Hemodynamics Flashcards
What is the formula for Fick CO?
CO = O2 consumption (mL/min) / VO2 difference (mL/100mL blood) x10
- O2 consumption estimated using 3 mL O2/kg or 125 mL/min/m2
- VO2 difference = difference (0.95 - 0.65) x 1.36 x Hgb x 10
**** Larger difference between A and V O2 content –> lower CO
What is the formula for cardiac index (CI)?
CI = CO (L/min) / BSA (m2)
- normal = 2.5 - 4 L/min/m2
When is Fick (CO) most accurate?
- low output states (valvular heart disease)
- TR
- multivalvular heart disease
- steady state
What is the problem with Fick (CO)?
estimate of O2 consumption
What PA sat correlates with low CO (on Fick)?
< 65%
What are quick estimates of Fick (CO) utilizing PA sats?
- PA sat 70-80% –> Normal CO
- PA sat < 65% –> Low CO
- PA sat > 80% –> High CO (or L-R shunt)
- AV graft for HD
When is TD (CO) more accurate?
Least accurate?
- Most accurate –> High Output States
- Inaccurate –> TR or AF
What is the formula for PVR (pulmonary vascular resistance, Woods units)?
PVR = mPAP - mPCWP / CO
**Normal range = 80-130 dynes
***Woods units x 80 = dynes
**** TPR = mPAP / CO
What is the formula for SVR (systemic vascular resistance)?
What is normal range?
SVR = mean systemic arterial pressure - mRAP x 80 / CO
- Normal range = 700-1600 dynes-sec/cm5
Describe the finding

Severe TR
- monophasic “CV” wave
- CV wave lifted completely off the baseline
- monophasic event in systole, occurring within the RA
- ventricularization of RA waveform

What constitutes a pathologic or abnormal “v” wave in PCWP tracings?
What are causes?
- “v” wave more than 10 mmHg than PCWP
- PCWP “v” waves
- MR
- VSD
- Noncompliant LA
- previous A-fib ablation procedures

Describe the findings

Pericardial Tamponade
- Rapid x only
- Blunted ‘y’ descent (no early diastolic RV filling)

Describe the findings

Pericardial constriction
- Rapid x and y descents
- y = early rapid diastolic RV filling

Describe when step-up O2 saturations are significant?
What does this imply?
Intra or Extra cardiac shunt may be present

Describe the findings

- a = atrial systole
- x = atrial relaxation, decrease of pressure
- c = closure of the TV
- v = ventricular systole, atrial diastole
- y = passive filling of the RV

Describe the findings

HOCM - Brockenbrough sign
- PVC –> ventricular contraction will be more forceful, and the pressure generated in the LV will be higher
- reduction in pulse pressure in a post-PVC beat
*
- reduction in pulse pressure in a post-PVC beat

How can you differentiate AS and HOCM on intracardiac pressure tracings?
Post-PVC
-
Pulse Pressure
- HOCM –> decrease
- AS –> increase
Valsalva
-
Gradient
- HOCM –> increase
- AS –> decrease

Describe the findings

AS

Describe the findings

HOCM: L heart pullback

Describe the findings

Provocable Gradient: Valsalva Maneuver

Describe locations for mixed venous O2 sats in shunt calculations:
- No L-R shunt
- L-R shunt present
- ASD
- No R-L shunt
- No L-R shunt
- Mixed venous = PA sat
- L-R shunt present
- Mixed venous = O2 sat in chamber proximal to shunt
- ASD
- Mixed venous = Caval O2 sat = (3 x SVC) + (1 x IVC) / 4
- No R-L shunt
- Mixed venous = PV O2 sat = FA O2 sat
What is a normal BP response to exercise?
25-70 mmHg
Describe the findings

ASD

Describe the findings

AR
- Corrigan’s pulse
- absence of dicrotic notch

What is the Gorlin formula?
Area (cm2) = value flow (mL/s) / K x C x √MVG
- K = constant = 44.3
- C = empiric constant
- AV, TV, PV = 1
- MV = 0.85
***MV flow = CO / DFP x HR
***AV flow = CO / SEP x HR
What is the simplified Gorlin or Hakki formula?
When does this formula differ?
AVA = CO / √MG
- differs by 18% +/- 13% from real formula
- Bradycardia
- Tachycardia
- Low flow states –> overestimate severity of AS
- CO < 2.5 L / min –> constants should be used
When is the Gorlin formula inaccurate?
- Regurgitation (concomitant)
- moderate or more AI
- Low output states
- Tachy/Brady cardia
***Assumes steady state and fixed orifice
What are factors that can increase the gradient in HOCM?
- increased contractility
- decreased preload
- volume depletion
- decreased afterload
What are factors that can decrease the gradient in HOCM?
- decreased contractility
- increased preload
- increased afterload
- phenylephrine
What is a normal LVOT VTI?
18-22 cm
- important to avoid PISA / flow convergence –> leads to overestimation
Calculate MVA?
MVA = 220 / PHT
- PHT = deceleration time x 0.29
- PHT = the time required for the velocity to drop to 1/2 the peak pressure
What is the grading severity of mitral stenosis?

What is the diagnosis?
- 65 year old man
- severe exertional dyspnea

severe AS
- delayed aortic pressure uprise
- PVC with compensatory pause –> increase in aortic pulse pressure

Describe the findings and key to differentiation

Pulse pressure change on post-PVC beat
- Severe AS
- increase in PP –> increased filling and more flow across the valve
- HOCM (“Brockenbrough-Braumwald” sign)
- decrease in aortic pulse pressure
- increased intracellular calcium –> contractility
- aortic pressure runoff –> decreased afterload –> worsening obstruction
- decrease in aortic pulse pressure

Describe the findings

Post-PVC aortic pulse pressure tracings
- severe AS
- HOCM

Describe the findings

Severe AR

Describe the findings

Acute severe AR
- diastolic equalization of pressures between LV and aorta

Describe the findings

Severe AR
- early closure of the Mitral valve
- well before onset of systole
- elevated LVEDP

Describe the findings and diagnosis

- Mitral inflow
- Inspiration –> decrease in mitral inflow velocity
- Expiration –> increase in mitral inflow velocity

Describe the findings and diagnosis

Effusive constrictive pericarditis
- Pericardial tamponade –>
- pericardiocentesis –>
- Constrictive pericarditis

Describe the findings and diagnosis

Mitral annular velocity –> important measure for differentiation

Describe the findings, diagnosis, treatment

Constrictive pericarditis –> Pericardiectomy
- Diastolic equalization of pressures
- Diastolic pressures elevated
- Ventricular discordance
- Enhanced ventricular interaction

What are key hemodynamic criteria to differentiate RCM and CP?
- LVEDP - RVEDP
- Constriction
- Restriction > 5
- RVSP
- Constriction < 50
- Restriction > 50
- RVEDP/RVSP
- Constriction > 0.3
- Restriction < 0.3

Describe the findings, diagnosis, treatment

Severe MS –> PMBV –> Pericardial tamponade
- Pericardiocentesis

Calculate the Qp/Qs
- High SVC 67%
- IVC 75%
- RA 87%
- RV 88%
- PA 89%
- PCWP 99%
- CO 5 L/min
- Hgb 12 g/dl

Qp/Qs = 3.0
