0071643192.pdf

ECG FINDINGS(SEEFIGURE1.10)

■ Atrial rate ranges from 250 to 300 bpm.
■ AV-node conduction of every 2 or 3 atrial impulses
■ Ventricular rate is classically 150 (2:1 conduction).
■ P waves have characteristic “saw tooth pattern.”

DIAGNOSIS

■ If in question may use adenosineto block the AV node and “uncover” the
underlying atrial rhythm

TREATMENT

■ If patient unstable →electrical cardioversion.
■ Synchronized
■ May be successful with 25–50J
■ Sedation, if possible
■ Otherwise→rate control with AV-node blocking agents.
■ Diltiazem
■ β-Blockers
■ Chemical cardioversion may then be tried.
■ Choices include:
■ Amiodarone
■ Ibutilide
■ Procainamide
■ Quinidine
■ Avoid: AV-nodal blocking drugs if accessory pathway suspected.

ATRIALFIBRILLATION(AFIB)

Atrial fibrillation is disorganized atrial electrical activity (rate >400 bpm)
withnoorganized atrial contraction. Ventricular rate is limited by the AV
node (or accessory pathway refractory period).

CAUSES

Causes are similar to atrial flutter. Alcohol use is commonly associated with
AFib (“holiday heart”).

ECG FINDINGS(SEEFIGURE1.11)

■ Irregularly irregular QRS complexes
■ No P waves
■ Variable rates of ventricular response (as high as 175 bpm)
■ QRS complex narrow unless
■ Preexisting conduction blocks
■ Accessory pathway (eg, Wolfe-Parkinson-White)

RESUSCITATION

FIGURE 1.10. Atrial flutter.

The ventricular rate in

untreated atrial flutter is

typically 150 bpm due to 2:1

conduction of atrial impulses.

Alcohol use is commonly

associated with AFib.

QRS complexes are narrow in

AFib unless there is a

preexisting conduction block

or an accessory pathway.