common Causes

• Atrial fibrillation with aberrancy
• Atrial fibrillation with pre-excitation
• Superior ventricular tachycardia (SVT) with aberrancy
• Ventricular tachycardia

Management

Shown below is an algorithm depicting the management of wide complex tachycardia according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias and the 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.

Characterize the symptoms: ❑ Asymptomatic ❑ Palpitations ❑ Dyspnea ❑ Fatigue ❑ Chest discomfort ❑ Lightheadedness ❑ Syncope Characterize the timing of the symptoms: ❑ Onset ❑ Duration ❑ Frequency

Identify possible triggers: ❑ Infection ❑ Caffeine ❑ Alcohol ❑ Nicotine ❑ Recreational drugs ❑ Hypovolemia ❑ Hyperthyroidism

❑ Examine the patient ❑ Order an EKG

Wide complex tachycardia QRS ≥ 120ms

Do the following simultaneously: ❑ Assess and support ABC's as needed ❑ Give oxygen ❑ Monitor ECG, BP, oxymetry ❑ Establish IV access ❑ Identify and treat reversible causes

Is the patient stable? Unstable signs include: ❑ Chest pain ❑ Congestive heart failure ❑ Hypotension ❑ Loss of consciousness ❑ Seizures

Yes

No

Is the rhythm regular?

Immediate synchronized cardioversion ❑ Give IV sedation if the patient is conscious ❑ Consider expert consultation

Regular rhythm

Irregular rhythm

Ventricular tachycardia or uncertain rhythm?

SVT with aberrancy?

Afib with aberrancy?

Pre-excited Afib (Afib + WPW)?

Recurrent polymorphic VT?

Torsade de pointes?

❑ Give amiodarone 150 mg IV over 10 min ❑ Repeat amiodarone as needed for a maximal dose of 2.2g/24h ❑ Prepare for elective synchronized cardioversion

❑ Attempt vagal maneuvers ❑ Give adenosine 6 mg rapid IV push ❑ If no conversion give 12 mg IV push ❑ May repeat 12 mg dose once

❑ Consider expert consultation ❑ Control rate e.g diltiazem or beta blockers ❑ Use beta blockers with caution in pulmonary diseases or CHF

❑ Consider expert consultation ❑ Avoid AV nodal blocking agents e.g adenosine, digoxin, diltiazem and verapamil ❑ Consider amiodarone 150 mg IV over 10 min

❑ Consider expert consultation

❑ Load with Magnesium 1-2 g over 5-60 min, then infusion

Antiarrhythmics

Shown below is a table summarizing the choices of the antiarrhythmic drugs for the different types of tachycardia according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.

Management of wide complex tachycardia SVT + BBB ▸ Vagal maneuvers (Class I, level of evidence B) OR ▸ Adenosine (Class I, level of evidence A) OR ▸ Verapamil (Class I, level of evidence A) OR ▸ Diltiazem (Class I, level of evidence A) OR ▸ Beta blocker (Class IIb, level of evidence C) OR ▸ Amiodarone (Class IIb, level of evidence C) OR ▸ Digoxin (Class IIb, level of evidence C) SVT or atrial fibrillation + Preexcitation ▸ Flecainide (Class I, level of evidence B) OR ▸ Ibutilide (Class I, level of evidence B) OR ▸ Procainamide (Class I, level of evidence B) OR ▸ Cardioversion (Class I, level of evidence C) Ventricular tachycardia or wide QRS tachycardia of unknown origin ▸ Procainamide (Class I, level of evidence B) OR ▸ Sotalol (Class I, level of evidence B) OR ▸ Amiodarone OR ▸ Cardioversion (Class I, level of evidence B) OR ▸ Lidocaine (Class IIb, level of evidence B) OR ▸ Adenosine (Class IIb, level of evidence C) OR ▸ Beta blocker (Class III, level of evidence C) OR ▸ Verapamil (Class III, level of evidence B) Wide QRS tachycardia of unknown origin + poor LV function ▸ Amiodarone (Class I, level of evidence B) OR ▸ Cardioversion (Class I, level of evidence B)

BBB: Bundle branch block; LV: Left ventricle; SVT: Supraventricular tachycardia

Differentiating SVT from VT

Shown below is a table summarizing some clues that help differentiate SVT from VT.

For more details about differentiating VT from SVT, click here

Do's

• Refer the patient to an arrhythmia specialist in case the tachycardia causes syncope or dyspnea as well as the wide complex tachycardia is of unknown cause.
• Place an ambulatory 24 hour Holter when the tachycardia is frequent and transient.
• Treat the patient as having a ventricular tachycardia when the diagnosis of supraventricular tachycardia can not be made.
• Suspect ventricular tachycardia in a patient with wide complex tachycardia and previous myocardial infarction or a history of structural heart disease.