Determine the following:

Rhythm: _______________________________________

Figure. No caption available.

Rate: ___________________________________________

P waves: _______________________________________

PR interval: ____________________________________

QRS complex: __________________________________

What's your interpretation?

(Answers on next page)

Name that strip: Answers

Rhythm: Regular

Rate: 48 beats/minute

P waves: Sinus P waves present; one P wave to each QRS complex

PR interval: 0.28 second (remains constant)

QRS complex: 0.08 to 0.10 second

Interpretation: Sinus bradycardia with first-degree atrioventricular (AV) block

Comment: A U wave is present.

First-degree AV block may occur from ischemia or injury to the AV node secondary to acute myocardial infarction (MI) (usually inferior wall MI), increased parasympathetic tone, drug effects (beta-blockers, calcium channel blockers, digitalis, amiodarone), hyperkalemia, degeneration of the conduction pathways associated with aging, and unknown causes.

First-degree AV block produces no signs or symptoms and requires no treatment. Because first-degree AV block can progress to a higher degree of AV block, the cardiac rhythm should continue to be monitored until the block resolves or stabilizes. Medications causing AV block should be reviewed and discontinued as prescribed.

First-degree AV block: Identifying ECG features

Rhythm: Regular

Rate: That of the underlying sinus rhythm; both atrial and ventricular rates will be the same.

P waves: Sinus, one P wave to each QRS complex

PR interval: Consistent; prolonged (greater than 0.20 second)

QRS complex: Usually normal duration (0.10 second or less)