Cardiovascular_Exam 2: Ch. 33, 34 Flashcards
What factors contribute to blood flow in a vessel
- compliance
- pressure and resistance
- velocity
- turbulent vs. laminar flow
Which coronary arteries provide blood to which part of the heart?
Right coronary artery supplies blood to right atrium, right ventricle, SA node, and AV node
Left coronary artery supplies blood to left atrium, left ventricle, and interventricular septum
What does Qp : Qs mean and what factors alter a normal ratio?
ratio to pulmonary to systemic flow, describes the magnitude of a vascular shunt
Qp=pulmonary flow
Qs=systemic flow
Normally=1:1. left to right shunts>1.0; right to left shunts Qp/Qs <1
A cardiac shunt is a pattern of blood flow in the heart that deviates from the normal circuit of the circulatory system
Catecholamine effect on cardiovascular system
Increase heart rate, bp, breathing rate, muscle strength, and mental alertness
Epinephrine effect on cardiovascular system
Increases heart rate. Vasoconstriction in most systemic arteries and veins. INCREASED CARDIAC OUTPUT and redistribution of the cardiac output to muscular and hepatic circulation with only a small change in the arterial pressure
Norepinephrine effect on cardiovascular system
Increase in heart rate and inotropy.
Vasoconstriction occus in most systemic arteries and veins.
INCREASED CARDIAC OUTPUT and SYSTEMIC VASCULAR RESISTANCE which results in an ELEVATION IN ARTERIAL BLOOD PRESSURE
Dopamine effect on cardiovascular system
increased pulse pressure, heart rate, and circulating epinepherine and norepinepherine levels
ACUTE CORONARY SYNDROME -STEMI
DEFINITION: ST elevation; continued coronary occlusion which leads to transmural infarction extending from endocardium to pericardium. Leads to myocyte necrosis and death.
CLINICAL MANIFESTATIONS: sudden severe chest pain that is prolonged. “Elephant sitting on chest”. Radiates to neck, jaw, back, shoulder, or left arm is common.
ACUTE CORONARY SYNDROME -UNSTABLE ANGINA (PRINZMETAL)
DEFINITION: type of acute CAD that results in reversible myocardial ischemia
CLINICAL MANIFESTATIONS: new onset angina, angina that occurs at rest, or angina that is increasing in severity or frequency. May also experience dyspnea, diaphoresis, and anxiety as it gets worse.
Evaluate the differences in the extent of an infarction of the myocardium secondary to an NSTEMI and a STEMI (these are 2 types of myocardial infarctions)
NSTEMI: ST depression and T-wave inversion. Thrombus is less liable and occludes the vessel for a prolonged period that leads to myocardial ischemia and leads to myocyte necrosis and death. Thrombus will break up before complete distal tissue necrosis and only myocardium directly under endocardium will be involved.
STEMI: ST elevation. When thrombus lodges permanently in vessel, the infarction will extend through the myocardium all the way to the endocardium or epicardium resulting in severe cardiac dysfunction.
Preload definition (also end diastolic volume)
amount of blood in ventricle at the end of atrial systole just prior to ventricular contraction
Afterload definition
resistance to ejection of blood from the left ventricle
Stroke volume definition
the amount of blood pumped of by a ventricle with each beat
End systolic volume definition
the volume of blood in the left or right ventricle at the end of the systolic ejection phase immediately before the beginning of diastole or ventricular filling
Ejection Fraction definition
a measurement % of how much blood the ventricle pumps out with each contraction
Cardiac output definition
the amount of blood the heart pumps through the circulatory system in a minute
A Fib causes
in atrial fibrillation, the signals in the upper chambers of the heart are chaotic. As a result, the upper chambers shake (quiver). The AV node is then bombarded with signals trying to get through to the lower heart chambers (ventricles). This causes a fast and irregular heart rhythm.
**100-175 bpm
A Fib risk factors
Advancing age High BP obesity European ancestory Diabetes heart failure ischemic heart disease hyperthyroidism CKD moderate to heavy alcohol use Smoking Englargement of chambers on the left side of the heart
A Fib Pathophysiology**
hypertension, structural, valvular, and ischemic heart disease illicit the paroxysmal and persistent forms of atrial fibrillation
A Fib Manifestions
palpitations, dizziness, CP, fainting, dyspnea, pallor, fatigue, nervousness, cyanosis
PVC causes
are extra heartbeats that begin in one of your heart’s two lower pumping chambers (ventricles). These extra beats disrupt your regular heart rhythm, sometimes causing you to feel a fluttering or a skipped beat in your chest.
PVC risk factors
caffeine, tobacco, drugs, exercise, high BP, anxiety, heart disease
What does pulmonary circulation do?
movingbloodbetweentheheartandthelungs.Ittransports deoxygenatedbloodtothelungstoabsorboxygenandreleasecarbondioxide.
PVC manifestations
palpitations, dizzy, anxiety
What is the role of lipoproteins?
Lipoproteins provide a transport for lipids, phospholipids, cholesterol, and triglycerides as described below. … Transport of cholesterol to organs and tissues; cholesterol is required for the formation of membranes of red blood cells and for the production of steroid hormones. In the liver it is converted to bile acids.
How do the lipoproteins inform your knowledge of a persons cardiovascular risk?
Very-low-density lipoproteins (triglycerides)
may contribute to hardening of the arteries or thickening of the artery walls (arteriosclerosis) — which increases the risk of stroke, heart attack and heart disease.
Normal <150
How do the lipoproteins inform your knowledge of a persons cardiovascular risk?
Low-density lipoproteins (LDL)
positive association with atherosclerosis; cholesterol
increased levels indicator of risk of CAD
Normal: <100
How do the lipoproteins inform your knowledge of a persons cardiovascular risk?
High-density lipoproteins (HDL)
-negative association with atherosclerosis; phospholipids
-referred to as the “good” cholesterol because it helps remove other, more harmful forms of cholesterol from your blood.
Normal >40
What are the risk factors for dyslipidemia?
Genetics, obesity, unhealthy diet, lack of exercise
Describe the progression of atherosclerosis.
- damaged endothelium
- fatty streak and lipid core formation
- fibrous plaque formation
- complicated lesion, possible rupture
What is peripheral artery disease and how does it manifest?
-common circulatory problem in which narrowed arteries reduce blood flow to the limbs, cause by atherosclerosis, smoking, drug use, etc
Manifestations:
Pain and tenderness of the affected part
Painful cramping in one or both of the hips thighs or calf muscles after certain activities such as walking or climbing stairs (claudication)
Leg numbness/weakness
Coldness in the lower leg or foot, especially when compared with the other side
Sore on the toes, feet or legs that won’t heal
What factors contribute to determining a blood pressure?
- cardiac output
- peripheral vascular resistance
- volume of circulating blood
- viscosity of blood
- elasticity of blood vessel walls
What is hypertension and what are common causes?
-increased cardiac output, increased peripheral resistance
-sustained elevation >140/90 adults
Risk factors: genetics, age, gender and race, environment, dietary
What is compliance
vascular compliance is the increase in volume a vessel is able to accommodate for a given increase in pressure. Compliance is an index of the elasticity of the vessel. Stiffness is the opposite of compliance.
What can cause increase in blood viscosity?
increase in red cell content, increased plasma levels of fibrinogen and coagluation factors, and dehydration
Discuss how electrolyte imbalances affect conduction, contraction or resistance with POTASSIUM
- Contributes to repolarization phase of the action potential
- *Hyperkalaemia can cause suppressed conduction, resulting in tall, peaked T waves, or a prolonged PR interval and a widened QRS interval, Cardiac arrest from complete heart block at much higher K.
- *Hypokalaemia, decreased membrane excitability. A typical ECG for a patient with hypokalaemia will show flattened T waves, U waves (waves following a T wave, not typically seen on standard ECG traces), depressed ST segments or premature ventricular or atrial complexes that may signal worsening conduction blockade; at the extreme it can indicate impending ventricular tachycardia.
Discuss how electrolyte imbalances affect conduction, contraction or resistance CALCIUM
-Contributes to cardiac and smooth muscle contraction
**Myocardial contractility may initially increase until the calcium level reaches >15 mg/dL. Above this level myocardial depression occurs. Hypercalcemia may cause hypertension. Many patients with hypercalcemia develop hypokalemia. Both of these conditions contribute to cardiac arrhythmias.
Discuss how electrolyte imbalances affect conduction, contraction or resistance MAGNESIUM
-Interacts with calcium, contributes to myocardial metabolism, improved vascular smooth muscle tone and peripheral vascular resistance, after load, and cardiac output
- Hypomagnesemia can cause arrhythmia; prolongation of conduction and slight ST depression
- Hypermagnesemia can cause hypotension; depresses conduction system