Wide complex tachycardia medical therapy

Resident Survival Guide

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

Overview

The management of wide complex tachycardia should begin by assessing the patient's ABCs (airway, breathing, and circulation). If the patient is unstable and either hypotension, altered mental status, chest pain, heart failure or seizures are present, then immediate synchronized cardioversion should be performed. If the patient is stable, the optimal management depends upon the differentiation of ventricular tachycardia versus supraventricular tachycardia with aberrant conduction as a cause of the wide complex tachycardia. A wide complex tachycardia should be assumed to be and managed as though it is due to ventricular tachycardia until proven otherwise. This is true even in a hemodynamically stable patient until proven otherwise (VT can often be hemodynamically stable). The initial management strategy includes avoiding the use of a long acting AV nodal blocking agent and drugs that suppress left ventricular contractility such as verapamil which can induce hypotension in a previously stable patient.

Medical Therapy

Wide complex tachycardia QRS ≥ 120ms

Do the following simultaneously: - Assess and support ABC's as needed - Give oxygen - Monitor ECG, BP, oxymetry - Identify and treat reversible causes (hypokalemia, hypomagnesemia

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 -Establish IV access - Give IV sedation if the patient is conscious - Consider expert consultation

Regular rhythm

Irregular rhythm

Ventricular tachycardia or uncertain rhythm?

Confirmed 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

- If certain VT is not present, 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

Algorithm based on ACLS guidelines for the management of tachycardia.

Critical Caveats in the Management of Wide Complex Tachycardia

• Verapamil should be avoided in patients with wide complex tachycardia as it can result in hemodynamic deterioration in patients with ventricular tachycardia.
• Do not use Ca²⁺ channel blocker, digoxin or adenosine if you don't not know the etiology of the wide complex tachycardia. Ca²⁺ channel blockers and digoxin can lead to accelerated conduction down a bypass tract which may in turn degenerate into VF.
• Though ACLS guidelines recommend a diagnostic trial of adenosine, it can precipitate VF in some patients with SVT. Patients who have underlying coronary disease may become ischemic from coronary steal. Rhythm can degenerate and lead to VF that cannot be resuscitated. Furthermore, some VT (specially those with structurally normal hearts) are adenosine responsive and can terminate.

  1. Etiology uncertain

     • Pronestyl 15 mg/kg load over 30 minutes then 2-6 mg/min gtt

  2. Ventricular tachycardia with active ischemia

     • Lidocaine 1 mg/kg q5-10 min up to 3 times then 2-6 mg/min gtt
     • If unsuccessful, pronestyl as above
     • If unsuccessful, IV amiodarone 150-300 load over 15-20 min. 30-60 mg/hr gtt for total of 1 gram

  3. Ventricular tachycardia in setting of cardiomyopathy

     • Skip lidocaine and go straight to pronestyl

  4. Positively SVT with aberrancy

     • Adenosine 6 mg rapid IV bolus in large vein. May repeat with 12 mg x2.
     • Lopressor 2.5-5.0 mg IV
     • Diltiazem 10-20 mg bolus followed by gtt 5-20 mg/hr
     • Verapamil 2.5-5.0 mg bolus.
     • Avoid digoxin. Takes too long to work and can be proarrhythmic
     • Pronestyl as above

  5. Antidromic AVRT

     • If 100% positive AF is not underlying, can terminate with a nodal blocker
     • If unsure, pronestyl as above