Network Fundamentals Flashcards
7 cards from real ECHOCARDIOGRAM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Network Fundamentals flashcards as text
Which cardiac structure serves as the primary pacemaker of the heart?
Answer: Sinoatrial (SA) node
The sinoatrial (SA) node, located in the right atrium, is the heart's primary pacemaker, generating electrical impulses at 60–100 bpm.
What is the intrinsic firing rate of the AV node when acting as a secondary pacemaker?
Answer: 40–60 bpm
The AV node has an intrinsic rate of 40–60 bpm, slower than the SA node, making it a secondary pacemaker.
On an echocardiogram, which finding would suggest AV conduction delay affecting mechanical function?
Answer: Simultaneous atrial and ventricular contraction
A very long PR interval can cause simultaneous atrial and ventricular contraction, visible on echo as an absent or truncated A-wave.
The Bundle of His bifurcates into which two structures?
Answer: Right and left bundle branches
The Bundle of His divides into the right and left bundle branches, which carry impulses to the ventricular myocardium.
In left bundle branch block (LBBB), how does septal motion typically appear on M-mode echocardiography?
Answer: Paradoxical (posterior) septal motion
LBBB causes paradoxical posterior septal motion on M-mode due to abnormal electrical activation sequence of the left ventricle.
Which echocardiographic Doppler parameter is most directly affected by variations in heart rate?
Answer: Mitral E/A ratio
The mitral E/A ratio changes with heart rate because faster rates shorten diastolic filling time, reducing the A-wave contribution and altering the E/A ratio.
What conduction pathway is responsible for the rapid spread of electrical impulses through the ventricular myocardium?
Answer: Purkinje fiber network
The Purkinje fiber network enables rapid conduction throughout the ventricular myocardium, ensuring near-simultaneous ventricular contraction.