Sinus Rhythm Interpretation Flashcards

A rhythm strip shows an upright P wave before every QRS complex, a regular R-R interval, a ventricular rate of 72 bpm, a PR interval of 0.16 seconds, and a QRS duration of 0.08 seconds. How would this rhythm be interpreted?

Answer: Normal Sinus Rhythm

This rhythm meets all the criteria for Normal Sinus Rhythm: a heart rate between 60-100 bpm, a regular rhythm, a P wave preceding every QRS complex, a constant PR interval between 0.12-0.20 seconds, and a QRS duration less than 0.12 seconds.

A Certified Rhythm Analysis Technician is reviewing an ECG strip and notes that the only abnormality is a heart rate of 48 beats per minute. All other parameters (P wave, PR interval, QRS complex, and regularity) are within normal limits. Which rhythm is most likely present?

Answer: Sinus Bradycardia

Sinus Bradycardia is characterized by a sinus rhythm with a rate of less than 60 beats per minute. Since all other aspects of the rhythm are normal, this is the correct interpretation.

Which of the following is the defining characteristic of Sinus Arrhythmia?

Answer: An irregular rhythm that varies with respiration

Sinus Arrhythmia is a variant of sinus rhythm where the R-R interval varies, often in relation to the respiratory cycle. The heart rate typically increases with inspiration and decreases with expiration, resulting in an irregular rhythm.

A patient's ECG shows a regular rhythm with a rate of 110 bpm. There is a P wave before each QRS complex, the PR interval is 0.14 seconds, and the QRS duration is 0.06 seconds. This rhythm is identified as:

Answer: Sinus Tachycardia

Sinus Tachycardia meets all the criteria for a sinus rhythm, but the heart rate is greater than 100 beats per minute. The rate of 110 bpm with otherwise normal sinus characteristics points to this diagnosis.

To be classified as a sinus rhythm, which of the following criteria regarding the PR interval must be met?

Answer: It must be between 0.12 and 0.20 seconds.

A key characteristic of any sinus rhythm (Normal, Bradycardia, Tachycardia) is a consistent PR interval that falls within the normal range of 0.12 to 0.20 seconds. This interval represents the time from the start of atrial depolarization to the start of ventricular depolarization.

A CRAT observes a rhythm strip where the P-P intervals and R-R intervals vary. The overall heart rate is 70 bpm, P waves are present and uniform, the PR interval is constant at 0.18 seconds, and the QRS is narrow. This description is most consistent with:

Answer: Sinus Arrhythmia

The key feature described is the variation in P-P and R-R intervals, which creates an irregular rhythm. With all other parameters (rate, P wave morphology, PR interval, QRS duration) being within normal sinus limits, the correct interpretation is Sinus Arrhythmia.