-a degree of variability in the heart rate
-common in young people
-HR fluctuates w/respiration or autonomic nervous system
When does the HR fluctuate w/sinus arrhythmia?
during respiration or autonomic nervous system
What is a dysrhythmia?
-abnormality of the cardiac rhythm
-problem w/impulse generation or conduction
Why are dysrhythmias significant?
it can indicate an underlying disorder and can impair cardiac output
What causes dysrythmias?
what is inappropriate automaticity?
a cell initiates action potentials when it isn't supposed to.
what are causes of inappropriate automaticity? (don't memorize)
what is triggered activity?
extra impulse is generated during or just after repolarization
what are causes of triggered activity? (don't memorize)
what is re-entry
cardiac impulse in one part of the heart continues to depolarize after the main impulse has finished
what are causes of re-entry (don't memorize)
simple explanation of re-entry
cardiac impulse goes in circles when it's not supposed to. "dog chasing tail"
an extra impulse just after repolarizatin is_______.
if a cell initiates action potentials when it isn't supposed it is known as _________.
-originates in SA node
-regular, rate <60
-underlying cause? increased influence of the parasympathetic nervous system
what population commonly has sinus bradycardia?
trained athletes b/c they have an increased stroke volume (SV) d/t training
what medications can induce sinus bradycardia?
what is the underlying cause of sinus bradycardia?
overactivity of the parasympathetic nervous system
where does sinus bradycardia originate?
-originates in SA node
-regular, rate >100 bpm
-underlying cause- over activity of sympathetic nervous system
When is sinus tachycardia normal?
What are some factors that can lead to sinus tach?
Where does sinus tach originate?
what is the underlying cause of sinus tach?
over activity of the SNS
-originates in the atria
-re-entry impulse that is repetitive and cyclic
-regular atrial rhythm w/a rate of >250
-venticular rate is slower
-underlying cause- ischemia, anything that makes the heart irritable e.g. caffeine, cocaine
what is the built in defense for atrial flutter and how does it work?
AV node. doesn't let impulses continue to ventricle
The atrial rate is faster than the venticle. T/F
Atrial flutter originates in the SA node. T/F
F. originates in the atria
what is the atrial rate during atrial flutter?
what is the underlying cause of atrial flutter?
ischemia, anything that makes the heart irritable
Atrial fibrillation (AF)
-multiple irritable spots in the atria
-irregularity irregular (both atrial and venticular)
-ventricular response rate is important. Why? if response is rapid: rapid ventricular response (RVR)
-underlying cause- ischemia or anything that makes the heart muscle irritable
Do atria contract during AF?
no, they quiver
Is the rhythm during AF regular?
No, completely random and disorganized
Which chamber is irregular w/AF?
Can pulse be measured during AF?
No, too irregular and pulse is random
Where is AF originated?
multiple irritable spots in the atria
sudden beginning and end. Gone within 24hr. Resolves spontaneously
Last at least a week
Last one year or longer
Happens in someone without previous heart px
-palpitations (d/t decreased CO)
When is AF a problem?
When CO is not enough
What is the main reason for sx w/AF?
Low CO. Not enough preload
-decreased CO- can get low enough for HF
-embolus, risk increased with:
*congestive heart failure
*Secondary preventiion of a previous embolic event
What are the risk factors for an embolus w/AF?
-congestive heart failure
-Secondary prevention of a previous emoblic event
If a pt is risk for embolus, what drug do they take?
-rhythm control: antidysrhthmic (ex. Amiodarone)
-rate control: beta blockers, Ca+ channel blockers
-stroke prevention: coumadin
When would drugs used to control rate be used w/AF?
when ventricular response is too high
Antidysrhythmic drug therapy
-treat only if the benefits outweigh the risk
*reduce sx- alters rhythm
*reduce mortality- probably not, may increase mortality
* worsen dysrhythmias and make new ones
*severe AE (ex. pulmonary toxicity)
Benefits of antidysrhytmics
reduce sx by altering rhythm
risks of antidysrhythmics
-worsen dysrhythmias and make new ones
-severe AE (pulmonary toxicity)
Amiodarone (Cordarone): Class
dysrhythmic (highly effective)
Amiodarone (Cordarone): MOA
complex effects on heart
Amiodarone (Cordarone): serious toxicities
-pulmonary toxicity- can lead to death
-fatal in 10%
-proarrythmic effects- may worsen arrythmias
Where must 1st dose of amiodarone (Cordarone) be given?
amiodarone (Cordarone): drug interactions
-CYP3A4 substrate so it has lots of interactions
Is amiodarone (Coradone) FDA approved for AF?
No, it is used off-label and used frequently
Dofetilide (Tikosyn): Class
What is dofetilide (tikosyn) FDA approved for?
restore and maintain NSR in aflutter or afib
dofetilide (Tikosyn): MOA
delays repolarization, reduces dysrhythmia
dofetilide (Tikosyn): AE
prolonged QT interval- torsades de pointes
dofetilide (Tikosyn): drug interactions
-avoid drugs that prolong the QT interval
Where can Tikosyn be administered?
What is infective endocarditis?
inflammation of endocardium
What is the usual cause of infective endocarditis?
What are vegetations?
fibrin growths of bacteria
Pathogenesis of infective endocarditis
-bacteria enters the bloodstream
-preexisting factors: injection drug user, valve px e.g. prosthetic valve
How does bacteria enter the bloodstream?
IV drugs, hemodialysis
Acute infective endocarditis
-staph aureus infection
-can attach healthy hearts
Subacute infective endocarditis
-less virulent organisms (not as strong)
-not as aggressive or damaging
-attack hearts w/an underlying disposition (valve surgery in the past)
Local manifestations of infective endocarditis
-heart murmur (from valve damage)
Systemic manifestation of infective endocarditis
Complications of infective endocarditis
Do complications occur early or late with infective endocarditis?
sac that eve lopes the heart
What is acute pericarditis?
acute inflammation of pericardium. If severe can spread locally
Causes of acute pericarditis
-Most common-- idiopathic. It is thought that most idiopathic is triggered by a virus
-MI, trauma, other causes
Healing options of acute pericarditis
-uncomplicated- heals quickly
-complicated- long-term problem
What causes chronic pericarditis?
acute epicarditis that doesn't heal
-sac layers stuck together
-impairs cardiac filling: can't relax and fill w/blood- becomes constrictive
-thickened parietal layer
-constricts great vessels!
Which pericarditis will have a thickened parietal layer?
-Prodromal: may be preceded by upper respiratory infection
-Systemic effects: flu-like sx
-Acute Pericarditis Triad (PEC): Pericardial friction rub, ECG changes, Chest pain
Acute Pericarditis Triad (PEC)
-Pericardial friction rub
How is pericarditis treated?
steriods et al to reduce inflammation
Can you get a pericardial effusion w/pericarditis?
what is pericarial effusion?
accumulation of non-inflammatory fluid in the pericardial sac
4 types of pericardial effusion
-serosanguineous (blood w/fluid)
-chylous (lymph drainage)
serosanguieous fluid will found w/pericardial effusion when?
when will chylous fluid be found w/pericardial effusion?
when will blood be found w/pericardial effusion?
trauma to heart
how much fluid is typically in pericadial sac?
How much fluid is typically in the pericardial sac w/pericardial effusion?
Pericardial effusion happens ONLY with pericarditits. T/F
F. It can happen with or without
Large or sudden pericardial effusion
What does tamponade mean?
too much fluid in sac to let heart relax, fill w/fluid, and pump
cardiac tamponade: CM
reduced SV will mean reduced ________.
Why will HR increase w/tamponade?
d/t reduced SV
what is pulsus paradoxus?
systolic BP increases w/exhaling. Difference b/t inspiration and exhalation
Stenosis w/valvular disease:
valve fails to open completely
How does stenosis affect the heart?
chamber behind bad valve has to work harder, leading to hypertrophy
What is regurgitation?
valve fails to close completely
How does regurgitation affect the heart?
blood flows backwards, not forwards. makes chamber work harder leading to hypertrophy
What is prolapse?
valve flops backward into the atrium during ventricular systole
How does prolapse affect the heart?
asymptomatic- rare complications. mostly benign
which valves commonly malfunction?
aortic and mitral
why are the mitral and aortic valves at higher risk?
left side is @ highest pressure
What will you hear when you auscultate the heart?
Valvular disease: etiology
-Age-related: valve calcification
-Rheumatic heart disease: Group A (B-hemolytic) streptococcal, autoimmune
Valvular disease CM are similar to those of:
CM of valvular disease
-sx of congestion
-sx of low CO
Which common co-morbidity worsens sx?
A-fib makes sx worse