Heart Failure Flashcards
What is heart failure with reduced ejection fraction
AKA systolic heart failure. Most common form
Left ventricle cannot generate enough pressure to eject blood forward through the aorta
Ejection fraction <40%
What is heart failure with preserved ejection fraction
Aka diastolic HF. Inability of ventricles to relax and fill during diastole leading to decreased filling and cardiac output
Characterized by high-filling pressures
Often the result of left ventricular hypertrophy
How does the SNS compensate for HF?
-Release of catecholamines
-increased HR, myocardial contractility and peripheral vasoconstriction
-Eventually leads to increased cardiac workload and O2 requirements
What do the kidneys do to compensate during HF?
-Kidneys respond to decreased blood flow by producing more renin which will activate the RAAS system
-Sodium and fluid are retained, peripheral vasoconstriction and BP are increased
What does the pituitary gland do in response to HF?
The posterior pituitary gland responds to decreased cerebral perfusion pressure and secretes ADH (causes sodium and water retention) creating increased blood volume in an already overloaded state
What is ventricular dilation?
-ventricles enlarge due to chronically elevated pressure
-Allows for greater filling volumes at first but eventually, muscle fibres are too stretched to contract effectively
-Decreased CO
What is Ventricular Hypertrophy? How does it compensate for HF?
-hypertrophy of myocardial cells increasing cardiac wall thickness in response to overwork + strain
-Initially adaptive but eventually hypertrophic muscle requires more O2 and has poorer contractility
-Coronary artery circulation is poor, dysrhythmias are common
What does BNP do in HF?
-Acts as counter-regulatory system
-regulate renal, cardiovascular and hormonal effect (i.e., increase diuresis, vasodilation, inhibit aldosterone)
-Cardiac decompensation occurs when these mechanisms can no longer maintain adequate CO and tissue perfusion becomes insufficient
What are the primary risk factors for HF?
Coronary artery disease and hypertension
What are the Cardiac Output regulatory mechanisms?
-Pre load, afterload
-Cardiac contractility
-Heart rate
What are the S&S of left sided (REF) HF
-Pulmonary congestion (cough, crackles, wheeze, blood tinged sputum, tachypnea)
-Tachycardia
-Exertional dyspnea
-Cyanosis
-Nocturnal dyspnea, orthopnea
What are the S&S of right sided (PEF) HF?
-Increased peripheral venous pressure
-Ascites
-Enlarged liver and spleen
-Dependent edema
-Distended jugular veins
-Anorexia + GI distress with weight gain
What is EF and what would a decreased EF indicate?
-Indicates the percentage of blood ejected from the left ventricle with each contraction
-EF is Beverly reduced in systolic or REF HF
-Decrease in EF indicates worsening HF
What is a normal EF range?
55-65%
How do angiotensin-converting enzyme inhibitors, such as enalapril work to reduce HF?
a. Cause systemic vasodilation
b. Increase cardiac contractility
c. Reduce preload and afterload.
d. Prevent conversion of angiotensin I to angiotensin II
e. Block sympathetic nervous system stimulation to the heart.
f. Promote the excretion of sodium and water in the renal tubules.