Ch. 20 Heart Failure and Circulatory Shock Flashcards
What is heart failure?
Heart Failure is a clinical syndrome that occurs when the heart is unable to pump adequate blood to meet the metabolic demands of the body
What is the cardio-renal model of heart failure?
It views heart failure as a disorder of excessive sodium and water retention (outdated model).
What is the view of heart failure as a hemodynamic disorder?
It looks at the reduced cardiac output or afterload.
What is the current understanding of heart failure?
heart failure as a neurohormonal model
What is “preload”?
“End diastolic volume”
What is “afterload”?
Amount of force needed to eject filled heart.
What determines afterload?
Determined by SVR and ventricular wall tension.
What determines preload?
Determined by venous return to the heart.
What is “contractility”?
Performance of cardiac muscle.
What are four general types of heart failure?
Systolic vs. diastolic
Dilated vs. hypertrophic
Left vs. right
High-output vs Low-output
What is systolic heart failure?
Impaired ejection of blood. Presence of signs and symptoms of heart failure with an ejection fraction of
What are the causes of systolic heart failure?
Muscle issues
Volume overload
Pressure overload
What are some of the muscle problems that can cause heart failure?
CAD, myocarditis, cardiomyopathy, conduction issues
What are some volume overload problems that can cause heart failure?
Valvular insufficiency, kidney disease
What are some pressure overload problems that can cause heart failure?
HTN
valvular stenosis
Pulmonary disease
What is diastolic heart failure?
Impaired filling during diastole
Presence of signs and symptoms of HF in the absence of systolic dysfunction (LVEF > 40%)
Myocardium is “stiff” (and often hypertrophied) and does not relax normally after contraction
What are the causes of diastolic heart failure?
Impaired ventricular stretch
Increased wall thickness
Delayed diastolic relaxation
What are some disorders that cause impaired ventricular stretch, that can cause diastolic heart failure?
pericardial effusion, pericarditis, amyloidosis
What are some disorders that cause increased heart wall thickness, that can lead to diastolic heart failure?
hypertrophy, myopathy
What are some factors that cause delayed diastolic relaxation, that can lead to diastolic heart failure?
Aging, CAD
Why is diastolic heart failure aggravated by tachycardia?
The heart already has a hard time filling properly, and in tachycardia there is even less time for the heart to fill between pumping
What are the risk factors for diastolic heart failure?
Women, obesity, HTN, diabetes mellitus
What is the main difference between systolic heart failure and diastolic heart failure?
Systolic = an ejection problem Diastolic = a filling problem
What do systolic and diastolic heart failure have in common?
A decreased cardiac output.
What are the CNS symptoms of left ventricular dysfunction (left-sided heart failure)?
Fatigue, weakness, confusion, dizziness (worsens over day)
What are the cardio-vascular manifestations of left ventricular dysfunction (left-sided heart failure)?
Hypotension, angina, tachycardia, palpitations, pallor, weak peripheral pulses, cool extremities, S3/S4
What are the renal complications of left ventricular dysfunction (left-sided heart failure)?
Oliguria (less urine) during the day
Night time = frequent urination
What are the manifestations of left ventricular dysfunction (left-sided heart failure)?
SOB (initially during exertion/orthopnea/PND) Cough, “cardiac asthma” (worse at night) Inspiratory crackles/expiratory wheezes Tachypnea Frothy/pink sputum (pulmonary edema)
What are the manifestations of right ventricular dysfunction (right-sided heart failure)?
Jugular vein distention/elevated central venous pressure Enlarged liver and spleen Dependent edema Ascites Polyuria at night Weight gain Hepatojugular reflux (HJR) BP changes Elevated BP (excess volume) Decreased BP (decreased cardiac output)
What is high-output heart failure?
Caused for excessive need for cardiac output. The heart compensates, and then fails from too much compensation.
What are the causes of high-output heart failure?
Severe anemia
Thyrotoxicosis/thyroid storm
What is low-output heart failure?
Caused by conditions decreasing pumping ability
What are the causes of low-output heart failure?
Coronary artery disease
Cardiomyopathy
What is the Frank-Starling mechanism of compensating for heart failure?
+Increased preload (end diastolic volume) will increase stroke volume.
-Stretch increases wall tension, increasing oxygen requirements
What is the sympathetic nervous system mechanism of compensating for heart failure?
+Increase in circulating catecholamines increase HR, contractility, peripheral vascular resistance, stroke volume, cardiac output.
-Increased workload
What is the renin-angiotensin-aldosterone system of compensating for heart failure?
+Increased concentration of renin, angiotensin II & aldosterone d/t decreased renal perfusion
-Increased preload, increased workload
What is the natriuretic peptide (ANP&BNP) mechanism of compensating for heart failure?
+Released in response to stretch, pressure, fluid overload (promote diuresis)
-Decreases preload, decreases cardiac output