CCS Diagnostic Testing & Imaging 3 — Questions and Answers
Question 1: A patient with hypertrophic cardiomyopathy undergoes echocardiography. Which measurement best quantifies left ventricular outflow tract obstruction?
- Peak LVOT gradient by Doppler (Correct answer)
- Left atrial volume index
- E/e' ratio
- Septal wall thickness
Correct answer: Peak LVOT gradient by Doppler
The peak LVOT pressure gradient measured by continuous wave Doppler directly quantifies the degree of dynamic obstruction in HCM.
Question 2: On a Holter monitor report, a patient shows RR intervals alternating between long and short cycles with a fixed relationship. This pattern is most consistent with:
- Second-degree AV block Mobitz type I (Wenckebach) (Correct answer)
- Complete heart block
- Atrial fibrillation
- Sinus arrhythmia
Correct answer: Second-degree AV block Mobitz type I (Wenckebach)
Wenckebach block shows progressive PR prolongation with eventual non-conducted P wave, causing a characteristic grouped beating pattern on Holter.
Question 3: Which stress imaging modality is preferred for evaluating coronary artery disease in a patient with left bundle branch block?
- Pharmacologic stress with vasodilator and nuclear imaging (Correct answer)
- Exercise treadmill ECG
- Exercise echocardiography
- Resting ECG only
Correct answer: Pharmacologic stress with vasodilator and nuclear imaging
LBBB causes septal motion abnormalities with exercise that can mimic ischemia on echo; vasodilator stress with nuclear imaging avoids this false-positive pattern.
Question 4: A coronary angiogram shows a lesion with 60% diameter stenosis. Fractional flow reserve (FFR) is measured at 0.78. What is the appropriate interpretation?
- Hemodynamically significant — revascularization is indicated (Correct answer)
- Not hemodynamically significant — medical therapy preferred
- Borderline result requiring repeat testing
- FFR cannot be applied to non-critical lesions
Correct answer: Hemodynamically significant — revascularization is indicated
An FFR ≤0.80 indicates hemodynamically significant ischemia, and revascularization of such lesions has been shown to improve outcomes.
Question 5: Which echocardiographic parameter is the best non-invasive estimate of left ventricular end-diastolic pressure?
- E/e' ratio (Correct answer)
- E/A ratio
- Deceleration time
- Isovolumetric relaxation time
Correct answer: E/e' ratio
The ratio of transmitral E velocity to mitral annular e' velocity (E/e') correlates strongly with invasively measured LVEDP.
Question 6: What is the 'string sign' seen on carotid duplex ultrasound?
- Near-occlusion of the internal carotid artery with minimal residual flow (Correct answer)
- Complete occlusion with no detectable flow
- Artifact from vessel wall calcification
- Normal variant in young patients
Correct answer: Near-occlusion of the internal carotid artery with minimal residual flow
The string sign describes severely reduced but still present flow through a near-totally occluded ICA, appearing as a thin stream on color Doppler.
Question 7: In cardiac CT for calcium scoring, which scoring method assigns weight based on both area and peak attenuation of calcified lesions?
- Agatston score (Correct answer)
- Volume score
- Mass score
- Pixel count score
Correct answer: Agatston score
The Agatston score multiplies the lesion area by a density factor (1-4) based on peak HU, making it the standard method for coronary calcium quantification.
CCS Diagnostic Testing & Imaging 3
A patient with hypertrophic cardiomyopathy undergoes echocardiography.
Which measurement best quantifies left ventricular outflow tract obstruction?