Echo in Cardiac Tamponade Flashcards
Evidence of decreased transmural filling pressure?
- Collapse of right heart chambers (RA diastolic inversion, RV early diastolic collapse)
- Plethora of IVC
RA diastolic inversion in tamponade?
- Seen when IPP exceeds RAP
- Inversion seen during late ventricular diastole or early ventricular systole when RAP at its lowest point
- RA inversion lasting > 1/3 cardiac cycle highly sensitive and specific to tamponade
RV early diastolic collapse in tamponade?
- RV collapse occurs when IPP exceeds RV pressure
- Usually occurs early-mid diastole when RV pressure is at its lowest point
IVC plethora in tamponade?
- IVC plethora reflects impaired systemic venous return to RA caused by increased RAP and/or RA compression secondary to increased IPP
- Dilated IVC + < 50% collapse
Absence of RA or RV collapse or IVC plethora?
Virtually excludes tamponade*
When may RADC and/or RVDC be absent in tamponade?
- Located PE (of left heart chambers)
- Pulmonary hypertension (very high right heart pressures)
Other than tamponade, when else may a dilated IVC be seen?
- Dilated IVC = elevated central venous pressures; also seen with:
- RV failure
- Elevation in RAP due to other causes
Evidence of exaggerated right and left heart filling with respiration?
- LA and LV inflow
- RA and RV inflow
Formula for calculating respiratory change?
% change = (first beat exp. - first beat insp.) / exp. x 100
Mitral significance of respiratory change (%)?
Mitral E > 30%
Tricuspid significance of respiratory change (%)?
Tricuspid > 60%
Normal mitral inflow?
Barely any noticeable change in mitral E velocity
(ITP falls with inspiration = fall in pulmonary venous pressure = fall in IPP = filling gradient only changes slightly)
Mitral inflow with tamponade?
- Smaller E velocity with inspiration, larger E velocity with expiration
- Prolonged IVRT
(IPP elevated = diastolic filling gradient between pulmonary veins and left heart falls during inspiration = smaller E velocity)
(Reduced diastolic filling gradient with inspiration = MV opens later prolonging IVRT)
Normal tricuspid inflow?
Slight increase in tricuspid inflow velocities with inspiration
(Inspiration = reduced IPP = augmentation of systemic venous return and filling to the right heart)
Tricuspid inflow with tamponade?
- Higher E velocity with inspiration compared to expiration
(Inspiration = increased early diastolic filling = increased venous return and reduced LV filling = IVS shift to left = increased inflow with inspiration)
Mitral/Tricuspid/Hepatic Venous/Pulmonary Venous flow with inspiration in tamponade?
- Mitral E velocity reduced with inspiration
- Tricuspid E increased
- Hepatic D velocity increased
- Pulmonary D velocity reduced
Mitral/Tricuspid/Hepatic Venous/Pulmonary Venous flow with expiration in tamponade?
- Mitral E increased
- Tricuspid E decreased
- Hepatic D velocity decreased, plus increase in flow reversal (AR velocity)
- Pulmonary D velocity increased
IVRT with tamponade?
Increased IVRT > 20% on 1st beat of inspiration compared with 1st beat of expiration
SVC flow in tamponade?
- Lack of normal increase in SVC flow with inspiration
- Loss of expiratory D velocity (i.e. no D wave)
Summary of LV filling on 1st beat of inspiration?
Reduced LV filling:
- Reduced mitral E velocity (< 30%
- Reduced pulmonary D velocity
- Increased IVRT (> 20%)
Summary of LV filling on 1st beat of expiration?
Increased LV filling:
- Increased mitral E velocity
- Increased pulmonary D velocity
- Reduced IVRT
Summary of RV filing on 1st beat of inspiration?
Increased RV filling:
- Increased tricuspid E velocity (> 60%)
- Normal increase in hepatic D velocity
- Normal increase, or reduced S & D +/- lack of inspiratory increase in SVC D velocity
Summary of RV filling on 1st beat of expiration?
Reduced RV filling:
- Reduced tricuspid E velocity
- Reduced, absent or reversed D hepatic D velocity with increase in AR
- Reduced SVC D velocity (absent in severe tamponade), increased AR
Evidence of enhanced ventricular interdependence?
- IVS bounce: change in LV/RV size
- Reduced stroke volume
Enhanced ventricular interdependence with inspiration?
- IVS shifts to the left
- RV cavity increases in size, LV cavity decrases
Enhanced ventricular interdependence with expiration?
- IVS shifts to the right
- LV cavity size increases, RV cavity decreases
Stroke volume with inspiration in tamponade?
Leftwards shift of IVS = decreased LV volume = reduced LV SV during inspiration
How is reduced stroke volume in tamponade identified?
Reduced transmitral inflow velocities
Formula to calculate stroke volume?
SV = CSA x VTI
CSA = 0.785 x d2
Normal range for stroke volume?
70 - 100mL
Challenges in cardiac tamponade?
- Pulmonary hypertension
- Chronic obstructive airways disease (COAD)
- Ventilated patients
- Low pressure cardiac tamponade
- Pleural effusion causing tamponade (pleural effusions can cause tamponade physiology)
Effect of COAD?
- Exaggerated increase in respiratory variation (mitral/tricuspid inflow) due to exaggerated ITP changes
- Hard to tell if respiratory changes are COAD or tamponade
How to distinguish COAD from tamponade?
- Use SVC profile
SVC profile in tamponade vs COAD?
- COAD: SVC shows marked increased of forward flow velocities with inspiration
- Tamponade: Loss of normal inspiratory increase in SVC flow, especially of diastolic forward flow velocities
Tamponade in ventilated patients?
- Respiratory changes opposite…
- MV increase E with inspiration
- TV decrease E with inspiration
- ITP increases during inspiration (increases rather than decreases as ventilator pushing air into lungs)
Identifying tamponade when low-pressure cardiac tamponade?
- Tamponade in setting of low ICP and low IPP
- Typical clinical findings are absent
- Echo findings are the same
