EKG Rhythm and Measurement Quiz

Which wave on the EKG represents atrial depolarization?

• P wave

• QRS complex

• T wave

• U wave

Answer explanation

The P wave on the EKG represents atrial depolarization, indicating the electrical activity that triggers the contraction of the atria. The QRS complex represents ventricular depolarization, while the T and U waves represent other phases.

What is the normal duration of the PR interval in seconds?

• 0.04–0.08 seconds

• 0.12–0.20 seconds

• 0.20–0.40 seconds

• 0.40–0.60 seconds

Answer explanation

The normal duration of the PR interval is 0.12–0.20 seconds. This interval represents the time taken for electrical impulses to travel from the atria to the ventricles, and values outside this range may indicate conduction abnormalities.

Which EKG component represents ventricular repolarization?

• P wave

• QRS complex

• T wave

• PR interval

Answer explanation

The T wave on an EKG represents ventricular repolarization, which is the process of the ventricles recovering after contraction. The P wave indicates atrial depolarization, and the QRS complex represents ventricular depolarization.

Which of the following best describes the QRS complex on an EKG?

• Represents atrial repolarization

• Represents ventricular depolarization

• Represents ventricular repolarization

• Represents atrial depolarization

Answer explanation

The QRS complex on an EKG represents ventricular depolarization, which is the electrical activity that triggers the ventricles to contract. This is crucial for pumping blood to the lungs and the rest of the body.

Which arrhythmia is characterized by a sawtooth pattern of flutter waves?

• Atrial fibrillation

• Ventricular tachycardia

• Atrial flutter

• Sinus bradycardia

Answer explanation

Atrial flutter is characterized by a distinct sawtooth pattern of flutter waves, often referred to as 'F-waves', typically seen on an ECG. This differentiates it from other arrhythmias like atrial fibrillation.

What is the correct way to calculate heart rate using the 1500 method on a regular EKG rhythm strip?

• Divide 1500 by the number of small boxes between two consecutive R waves

• Divide 1500 by the number of large boxes between two consecutive R waves

• Multiply the number of QRS complexes in 6 seconds by 10

• Count the number of QRS complexes in 3 seconds

Answer explanation

The correct method to calculate heart rate using the 1500 method is to divide 1500 by the number of small boxes between two consecutive R waves. This provides an accurate heart rate based on the EKG strip.

A rhythm strip shows a regular rhythm with a rate of 150 bpm, narrow QRS complexes, and visible P waves before each QRS. Which rhythm is most likely present?

• Sinus tachycardia

• Atrial fibrillation

• Ventricular fibrillation

• Sinus bradycardia

Answer explanation

The rhythm strip shows a regular rhythm at 150 bpm, narrow QRS complexes, and visible P waves before each QRS, indicating sinus tachycardia. Atrial fibrillation would not have visible P waves, and the other options do not match the characteristics.

If the QT interval measures 0.48 seconds on a rhythm strip, what does this indicate?

• Normal QT interval

• Prolonged QT interval

• Shortened QT interval

• Unable to determine

Answer explanation

A QT interval of 0.48 seconds is considered prolonged, as a normal QT interval typically ranges from 0.36 to 0.44 seconds. Therefore, this indicates a prolonged QT interval.

Which of the following is considered a lethal arrhythmia?

• Sinus tachycardia

• Atrial flutter

• Ventricular fibrillation

• First-degree AV block

Answer explanation

Ventricular fibrillation is a lethal arrhythmia characterized by chaotic electrical activity in the heart, leading to ineffective pumping and potential cardiac arrest. The other options are not considered lethal.

A patient’s EKG shows no identifiable P waves, irregularly irregular rhythm, and narrow QRS complexes. What is the most likely arrhythmia?

• Atrial fibrillation

• Sinus rhythm

• Ventricular tachycardia

• Atrial flutter

Answer explanation

The EKG findings of no identifiable P waves, an irregularly irregular rhythm, and narrow QRS complexes are characteristic of atrial fibrillation, making it the most likely arrhythmia in this case.