Unit 7: Cardiology STUDY GUIDE Flashcards
Differentiate between the terms “preload” and “afterload”.
Preload is volume and pressure in ventricle after filling with blood (diastole). Determined by how much blood is left at the end of contraction (ESV) and venous blood return during diastole. After load is the force of resistance that the heart has to overcome to pump blood. Preload is after diastole, after load is before systole.
Afterload is commonly caused by HTN and HF
Explain what each segment of a normal electrocardiogram represents (P-wave, pr- interval, QRS interval, T-wave).
- P- wave is (R) atrial depolarization when the action begins after SA node starts it
- PR interval is the time between atrial activation to ventricle activation. Wildfire spreading from A to V.
- QRS interval captures the period of ventricular depolarization. Amp varies among ppl.
- T-wave is ventricular repolarization, when part is over.
- ST wave encompasses the depolarization and repolarization of the ventricles.
Describe “orthostatic hypotension” and list the conditions that increase the risk of this happening.
AKA postural HTN is when systolic BP drops more than 20 mm/Hg or diastolic drops more than 10 mm/Hg. A drop in BP that occurs when the person stands up after sitting or lying. Pt will feel dizzy, and lightheaded, and may faint. Metabolic, endocrine, and CNS/PNS disorder may cause this.
Differentiate between primary and secondary hypertension
Primary HTN is 140-159/90-99 it is when the systolic pressure is consistently high.
Involves genetics and environment. Influenced by neurohormonal effects and their effects on IV volume and peripheral vascular resistance. Increase risk of target organ disease, MI, kidney disease, and stroke. RAAS contributes to water and sodium retention and more vascular resistance, endothelial resistance, and platelet aggregation.
Secondary HTN is >160/>100
it is consistent elevation of diastolic BP. Also inr=creases risk for target organ disease, MI, kidney disease, and stroke. There is an underlying disease/med that causes increased peripheral vascular resistance or C.O. If you remove problem HTN will resolve. Ex: pheochromocytoma, meds, renal vascular or parenchymal disease, and adrenocorticol tumors.
List the stages of hypertension and the resulting blood pressure readings that would indicate each stage.
Normal <120/<80
ELevated 120-139/80-89
Stage 1 HTN 140-159/90-99
Stage 2 HTN >160/>100
Describe the stages of atherosclerosis in the order in which they occur.
Stage 1- Damage to the endothelium of a. Think smoking, HTN, toxins, viruses, and immune rxns.
Stage 2- Foam cells create a fatty streak when macrophages invade intima and engulf oxidized LDLs (foam cells).
STage 3- Fibrous plaque is formed as macrophages release growth factors which cause collagen to cover fatty streak.
Stage 4 Complicated plaques where they rupture. Leads to platelet adhesion, clotting cascade, and rapid thtombus formation.
Describe how to calculate the Mean Arterial Pressure (MAP) and what it means to the health of the patient.
The average pressure against walls of the aa. in heart cycle. Normal range is 70-100mmHg and can tell us if blood is working well enough to supply vital organs. Less than 70 is concerning. SBP+(2xDBP)/ 3
Describe the Ejection Fraction and indicate the normal levels for both genders.
Amount of blood ventricles eject with each heartbeat. EF= (SV/EDV)x100
SV- mL of blood per beat
Describe how the sympathetic nervous system, Overactive RAAS and natriuretic hormones and electrolyte imbalances impact the development of primary hypertension.
the fight-or-flight system will cause HR to increase and vasoconstriction.
C.O. is increased and restricts peripheral vessels.
Narrows inner lumen which will increase intravascular pressure.
In primary HTN, RAAS is overactive which causes retention of salt and water and increases vascular resistance.
Natriuretic hormones keep Na excretion in balance, so changes in RAAS and SNS will decrease sodium excretion.
Explain the impact of inflammation, obesity, insulin resistance, and chronic stress on primary hypertension.
Primary HTN is when systolic pressure is consistently elevated, an epigenetic disease. Inflammation is a natural response to a foreign substance that the body sees as a threat and it releases chemicals that will in turn damage to blood vessels. Can lead to high BP as macrophages raise blood flow. Obesity plays a role because extra fat will compress on organs, like kidneys which can activate RAAS system and that increases vascular resistance as well a decreased excretion of water and Na, causing heart to contract stronger and putting more pressure on walls.
Chronic stress will activate the SNS and the body will produce more hormones from adrenal glands which cause vessels to constrict in efforts to increase oxygen levels.
Explain how increased vascular resistance impacts the development of primary hypertension (be sure to describe the role of the SNS system, arteriolar remodeling, and vessel dysfunction).
Increased vascular resistance can be due to a variety of reasons, but they all increase the pressure exerted against walls of blood vessels d/t a factor that increases the amount of work that must be done to get the blood to flow.
Describe the cardiovascular complications associated with hypertension (heart, brain, blood vessels, kidneys, eyes, and encephalopathy)
HTN is consistently elevated BP d/t vasoconstriction, increased vascular resistance, and more fluid in blood.
The heart will work harder and less blood flow in aa. of heart. We can get LVF, MI, and even HF.
The brain will receive less blood, vessel walls will weaken and atherosclerosis will quicken. We can get TIAs, cerebral thrombosis, aneurysm, hemorrhage, acute brain infarction/
Blood vessels will constrict and weaken. We can get dissecting aneurysm
Kidneys will go on overdrive and the RAAS system will be overstimulated meaning more water and Na will be held onto. SNS will also be stimulated. We can get glomerulosclerosis, decreased GFR, and end-stage renal disease.
In the eyes, HTN will cause retinal vascular sclerosis, and increased retinal a. pressure and lead to HTN retinopathy, retinal exudates, and hemorrhages.
Encephalopathy: high arterial BP leads to cerebral arterioles being unable to regulate blood flow to cerebral capillary beds. Pushes fluid out of tissues. May lead to death.
Describe the pathophysiology and signs and symptoms of Aortic aneurysms.
Patho: When blood vessels weaken, an aneurysm will form, which is like a balloon in the vessel. Most common cause of an arterial aneurysm is atherosclerosis, followed by HTN, smoking, infections, and collagen-vascular disorders.
After an MI, an aortic aneurysm is likely to occur because an MI weakens or kills the heart myocardium. Tension in the ventricles can cause the weakened mm. to stretch into a thin layer and a bulge will form.
S/S: generally, asymptomatic, once they rupture SEVERE pain and hypotension ensue in the area where it occurred.
True aneurysms affect the 3 layer of heart and are FUSIFORM
False aneurysms are from trauma and blood escapes the lumen of vessel, similar to fusiform shape .
Describe the pathophysiology and signs and symptoms of Thoracic aortic aneurysms.
Patho: aortic aneurysm that has ruptured in the thoracic portion of the aorta d/t weakening of a. wall.
S/S: pain and hypotension. Dysphagia, dyspnea
Describe the pathophysiology and signs and symptoms of Aneurysms in the extremities
patho: blood flow blocked, most commonly by HTN. Again, pressure in aa. increases and this causes the lining of vessels to extend and create fusiform or saccular aneurysms. Saccular is more common in the circle of Willis and fusiform outside of brain.
S/S: ischemia (localized pain, swelling, pallor, poikilothermia, and even paralysis.
Describe the pathophysiology and signs and symptoms of Cerebral aneurysms in the circle of Willis
patho: Circle of Willis is the site where most aneurysms in brain occur. A result of increased IC pressure with a weak vessel that bulges out. Most are not found until after they rupture and hemorrhage.
S/S: depend on site and type. Often asymptomatic, but can cause severe headache or dizziness and CN compression.
Describe the pathophysiology and signs and symptoms of aneurysms in the heart.
Patho is same as all other aneurysms, aa. weaken as a result of damage to vessel from HTN, atherosclerosis, etc.
S/S: abnormal heart rhythm or HF and may lead to blood clot in brain or other organs.
Describe what happens when the heart muscle suffers myocardial ischemia (be sure to talk about the length of time until recovery of the tissue is no longer possible and what happens then).
MI happens when there is not enough O2 to meet demands. Cells are damaged from this lack of O2.
MI is most commonly caused by coronary blood flow decreasing from atherosclerosis in coronary circulation aka CAD.
Myocardial cells become ischemic within 10 secs of being deprived of O2. The heart starts to give out and pumps blood less effectively, lactic acid build-up because there is not enough glucose for aerobic respiration. The heart loses the ability to contract and CO decreases. If O2 isn’t replenished in cardiac cells within 20 min, MI will occur.
Thoroughly describe the pathophysiology, signs and symptoms, and assessment associated with left- versus right-sided heart failure.
HF is when heart can no longer provide enough CO. Main culprit: MI.
Left-sided HF
Can be divided into LHF with preserved or reduced EF.
- LHF with reduced EF , aka systolic HF, is when EF is less than 40% (normal is 50-
- LHF with preserved EF aka diastolic HF. Can happen with systolic or on its own
Patho:
S/S: dyspnea, orthopnea, pulmonary edema, crackle and S3 gallop
Right-sided HF is the result of LHF. Patho: the increase in pulmonary circulation that caused the L-sided HF also increased vascular resistance. This causes peripheral edema and hepatosplenomegaly.
- Cor Pulmonale is RHF that happens without LHF. It is d/t pulmonary disease that causes hypoxia, such as COPD, CF, or ARDS which will cause increased R.V afterload
S/S:
Thoroughly describe the pathophysiology, signs and symptoms, and assessment findings associated with pericardial effusion
Pericardial effusion is when fluid accumulates in the pericardial cavity, as seen in pericarditis. In most cases, no known cause (20%) but can be caused by neoplasm or infection, acute pericarditis, surgery, chemo, or autoimmune disorders
Acute pericardial effusion is more dangerous because the heart does not have enough time to accommodate to the increased pressure from the influx of fluid.
This can lead to cardiac tamponade which will prevent the ventricles from expanding and functioning properly. If the pressure from the fluid is equal to the diastolic pressure, this can lead to increased venous pressure, systemic venous congestion, and s/s of RHF (JVD, edema, and hepatomegaly).
If there is not enough blood in atria, there won’t be enough in the ventricles, which causes decreased SV and reduced C.O.