Heart Failure Cases Flashcards
What is heart failure
A complex clinical syndrome Result of any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood NOT necessarily “congestive” heart failure HF is a progressive disorder There is tremendous clinical heterogeneity
Poor prognosis of outcomes for heart fail pts:
repeat hospitalizations
What intrinsic factors contribute to CO?
Contractility and heart rate
What extrinsic factors contribute to CO?
Preload and Afterload
Heart Rate effects of Cardiac Output Tachycardia______ diastolic filling time.
decreases –> issue bc in heart fail we increase HR bc we need more blood but this will decrease diastolic fill time thereby reducing CO
Why is it an issue for pts with diastolic dysfunction to have tachycardia?
bc the heart fills with blood during diastole, if we have tachycardia, we decrease time spent in diastole.
In heart fail pts, impaired contractility leads to inability to handle volume thus ______ increases
CVP
What is La Places law?
Wall stress = Pressure x radus/ 2x wall thickness
In heart fail, pt experiences increase pressure, as a result what happens to the heart?
(think about La Place’s Law)
wall stress = Pxr/2h
h is wall thickness, as P increases, we would increase wall stress. To resist increase in wall stess, the heart with increas it’s wall thickness, h, via hypertrophy. After a certian point, it cannot hypertrophy anymore and we end up with decreased CO
CO = HR x SV thus as heart beast faster, we should increase CO. But this isn’t quite the case… why?
as HR increases, it has a shortened diastole, thus HR can affect SV (bc SV is determined by diastolic filling time)
If HR is increased enough to decrease SV, what happens to preload and afterload?
Preload will decrease in response to decreased SV… afterload can change to compensate for decreased SV
When does active reuptake of Ca+ back into teh SR occur?
Diastole
How can increase in HR be a bad thing for pt with heart fail?
Pt with tachycardia and heart fail is bad because these pts depend on a longer diastolic filling time to generate adequte SV. When we see heart fail pt with tachycardia, it means they have no other way to generate CO except increase in HR
The amount a contracting heart must overcome to eject blood into the vasculature
afterload
Assuming no change in CO, when vasculature is contracted, more blood remains in arterial circulation… What happens to venous pressure?
Venous pressure decreases with each stroke
When afterload is reduced via vasodialation, flow across the systemic circulation is enhanced and central venous pressure will….
Increase
As a failing heart dilates ts wall stress increases. _________ is a compensatory mech for chamber dilation
Ventricular hypertrophy
Diuretics work to decrease __________ in order to decrease afterload in heart fail pts with compensatory hypertrophy
LV end diastolic pressure
- Sodium content in diet
- Excessive fluid intake
- Renal failure
all contribute to increased:
Preload
- Uncontrolled Hypertension
- Pulmonary embolism
- Severely dilated ventricle
all contribute to
increased AFterload
- Increased metabolism
- Fever
- Infection
- Anemia
- Tachycardia
- Hyperthyroidism
- Pregnancy
- Slow heart rate
all contribute to
increased HR
Acute MI
• Negative
Inotrope
• Alcohol
all contribute to
decreased contractility
What are the key components of the cycle of congestion in AHF
Myocardial ischemia–> worsening HF–> elevated LVEDP–> increased wall stress adn increased functiona MR–> myocardial oxygen deman–> back to ischemia
Role of the physician in Acute Heart Fail pts.
- Identify the etiology of acute heart failure
- Appropriately treat acute heart failure to achieve a stable hemodynamic equilibrium.
- Reverse (if possible) the exacerbating stimulus.
Assesment we need to perform on pt with AHF
- History and Physical Examination
- Laboratory Testing
- Echocardiogram (Non-Invasive Imaging)
- Swan-Ganz Catheter (Invasive hemodynamics)
What are some key questions to ask for in pt history in pt with AHF?
What do you eat for breakfast, lunch, dinner, snack, restaurants?
Do you weigh yourself every day?
How far can you walk?
How many pillows do you sleep with? Do you wake up short of breath?
Any recent changes to your medication?
Do you have chest pain?
What types of murmurs will we hear on pt with AHF?
Mitral regurgitation (Don’t rule out papillary rupture)
Crescendo-decrescendo murmur of Aortic stenosis
S3 Gallop
P2 “knock” suggests RV volume or pressure overload