Fluttering in her chest!

Fluttering in her chest!

Learning Objectives:

1. Describe ECG criteria for narrow complex tachycardia.

2. Describe the treatment algorithm for narrow complex tachycardia.

ECG Criteria for Narrow-Complex Tachycardia:

1. Use 12 lead ECG, clinical information, vagal maneuvers and adenosine to distinguish between ectopic atrial tachycardia, multifocal atrial tachycardia, and paroxysmal supraventricular tachycardia.

2. The heart rate is fast and regular.

3. P waves may be hidden in T waves. If visible, the P waves are upright.

4. There is a fixed, 1-to-1 relationship between the P waves and QRS complexes or 2-to-1 block may be present.

5. The impulse in atrial tachycardia arises in the atria and spreads to the AV node. The impulse travels down the conducting system and spreads through the ventricles resulting in a narrow QRS complex. If aberrant conduction is present, the QRS will be wide.

6. The heart rate in atrial tachycardia is 150 to 250 beats per minute. A QRS follows every P wave or 2-to-1 block may occur. The P wave may be superimposed on the T wave and be difficult to identify.

7. Atrial tachycardia can be difficult to distinguish from sinus tachycardia. Heart rate greater than 150 beats per minute and an abnormal P wave favor atrial tachycardia.

8. It can be difficult to distinguish ventricular tachycardia from supraventricular tachycardia with aberrant conduction. The presence of P waves or irregularity in rate favor supraventricular tachycardia. When in doubt assume the rhythm is ventricular tachycardia.

Treatment Algorithm for Tachycardia (Narrow-Complex):

1. Administer oxygen and determine if the patient is stable or unstable.

2. If unstable: Synchronized cardioversion

a. For supraventricular tachycardia and atrial flutter, start at 50 J and increase as needed.

b. For atrial fibrillation, start at 100 J and increase as needed.

c. May need to resynchronize after each shock.

d. If synchronization results in too long a delay, may use unsynchronized shocks.

e. Consider administration of a sedative by anesthesia service prior to electrical cardioversion.

3. If stable, call cardiologist, use 12 lead ECG or rhythm strip to determine if QRS is narrow or wide:

a. If narrow and regular:

1) Try vagal maneuvers or adenosine 6 mg then 12 mg - if converts the rhythm was probably reentry supraventricular tachycardia. Consider blocking AV node with diltiazem or beta-blocker.

2) If doesn't convert - probable atrial flutter, atrial tachycardia, or junctional tachycardia. Consider controlling rate with diltiazem or beta-blocker.

b. If narrow and irregular:

1) Probable atrial fibrillation, or possible atrial flutter or multifocal atrial tachycardia. Consider controlling rate with diltiazem or beta-blocker.

c. If wide and regular:

1) Probable ventricular tachycardia. Consider amiodarone 150 mg load over 10 minutes.

2) Possible SVT with aberrancy. Consider adenosine.

d. If wide and irregular:

1) Possible atrial fibrillation with aberrant conduction. Consider controlling rate with diltiazem or beta-blocker.

2) If atrial fibrillation plus pre-excitation Wolff-Parkinson-White syndrome - consider amiodarone. Avoid adenosine, digoxin, diltiazem, verapamil.

3) If Torsades de Pointes, give magnesium.