week 4: acute coronary syndromes, ht failure, arrythmias, etc Flashcards
by what percentage does a major coronary artery need to be narrowed for blood flow to be impaired under myocardial demand?
50%
____ ____ develops if the supply of coronary blood cant meet demand of myocardium for oxygen and nutrients
myocardial ischemia
myocardial ischemia causing chest pain is called ____
angina pectoris
what does angina pectoris feel like?
heaviness, pressure, moderately severe pain
pain may radiate to the neck, lower jaw, left arm, left shoulder, occasionally the back or down the right arm
pallor, diaphoresis, dyspnea
pain usually relieved by rest and nitrates
women: may not present this way, may have atypical chest pain, palps, sense of unease, severe fatigue
pain from angina pectoris is caused by?
lactic acid and abnormal stretching
two types of angina are:
stable and prinzmetal
_____ angina is caused by gradual luminal narrowing and hardening of arterial walls, vessels cant dilate in response to myocardial demand. *assoc with physical exertion or emotional stress)
stable
AKA reversible myocardial ischemia
patient may experience normal physical exam bw episodes
____ angina (aka variant angina) is from transient ischemia of myocardium. occurs unpredictably and almost always AT REST
prinzmetal angina
how much time do you have when there’s a myocardial oxygen deficit?
20 min!!!
management of reversible ischemia (stable)
need to increase oxygen delivery by improving coronary artery blood flow and to reduce myocardial oxygen consumption
NITRATES!! improve coronary blood flow and reduce myocardial demand by decreasing peripheral vascular resistance and venous return to the heart (preload) thereby reducing cardiac workload
-help to vasodilate, immediate relief
B-Blockers: diminish catecholamine induced elevations of heart rate, contractility, and blood pressure. leads to enhanced oxygen delivery to heart
_____ results in reversible myocardial ischemia – signal that an atherosclerotic plaque that has ruptured, and an infarction may soon follow
unstable angina
the thrombus is rapidly changing and if it occludes the vessel for no more than 10-20 minutes, myocardial necrosis occurs
unstable angina presents as:
-new onsent
-angina occurring at rest
-angina increasing in severity or frequency
may experience increased dyspnea, diaphoresis, anxiety
true or false:
approx 20% of people w unstable angina progress within hours to days to MI or death
true
how to manage unstable angina?
immediate hospitalization
oxygen
asprin
nitrates
morphine
_______ ______ is when coronary blood flow is interrupted for an extended period leading to myocyte necrosis
Myocardial Infarction
true or false
in majority of MI, decrease in coronary flow is the result of atherosclerotic CAD
true
the ____ of ischemia determines the size and character of infarction
duration
subendocardial and transmural are 2 types of:
myocardial infarction
____ MI = if thrombus breaks up before complete tissue necrosis; only directly beneath endocardium
termed non-STEMI
subendocardial
_____ MI = if thrombus lodges permanently in vessel, infarction extends all the way through myocardium - from endo to epicardium
STEMI
highest risk - require immediate intervention
transmural
STEMI = ___ elevation MI
STEMI = ST elevation MI
more severe!!
______- when ischemic injury is exacerbated once blood flow is restored
involves release of oxygen radicals, ca influx, ph changes, causes sustained mitochondrial permeability
reperfusion injury
_____ is released during myocardial ischemia
angiotensin II
clinical manifestation of MI
sudden, severe chest pain
heavy, crushing, “elephant”
increased heart rate, blood pressure
severe = hypotension
which is the most commonly occluded artery and most associated with death after MI?
left anterior descending artery (LAD)
what is the most specific lab indicator of MI ?
cardiac troponin I
has sensitivity of more than 95% for the diagnosis of acute MI
troponin released when myocardium is damaged
_____ occurs when the heart is unable to generate adequate cardiac output (55%) - inadequate perfusion of tissues or increased diastolic filling pressure of left ventricle or both
heart failure
most common predisposing risk factors of heart failure?
ischemic heart disease and htn
most causes of heart failure result in dysfunction of _____
left ventricle (systolic and diastolic ht failure)
left sided congestive heart failure process
- left ventricle weakens and cannot empty
- decreased cardiac output to system
- decreased renal blood flow stimulates RAAS and aldosterone secretion ( increase blood pressure/Na and H2O in body)
- backup of blood into pulmonary vein
- high pressure in pulmonary capillaries leads to pulmonary congestion of edema
where does blood back up during left sided congestive ht failure?
pulmonary vein
cardinal signs of CHF
dyspnea
fatigue
edema
orthopnea
coughing frothy sputum
decreased urine
evaluation of CHF
x ray ( assess heart size and pulmonary congestion) and echocardiography (confirm decreased cardiac output and cardiomegaly)
almost all heart failure results in ____
cardiomyopathy (dzs that weakens ability to pump blood)
_____ is the inability of the right ventricle to provide adequate blood flow into pulmonary circulation
most often results from left heart failure
right sided ht failure
right sided heart failure causes fluid to back up into where?
the veins of the systemic circulation
key sxs of right sided ht failure =
pitting edema
jugular vein distention
flow of right ht failure
- right ventricle weakens and cant empty
- decreased cardiac output to system
- decreased renal blood flow stimulates RAAS and aldosterone secretion
- back up of blood in systemic circulation
- increased venous pressure results in edema in legs and liver and abd region
- very high venous pressure causes distended neck veins and cerebral edema
_____ is a disturbance of heart rhythm
arrhythmia or dysrhythmia
two types of arrhythmias are:
sinus brachycardia and sinus trachycardia
_____ is a cardiac rhythm w a rate of fewer than 60 beats per minute
sinus brachycardia
sinus brachycardia is common in ___ ____
athletes and during sleep
which patients often have sinus brachycardia?
patients with congestive heart failure
sxs of sinus brachycardia
most are asymptomatic
some: fatigue, lightheadedness, dizziness, exercise intolerance, syncope, worsening of anginal sxs, worsening of ht failure, cognitive slowing
_____ is a regular cardiac rhythm in which heart beats faster than normal and results in increased (cardiac output greater than 100 bpm)
sinus tachycardia
sxs of sinus tachycardia
dyspnea, chest pain, lightheadedness, dizzy, syncope, presyncope
_____ occurs when heartbeat is initiated by purkinje fibers rather than SA node
premature ventricular cxn (PVC)
pvc occurs before a reg heartbeat so there is a pause before the next regular heartbear
very common
what does patient feel during PVC?
skipped heartbeat and then fluttering sensation
PVC manifests in ___ ___ pulse rate
regularly irregular
____ is the most common sustained cardiac arrhythmia
atrial fibrillation
loss of atrial cxn and the rapidity and irregularity of the ventricular rate =
atrial fibrillation AF
___ has a pulse rate of greater than 300 bpm
AF
sxs of AF
irregular heart beat, palps, dizziness, SOB, tiredness, anxiety
does A FIB have a higher risk of stroke?
yes
6-fold increase
(1.5-2 fold for mortality)
arrhythmias originating from ventricular myocardium or His-Purkinje system are grouped under _____
Ventricular arrhythmia VA
*____ is an extremely dangerous rhythm significantly compromising cardiac output and ultimately leading to sudden cardiac death (SCD) *
ventricular fibrillation
the most common presentation for VF is sudden collapse from _____
cardiac arrest
true or false
w/o treatment, VA is fatal within minutes
true
treatment of ventricular fibrillation
CPR, AED
____ is the vasospasm in the small of arteries/arterioles of fingers
raynauds
what is raynauds triggered by?
cold and emotional stress
sxs of raunauds?
pallor, cyanosis, rubor
changes in skin color, pallor, numb, sensation of cold, cyanotic skin that turns to rubor (redness) as vasospasm ends and capillaries engorge w oxy blood
rubor comes w throbbing pain
skin returns to normal after attack
but freq prolonged attacks interfere with cellular metabolism causing skin of fingertips to thicken and nails to become brittle
