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QOD Exam 2 Questions And Correct Answers
How does hypertension affect afterload?
Afterload: resistance the heart must overcome eject blood from a given chamber.
HTN increases afterload bc the heart must generate more force to overcome the increase in BP. This creates afterload for LV (systemic HTN) or RV (pulmonary HTN).
In aortic valve stenosis, the heart must generate more pressure to push blood through the narrowed heart valve.
Why might someone with long-standing hypertension develop heart failure?
If the heart has to continually work against high BP, the heart will hypertrophy (pathologic) to compensate, just like any other muscle that has to work against increased resistance. This contributes to ventricular wall stiffness and decreased chamber size. Both of these factors can contribute to diastolic dysfunction and heart failure.
A patient has been diagnosed with left sided heart failure and an ejection fraction of 33%. What is the significance of this EF?
Ejection fraction tells us percent of EDV is pumped out of the heart with each beat, related to cardiac output. A normal EF is somewhere between 55%-70%. A person with an EF of 33% has systolic dysfunction. Results in a subsequent drop in cardiac output.
A patient has been diagnosed with left sided heart failure and an ejection fraction of 33%. How would this patient's left ventricular end-systolic volume (ESV) compare to someone with a healthy heart?
ESV would be increased bc more blood would be remaining in the ventricle at the end of systole. When the heart relaxes during diastole, the heart continues to fill as normal, and the blood returning during diastole is added to the excess blood already in the ventricle.
This will lead to increased ventricular pressures, which cause excessive stretch of the ventricle. The increased stretch of the myocardium will lead the atria and ventricles to release ANP and BNP respectively, which increase sodium (and therefore water) excretion in the kidneys.
What is a valve stenosis and valve regurgitation (incompetence)?
Valve stenosis: thickened, stiff, scarred, or malformed valve that does not open fully.
Regurgitation is an "incompetent" valve that does not close fully.
How could valve disorders lead to heart failure?
Both stenosis and regurgitation disrupts unidirectional flow, leading to congestion in the chambers and structures before the valve.
Aortic stenosis > blood backs up into LV > ventricle dilates and hypertrophies to compensate, eventually become inadequate (remodeling of heart becomes pathologic)
blood backs up into LA > blood backs up into lungs (pulmonary edema) and signs of inadequate organ perfusion (dizziness, possible fainting, chest pain, low urine output, diminished pulses, etc.)
With mitral stenosis or regurgitation, there is congestion in LA, hypertrophy, and increased ESV. Why does LV have decreased ESV?
- With mitral stenosis, less blood makes it into the left ventricle during filling, which decreases end diastolic volume. If you start with less blood at the beginning of systole, you will have less at the end of systole as well.
- Mitral regurgitation reduces LV afterload. How? Because you essentially now have two "doors" out of which blood can escape during systole (both the aortic valve and the mitral valve are now allowing blood out during systole). Since blood is escaping out of both valves, more blood is pumped out during systole, leading to a lower left ventricular
leading to rising pulmonary artery pressure. Scar tissue formation can compress existing vessels, also leading to an increase in vessel pressure.
- Decreased oxygen in lungs leads to arterial vasoconstriction (lungs shunt blood away from areas of low oxygen). Decrease in pulmonary oxygen contributes to chronic vasoconstriction, which contributes to pulmonary HTN.
What would happen to right ventricular end-diastolic volume in this case? How about right ventricular end-systolic volume?
The right side is not a thick muscle, only meant to beat against low pressures. Pulmonary HTN will cause RV to dilate and hypertrophy over time, and this process becomes pathologic. This is known as "cor pulmonale", a right-sided heart failure induced by lung disease. RV EDV and ESV will increase as right side of heart dilates to accommodate more blood.
A person had abdominal surgery and is in severe pain. Because of this, their breathing is shallow. Would this be considered an obstructive or restrictive breathing problem?
Restrictive. Nothing in the case indicates an obstruction to expiratory airflow. With abdominal and chest surgery pain, patients don't want to breathe deeply. This leads to a functional restriction (they aren't breathing in much because expanding their lungs leads to pain). Breathing out is not usually impeded unless another situation develops (ex. mucus plugs in their airways).
What is the difference between extrinsic and intrinsic lung disease?
Extrinsic: problem is outside lungs
Intrinsic: problems originating inside lungs
What are common restrictive breathing disorders?
Extrinsic: Neuromuscular diseases, chest wall deformities (ie. scoliosis, kyphosis), obesity, MD, myasthenia gravis, polio, ALS (Lou Gehrig's Disease).
Intrinsic: idiopathic pulmonary fibrosis/IPF, sarcoidosis, black lung/miners lung, asbestosis
What are common obstructive breathing disorders?
refractory asthma, COPD, obstructive sleep apnea/OSA, bronchiectasis and cystic fibrosis
You are a nurse assisting with pulmonary function tests in an outpatient setting. You have four clients coming by this morning. Which client would you expect to have a decreased FEV1/FVC ratio?
A. A woman with emphysema
B. A man with pulmonary fibrosis
C. A man with a C5 spinal cord injury
D. A woman who is clinically obese with a BMI of 40
Emphysema is an obstructive disorder which compromises the ability to expire air due to airways collapsing. While both FEV1 and FVC tend to drop in emphysema, FEV1 drops more dramatically, leading to a decrease in the FEV1/FVC ratio.
The other disorders listed are restrictive diseases, which will result in less inspired air, leading to a total decrease in all lung volumes. The FEV1/FVC ratio often does not change much in restrictive lung disease (and in many cases, it can increase). This is because they tend to be able to move air out of the lungs just fine. They just start with overall lower volumes to begin with.
What are the similarities between asthma and COPD?
Both asthma and COPD are obstructive respiratory disorders that cause problems with expiring air. This leads to air trapping and hyperinflation of the lungs. Both can have flares that are triggered by exposures to environmental allergens, and both will cause a reduction in the FEV1/FVC ratio.
d. Aortic regurgitation- Blood moves backward during diastole, which overfills the ventricle. This results in a loss of SV and a reduction in ejection fraction (the blood initially moves out during systole, but then some of it travels backward back to the ventricle). This overfills the ventricle and causes an overall reduction in the ejection fraction.
e. Restrictive cardiomyopathy: the heart becomes stiff from infiltrative connective tissue. This impedes the heart's ability to relax and fill.
f. Dilated cardiomyopathy: ventricular chamber is large (dilated) and the muscle is reduced in size. This leads to problems pumping.
g. Long-standing anorexia nervosa: cause heart muscle fibers to degenerate because of lack of nutrients to maintain healthy cardiac muscle. This leads to a weak cardiac pump, systolic issue.
