CVS Flashcards
Identify 4 unique functional properties of cardiac cells.
automaticity - independent electrical activity and initiation
excitability - ability to respond to external stimuli (chemical, mechanical, or electrical)
conductivity - conducting electrical activity from cell to cell
contractility - contraction in response to stimulus
What is starling’s law?
the greater the stretch, the greater the contraction
What happens when Beta 1 sympathetic receptors are stimulated?
increased heart rate, increased force of contraction, increased speed of conduction via the AV Node, increased oxygen consumption
What happens when beta 2 adrenergic receptors are stimulated?
affects the heart, lungs, and skeletal muscle by dilation, and increased organ perfusion
What is the inherent rates of the SA node?
60-100 bpm
What is the intrinsic rate of the av junction?
40-60 bpm
What is the intrinsic pacemaker rate of the purkinje fibres?
20-40 bpm
What does PQRST mean?
P - Precipitating factors Q - Quality and Quantitative R - Radiating S - Signs and Symptoms T - Timing and Treatment
What are the characteristics of S3?
end diastolic sound, normal in pregnancy, children, and YA due to rapid ventricular feeling, abnormal after 40 years. Causes are acute MI, heart failure, valve disease, systematic or pulmonary hypertension
Why are hemoglobin, WBC and platelets so important when assessing your adult cardiac patient?
Hemoglobin oxygen carrying capacity not below 90
WBC inflammation, infection
Platelets - risk of coronary artery disease - increased clotting factors
How does magnesium affect the heart?
affects AV node conduction
How does creatine kinase show cardiovascular function?
- enzyme specific to brain, myocardium, skeletal muscle
- followed to determine timeline of the injury
- level rises 4 - 8 hours, peaks in 24 hours, decreases in 48-72 hours
- total CK
- CK - MB enzyme more specific to myocardium
How does troponin show cardiac function?
released into the circulation with cellular damage
specific to myocardial cells - most sensitive indicator of myocardial damage
rises in 4 to 6 hours; remains detectable for 7 - 15 days (is undetectable by 2 weeks)
How does BNP indicate cardiac function?
brain natriuretic peptide
hormone secreted from the ventricles of the heart
secreted in response to changes in pressure (stretch) occurring when heart failure develops and worsens
How does CRP indicate cardiac function?
indicates acute inflammation
trend more beneficial
increased CRP levels correlate with increased cardiac risk
-threeford increase in risk of acute MI
How does HbgA1c indicate cardiac function?
minor component of hemoglobin to which glucose is bound
higher the glucose concentration in blood, higher the level of HbA1c
not influenced by daily fluctuations in blood glucose; reflects average glucose levels over prior six to eight weeks
What is the formula for figuring out MAP?
SBP + 2 DBP divided by 3
What are the characteristics of central venous pressure?
reflects preload - end diastolic volume
normal 2 - 6mmHg
mean reading used
obtained through CVC
What is the normal ejection fraction?
55-70%
define afterload
the amount of resistance to flow the ventricles must overcome to eject blood from the heart
increased afterload means an increased workload of the heart
What are the steps to troubleshooting a pacemaker?
- find pacemaker rate
- should it have fired? if there is an intrinsic beat between pacer beats it shouldn’t fire
- is it sensing?
Define arterosclerosis
hardening of the arteries
Define atherosclerosis
chronic inflammatory disorder
formation of plaque with fibrous cap
define coronary artery disease
progressive atheroslerotic disoder, narrowing to complete occlusion of coronary arteries.
What are the three types of angina?
stable - predictable, specific triggers, responds to treatment
unstable - unpredictable, increased frequency, increased duration, no response to treatment
variant - prinzmetal angina, coronary artery spasm, occurs with or without atherosclerotic lesions
What are the immediate treatments for a suspected MI?
early triage initiate O2 vital signs data collection ECG initiate medications such as ASA and clopidigrel
What do beta blockers do?
decreases cardiac workload, myocardial O2 demand, decreases risk for tachyarrythmias
What do ACE inhibitors do?
blocks conversion of angiotensin I to angiotensin II
prevents Na and water reabsorption
reduces afterload
What are the considerations to unfractionated heparin?
response to medication unpredictable
narrow therapeutic window
closely monitor PTT
acts within minutes of administration
What are the considerations of low molecular weight heparin?
more predictable and sustained response
proven better efficacy
no need for lab monitoring
ease of administration
What are some complications of an acute MI?
dysrhythmia shock papillary muscle rupture ventricular septal rupture pericarditis sudden cardiac death
What are some medications to treat tachycardic rhythms?
adenosine, amiodarone, metoprolol, sodium channel blockers (procanimide, lidocaine, dilantin, propalenone), diltiazem (calcium channel blocker)
Which phase of the cardiac cycle is altered by calcium channel blockers?
phase 2, depressed SA and AV node conduction
What are the benefits of atropine?
stimulation of SA node
increases cardiac workload
What are the effects of dopamine?
increased contractility, increased heart rate, vasoconstriction, smooth muscle constriction
What are the effects of norepinepherine?
increased cardiac workload
severe peripheral vasoconstriction
commonly needed in septic shock
What are the diagnostic criteria of pericarditis?
chest pain that worsens on deep inspiration due to increased thoracic pressure
positioning helps relieve pain
non-focal ST elevation
myocardial biomarkers not elevated
What are the treatments for pericarditis?
avoid thromolytics
unrelieved by nitro or narcotics
treat with NSAIDS
may require tap if pericardial effusion develops
nothing to increase fluid around pericardial sac
What is the pathophysiology of pericarditis?
inflammation of the pericardial sac
severe chest pain
pericardial friction rub
common post MI
What is the pathophysiology of endocarditis?
infection of the endothelial lining of the heart with valvular involvement
can be caused by IV drug users, diabetics, male, coronary artery disease
What would be the clinical signs and symptoms of acute heart failure?
SOB, pulmonary and peripheral edema, decreased LOC, decreased cerebral perfusion, hypoxemia, respiratory alkalosis, decreased BP, tachycardia, mottle, cold, clammy skin, decreased u/o
What are the effects of hydralazine?
potent arterial vasodilator, smooth muscle relaxant, can cause reflex tachycardia
What is the normal J value for defibrilation?
120-360J, usually 200
what are the usual J for synchronized cardioversion?
50-200J
What are the characteristics of a junctional rhythm?
Rate: 40-60 Rhythm: regular P waves: inverted or buried in QRS PR: <0.12 if prior to QRS QRS: 0.04-0.10 escape rhythm ?lost atrial kick
What are the characteristics of AV block?
Rate: normal Rhythm: regular P waves: normal, precede each QRS complex PR: >0.20 seconds QRS: 0.04-0.1
Describe the characteristics of second degree AV block type 1
Rate: normal Rhythm: a - regular v - irregular P waves: normal PR: gradually lengthens until it drops QRS QRS: 0.04-0.1
Describe the characteristics of second degree AV block type 2
Rate: A> than ventricular because some v beats blocked
Rhythm: A regular, V irregular
P wave: normal in size and shape
PR interval: normal or slightly prolonged but consistent
QRS: usually 0.04-0.1 when present
What is the dicrotic notch in an arterial waveform indicative of?
the aortic valve closing at the end of systole
What is measured by a pulmonary capillary wedge pressure?
measures CVP of left ventricle
What are the important points about monitoring CVP?
- inaccurate for preload because all kinds of factors can influence pressure (vasoconstriction/dilation)
- tells info about right atria because as systolic starts to fail, preload increases because right side backs up with blood
- normal is 2-6mmHg
Which drugs are used for rhythms that are too fast?
adenosine, amiodarone, metoprolol, and diltiazem
Which drugs are used for management of rhythms that are too slow?
atropine
dopamine
norepinephrerine
