HLTH cardio system review Flashcards
heart location
located within the mediastinum and the double walled pericardial sac
3 layers of the heart
endocardium, myocardium, and epicardium
atrioventricular valves
bicuspid or mitral valve (left side) and tricuspid valve (right side)
where does the heart conduction pathway begin?
the SA node
sinus rhythm
rhythm established by the SA node
order of flow of heart conduction
SA node > AV node > bundle of His > right and left bundle branches > purkinje fibres
P wave of ECG
is the atrial depolarization
QRS wave
ventricular contraction (and atrial relaxation but this is masked)
T wave
represents repolarization of the ventricles
what detects changes in BP?
the baroreceptors in the aorta and carotid arteries
sympathetic receptors in the heart
beta1-adrenergic receptors
two arteries branching off the aorta
left and right coronary arteries
what does the left coronary artery branch into?
the left anterior descending artery and the left circumflex artery
what does the right coronary artery branch into?
the right marginal artery and the posterior interventricular artery
when is blood flow to the heart the greatest?
during diastole or relaxation
collateral channels
exist between vessels and are important if one gets obstructed; more develop with aerobic exercise
what does the right coronary artery supply?
the right side of the heart, the posterior left ventricle, and the posterior interventricular septum
what does the left coronary artery supply?
the anterior sides of the ventricles, the anterior septum, and the left atrium
lubb sounds
closing of the AV valves
dubb sounds
closing of the semilunar valves
what causes heart murmurs?
defective valves that don’t close completely or a hole in the heart septum
apical pulse
refers to pulse measured at the heart itself
pulse deficit
difference between the radial pulse and the apical pulse
cardiac output
the volume of blood ejected by a ventricle in one minute; SV x HR
cardiac reserve
refers to the heart’s ability to increase output in response to increased demand
preload
refers to the heart at the end of diastole with ventricles at their maximum volume
afterload
the force required to eject blood from the ventricles
blood pressure
refers to pressure against the systemic arterial walls
systolic pressure
is the pressure exerted by the blood during systole of the left ventricle
diastolic pressure
refers to pressure that is sustained during diastole
pulse pressure
difference between systolic pressure and diastolic pressure
peripheral resistance
forces opposing blood flow such as friction
2 ways BP is elevated by the sympathetic system
beta1-andregenic receptors increase HR and vasoconstriction occurs
what is an ECG useful for?
myocardial infarction, infections, and arrhythmias
echocardiography
ultrasound is used to record images of the heart and valve movements; useful for valve defects and congenital defects
nuclear imaging
is done with thallium and can asses the size of an infarction
single-photon emission
can assess cardiac ischemia at rest
troponin blood tests
can measure the level of blood proteins called troponins that are released when the myometrium is damaged
doppler studies
a microphone that assess blood flow or obstruction of a vessel
benefits of exercise for the heart
decreases serum lipid levels, increases high-density lipoprotein levels, and reduces stress
smoking effects on the heart
increases vasoconstriction and heart rate, increases platelet adhesion and thrombus formation, and increases serum lipid levels
vasodilators example and function
decrease peripheral resistance, but may also decrease blood pressure; ex. nitroglycerin or isosorbide
beta-blockers function and example
prescribed for hypertension and dysrhythmias and act on beta1-adrengenic receptors; ex. metoprolol or atenolol
calcium channel blockers
block the movement of calcium into the smooth muscle, thus decreasing contractions
digoxin
slows conduction of heart rate (less frequent but more powerful) and used for atrial dysrhythmias
side effects of antihypertensive drugs
orthostatic hypotension
anticoagulant drugs
aspirin or warfarin, however, hemorrhage can be a risk
cholesterol or lipid lowering drugs
are prescribed when exercise and diet are ineffective and are the statin drugs, ex. simvastatin
what does coronary heart disease include?
angina pectoris or an MI
dangers of coronary heart disease
decreased O2 delivery to the myocardium
cause of angina
a deficit of O2 to the myocardium which can be caused by obstructions, spasms, or hypertrophy of the heart
variant angina
when vasospasm occurs at rest
unstable angina
refers to prolonged pain at rest, perhaps the result of a break of an atheroma
what usually precedes angina?
an increased demand for O2; can be exercise, getting angry, following an infection, or eating a large meal
signs of angina
chest pain that can radiate to the neck or left arm, followed by pallor, diaphoresis (excessive sweating), or nausea
treatment for angina
usually vasodilators like nitroglycerin
myocardial infarction
is a heart attack due to death of myocardial tissue due to ischemia
risk for those surviving an MI
recurrent MI, CHF, or stroke
2 broad types of MIs
ST elevation or non-ST elevation
most common cause of an MI
atherosclerosis with thrombus attached
3 causes of an infarction
thrombus in an artery grows, vasospasm + partial obstruction, or thrombus breaks away and lodges in a smaller artery
what happens to the heart tissue following infarction?
necrosis, inflammation, and fibrous tissue develop, as well enzymes are released
warning signs of an MI
persistent chest pain radiating to the left arm, pallor, and rapid, weak pulse
what treatment can prevent permanent heart tissue damage before an MI?
thrombolytic therapy
what enzymes are elevated during an MI?
LDH-1, aspartate aminotransferase, and creatine phosphokinase with M and B subunits
what causes death during an MI?
ventricular arrhythmias and fibrillation
Cardiogenic shock
occurs if the pumping capability of the left ventricle is greatly impaired
silent MI
no pain is present but gastric discomfort may indicate the infarction
heart block
occurs when conduction fibres in the infarcted area can no longer function due to problems in the AV node or bundle of His
what are major causes interfering with the heart conduction cycle?
damage to the system or electrolyte imbalances (resulting from stress, fever, hypoxia, infection, or drug toxicity)
major problems with irregular heart contractions?
they interfere with normal filling and emptying cycles of the heart
a very rapid heart rate reduces cardiac output because
it reduces ventricular filling
brachycardia rate and cause
less than 60 bpm and is often an issue with the vagus nerve and the PNS; can cause increased SV
tachycardia rate
100-160 bpm
sick sinus syndrome
is alternating bradycardia and tachycardia
most common dysrhythmias
atrial conduction abnormalities
extra contractions name
ectopic beats
premature atrial contractions
are extra contractions or ectopic beats usually resulting from irritable muscle cells outside of the conduction pathway
palpitations
rapid or irregular heart beats resulting from excessive caffeine intake, smoking, or stress
atrial flutter
rate of 160-350 bpm and is due to the AV node delaying conduction
atrial fibrillation
more than 350 bpm and causes pooling of blood in the atria
what is atrial fibrillation treated with?
anticoagulants
first-degree block
the time between atrial and ventricular contractions is delayed
second-degree block
when a conduction delay at the AV node results in intermittent missed ventricular
contractions
total or third degree block
occurs when there is no transmission from the atria to the ventricles, causing the ventricles to contract at a rate of 30-45 bpm; the ventricles are totally independent of the atria
bundle branch block
occurs as a result of a problem in one of the bundle branches; does not alter CO but does show up on a ECG as a prolonged QRS wave
ventricular tachycardia
reduces CO because ventricular filling is reduced
ventricular fibrillation
muscles are contracting independently and rapidly and this is ineffective is ejecting blood, causing hypoxia to the myocardium
PVCs
are additional beats from a ventricular muscle cell and usually are no concern, but if occur frequently this can cause ventricular fibrillation and CHF
stroke volume
ESP - EDP
problem with bradycardia
can cause increased SV
problem with tachycardia
can decrease CO
treatment for arrhythmias
changing medication (potassium sparing diuretics or beta-blockers), beta-adrenergic blockers, calcium blockers, digoxin (atrial), or pacemakers
cardiac arrest
cessation of all heart activity causes no oxygen delivered to the body
congestive heart failure
occurs when the heart is unable to pump blood to meet the metabolic needs of the body; usually one side of the heart fails first, followed by the other side
how do the body’s compensation mechanisms make CHF worse?
reduced blood flow causes aldosterone secretion, but vasoconstriction adds to the heart’s workload; SNS response also increases HR; and the heart chambers dilate and then hypertrophy
2 basics effects resulting from CHF
CO decreases (causes lethargy, fatigue, and acidosis) and backup congestion occurs
left-sided CHF
the left ventricle pumping is impaired, causing systemic circulation volume to decrease and for blood to be backed up returning to the left ventricle; pulmonary edema occurs
right-sided CHF
the right ventricle pumping is impaired, causing congestion in the systemic circulation, apparent in the feet, legs, and hepatic circulation
leading cause of CHF
coronary artery disease
cor pulmonale
is right-sided CHF due to pulmonary disease
forward effects of CHF
same for both left and right sided; are fatigue, weakness, dyspnea, exercise intolerance, cold intolerance, and dizziness
backup effects of left-sided CHF
dyspnea (when lying down), cough, and paroxysmal nocturnal dyspnea
paroxysmal nocturnal dyspnea
occurs when sleeping and waking up short of breath and possibly hemoptysis; due to pulmonary edema
backup effects of right-sided CHF
edema in the lower limbs, hepatomegaly, splenomegaly, ascites, flushed face, distended neck veins, headache, and visual disturbances
signs of CHF in children
feeding difficulties, delayed growth, sleep problems, and cough
congenital heart defects
are valve, septal, shunt, or vessel problems developing in the first 8 weeks of embryonic life; can be environmental or genetic
left-to-right shunt
blood from the left side of the heart goes to the right side, leading to increased volume in the pulmonary circulation and decreased CO
right-to-left shunt
blood from the right side of the heart goes to the left side, causing the lungs to be bypassed
acyanotic conditions
result when systemic blood consists of oxygenated blood
cyanotic conditions
venous blood mixes with arterial blood, permitting significant amounts of unoxygenated blood to bypass the lungs and enter the systemic circulation; causes bluish colour of the lips and nails
signs of a minor heart defect
heart murmur
signs of a major heart defect
pallor, cyanosis, dyspnea, clubbed fingers, delayed growth, cold and exercise intolerance, tachycardia, and squatting position
most common congenital heart defect
ventricular septal defect
ventricular septal defect
is a hole in the interventricular septum, causing a left-to-right shunt of blood; this results in more blood entering the pulmonary circuit (causes pulmonary hypertension) and less in the systemic
what valves are most often defected?
semilunar valves
stenosis for valves
refers to the narrowing of a valve
incompetence for valves
refers to a valve not completely closing, causing backflow of blood
Mitral valve prolapse
refers to abnormally large leaflets that backwards with pressure
result of valvular defects
the heart has to work harder to maintain pumping and SV, causing the heart to hypertrophy and eventually fail
4 defects in the tetralogy of fallot
pulmonary valve stenosis, VSD, dextroposition of the aorta, and right ventricle hypertrophy
result of the tetralogy of fallot
the pulmonary circulation receives low amounts of unoxygenated blood from the right ventricle and the oxygen deficit is great
rheumatic fever
results from an abnormal immune response occurring a few weeks after an untreated infection; inflammation will affect the heart, skin, and joints, and scar tissue will form in the heart
what is the cause of rheumatic fever?
a group A beta hemolytic streptococcus
what does the preceding infection of rheumatic fever present as?
an upper respiratory infection, strep throat, tonsillitis, or pharyngitis
problems of pericarditis and rheumatic fever
may cause effusion, which impairs filling
problems of myocarditis and rheumatic fever
may cause aschoff bodies to develop, which interfere with conduction
problems of endocarditis and rheumatic fever
endocarditis is the most common and the mitral valve is usually affected; valves are affected, causing verrucae to form and can result in stenosis
verrucae
are wart like vegetations on the outer edge of valves
effects of rheumatic fever not in the heart
joints are inflamed, skin develops rashes, nontender cutaneous lesions may form on extensor surfaces, and the basal nuclei in the brain are affected, causing rapid, jerky movements
antibodies present for rheumatic fever
antistreptolysin O antibodies
how does rheumatic fever manifest in later years
heart murmur and arrhythmias
infective endocarditis
occurs when organisms invade the endocardium, causing inflammation and vegetations (fibrin, platelets, blood cells, and microbes) to develop around valves; can be acute or subacute
example of an organism causing acute infective endocarditis
S aureus
example of an organism causing subacute infective endocarditis
streptococcus viridans
risk factors for developing infective endocarditis
valve defects, rheumatic fever, mitral prolapse, and those with a depressed immune system
subacute endocarditis signs
fever, anorexia, splenomegaly, painful red nodes on the fingers, or CHF
acute endocarditis signs
spiking fever, chills, drowsiness, and impairment of heart function
pericarditis
is usually secondary to another condition and can be acute or chronic; is large amounts of fluid accumulate, expansion and filling of the heart may be impaired, usually affecting the right side first
serous fluid indication
inflammation
purulent fluid indication
infection
blood in fluid indication
trauma or cancer
chronic pericarditis
signs are gradual and can cause adhesions between pericardial membranes, causing this to become tough and limiting movement
signs of pericarditis
chest pain, dyspnea, tachycardia, cough, friction rub may be present, and neck veins may be distended
another name for essential hypertension
primary
secondary hypertension
is caused by renal problems, endocrine problems, or an pheochromocytoma
pheochromocytoma
a benign tumor of the adrenal medulla or SNS ganglion chain
malignant hypertension other name
resistant
malignant hypertension
is an emergency and can damage organ damage, including damage to the CNS and renal system
rate for hypertension
above 140/90
essential hypertension
occurs when there is an increase in arterial vasoconstriction and peripheral resistance; this often causes decreased RBF, triggers RAAS system and more vasoconstriction; over time vessels are damaged, become hard and thick
complications of hypertension
wall may tear, causing an aneurysm, atheroma formation is triggered, and necrosis may develop
areas most frequently impacted by hypertension
kidneys, brain, and retina
signs of hypertension
fatigue, malaise, and morning headache
shock
is caused by decreasing BV, leading to decreased tissue perfusion and general hypoxia, CO is usually low
hypovolemic shock
is due to loss of circulating blood and can result following hemorrhage, burns, dehydration, or infections like pericarditis or pancreatitis
cardiogenic shock
is due to decreased pumping capability of the heart and may result following an MI of the left ventricle or arrhythmias
vasogenic shock
is vasodilation due to a loss of sympathetic and vasomotor tone and can be due to fear or pain, spinal cord injury, or hypoglycemia (insulin shock)
anaphylatic shock
is vasodilation and increased permeability following an allergic reaction
septic shock
is vasodilation due to severe infection, usually caused by gram-negative bacteria
3 things blood pressure is determined by
blood volume, heart contraction, and peripheral resistance
result of hypoxia from shock
anaerobic metabolism and increased lactic acid production
compensation mechanisms for shock
SNS activation, adrenal cortex stimulation, RAAS system, ADH secretion, glucocorticoid secretion, and acidosis stimulates respirations
does acidosis or alkalosis occur with shock?
acidosis
signs of shock
first signs are thirst, agitation and restlessness; this is followed by cool, pale, moist skin, tachycardia, hyperventilation, and oliguria
arteriosclerosis
is a general term for all arterial changes; elasticity is lost, walls become thick and hard, and the lumen narrows which all can lead to necrosis and ischemia
peripheral vascular disease
refers to any vessel abnormality outside of the heart
atherosclerosis
refers to the presence of a atheroma, which are plaques consisting of lipids, cells, fibrin, and debris, often with attached thrombi
where do atheroma’s often form?
large arteries, typically at merging points
low-density lipoproteins
are the bad lipids and have a high lipid content; they transport cholesterol from the liver to cells
high-density lipoproteins
are the good lipids and have a low lipid content; they transport cholesterol from the peripheral cells to the liver
how do thrombus develop?
usually following an injury, the inflammatory response causes an accumulation of WBCs and lipids, the smooth muscle proliferates and multiples, and platelets adhere to this; as this develops, prostaglandins are released, causing vasospasm and more inflammation
signs of atheroma formation
weakness and fatigue in the legs, intermittent claudication, sensory impairment, weak peripheral pulse, and pallor/cyanosis
intermittent claudication
leg pain associated with exercise due to muscle ischemia
aneurysm
is a localized weakening and dilation of an arterial wall
most common location for aneurysms
thoracic or abdominal aorta
saccular aneurysm
occurs on one side of the vessels
fusiform aneurysm
occurs on both sides of the vessel and is circumferential
dissecting aneurysm
is when there is a tear in the tunica intima, causing blood to flow along the length of the vessel between layers
causes of an aneurysm
atheromas, trauma (car accidents), syphilis, and congenital defects
signs of an aneurysm
pain and shock symptoms
