Basic Cardiac Rhythm Interpretation Questions and Answers – Latest Update 2026/2027 (100% Correct | Graded A+.

Basic Cardiac Rhythm Interpretation Questions and
Answers – Latest Update 2026/2027 (100% Correct |
Graded A+.



Evaluate: consistent appearance and 1:1 relationship with
QRS complex.




If not identical some, or all, may be atrial, but not SA node, in
origin.




IF >1 P-wave precedes QRS a heart block may be present.




PR Interval

➫ Impulse traveling time from the atrium to the ventricles.

P Wave

➫ Atrial Depolarization stimulated by the firing of the SA
node.

,Measure from the beginning of the P-wave to the beginning of

the QRS complex.




Evaluate: Duration & regularity of interval.




Measure from beginning of Q-wave to end of S-wave where it

returns to baseline.




Evaluate: all complexes should look alike in the same lead.

Normal Duration < 0.12 seconds.




Widening QRS complex suggests bundle branch block or
other conduction delay.

, ST segment

➫ Represents the completion of ventricular depolarization

and the beginning of ventricular repolarization.




Along isoelectric line between the end of the QRS complex

and the beginning of the T-wave.




If > 0.20 seconds a conduction delay called an AV heart block
is present.




QRS complex

➫ Ventricular Depolarization



Depressed with myocardial ischemia. Elevated with
myocardial infarction.