Advanced Pathophysiology Exam 2 (Cardiovascular II Section)

What is the normal conduction of the cardiovascular nodes?

SA node --> AV node --> Bundle of His + ventricular conduction system --> Purkinje fibers --> ventricular contraction

What happens when you have dysfunction of normal conduction in the heart?


What are the 5 phases of cardiac action potentials?

-phase 0 = rapid depolarization
-phase 1 = early repolarization
-phase 2 = plateau
-phase 3 = rapid repolarziation
-phase 4 = resting

What happens when you have a dysfunction in any of the stages of cardiac action potentials?

Cardiac conduction abnormalities/arrhythmias

What are the three refractory periods?


What is an absolute refractory period?

Insensitive to stimuli

What is a relative refractory period?

More intense stimuli needed for response

What is a supernormal refractory period?

Weak stimuli can initiate a response

Which refractory period do medications target for arrhythmia?

Absolute refractory period prevent cells from generating a new impulse which causes cessation of arrhythmia

What does a P wave show on the ECG?

-SA node
-atrial depolarization

What does the QRS complex show on the ECG?

-ventricular depolarization
-atrial repolarization (hidden)

What does the T wave show on the ECG?

Ventricular repolarization

What is the isoelectric line between P and Q waves?

Depolarization of AV node, bundle branches, and Purkinje system

What are the causes of disorders in the cardiac conduction system?

-congenital defects
-degenerative changes
-myocardial ischemia
-myocardial infarction
-fluid and electrolyte imbalance, specifically potassium and magnesium

True or False? Medications for disorders of cardiac conduction system are at risk of producing different types of arrhythmias, even though they are used for treating arrhythmias.


What are the types of disorders of the cardiac conduction system?

-sinus node
-supraventricular --> originate from atria
-ventricular --> originate from ventricle
-conduction disorders

What are the types of sinus node arrhythmias?

-sinus bradycardia
-sinus tachycardia
-sinus arrest

What is sinus bradycardia?

-slow heart rate (<60 beats/min)
-normal P wave and PR interval
-vagal stimulation --> vagus nerve causes heart to slow down

What is sinus tachycardia?

-rapid heart rate >100 beats/min
-normal P wave and PR interval
-enhanced automaticity --> SNS or withdraw of vagal stimulation

What is sinus arrest?

-irregular pulse
-no impulse from SA node which puts you at risk for other cardiac arrhythmias

What are the types of supraventricular arrhythmias?

-premature atrial contractions
-paroxysmal supraventricular tachycardia
-atrial flutter
-atrial fibrillation

What is premature atrial contractions?

-originates in the atrial conduction pathway before the next SA node impulse
-pause between two normal beats
-often interrupts timing of next beat

What are the causes of premature atrial contraction?

-myocardial infarction
-electrolyte imbalance

What is paroxysmal supraventricular tachycardia?

-originates in Bundle of His
-reentry mechanism

What are the two conduction pathways of paroxysmal supraventricular tachycardia?

-slow and fast with different rates
-two conductions will overlap and connect and make a circle

What is atrial flutter?

-ectopic tachycardia
-rapid atrial activation
-saw tooth pattern --> sometimes you have one extra point of generation that is not through SA node

What is ectopic tachycardia?

Beat originates elsewhere other than SA node

What is atrial fibrillation?

-no identifiable P-wave
-irregularly irregular QRS --> variable R-R interval
-loss of atrial kick
-rapid, disorganized atrial activation
-uncoordinated atrial contraction --> you will have multiple extra points of conduction that are not through SA Node

What is atrial kick?

-when blood flow comes from ventricular contraction
-loss of this means ventricle does not fill up with enough blood, conditions will become decompensated
-ex: heart failure

What is the most common type of supraventricular arrhythmias?

Atrial fibrillation

What is the mechanism of atrial fibrillation?

Blood can pool in atria without it being pumped out --> clots form in atria --> clots can be forced out of atria to other parts of body and lead to other complications

What are the common causes of atrial fibrillation?

-mitral valve disease
-heart failure
-ischemic heart disease
-congenital defects
-cardiac surgery

What are the risk factors of atrial fibrillation?

-age > 60
-thyroid disease
-structural heart disease
-severe lung disease
-excessive alcohol use

What are the clinical signs/symptoms of atrial fibrillation?

-chest pain
-acute pulmonary edema

What kinds of complications arise from atrial fibrillation?

-stroke from atrial clot --> thrombus formation
-decrease CO --> loss of atrial kick
-ventricular arrhythmias
-heart failure exacerbations

What are the three types of atrial fibrillation?


What is paroxysmal atrial fibrillation?

-lasts <7 days
-self terminates = goes back to normal without treatment

What is persistent atrial fibrillation?

-lasts >7 days
-usually requires intervention (pharmacological/non-pharmacological)

What is permanent atrial fibrillation?

-attempts to terminate fail
-lasts for long period of time (1 year)

What is new onset?

1st episode of atrial fibrillation

What is lone atrial fibrillation?

Someone has atrial fibrillation without other comorbidities

What is atrial fibrillation with RVR?

Tachycardia + atrial fibrillation --> goal is to control rapid ventricular response with medication

What are premature ventricular contractions?

-initiated by ventricle --> abnormal, should be in atria
-skipped beat --> compensatory pause
-may progress to VT or VF

What are the causes of premature ventricular contractions?

-ischemia to heart
-electrolyte disturbances

What is ventricular tachycardia?

-originates in ventricle
-increased automaticity in ventricle
-fast heart rate: 170-250 beats/min
-life threatening --> can be sustained or non-sustained

What is Torsades de Pointes?

-type of ventricular tachycardia
-prolonged QT interval
-unstable rhythm --> ventricular tachycardia --> death

True or False? QT is dependent and must be adjusted at a HR >80 bpm with QTc.

False. Must be adjusted at HR >60 bpm.

What is ventricular flutter/fibrillation?

-fatal arrhythmia
-sudden cardiac death
-no cardiac output
-ventricles do not contract, only quiver
-only defibrillator can correct this

What are the risk factors of ventricular flutter/fibrillation?

-other arrhythmias that are not controlled
-ischemic heart disease
-severe heart failure

What are complications of ventricular arrhythmias?

-rapid heart beat
-hemodynamic instability
-loss of pulse

What are the types of disorders of atrioventricular conduction?

-first-degree AV block
-second-degree AV block
-third-degree AV block/complete heart block

What is the first-degree AV block?

Prolonged PR interval

What is type 1 second degree AV block?

-progressively prolonged PR interval until beat drops
-no symptoms most of the time
-can occur from one or more impulses failing to conduct to the heart
-can occur from myocardial infarction

What is type 2 second degree AV block?

-no PR interval change
-sudden dropped ventricular contraction

What is third degree AV block?

-complete heart block
-independent atrial and ventricular rate
-slow rate (~30 bpm)
-most severe, needs to be treated immediately
-decrease CO

What can AV conduction defects be due to?

-scar tissue to heart
-electrolyte disturbance
-acute ischemia
-myocardial infarction

What are complications of AV block?

-heart failure

What are the pharmacological treatments of arrhythmias?

-Class 1 = sodium channel blockers
-Class 2 = beta blockers
-Class 3 = potassium channel blockers
-Class 4 = calcium channel blockers

What are the non-pharmacological treatments of arrhythmias?


What does a cardioversion do to treat arrhythmias?

Electrical current to heart to put it back into rhythm

What does an ablation do to treat arrhythmias?

Procedure that will destroy tissue that is causing abnormal impulse that is being generated

What is a stroke?

-brain attack
-blockage or obstruction, decreased blood flow to brain, decreased oxygenated blood flow to brain
-damage of brain tissues
-permanent neurological deficit if left untreated for too long

True or False? Stroke is the third leading cause of death.


What are the non-modifiable risk factors of stroke?

-> 55 years old
-being female
-African Americans, Hispanic, Asian/Pacific Islanders
-prior stroke
-family history

What are modifiable risk factors of stroke?

-atrial fibrillation
-cardiac disease
-drugs and alcohol

What are the types of stroke?


What is ischemic stroke?

-Cerebrovascular obstruction --> decreased blood flow to area of brain --> kills cells of brain and neurological deficit
-most common

What is an embolic obstruction?

-clot that travels to brain (commonly from brain)

What is thrombosis?

Atherosclerotic plaque breaks and forms a clot and goes to the brain

What are the five main mechanisms of ischemic stroke?

-large vessel
-small vessel
-unusual causes

What is an ischemic penumbra?

-tissues surrounding area of infarction where you have a central core of dead cells or damaged from decreased blood flow
-surrounding this area is an ischemic band = areas of cells that are minimally perfused --> can die if they do not get perfused
-if th

What is the treatment for ischemic stroke?

Reperfusion therapy from thrombolytic therapy

What is hemorrhagic stroke?

-rupture of a blood vessel --> can happen from uncontrolled hypertension, aneurysm, structural malformation
-13% of strokes
-frequently fatal

True or False? Hemorrhagic strokes have a penumbra.

False. They do not have a penumbra.

What are the most common predisposing factors of hemorrhagic stroke?


True or False? You must rule out hemorrhagic stroke before treating ischemic stroke.


What are the clinical presentations for ischemic stroke or TIA?

-determined by cerebral artery affected
-time is important because brain damage is permanent

What are the common symptoms of ischemic stroke or TIA?

-weakness/numbness (one-sided)
-vision loss in one eye
-aphasia/slurred speech
-headache, confusion

What treatments do you use for stroke?

-stroke centers/teams
-reverse ischemia
-thrombolytic agents
-secondary prevention

True or False? Thrombolytic agents are contraindcated in ischemic stroke but not hemorrhagic.

False. It is contraindicated in hemorrhagic stroke, but not ischemic.

What is a transient ischemic attack (TIA)?

-ministroke/brain angina
-focal ischemic neurologic deficits <24 hours
-early warning for ischemic stroke

True or False? TIA has a penumbra without infarction.


What valves do valvular disorders affect the most?

Aortic and mitral valve

What is valvular heart disease?

-increase workflow of heart = increase output
-seen by murmurs from turbulent blood flow

What are causes of valvular heart disease?

-congenital heart defect
-trauma to heart
-ischemic heart damage

What are the two types of valvular heart diseases?


What is stenosis?

-obstruction of blood flow
-opening problem
-narrowing of valve opening --> decreased blood flow
-symptoms first with exercise

What is regurgitant?

-inability of heart to close
-closing problem
-distortion of the valve
-valve permits backflow of blood

What are treatments for valvular heart disease?

-route echocardiogram to monitor progression
-repair surgery
-replacement surgery (mechanical vs. tissue (porcine, bovine), long term anticoagulation)

What is the valve location of mitral valve stenosis?

Left atrium --> left ventricle

What are the adverse outcomes of mitral valve stenosis?

-left atrial enlargement --> blood stays in atrium
-decreased cardiac output with exercise --> blood not being pumped out
-pulmonary hypertension --> holding on to blood

What are the signs of mitral valve stenosis?

-murmur --> diastolic (low pitched, rumbling)
-pulmonary congestion

What are the symptoms of mitral valve stenosis?

-paroxysmal noctural dyspnea
-chest pain

What is the valve location of mitral valve regurgitation?

Left atrium --> left ventricle

What are the adverse outcomes of mitral valve regurgitation?

-left atrial and ventricular enlargement --> regurgitation going backward and forward --> increased risk of A fib
-decreased CO due to backflow

What are the signs of mitral valve regurgitation?

-murmur --> holosystolic (high pitched)
-pulmonary congestion

What are the symptoms of mitral valve regurgitation?

-none in mild cases
-cardiogenic shock in severe cases

What is the valve location of mitral valve prolapse?

Left atrium --> left ventricle

What are the adverse outcomes of mitral valve prolapse?

-may or may not be "leaky" (regurgitation) because of floppy leaflets
-increased risk of infective endocarditis

What are the signs of mitral valve prolapse?

Murmur --> mid-systolic clicks, followed by late systolic)

What are the symptoms of mitral valve prolapse?


What is the valve location of aortic valve stenosis?

Left ventricle --> aorta

What are the adverse outcomes of aortic valve stenosis?

-left ventricular enlargement (chamber size maintained)
-decreased cardiac output as disease progresses

What are the signs of aortic valve stenosis?

-loud systolic ejection murmur or split S2
-heart failure signs (volume overload)

What are the symptoms of aortic valve stenosis?

-heart failure

What is the valve location of aortic valve regurgitation?

Left ventricle --> aorta

What are the adverse outcomes of aortic valve regurgitation?

-left ventricular enlargement
-increased cardiac output at first, but ventricular eventually falls
-end diastolic volume increases = increase in CO, followed by decrease

What are the signs of aortic valve regurgitation?

-murmur --> diastolic (high pitched, blowing sound)
-widened pulse pressure/water hammer pulse

What is pulse pressure?

-difference between diastolic and systolic pressure
-when blood rushes back from backflow, decrease in diastolic pressure, systolic pressure is normal

What is water hammer pulse?

Larger volume in heart causing harder pulses

What are symptoms of aortic valve regurgitation?

-paroxysmal nocturnal dyspnea
-heart failure

What is hypertrophic cardiomyopathy?

-left ventricular hypertrophy = enlargement of left ventricle
-thickening of myocardial wall at left ventricle
-leads to abnormal diastolic filling of blood, cause cardiac arrhythmia, or obstruction of blood out of left ventricle

What is the most common cardiomyopathy?

Hypertrophic cardiomyopathy

True or False? Hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in young athletes.


What are the symptoms of hypertrophic cardiomyopathy?

-chest pain
-exercise intolerance

What are complications of hypertrophic cardiomyopathy?

-atrial fibirllation
-heart failure

What are some treatments of hypertrophic cardiomyopathy?

-negative ionotropes --> make heart beat lighter
-septal myectomy --> surgical repair
-alcohol ablation --> use alcohol to kill tissue

What is dilated cardiomyopathy?

-ventricular enlargement
-reduction in ventricular wall thickness
-impair systolic function of one or both ventricles

True or False? Dilated cardiomyopathy is only caused by genetics.

False. There are secondary causes like infection, cardiotoxin, alcohol, and other meds.

True or False? Dilated cardiomyopathy is the common cause of heart failure.


What are the symptoms of dilated cardiomyopathy?

-reduced exercise capacity

What are the complications of dilated cardiomyopathy?

-secondary mitral valve regurgitation
-abnormal cardiac rhythms
-thrombus formation leading to systemic emboli

What are the risk factors of peripartum cardiomyopathy?

-African American
-older women
-twin fetuses
-use of tocolytic therapy to prevent premature labor

What are the diagnostic criteria of peripartum cardiomyopathy?

-heart failure in last month of pregnancy or within 5 months of delivery
-no cause of heart failure
-no cause of heart failure before last month of pregnancy
-evidence of systolic dysfunction

What is stress cardiomyopathy?

-aka Tako-Tsubo
-broken heart syndrome
-ventricle will balloon
-caused by psychological or emotional stress
-presents as a STEMI but no coronary artery disease present

What is the pericardium?

-lining that surrounds heart
-double layered serous membrane
-isolate heart from other thoracic structures
-maintain position of heart in thorax
-prevent it from overfilling
-serve as barrier to prevent filling

What is pericarditis?

-inflammation of pericardium
-acute (<2 weeks)
-caused by infections, ischemia, physical damage
-can lead to pericardial effusion if not treated

What are signs and symptoms of pericarditis?

-chest pain
-pericardial friction rub
-ECG changes

What ECG changes could occur in pericarditis?

-ST segment elevation
-PR segment depression

What is pericardial friction rub?

Inflammed surfaces rubbing together

What are treatments of pericarditis?


What is pericardial effusion?

-accumulation of fluid in pericardial cavity --> fluid overload

What are causes of pericardial effusion?

-myocardial infarction

What are signs and symptoms of pericardial effusion?

-if small = none
-heart failure symptoms (shortness of breath, edema) --> due to volume overload

What is cardiac tamponade?

-life threatening form of pericardial effusion
-compression of heart chambers
-large pressure from fluid collapses chambers of heart, blood cannot go through causing caridogenic shock

What are signs and symptoms of cardiac tamponade?

-pulsus paradoxus
-distant heart sounds

What is pulsus paradoxus?

Exaggeration of normal pulses of heart with respiration, because pulse is weak during inspiration and higher when exhaling

What are treatments of cardiac tamponade?

-pericardiocentesis --> removal of excess fluid
-perciardial window surgery --> cut hole in pericardium

Why are the heart sounds so distant in cardiac tamponade?

Fluid is blocking it and chambers are compressed