0071643192.pdf

■ Stable patient: Medical therapy with procainamide or amiodarone may

be tried.

■ Blocks the accessory pathway

■ Increases transmission through the AV node

■ Hold for hypotension, 50% QRS widening

A 45-year-old male presents to the ED complaining of palpitations. He has

a history of alcohol abuse and chronic pain, for which he takes a tricyclic

antidepressant. He is awake and alert with a BP of 120/60 and an initial

pulse of 80. The monitor shows intermittent runs of torsades de pointes. What is

your initial treatment for this patient?

Torsades is a type of polymorphic VT that occurs in the setting of prolonged

repolarization, which in this patient is likely due to hypokalemia, hypomagne-

semia, and/or tricyclic antidepressant use. Since he is stable, begin treatment with

a magnesium sulfate infusion. If this is unsuccessful, try shortening repolarization

by increasing the ventricular rate via isoproterenol infusion or overdrive pacing.

VENTRICULARTACHYCARDIA(VT)

Ventricular tachycardia is defined as >3 consecutive ectopic ventricular beats.

It is grouped according to ECG pattern.

■ Monomorphic VT

■ Ectopic beats are morphologically the same.

■ Polymorphic VT

■ QRS complexes have many different shapes.

■ Sicker heart

Common variants of VT include:

■ Torsades de pointes (atypical VT)

■ Type of polymorphic VT occurring in a patient with a long QT

(> 600 msec)

■ QRS axis shifts from positive to negative in a single lead.

■ Bidirectional VT

■ Unique form of VT where QRS axis changes periodically

■ Associated with digitalis toxicity

■ Brugada syndrome

■ Hereditary syndrome characterized by structurally normal heart, abnor-

mal resting ECG, and sudden cardiac death from polymorphic VT or

VFib

■ Resting ECG is characterized by RBBB pattern and ST elevation in

V 1 -V 3 (see Figure 1.15).

CAUSES

Causes include

■ Virtually any form of structural heart disease

■ Trauma

■ Hypothermia

■ Severe electrolyte abnormalities

■ Familial disorders (eg, Brugada syndrome, congenital long QT syndrome)

■ Medications that prolong the QT interval

RESUSCITATION

Therapeutic options for

patients with WPW who

present with rapid AFib are

procainamide, amiodarone,

or electrical cardioversion.