Block 2 - CHF Physiology Flashcards
What is HF?
Inability of heart to pump adequate amount of blood to meet metabolic needs
What are the primary HFs?
- Muscular contraction problem (decreased ejection)
- Muscular relaxation problem (inadequate filling)
- Combination of contraction and relaxation
What is CO?
Amount of blood pumped out of the heart in L/min
What are the systems affected by HF?
RAAS and SNS
What causes volume overload and fatigue?
Response to compensatory mechanism triggered by decreased CO for long term maintenance
What mechanisms can exacerbate HF?
- Fluid retention
- Vasoconstriction
- Myocardial stimulation
What are the symptoms of HF?
- Fatigue
- SOB
- Inability to exercise
- Swelling in extremities (edema)
How is HF diagnosed?
Increased BNP levels with HF
What is BNP?
Secreted cardiomyocytes in response to excess stretching from increased ventricular blood volume
PreproBNP → ProBNP → BNP + NT-proBNP
What does BNP do?
- Vasodilation → decrease resistance
- Naturesis and diuresis → reduced BV
- Decrease CO and pressure
What are the concepts of HF that reinforce it being a progressive disorder?
- Initial cardiac injury
- Compensatory mechanisms
- Secondary damage
- Cardiac decompensation
What kind of cardiac injury leads to HF?
- Damages of heart
- Impairs heart ability to contract
- Reduce pumping capacity of heart
What are the compensatory mechanisms used to control HF?
- Activate with reduction in pumping capacity
- Maintaining near-normal left ventricle functions (SNS, RAAS, Inflammatory mediators)
- Maladaptive over time
What are secondary damages that caused by HF?
- End organ damage (ventricle)
- Left venatricular remodeling
What are classifications of HF?
- Chamber affected
- Type of HF
- Clinical sequelae
- Type and timing of symptoms
What is left-sided HF? Outcomes?
Causes volume overload and venous congestion in lungs → Na+ and H2O retention → pulmonary venous congestion → Fatigue and SOB
What is the difference between forward and backward failure LHF?
F: Fails to put enough out (decreased urine, palpitations, fatigue)
B: Fails to relieve enough in (congestion, fluid buildup)
What is Right sided HF? Pathophys?
- Caused by LVF
- More vulnerable to volume overload than LV
- When LV fails, pulmonary venous congestion increases RV work → Generating more force → venous congestion
What are the results in RHF?
- Elevated jugular pressure
- Liver congestion
- Peripheral edema
What are the results of isolated RV failure?
- Incomplete LV filling
- Decreased CO
- Contributes to HF
T or F: Reduced CO is always caused by reduced contractility
False
What is SV?
Amount of blood pumped out of the heart with each beat
What is EF?
Percentage of blood ejected from the ventricles with each contraction
EF = SV/EDV
What is the difference between systolic and diastolic HF?
S: HF with reduced EF
D: HF with preserved EF
What kind of HF is a majority of cases?
low output HF
What is low-output HF?
Heart can’t pump a sufficient amount of blood
CO is reduced
Tissue perfusion decreases
Cells don’t receive sufficient O and nutrients
T or F: HF is chronic
True
How can patients manage their HF?
- Meds
- Low sodium
- Symptom monitoring
- Weight and vital sign monitoring
- Health status decision making
Individuals with chronic HF may develop ______ requiring ______
Acute decompensated HF; hospitalization
What are the causes of ADHF?
- Stress
- Infection
- Diet and med nonadherence
- Poor health
- High BP
- MI
- Alcohol and endocrine disorders
ADHF can range from ___ to ___
Volume overload to cariogenic shock
T or F: Acute HF can NOT be isolated.
False
Patients can recover from event but must take inotropic meds or have mechanical support
Classifications of heart disease are based on _____ according to the _____
Functional capacity; NY Heart Association