Ventricular Diastolic Filling & Function (Lecture 1) Flashcards
What are the four phases of Diastole?
Isovolumetric Relaxation
Early Rapid Diastolic Filling
Diastasis
Late Diastolic Filling (Atrial Contraction)
Pick which phase of Diastole this fits for:
- Starts with Ao valve closure, followed by a rapid decline in LV pressure
- LV pressure falls below LA pressure, MV opens ending the IVR period
Isovolumetric Relaxation
Pick which phase of Diastole this fits for:
- Occurs right after MV opening, LVP falls below LAP
- LV volume and LVP increase – contributes to 70-80% of LV filling
- Filling rate and time of LA to LV flow determined by pressure, ventricular relaxation
(elastic recoil of LV), and compliance of the ventricles
Early Rapid Diastolic Filling
Pick which phase of Diastole this fits for:
- Pressures in atria and ventricles equalize during this period of lower ventricular filling
- Equalization due to simultaneous ↓LAP and ↑LVP
- Duration depends on HR, longer at low HR and absent with fast HR
Diastasis
Pick which phase of Diastole this fits for:
- LA pressure exceeds LV pressure with atrial contraction, second pulse of LV filling (atrial
kick) - In normal patients – contributes to 20% of total ventricular filling
Late Diastolic Filling (Atrial Contraction)
What are the parameters of Diastolic Function?
Ventricular Relaxation
Myocardial or Chamber Compliance
Filling Pressures
And additionally: Elastic Recoil of the Ventricle, Pericardial Constraint
When does Ventricular Relaxation occur?
During Isovolumetric Relaxation and Early Diastolic Filling
What are examples of Intrinsic factors that affect IVRT?
Stiff myocardium, infiltrative disease, LVH
What are examples of Extrinsic factors that affect IVRT?
Pericardial constraint (constrictive pericarditis, pericardial tamponade)
A more compliant ventricle will allow less or more blood to fill the ventricle?
It will allow more blood
A less compliant ventricle will allow (ess or more blood to fill the ventricle?
Less blood
Compliance is the ratio of what?
Change in volume to change in pressure (dV/dP)
What is the inverse of compliance?
Stiffness
What is the equation for Stiffness?
The ratio of change in Pressure to change in Volume (dP/dV)
What are six factors that affect late diastolic filling?
- Cardiac rhythm
- Atrial contractile function
- Ventricular end-diastolic pressure
- Heart rate
- The timing of atrial contraction
- Ventricular diastolic function
What are 3 factors that that Affect Peak Early Diastolic
Filling Rate?
- Changes in preload that affect the initial pressure difference between the ventricle and the atrium (e.g., increased with volume loading, decreased with volume depletion)
- A change in transmitral volume flow rate (e.g., increased with coexisting mitral regurgitation)
- A change in atrial pressure (e.g., elevated LV end-diastolic pressure – stiff ventricle)
What are the RA pressures?
0-5mmHg (low)