Hemodynamics

Question 1

What is the formula for Fick CO?

Answer 1

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

Question 2

What is the formula for cardiac index (CI)?

Answer 2

CI = CO (L/min) / BSA (m²)

• normal = 2.5 - 4 L/min/m2

Question 3

When is Fick (CO) most accurate?

Answer 3

• low output states (valvular heart disease)
  
  • TR
  • multivalvular heart disease
• steady state

Question 4

What is the problem with Fick (CO)?

Answer 4

estimate of O2 consumption

Question 5

What PA sat correlates with low CO (on Fick)?

Answer 5

< 65%

Question 6

What are quick estimates of Fick (CO) utilizing PA sats?

Answer 6

• PA sat 70-80% –> Normal CO
• PA sat < 65% –> Low CO
• PA sat > 80% –> High CO (or L-R shunt)
  
  • AV graft for HD

Question 7

When is TD (CO) more accurate?

Least accurate?

Answer 7

• Most accurate –> High Output States
• Inaccurate –> TR or AF

Question 8

What is the formula for PVR (pulmonary vascular resistance, Woods units)?

Answer 8

PVR = mPAP - mPCWP / CO

**Normal range = 80-130 dynes

***Woods units x 80 = dynes

**** TPR = mPAP / CO

Question 9

What is the formula for SVR (systemic vascular resistance)?

What is normal range?

Answer 9

SVR = mean systemic arterial pressure - mRAP x 80 / CO

• Normal range = 700-1600 dynes-sec/cm⁵

Question 10

Describe the finding

Answer 10

Severe TR

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

Question 11

What constitutes a pathologic or abnormal “v” wave in PCWP tracings?

What are causes?

Answer 11

• “v” wave more than 10 mmHg than PCWP
• PCWP “v” waves
  
  • MR
  • VSD
  • Noncompliant LA
    
    • previous A-fib ablation procedures

Question 12

Describe the findings

Answer 12

Pericardial Tamponade

• Rapid x only
• Blunted ‘y’ descent (no early diastolic RV filling)

Question 13

Describe the findings

Answer 13

Pericardial constriction

• Rapid x and y descents
  
  • y = early rapid diastolic RV filling

Question 14

Describe when step-up O2 saturations are significant?

What does this imply?

Answer 14

Intra or Extra cardiac shunt may be present

Question 17

Describe the findings

Answer 17

• 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

Question 21

Describe the findings

Answer 21

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
    *

Question 22

How can you differentiate AS and HOCM on intracardiac pressure tracings?

Answer 22

Post-PVC

• Pulse Pressure
  
  • HOCM –> decrease
  • AS –> increase

Valsalva

• Gradient
  
  • ​HOCM –> increase
  • AS –> decrease

Question 23

Describe the findings

Answer 23

AS

Question 24

Describe the findings

Answer 24

HOCM: L heart pullback

Question 25

Describe the findings

Answer 25

Provocable Gradient: Valsalva Maneuver

Question 26

Describe locations for mixed venous O2 sats in shunt calculations:

• No L-R shunt
• L-R shunt present
• ASD
• No R-L shunt

Answer 26

• 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

Question 27

What is a normal BP response to exercise?

Answer 27

25-70 mmHg

Question 28

Describe the findings

Answer 28

ASD

Question 29

Describe the findings

Answer 29

AR

• Corrigan’s pulse
• absence of dicrotic notch

Question 31

What is the Gorlin formula?

Answer 31

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

Question 32

What is the simplified Gorlin or Hakki formula? When does this formula differ?

Answer 32

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

Question 33

When is the Gorlin formula inaccurate?

Answer 33

* Regurgitation (concomitant) * moderate or more AI * Low output states * Tachy/Brady cardia \*\*\*Assumes steady state and fixed orifice

Question 39

What are factors that can increase the gradient in HOCM?

Answer 39

* increased contractility * decreased preload * volume depletion * decreased afterload

Question 40

What are factors that can decrease the gradient in HOCM?

Answer 40

* decreased contractility * increased preload * increased afterload * phenylephrine

Question 41

What is a normal LVOT VTI?

Answer 41

18-22 cm * important to avoid PISA / flow convergence --\> leads to overestimation

Question 42

Calculate MVA?

Answer 42

MVA = 220 / PHT * PHT = deceleration time x 0.29 * PHT = the time required for the velocity to drop to 1/2 the peak pressure

Question 43

What is the grading severity of mitral stenosis?

Answer 43

Question 44

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

Answer 44

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

Question 45

Describe the findings and key to differentiation

Answer 45

**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

Question 46

Describe the findings

Answer 46

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

Question 47

Describe the findings

Answer 47

**Severe AR**

Question 48

Describe the findings

Answer 48

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

Question 49

Describe the findings

Answer 49

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

Question 50

Describe the findings and diagnosis

Answer 50

* Mitral inflow * Inspiration --\> decrease in mitral inflow velocity * Expiration --\> increase in mitral inflow velocity

Question 51

Describe the findings and diagnosis

Answer 51

**Effusive constrictive pericarditis** * Pericardial tamponade --\> * pericardiocentesis --\> * Constrictive pericarditis

Question 52

Describe the findings and diagnosis

Answer 52

Mitral annular velocity --\> important measure for differentiation

Question 53

Describe the findings, diagnosis, treatment

Answer 53

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

Question 54

What are key hemodynamic criteria to differentiate RCM and CP?

Answer 54

* LVEDP - RVEDP * Constriction * Restriction \> 5 * RVSP * Constriction \< 50 * Restriction \> 50 * RVEDP/RVSP * Constriction \> 0.3 * Restriction \< 0.3

Question 55

Describe the findings, diagnosis, treatment

Answer 55

Severe MS --\> PMBV --\> **Pericardial tamponade** * **Pericardiocentesis**

Question 56

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

Answer 56

Qp/Qs = 3.0