Ch 12: The Heart Flashcards
what is congestive heart failure
inability to effectively pump blood to meet metabolic demands of peripheral tissue
can lead to ischemic heart disease (IHD) and hypertension (HTN)
what is the mechanism of the progression to congestive heart failure
increased mechanical work (due to pressure overload, volume overload, or trophic signals) leads to cellular hypertrophy from increase DNA ploidy (replication without division)
what does pressure overload of the heart lead to
sarcomeres assemble parallel
leads to concentric wall thickness and increase in mass
what does volume overload of the heart lead to
sarcomeres assemble in series which leads to ventricular dilation and an increase in mass
what happens during hypertrophy of the heart in terms of capillaries
increase in tissue size but no increase in capillary numbers
leads to decrease in oxygen and nutrient supply
what happens during hypertrophy of the heart in terms of increase in mass/heart rate/contractility
as mass/HR/contractility go up, so do metabolic demands
what happens during hypertrophy of the heart in terms of increase in fibrous tissue deposition
increased resistance to diastolic filling
what happens during hypertrophy of the heart in terms of increased gene expression
more cell growth and protein expression
what is forward failure/effects of left sided CHF
low cardiac output
what is backward failure/effects of left sided CHF
left sided CHF leads to increased ventricular volume and pressure
this increased pressure and volume backs up to the pulmonary veins and leads to congestion/edema within the pulmonary system
what two things are used to assess extent of congestive heart failure
brain natriuretic peptide (BNP) and ECG
what occurs in left sided congestive heart failure:
-causes
-mechansim
-compensation mechanisms
usually caused by ischemic heart disease (IHD), hypertension, aortic and mitral valvular disease, or primary myocardial disease
blood backs up into left ventricle which leads to inadequate tissue perfusion
compensation: catecholamine release, RAAS, and ADH
what happens in regards to the kidneys when we have myocardial dysfunction (decreased CO and BP)
decreased perfusion to kidneys
increase in angiotensin 2 and aldosterone
cause retaining of sodium and water, increased BP and HR
ventricular remodeling
what is systolic left sided congestive heart failure
inability to pump
reduced contractibility of left ventricle leads to decreased CO and BP
inadequate tissue perfusion
what is diastolic left sided congestive heart failure
inability to fill
left ventricle stiff and cannot relax during diastole
leads to pulmonary congestion that gets worse with more demand
can be caused by hypertension from diabetes, obesity, and b/l renal artery stenosis
what is right sided congestive heart failure
inability of the right side of heart to pump blood to the lungs
usually caused by left sided CHF or lung disorders (cor pulmonale)
affects brain and kidney
what is backward failure/effects of right sided CHF
systemic and venous congestion
what is forward failure/effects of right sided CHF
low cardiac output
how does left sided heart failure effect the heart
leads to left ventricular hypertrophy
may also cause left atrium dilation
how does left sided heart failure effect the lungs and what do patients present with
pulmonary congestion and edema with wet heavy lungs
dyspnea (trouble breathing on exertion) which leads to orthopnea (shortness of breath while lying down), paroxysmal nocturnal dyspnea, and dyspnea at rest
how does left sided heart failure effect the kidneys
retention of salt and water which leads to increase of interstitial fluid and blood volumes
prerenal azotemia (buildup of toxins in blood)
how does left sided heart failure effect the brain
only seen in advanced stages of CHF
cerebral hypofusion (not enough blood to the brain) leads to hypoxic encephalopathy (brain injury due to not enough oxygen)
leads to irritability, loss of attention span, and restlessness that can lead to stupor (daze) and coma
what are the overall effects of right sided HF
engorgement of systemic and portal venous systems
little pulmonary congestion
what are the effects of right sided HF on heart
hypertrophy of right atrium and ventricle
what are the effects of right sided HF on liver and portal system
ascites, congestive heptaomegaly, and passive congestion (nutmeg liver) all lead to centrilobular necrosis and cardiac sclerosis or cirrhosis (cirrhosis of liver due to heart condition)
what is the effect of right sided HF on the spleen
congestive splenomegaly
what is the effect of right sided HF on the kidney
more pronounced congestion than left sided HF
what are the effects of right sided HF on the subcutaneous tissue
peripheral edema and anasarca
what is the effect of right sided HF on the brain
hypoxic encephalopathy
what is ischemic heart disease
a group of syndrome caused by lack of oxygen, nutrients, and removal of wastes
most are due to coronary atherosclerosis (coronary artery disease)
can also be caused by coronary emboli, myocardial vessel inflammation, or vascular spasm
usually begins silent then causes a sudden onset of symptoms
what three coronary vessels are most involved in coronary artery disease
left anterior descending
right coronary artery
left circumflex artery
what are four clinical manifestations of ischemic heart disease
angina pectoris (chest pain)
myocardial infarction (MI - heart attack)
chronic IHD with heart failure
sudden cardiac death (SCD)
what is angina pectoris
paroxysmal (sudden spasm) and recurrent attacks of substernal or precordial chest discomfort
aka “chest pain”
what are the three types of angina
stable (typical)
preinzmetal variant
unstable (crescendo)
what is stable (typical) angina
most common
caused by imbalance of perfusion and demand
presents as pain with exertion of increase in demand
pain is crushing or squeezing that radiates
treated with: rest or vasodilators
what is prinzmetal variant angina
episodic ischemia caused by coronary artery spasm
what is unstable (crescendo) angina
caused by plaque disruption, thrombus, or vasospasm
prolonged pain greater than 20 mins occurring at rest
what is a myocardial infarction:
-define
-who is most susceptible
-which area of heart is most susceptible
death of cardiac muscle due to prolonged ischemia (heart attack)
most occur in those over 65
most occur in the left ventricle
what are four risk factors for a MI
increase age
male gender
postmenopausal women
increased atherosclerosis
what is the mechanism of most MIs
atherosclerotic plaque is disrupted which activates steps 1-3 of hemostasis
vessel becomes completed occluded
what are the less common mechanisms of MIs
vasospasms due to atherosclerosis, platelet aggregation, or drug ingestions (cocaine)
emboli
vessel disorders, hematologic abnormalities, amyloid deposition, and vascular dissection
what is a transmural infarction
occlusion of epicardial vessels (coronary arteries) which leads to necrosis of ventricular wall
what is a subendocardial (nontransmural) infarction
plaque becomes disrupted which leads to a thrombus becoming lysed
leads to necrosis of 1/3rd-1/2 half of ventricular wall
what are the three clinical manifestations of MIs
rapid, weak pulse
diaphoresis (sweating)
dyspnea (difficulty breathing)
what are the 2 ECG changes seen in MIs
ST segment deviations and T wave inversions
what are the 2 common myocardial proteins in the blood that are tested for during an MI
troponin 1 and troponin T
explain how myocardial proteins become elevated in the blood during an MI
onset of MI
plasma membrane of dead myocytes becomes leaky
troponin leaks out of cell and into the blood circulation
numbers peak 24-48 hours after event
what are the two methods to treat MIs
reperfusion: catheterization and coronary bypass
what is catheterization
a reperfusion method to treat a MI
catheter is placed (usually into the femoral vein) up into the heart to help identify occluded area
then a stent or balloon angioplasty is done to open up the occluded vessel
what is coronary bypass
a reperfusion method used to treat a MI
heart surgery which makes a new path around the occluded artery
what are 8 complications of an MI
arrhythmias
CHF + cariogenic shock
mural thrombus
myocardial rupture
papillary muscle dysfunction
pericarditis
ventricular aneurysm
chamber dilation
what is an arrhythmia or dysrhythmia
abnormalities of the myocardial conduction system
can be sustained or sporadic (paroxysmal)
what are the two main causes of arrhythmias or dysrhythmias
structural changes in the conduction system
intrinsic myocyte electrical instability
explain structural changes in the conduction system which leads to arrhythmias or dysrhythmias
ischemic injury (most common)
hypertrophy or inflammation - both lead to irregular depolarization
explain intrinsic myocyte electrical instability which leads to arrhythmias or dysrhythmias
mutations in ion channels lead to irregular depolarization or repolarization
where can arrhythmias or dysrhythmias originate from
issues with atrium (supraventricular) or ventricular
conduction system or with myocyte themselves
what are some manifestations of arrhythmias and dysrhythmias
tachycardia (rapid heart beat)
bradycardia (slow heart beat)
irregular rhythm with normal ventricular contration
chaotic depolarization without ventricular contraction
no electrical activity (asystole)
what happens if you have sustained arrhythmia and what are the three things it can present with
loss of adequate cardiac output which leads to:
lightheadedeness
syncope (loss of consciousness)
sudden cardiac death
what is sudden cardiac death (SCD) and what are some of its causes
unexpected death from cardiac causes
usually due to lethal arrhythmias like asystole or ventricular fibrillation (VF) (irregular heartbeat that affects ventricles)
what is sick sinus syndrome
SA node is damaged which leads to bradycardia
what is atrial fibrillation
malfunctioning atrial cells lead to independent and sporadic depolarizing
leads to irregular HR
what is heart block and what causes it
heart block: heart beats slowly or abnormally
caused by AV node dysfunction
can lead to first, second, or third degree heart block
what is long QT syndrome
prolonged QT segments (ventricular depolarization and depolarization)
makes you more susceptible to serious ventricular arrhythmias
what is hypertensive heart disease
heart disease caused by chronic blood pressure elevation
affects LV, LA, and coronary arteries
what is the mechanism of hypertensive heart disease
hypertension leads to increase demands, pressure overload, and ventricular hypertrophy
what causes left-sided hypertensive heart disease
systemic hypertension
what causes right-sided hypertensive heart disease
pulmonary hypertension (cor pulmonale) - if there is too much pressure in your lungs, the right side of your heart has to pump harder to overcome that pressure and get blood into the lungs
