Case 01 / 12B3Diagnostic
Oximetry run on room air: SVC 68%, IVC 76%, RA 84%, RV 85%, PA 85%, pulmonary vein 98%, aorta 96%. What is the Qp/Qs?
Pick an answer. The verdict, the explanation and a note on every option appear here.
B · 40%Reading time so far 00:00
RCIS diagnostic procedures: hemodynamics, waveforms and the math, worked
Diagnostic Procedures is domain B of the RCIS exam, and it carries 40% of the scored items, about 60 of 150, more than any other domain. Most of those points come from measuring work: reading pressures and waveforms, then turning numbers into a cardiac output, a resistance, a valve area or a shunt ratio. This guide maps the task lines, works each formula with units, and ends with 12 cases.
B1–B14Reading time so far 00:29
What domain B covers: the 14 task lines
Domain B has 14 task lines, B1 to B14, in the outline CCI publishes for exams from July 2024. CCI weights the domain as a whole and nothing below it, so a percentage per task in any prep source is invented.
Share of scored items by domain, content outline for exams from July 1, 2024 (CCI, checked September 2026).
| Task | What it asks you to do |
|---|---|
| B1 | monitor rate, rhythm, pressure, SpO₂ and end-tidal CO₂ |
| B2 | coronary angiography and the left ventriculogram |
| B3 | right heart work: waveforms, every formula, biopsy setup |
| B4 | 12-lead ECG: infarct location, bundle branch block, ischemia |
| B5 | intracardiac echo |
| B6 | IVUS and OCT |
| B7 | cardiac structures on ultrasound |
| B8 | FFR and iFR |
| B9 | radiation safety and C-arm geometry |
| B10 | radiographic setup and positioning |
| B11 | acquiring and reading the images |
| B12 | anticipating the next drug |
| B13 | what a drug does to the numbers |
| B14 | vascular access, including ultrasound-guided |
Expect to be asked what the numbers mean or what comes next, rarely for a bare definition. The formula work lives in B3.
B3Reading time so far 01:25
Normal pressures and saturations to know cold
Every waveform and calculation case is read against these numbers. Textbooks differ by 1 to 4 mmHg, so learn the shape of each range, not its last digit.
| Site | Typical normal | Rule to remember |
|---|---|---|
| RA mean | 2–6 mmHg | a wave taller than v |
| RV | 15–30 / 0–8 | systolic = PA systolic without pulmonic stenosis |
| PA | 15–30 / 4–12, mean 10–20 | diastolic tracks the wedge if PVR is normal |
| PCWP / LA | 4–12 mmHg | v wave taller than a |
| LV | 90–140 / 3–12 | systolic = aortic systolic without AS |
| CO / CI | 4–8 L/min; 2.5–4.0 L/min/m² | low CI plus a high wedge suggests shock |
Saturations: arterial 95–100%, pulmonary vein about 98% (assumed if not drawn), SVC about 70–75%, IVC higher at 75–80%, mixed venous about 75%, and the coronary sinus lowest at 30–40%.
B3Reading time so far 02:17
Waveforms: what each wave means and what distorts it
The exam describes tracings in words: timing against the ECG, height, the slope of each descent. The a wave is atrial contraction after the P wave; c is the AV valve closing, just after the QRS; the x descent is atrial relaxation; v is filling against the closed valve, peaking after the T wave; y is emptying once the valve opens.
| What you see | Most likely cause |
|---|---|
| No a wave | atrial fibrillation |
| Cannon a waves | AV dissociation: complete heart block or VT |
| Giant c–v wave in the RA, steep y | severe tricuspid regurgitation |
| Large wedge v wave | mitral regurgitation, but also VSD or a stiff left atrium |
| Blunted or absent y descent | tamponade |
The wedge copies the LA about 100–200 ms late, and it stands in for LVEDP except in mitral stenosis, where it reads high. Three artifacts come up again and again:
- Overdamping (bubble, clot, kink): systolic falls, diastolic rises, the notch disappears.
- Leveling: a transducer set below mid-chest reads high, about 0.74 mmHg per centimeter.
- Peripheral amplification: femoral systolic reads higher than central aortic, so align tracings before measuring an AS gradient.
CalcReading time so far 03:18
Hemodynamic calculations on the RCIS: output and resistance
Five formulas cover nearly every calculation case: Fick output, systemic and pulmonary resistance, Gorlin and Hakki valve area, and the shunt ratio. Work each by hand once.
Fick cardiac output and indexWorking
- Assumed VO₂
- 125 mL/min/m²
- BSA
- 2.0 m²
- Hemoglobin
- 13.5 g/dL
- SaO₂ / SvO₂
- 96% / 66%
- VO₂ = 125 × 2.0 = 250 mL/min
- A–V O₂ difference = (0.96 − 0.66) × 1.36 × 13.5 × 10
- =55.1 mL O₂ per liter
- CO = 250 ÷ 55.1
- ≈4.54 L/min
- CI = 4.54 ÷ 2.0
- ≈2.3 L/min/m²
CO ≈ 4.5 L/min, CI ≈ 2.3 L/min/m²
The ×10 turns mL per dL into mL per liter; drop it and the output comes out ten times too high.
SVR and PVR from one set of numbersWorking
- Aortic mean
- 94 mmHg
- RA mean
- 6 mmHg
- PA mean
- 34 mmHg
- PCWP
- 14 mmHg
- CO
- 5.0 L/min
- SVR = (MAP − RA) ÷ CO = (94 − 6) ÷ 5.0
- =17.6 WU × 80 = 1408 dyn·s·cm⁻⁵
- PVR = (mean PA − PCWP) ÷ CO = (34 − 14) ÷ 5.0
- =4.0 WU × 80 = 320 dyn·s·cm⁻⁵
SVR ≈ 1408 dyn·s·cm⁻⁵ (mildly raised); PVR 4 WU (raised)
Each resistance subtracts its own outflow pressure: RA for systemic, wedge for pulmonary. Subtract the RA on the pulmonary side and you get 448, a ready-made distractor.
B3Reading time so far 04:38
How to calculate valve area for the RCIS: Gorlin and Hakki
Work Gorlin in full; use Hakki in your head to check the range. They agree while the heart rate stays between 60 and 100. For the mitral valve, swap in the diastolic filling period and the constant 37.7.
Aortic valve area, GorlinWorking
- CO
- 4200 mL/min
- Heart rate
- 72 bpm
- Ejection period
- 0.32 s/beat
- Mean gradient
- 36 mmHg
- AVA = CO ÷ (HR × SEP × 44.3 × √mean gradient)
- =4200 ÷ (72 × 0.32 × 44.3 × 6)
- =4200 ÷ 6124
- ≈0.69 cm²
AVA ≈ 0.69 cm², severe (below 1.0 cm²)
Hakki check: 4.2 L/min ÷ √36 = 0.70 cm². Forget the square root in Gorlin and you get 0.11.
B3Reading time so far 05:21
Shunts: the oximetry run and Qp:Qs
A shunt case gives saturations chamber by chamber, and the answer is decided before you divide.
Find the step-up
About 7% at the atrial level, about 5% at the ventricle or great vessels.
Pick the mixed venous sample
The chamber before the step-up: the Flamm blend (3 × SVC + IVC) ÷ 4 for an atrial shunt, the RA for a VSD, the RV for a PDA.
Divide
Qp:Qs = (SaO₂ − mixed venous) ÷ (pulmonary vein − PA). Hemoglobin and VO₂ cancel, so ignore them.
Qp:Qs, ventricular-level step-upWorking
- RA / RV / PA
- 70% / 83% / 84%
- Pulmonary vein
- 98% (assumed)
- Aorta
- 96%
- Step-up RA → RV = 13%: ventricular level
- Mixed venous = RA = 70%
- Qp:Qs = (96 − 70) ÷ (98 − 84) = 26 ÷ 14
- ≈1.9
Qp:Qs ≈ 1.9, a moderate left-to-right shunt
Use the PA as mixed venous and you get 0.86, a net right-to-left reading: the sign of a wrong sample.
Bands: below 1.5 small, 1.5 to 2.0 moderate, 2.0 or more large, below 1.0 net right-to-left.
Drill the formulas on your phone
The app carries more domain B calculation cases with the working shown.
B3Reading time so far 06:14
Constriction, restriction, tamponade, AS and HCM in the lab
The exam likes pairs that look alike on one tracing and split on another. Learn the discriminator.
| Finding | Constriction | Restrictive cardiomyopathy |
|---|---|---|
| Dip-and-plateau | present | present too |
| LVEDP − RVEDP | 5 mmHg or less | more than 5 mmHg |
| RV and LV systolic peaks on inspiration | discordant | concordant |
Tamponade blunts the y descent; constriction deepens it. In the AS and HCM pair, the Carabello sign belongs to critical AS: arterial pressure rises as the catheter is pulled back out of the valve. Brockenbrough–Braunwald–Morrow belongs to obstructive HCM: on the beat after a PVC the aortic pulse pressure falls, where in fixed AS it rises.
B2 · B11Reading time so far 06:52
Angiographic views, coronary dominance and catheters
A projection is named for where the detector sits, not the tube. Cranial views open the LAD and diagonals; caudal views show the left main and circumflex; LAO caudal (the spider) shows the left main bifurcation. The RAO 30° ventriculogram shows the anterior, apical and inferior walls plus mitral regurgitation; LAO shows the septum and a VSD.
Dominance is set by the artery that gives off the PDA, and most people are right-dominant. The AV-node artery comes from the dominant vessel, which links B11 to B4: an inferior infarct plus heart block is one story. To back an Amplatz out, you advance it.
B6 · B8Reading time so far 07:29
IVUS, OCT, FFR and iFR: the thresholds
Three numbers: FFR 0.80 or less is significant at maximal hyperemia; iFR 0.89 or less at rest, with no adenosine; resting Pd/Pa 0.91 or less. Equalize the wire with aortic pressure before crossing.
Fractional flow reserveWorking
- Pa / Pd
- 92 / 71 mmHg
- State
- IV adenosine hyperemia
- FFR = Pd ÷ Pa = 71 ÷ 92
- ≈0.77
FFR ≈ 0.77: significant
0.77 means distal pressure is 77% of aortic. It does not mean a 77% stenosis.
| Feature | IVUS | OCT |
|---|---|---|
| Resolution | about 100–150 µm | about 10–20 µm |
| Depth | up to about 8 mm, whole wall | about 1–3 mm |
| Blood | no clearing | needs a flush bolus |
B9Reading time so far 08:01
Radiation safety: geometry decides the dose
Picture the tube, the patient and the detector, then ask which change moves the dose.
Inverse square lawWorking
- Distance
- 1 m → 2 m
- Dose ∝ 1 ÷ distance²
- =(1 ÷ 2)²
- =¼
Double the distance, a quarter of the dose
- Tube far from the patient, detector close.
- Magnification raises patient dose; collimation and a lower frame rate cut it.
- Scatter is highest on the tube side, so stand on the detector side.
- Fluoro time is the weakest dose measure because it ignores cine.
B12–B14Reading time so far 08:33
Drugs and access: B12 to B14
Pharmacology here is anticipation: from the monitor, which drug will the physician ask for next?
| Picture | Read it as | Expect |
|---|---|---|
| Hypotension with bradycardia | vasovagal | legs up, fluids, atropine |
| Hypotension with tachycardia, hives, wheeze | anaphylaxis | epinephrine first; antihistamines only as add-ons |
| Low eGFR before a contrast case | kidney injury risk | saline and less contrast, not N-acetylcysteine |
For femoral access the target is the common femoral artery over the medial third of the femoral head. Too high risks a retroperitoneal bleed; too low, a pseudoaneurysm. The exam asks what you recognize; treatment calls are the physician's.
TrapsReading time so far 09:01
Six traps that cost points in domain B
| The slip | The correct version |
|---|---|
| PA saturation as mixed venous with a shunt | chamber before the step-up |
| Flamm as a simple average | 3 SVC to 1 IVC, divided by 4 |
| Wood units × 8 | × 80 |
| Thermodilution with severe TR or a shunt | use Fick |
| Dip-and-plateau means constriction | look for discordance |
| FFR and iFR share a cut-off | 0.80 vs 0.89 |
RunReading time so far 09:28
Hemodynamics practice questions: 12 domain B cases
These 12 cases are domain B only, and 7 of them involve a calculation. The exam gives you 2 hours 50 minutes of question time for 170 questions, about 60 seconds a case. Read the note under every option: each wrong one names a slip.
0 of 12 answered
Next: worked RCIS exam questions from the other domains, the full practice test, the interventional procedures guide for domain C, or the RCIS study guide for a week-by-week plan.
Key takeaways
- Domain B is 40% of the scored exam, about 60 items.
- Fick, SVR/PVR, Gorlin, Hakki and Qp:Qs cover nearly every calculation.
- Carabello rises, Brockenbrough falls; discordance means constriction.
- Write units beside every number and round once, at the end.
FAQReading time so far 10:25
Questions people ask
What hemodynamic calculations are on the RCIS?
Fick cardiac output and index, systemic and pulmonary resistance, Gorlin and Hakki valve area, the Qp:Qs shunt ratio, mean arterial pressure and FFR, all in domain B.
How do you calculate valve area for the RCIS?
Gorlin: output in mL/min ÷ (heart rate × ejection or filling period × constant × √mean gradient), with 44.3 for the aortic valve and 37.7 for the mitral. Check it with Hakki: L/min ÷ √gradient.
How much of the RCIS exam is hemodynamics?
CCI publishes weights by domain only. Domain B, home of the hemodynamics, is 40% of the 150 scored items; no split inside it is published.
NextReading time so far 10:56
Keep the log going
Work the free case run here, then carry the full RCIS bank with you: the app sorts questions by the same five domains and keeps the explanation for every option.