Sinus Rhythms Flashcard
Rationale
C. Rationale: When the SA node completely fails, a long period of asystole will occur. This long pause will be terminated when escape complexes begin, most likely in the atria first or the ventricles. Compared to atrioventricular block, the presence of P waves indicates that the SA node is producing an impulse, but it is being blocked somewhere at the level of the AV node.
Question
A sinus pause is represented by which one of the following ECG findings?
a. Only the P wave is present
b. Only the QRS complex is present
c. A flat line
d. Only the T wave is present
Answer
c. A flat line
Rationale
D. Rationale: The sinus arrhythmias may show a pattern seen in normal sinus rhythms. However, there is an irregularity of the R-R interval.
Answer option A: There is no rhythm referred to as non-sinus rhythm.
Answer option B: Sinus tachycardia is a regular rhythm that would display regular R-R intervals.
Answer option C: Normal sinus rhythm is a regular rhythm that would display regular R-R intervals.
Question
What can you conclude in an ECG strip showing P waves and irregular R-R intervals?
a. Non-sinus rhythm
b. Sinus tachycardia
c. Normal sinus rhythm
d. Sinus arrhythmia
Answer
d. Sinus arrhythmia