A nurse is reviewing ECG rhythm strips for a group of clients. The nurse should identify that which of the following rhythms indicates bradycardia?

A.
A

B.
B

C.
C

D.
D

The correct answer is C.

Explanation:

Bradycardia is defined as a heart rate that is slower than normal, specifically a rate below 60 beats per minute (bpm) in adults. When reviewing ECG rhythm strips, several characteristics can help identify bradycardia, such as the rate, rhythm regularity, and waveform characteristics.

Characteristics of Bradycardia on an ECG:

1. Heart Rate: The most defining feature of bradycardia is a heart rate of less than 60 bpm. On the ECG strip, this is reflected by fewer QRS complexes per minute.
2. Rhythm Regularity: In sinus bradycardia, the rhythm is regular, meaning the distance between consecutive QRS complexes (R-R interval) remains consistent, but the rate is slow.
3. P Wave: The P wave should be present and precede every QRS complex, indicating that the heart’s electrical impulse is originating from the sinoatrial (SA) node.
4. PR Interval: The PR interval remains within the normal range (0.12 to 0.20 seconds), suggesting that the atrioventricular (AV) conduction is intact.

Rhythm C Analysis:

• Rate: The rhythm strip labeled as C shows a heart rate below 60 bpm. This slow rate is the primary indicator of bradycardia.
• P Waves and QRS Complexes: The P waves appear regularly before each QRS complex, indicating that the impulse is originating from the SA node, consistent with sinus bradycardia.
• Regular Rhythm: The rhythm is regular, with consistent R-R intervals, further supporting a diagnosis of sinus bradycardia.

Clinical Significance:

• Causes: Bradycardia can be caused by several factors, including increased vagal tone, hypothyroidism, electrolyte imbalances, or as a normal variation in athletes.
• Symptoms: Some clients with bradycardia may be asymptomatic, while others may experience symptoms such as dizziness, fatigue, shortness of breath, or syncope.
• Management: The management of bradycardia depends on the presence of symptoms. Asymptomatic bradycardia may not require intervention, while symptomatic bradycardia might necessitate treatments such as atropine, pacing, or addressing the underlying cause.

In summary, Rhythm C is indicative of bradycardia because it demonstrates a slow heart rate of fewer than 60 beats per minute, with regular rhythm and appropriate P wave and QRS complex relationships, consistent with sinus bradycardia.