CCI Pacemaker and Implantable Device Assessment 3

Question 1

What is the primary indication for an implantable cardioverter-defibrillator (ICD)?

Accepted Answer

Prevention of sudden cardiac death from ventricular arrhythmias

Answer

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.

Question 2

Cardiac Resynchronization Therapy (CRT) is most beneficial for which patient population?

Accepted Answer

Heart failure with reduced EF, LBBB, and QRS ≥150 ms

Answer

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.

Question 3

What minimum percentage of biventricular pacing is generally targeted to achieve optimal CRT benefit?

Accepted Answer

>98%

Answer

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.

Question 4

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:

Accepted Answer

Appropriate ICD therapy for ventricular fibrillation

Answer

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.

Question 5

What is the typical heart rate threshold used to define the VF detection zone in an ICD?

Accepted Answer

>200 bpm

Answer

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.

CCI - Cardiovascular Credentialing International Practice Test

CCI - Cardiovascular Credentialing International Practice Test

CCI Pacemaker and Implantable Device Assessment 3