Cardiac Rhythm Management Devices Flashcards
7 cards from real CVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cardiac Rhythm Management Devices flashcards as text
Which pacemaker parameter defines the minimum interval between a sensed or paced event and the next pacing output?
Answer: Refractory period
The refractory period prevents the pacemaker from responding to signals (such as T-waves) immediately after a paced or sensed event.
In a dual-chamber pacemaker, what occurs during crosstalk inhibition?
Answer: The ventricular lead senses atrial pacing output and inhibits ventricular pacing
Crosstalk occurs when the ventricular sensing channel detects the atrial pacing stimulus, potentially inhibiting ventricular output and causing dangerous pauses.
Which ICD therapy is delivered first in a standard tiered-therapy protocol for ventricular fibrillation?
Answer: High-energy defibrillation shock
Ventricular fibrillation is not amenable to ATP or synchronized cardioversion, so devices deliver high-energy unsynchronized defibrillation as first-line therapy.
A patient's ICD interrogation shows 'T-wave oversensing.' What is the most likely consequence?
Answer: Inappropriate shock delivery
T-wave oversensing causes the device to double-count cardiac events, potentially satisfying tachycardia detection criteria and delivering inappropriate therapy.
What does the term 'cardiac resynchronization therapy (CRT)' specifically aim to correct?
Answer: Interventricular and intraventricular mechanical dyssynchrony
CRT uses biventricular pacing to resynchronize the contraction of the left and right ventricles, improving cardiac output in patients with heart failure and conduction delay.
Which radiographic finding on chest X-ray suggests a right ventricular lead perforation?
Answer: Lead tip projecting beyond the cardiac silhouette into the lung field
Perforation is suggested when the lead tip projects beyond the cardiac border, indicating penetration through the myocardium into the pericardial space or beyond.
During threshold testing, pacing at 2× the chronic threshold is recommended to ensure what safety margin?
Answer: Adequate capture with tolerance for lead maturation impedance changes
Programming output at 2× the pacing threshold provides a safety margin to maintain capture despite the normal rise in threshold that occurs during lead maturation (weeks post-implant).