Pacemaker and Implantable Device Assessment Flashcards
7 cards from real CCI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pacemaker and Implantable Device Assessment flashcards as text
What is the primary indication for an implantable cardioverter-defibrillator (ICD)?
Answer: Prevention of sudden cardiac death from ventricular arrhythmias
ICDs are implanted primarily for secondary prevention of sudden cardiac death in survivors of VF or sustained VT, or for primary prevention in high-risk patients with reduced ejection fraction.
Cardiac Resynchronization Therapy (CRT) is most beneficial for which patient population?
Answer: Heart failure with reduced EF, LBBB, and QRS ≥150 ms
CRT has the strongest evidence of benefit in patients with symptomatic heart failure with reduced ejection fraction (≤35%), left bundle branch block, and a QRS duration ≥150 ms.
What minimum percentage of biventricular pacing is generally targeted to achieve optimal CRT benefit?
Answer: >98%
Studies show that biventricular pacing percentage below 98% is associated with diminished CRT benefit; the clinical goal is to maximize biventricular pacing as close to 100% as possible.
During ICD device interrogation, a stored electrogram shows a fast, polymorphic ventricular rhythm followed by a shock that restored sinus rhythm. This most likely represents:
Answer: Appropriate ICD therapy for ventricular fibrillation
A stored electrogram showing rapid polymorphic ventricular activity that terminates after an ICD shock returning to sinus rhythm is consistent with appropriate therapy for ventricular fibrillation.
What is the typical heart rate threshold used to define the VF detection zone in an ICD?
Answer: >200 bpm
The VF detection zone is typically programmed above 200 bpm (cycle length <300 ms), as this range captures rates consistent with ventricular fibrillation while avoiding overlap with fast VT zones.
Which feature of a non-MR-conditional pacemaker or ICD is the primary concern when a patient requires MRI?
Answer: Electromagnetic interference causing oversensing or inappropriate pacing
The strong magnetic and radiofrequency fields of MRI can cause non-MR-conditional devices to pace asynchronously, oversense, inhibit pacing, deliver inappropriate shocks, or sustain damage to leads and circuitry.
Anti-tachycardia pacing (ATP) in an ICD functions by delivering which type of therapy?
Answer: A series of rapid pacing stimuli to overdrive and terminate ventricular tachycardia
ATP delivers a burst of pacing stimuli faster than the detected tachycardia rate, capturing the reentrant circuit and terminating ventricular tachycardia without delivering a painful shock.