rrd 7 Flashcards
cardiovascular diseases pt 2 (120 cards)
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