Which of the following is characteristic of an ECG tracing for a first-degree heart block?
A)The PR intervals are greater than 0.20 seconds in duration.
B)The P waves are inverted.
C)Not all of the P waves are followed by QRS complexes.
D)The underlying rhythm is slow.

Question

Quizplus · Accepted Answer

In first-degree heart block, the PR interval is prolonged, typically greater than 0.20 seconds in duration. The P waves and QRS complexes are normal, and there are no missing beats or dropped QRS complexes. The underlying rhythm may be normal or slightly slow, but this is not a defining characteristic of first-degree heart block. P waves being inverted or not followed by QRS complexes are not characteristic of first-degree heart block.

Which of the Following Is Characteristic of an ECG Tracing