Lecture 9: Cardiac Failure Flashcards
What is the definition of cardiac failure?
Exists when the heart is unable to pump sufficient blood to meet the metabolic needs of the body at normal filly pressures and despite venous return.
What is congestive heart failure?
Clinical term
Syndrome of complex and variable clinical signs and symptoms
If the heart is not pumping blood properly it’s going to bank up somewhere
When does myocardial dysfunction occur?
Normal function at rest Deficient function under stress: - exercise - temperature extremes - meals - infections - fast or slow HR
What are the two sorts of heart failure?
Problem with pumping
Problem with filling
What is ejection fraction?
The fraction of blood ejected from the heart with each beat
Calculated by SV x EDV
Predicts life expectancy
What is systolic ventricular failure?
Characterised by reduced ejection fraction - measure of contracility
What occurs with systolic ventricular failure?
Systolic myocardial dysfunction Reduced SV Increased LV end-diastolic volume Restoration of SV Low EF (SV/LVEDP)
What is diastolic ventricular failure?
Impaired filling at normal pressures
Reduced ventricular diastolic distensibility
- Myocardial concentric hypertrophy (aortic stenosis, systemic hypertension)
- Pericardial constraint (fibrosis, fluid)
What occurs with diastolic ventricular failure?
Reduced diastolic distensibility Reduced SV Increased LVEDP Restoration of SV Normal EF
What are the 4 sorts of ventricular failure?
Left alone
Right alone
Left and right together
Left followed by right
What compensatory mechanisms occur?
Activation of sympathetic nervous system increases
Activation of RAS increases
Increased vasopressin (ADH
Increased endothelin (vasoconstrictor)
Increased ANP (vasodilator released from heart, suppresses renin release)
Ventricular dilation
Ventricular hypertrophy
What does increased sympathetic activation cause?
Increased HR to increase CO Increased myocardial contractility Arterial vasoconstriction to increase TPR Venous vasoconstriction Salt and water retention
What does renin activation cause?
Arterial vasoconstriction
Venous vasoconstriction
Salt and water retention
What are the consequences of increased LVEDP?
Increased LA pressures Increased pulmonary vein pressures Increased pulmonary capillary pressures - reduced lung compliance - diversion of blood to upper lobes - transduction of fluid (pulmonary edema) - effusions, wheeze, cough with frothy sputum
What are the consequences of increased RVEDP?
Increased RA pressures
Increased jugular venous pressure
- hepatic congestion
- tissue fluid accumulation
