CCS CCS Hemodynamics & Cardiac Monitoring 2 — Questions and Answers
Question 1: A cardiac index (CI) below which value is considered critically low and indicative of severe hemodynamic compromise?
- 3.5 L/min/m²
- 2.5 L/min/m²
- 2.2 L/min/m²
- 1.8 L/min/m² (Correct answer)
Correct answer: 1.8 L/min/m²
A cardiac index below 1.8 L/min/m² is associated with cardiogenic shock and indicates critically impaired cardiac performance requiring urgent intervention.
Question 2: In a normal 12-lead ECG, the PR interval represents conduction through which structures?
- SA node to ventricular myocardium
- AV node and His-Purkinje system (Correct answer)
- Bundle branches only
- Ventricular repolarization
Correct answer: AV node and His-Purkinje system
The PR interval represents conduction time from the atria through the AV node, bundle of His, and bundle branches before ventricular activation.
Question 3: Which hemodynamic finding distinguishes right heart failure from left heart failure?
- Elevated PAWP with normal CVP
- Elevated CVP with normal or low PAWP (Correct answer)
- Low SVR with high CO
- High MAP with normal CVP
Correct answer: Elevated CVP with normal or low PAWP
Right heart failure causes elevated central venous pressure (CVP) with relative preservation of left-sided filling pressures (PAWP), reflecting isolated right ventricular dysfunction.
Question 4: Mixed venous oxygen saturation (SvO2) below 60% most likely indicates:
- Excessive oxygen delivery
- Increased oxygen extraction due to low cardiac output or high demand (Correct answer)
- Pulmonary embolism
- Hyperoxia
Correct answer: Increased oxygen extraction due to low cardiac output or high demand
SvO2 <60% indicates that tissues are extracting more oxygen than normal, suggesting inadequate oxygen delivery relative to demand, often from low cardiac output.
Question 5: A dicrotic notch on an arterial pressure waveform corresponds to which cardiac event?
- Mitral valve closure
- Aortic valve closure (Correct answer)
- Tricuspid valve opening
- Pulmonary valve opening
Correct answer: Aortic valve closure
The dicrotic notch represents the brief pressure increase caused by aortic valve closure at the end of systole, visible on the downslope of the arterial waveform.
Question 6: Which condition causes a cannon 'a' wave on the jugular venous pulse (JVP)?
- Atrial fibrillation
- Complete heart block with dissociated atrial and ventricular contractions (Correct answer)
- Sinus tachycardia
- Aortic regurgitation
Correct answer: Complete heart block with dissociated atrial and ventricular contractions
Cannon 'a' waves occur in complete heart block when the atria contract against a closed tricuspid valve (simultaneous atrial and ventricular contraction), producing large pressure waves.
CCS CCS Hemodynamics & Cardiac Monitoring 2
A cardiac index (CI) below which value is considered critically low and indicative of severe hemodynamic compromise?