2 Heart Rate and Rhythm Assessment Online Quiz Questions

At the standard paper speed of $25\ \text{mm/s}$, each small ECG square represents $0.04$ seconds.

Which electrical event is represented by the QRS complex?

If successive R–R intervals measure 4, 4, 4, and 4 large squares, the ventricular intervals are regular.

At $25\ \text{mm/s}$, a PR interval spans 4 small squares. Which option gives both its duration and whether it is within the usual adult reference range?

A QRS complex spans 2 small squares at $25\ \text{mm/s}$. Using the common $0.12$-second cutoff, how should it be classified?

A QT interval spans 10 small squares at $25\ \text{mm/s}$. What is the measured QT interval in seconds?

Because QT varies with heart rate, what corrected measurement is typically considered when interpreting the QT interval?

Select all accurate statements about ECG waveforms and the PR interval.

When describing a rhythm strip in addition to calculating its rate, which features are appropriate to assess? Select all that apply.

On a rhythm strip, some P waves are not followed by QRS complexes. Write a concise interpretation of the observed P-to-QRS relationship and state whether you can assume every atrial impulse is conducted.

A regular rhythm has 3 large squares between consecutive R waves. Using the large-square method at $25\ \text{mm/s}$, what is the estimated ventricular rate?

At a paper speed of 25 mm/s, an interval spans 3 large squares. How long is the interval?

A rhythm strip has successive R–R intervals of 4, 4, 5, and 4 large squares. How should the ventricular rhythm be described?

At a paper speed of 25 mm/s, the PR interval spans 4 small squares. What is the PR interval in seconds?

An irregular 10-second rhythm strip contains 13 QRS complexes. What is the estimated average ventricular rate?

At a paper speed of 25 mm/s, a QRS complex spans 2 small squares. Which choice gives both its duration and its classification using the common 0.12-second cutoff?

At a paper speed of 25 mm/s, a measured QT interval spans 10 small squares. What is the measured QT interval in seconds?

A measured QT interval should be interpreted in relation to heart rate, typically by considering a corrected QT (QTc).