Acute Heart Failure Flashcards
What is heart failure?
The result of any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood
Overall five year mortality for heart failure?
60%
What is the biggest risk for HF
Age
What factors influence cardiac output?
- Contractility
- Heart Rate
- Total peripheral resistance/wall stress
- Preload
How does heart rate affect cardiac output?
Tachycardia decreases diastolic filling time which decreases stroke volume and eventually decreases CO
What is central venous pressure?
Pressure that increases with increased volume, peripheral resistance, or compliance - Reflects the amount of blood returning to the heart
How is Afterload related to Wall Stress
As afterload increases, so does wall stress, which is compensated with hypertrophy
What is the equation for wall stress?
Wall Stress = (Pressure x Radius)/(2x wall thickness)
What are some exacerbating factors in Acute Heart Failure associated with decreased contractility?
Acute MI
Negative inotrope
Alcohol
What are some exacerbating factors in acute heart failure associated with increased heart rate?
- Increased metabolism
- Fever
- Infection
- Tachycardia
- Hyperthyroidism
- Pregnancy
* slow heart rate is also exacerbating for AHF
What are some exacerbating factors in acute heart failure associated with increased preload?
- Sodium content in diet
- Excessive fluid intake
- Renal failure
What are some exacerbating factors in acute heart failure associated with changes in afterload?
Uncontrolled hypertension
Pulmonary embolism
Severely dilated ventricle
What is the cycle of congestion in AHF
A process mediated by the kidneys: Myocardial oxygen demand → Myocardial ischemia → Worsening HF → Elevated Left Ventricular End Diastolic Pressure → Increased Wall stress → Myocardial oxygen demand →…
What are the goals of the physican in treating AHF?
- Identify the etiology of acute heart failure
- Appropriately treat acute heart failure to achieve a stable hemodynamic equilibrium
- Reverse (if possible) the exacerbating stimulus
What does the LVEDP directly increase in the heart?
Wall stress
What are methods of assessing a patient with Acute Heart Failure?
History and physical examination
Laboratory testing
Echocardiogram (Non invasive)
Swan-Ganz Catheter (Invasive)
Describe the Frank-Starling Relationship
Connects force and muscle fiber length - the more myosin actin cross bridges made to cycle, the more contractile force will be generated - as the fiber stretches, there is a greater number of bridges available and greater contraction but at some point the fibers can be stretched to a length where optimal cross bridging no longer happens
Physical exam findings with AHF: Murmurs
- Mitral regurgitation
- Crescedo-decrescendo murmur of aortic stenosis
- S3 gallop
- P2 “knock” suggests RV volume or pressure overload
Physical exam findings with AHF (besides murmurs)
- Distended jugular veins
- Pulmonary: tachypnea, inspiratory crackles
- Lower extremity edema
- Hypotension
- Decreased pulses - intermittent pulses
- Cold clammy skin
- Tachycardia
How fast must tachycardia be to increase suspicion of AHF
Not very fast - even rates of 110 bpm should raise suspicion
What are the two most important physical exam findings in AHF?
Third heart sound and high jugular venous pressure (distended neck veins)
What lab tests do you perform in AHF? (what do you look for)
- Brain natriuretic peptide (in atria and ventricles in response to stress)
- Troponin: Risk stratification and diagnostic tool
- Elevated BUN and Creatine
- Basic metabolic panel (electrolyte imbalance)
- CBC: evaluate for anemia or hemoconcentration
ELevated _______ in HF are common and predict death
Troponins