rrd 7 Flashcards
cardiovascular diseases pt 2
HR and rhythm changes that may pathologically affect CO
- tachycardia
- bradycardia
- rhythm pattern irregular
tachycardia
HR faster than normal (>100 bpm)
causes of tachycardia
- SNS neurohormonal influences
- certain electrolyte changes (EX: hyperkalemia - hypopolarization)
- glitches in SA node and AV node regulation (genetic, idiopathic, chronic disease-related)
neurohormonal influences of SNS causing tachycardia
- SNS governs fight or flight
- kicks in during activity, stress, need to compensate in situations such as shock, heart attack, etc.
- secretes epinephrine -> bind with beta receptors of heart -> increases HR
bradycardia
HR slower than normal (<60 bpm)
causes of bradycardia
- ParaNS neurohormonal influences
- certain electrolyte changes (EX: hypokalemia -> hyperpolarization)
- ischemia from right coronary artery (RCA) narrowing/blockage (RCA feeds SA + AV node)
- glitches in SA node and AV node regulation (genetic, idiopathic, chronic disease-related)
neurohormonal influences of ParaNS causing bradycardia
- ParaNS governs slower processes (digestion, urination)
- related to heart, vagus nerve secretes ACh -> decreases HR
rhythm pattern that can affect cardiac fxn
- dysrhythmia (or arrhythmia) like:
- atrial fibrillation (Afib)
- ventricular fibrillation (Vfib)
dysrhythmia (arrhythmia) causes include
- ischemic/infarcted tissue interferes w/ normal impulse conduction
- electrolyte imbalances (esp related to K+, hypo + hyper)
- age-related wear & tear of conduction system
atrial fibrillation - Afib
a chaotic series of electrical impulses in the atria that cause them to quiver ineffectively instead of contracting smoothly
afib is fairly common amongst _____, due to heart disease or simple _____ - 3% of ______ population has chronic afib
- elderly
- aging
- adult
afib can occur during ______ but most often begins when myocardium has to endure ______ stain or a chronic problem such as _____.
- acutely ischemic situations
- long-term hypoxic
- heart failure
categories of possible sequelae of afib
- small but sometimes significant decrease in CO
- pooling of blood in atria
small/significant decrease in CO as sequelae of afib
- atria have small coordinated contraction @ end of diastole (atrial kick)
- helps propel more blood into ventricles before they contract
- when atria quiver instead of contracting effectively -> diminish CO to varying degrees bc no atrial kick
pooling of blood in atria as sequelae of afib
- if atria muscles quiver instead of delivering blood to ventricles = blood remain in atria
- form static pools = thrombi + emboli formation
atrial thrombi/emboli formation bc pooling of blood in atria as sequalae of afib
- atrial thrombi in LA
- thrombi gets loose -> become emboli to brain arteries
- stroke (S/S weak on one side, confusion, etc. bc brain ischemia)
venous thrombi/emboli formation bc of blood pool in atria as sequalae of afib
- venous thrombi in RA
- thrombi gets loose -> emboli to lungs
- PE (S/S SOB, chest pain, hemoptysis, shock/decreased BP & perfusion)
T/F people with afib will most likely have fatal outcomes
FALSE: people can often live fine with stable afib as long as they are on meds to help prevent thrombi (clots) and keep HR from being too fast
ventricular fibrillation - Vfib
chaotic series of electrical impulses in the ventricles that cause them to quiver ineffectively instead of contracting smoothly
Vfib is the _____ dysrhythmia because?
- deadliest
- results in no CO at all -> no perfusion to brain -> unconsciousness & death
stroke volume (SV) changes that may pathologically affect CO
- contractility changes (negative inotropic changes)
- preload changes
- afterload changes
pathologic contractility changes
- ischemia: something blocking coronary arteries -> ischemia to heart muscle distal to plaque -> decreased contract
- neurohormonal and electrolyte effects can also influence inotropic status - similar to what they do to HR
preload changes that can be pathologic
- increased preload -> increased blood volume = fluid volume overload -> increase workload on sick heart
- decreased preload -> decreased blood volume = fluid volume deficient -> decrease CO + BP
afterload changes that are pathologic
- pathologically increased afterload makes it harder for the ventricles to eject blood into the receiving arteries
- decreased afterload for the LV related to massive peripheral arterial vasodilation -> shock state
increased afterload for RV
lung disorders (chronic bronchitis) cause pulmonary artery vasoconstriction -> increased pulm vasc resis
increased afterload for LV
atherosclerosis of aorta and systemic arteries
- peripheral arterial vasocon; HTN -> increased syst vasc resis
anaphylaxis from allergic rxn example of massive vasodilation related to decreased afterload
- over-release of inflamm mediators over-dilates blood vessels
- blood pools in periphery
- less volume centrally
- decreased BP
- shock
shock example of massive vasodilation related to decreased afterload
septic shock - same principle but the inflammatory mediator release is caused by toxins of bacteria
coronary artery disease (CAD)
a disorder in which the coronary arteries are narrowed and/or occluded
risk of getting CAD
- increased w/ elevated serum levels of homocysteine
- correlated with an elevated serum C-reactive protein (CRP)
homocysteine
amino acid that can contribute to atherosclerosis via oxidative damage
- some people more prone to having higher homocysteine levels than others
c-reactive protein (CRP)
linked to inflammatory process of plaque formation in the coronary arteries
T/F infarction can happen to any tissue in the body
TRUE
____ is the primary problem in CAD - coronary vessels are ____ and occluded by _____ due to the atherosclerotic/inflammatory processes
- ischemia
- narrowed
- plaques
ischemia to cardiac cells is a _____ influence on the heart and can lead to?
- negative inotropic
- decreased cardiac output
if not revered, ischemia leads to cellular death (_______); tissue _____ in the heart caused by ischemia is known as _____ which is an even worse _________.
- necrosis, necrosis
- myocardial infarction
- negative inotropic influence
various cells in the cardiac tissue can be affected to ______ and may all be in?
- different degrees
- different stages of O2 deprivation
spectrum of ischemia
- mild ischemia to maximal ischemia
- mild: effect on cells mini and can be reversed by restore O2
- max: infarction (irreversible)
there is a great _____ in patient presentation and sometimes S/S is?
- variety
- mild + vague and/or patient might just have nausea, back pain, etc.
most common symptom of CAD is?
angina
angina
- painful constriction or tightness
- short for angina pectoris (chest pain)
- refers to ischemic pain in heart muscle
characteristics of classic angina
- tightness, heaviness (elephant sitting on me); burning, indigestion-like
- pain radiates into areas like left arm, jaw, back
- clenched fist over sternum
- intensity varies
- duration of 3-5 mins and may go away on own (nitroglycerin needed to relieve it sometimes)
- exacerbated by exercise and lessened by rest
CAD status of a person is based on?
degree of coronary occlusion and ischemia - usually reflected in severity of S/S
a person w/ CAD can be?
- asymptomatic
- symptomatic: stable angina or acute coronary syndrome (ACS)
stable angina
- pain pattern predictable and well-controlled by lifestyle changes, meds, etc.
- “tightness in chest center when I walk too long, always goes away when take one NTG”
patho of stable angina
- blockage/plaque causes angina develop slowly w/ no dramatic changes
- steady, small, subtle ischemia to tissues stimulate arteriogenesis
- establishment of collateral circulation - new branches of coronaries develop + feed tissue beyond occluded or nearly-occluded vessel
- the better the collateral circulation, the more stable the CAD
treatment of stable angina is focused on?
- maximizing coronary patency -> increase perfusion to myocardium
- decreased workload of heart
treatment of stable angina includes?
- NTG under tongue prn and/or daily as patch or extended release pill -> dilates coronary arteries so artery can bring more oxygen to myocardium
- aspirin as anti-inflamm and decrease platelet adhesion (less clotting = less chance of worse plaque)