Adv Med Surg: Exam 1

dysrhythmia, cv disease - mi, sympathomimetic, preload and afterload

What are pacemaker cells?

automatic cells designed to create/start a node (capable of generating an electrical impulse)

What are muscle cells?

cells that contract and relax

What is the order of the cardiac conduction system?

SA Node—> AV Node—> Bundle of His—> R and L Bundle Branches—> Purkinje Fibers

If there is a change in cardiac rhythm…

assess the patient

What do tachys do that can be bad/detrimental?

increase myocardial o2 demand, decrease ventricular filling time, decrease coronary artery perfusion time

What do bradys do that can be bad/detrimental?

decrease cardiac output, can cause syncope, chest pain

Cardiac Output=

Cardiac Output = Heart Rate x Stroke Volume

What is stroke volume

amount of blood pumped out with every beat of the heart

How to get HR from a 6 second EKG strip

count QRS complexs and multiple by 10

P wave

atrial depolarization

What is the star represent

It is a time delay so the atria have time to pump and fill the ventricles

Normal length of PR interval

0.12-0.20 seconds

What does the QRS Complex represent

ventricular depolarization

Normal QRS Complex length

0.06-0.10 seconds

What does the ST Segment represent?

early repolarization

if the ST segment is above/below the isoelectric line, it could be a sign of

cardiac ischemia/infarction

What does the T wave represent

ventricular repolarization

What does the QT wave represent

ventricular depolarization and repolarization

If QT interval becomes prolonged, pt could be at risk for what rhythm?

torsades de pointes (lethal ventricular dysrhythmia)

Calculating a regular rhythm heart rate

number of small blocks between each complex and follow to the corresponding HR. only use rate table for regular rhythm

calculating HR for irregular rhythm

count number of QRS complex’s in a 3 second strip and multiply by 20. count the number of QRS complexes in a 6 second strip and multiply by 10

Normal Sinus Rhythm

electrical impulse starts in SA node, regular rate and rhythm (60-100), impulse travels through normal conduction pathway

Atrial conduction=

1 P wave before each QRS, consistant in shape

Sinus Tachycardia

everything is normal, but rate is above 100 BPM. Happens when SA Node creates an impuse at a faster than normal rate

how to treat sinus tach

treat underlying cause!!! monitor (most lethal dysrhythmia).. also can be put on beta blocker

sinus brady

occurs when SA Node creates an impulse at slower than normal rate. rate less than 60

tx for sinus brady

monitor, treat underlying cause, atropine if caused by vagal mechanism

causes of sinus brady

decreased metabolic needs, athletic training, hypothyroidism, vagal stimulation, meds (beta blockers, calcium channel blockers), idiopathic SA Node dysfunction, increased ICP, MI

vagal stimulation

enhanced pressure in heart (having BM, vomiting, bearing down)

causes of sinus tach

stress, blood loss, anemia, shock, hypovolemia, heart failure, pain, fever, exercize, anxiety, hypoxia….

What are atrial dysrhythmias

a fib, a flutter, premature atrial contractions (PAC)

Premature Atrial Contraction (PAC)

premature, ectopic electrical impulse discharges in atrium before next normal impulse of SA Node

Ectopic beat

a pacemaker site outside of the SA node (not where is it supposed to be)..complex comes in early

PAC criteria

rhythm: regular except where premature beat occurs

rate: rate of underlying rhythm

atrial conduction: P wave before the ectopic beat is different from P wave of underlying rhythm

PAC causes

caffine, alc, HF, anxiety

True or false, PACs are common in normal, healthy hearts

true

tx for PAC

dont really treat, just get rid of cause

what is this

sinus tach

what is this

normal sinus rhythm

what is this

sinus brady

what is this

sinus with PAC

look for _____ when looking at PAC in a rhythm strip

pointy t wave, p wave hiding on top of t wave

Atrial Flutter

atria are depolarized at rates of 250-400x/min, multi p’s for every QRS

A flutter cause

reentry circut

what happens in A flutter

not all the atrial impulses are conducted into the ventricle, causing a therapeutic block at the AV node

t/f: the adult heart can tolerate a flutter

false, we need to slow it down

How to tell A flutter on a strip

“p” waves produce a saw-tooth pattern called flutter waves

causes of a flutter

underlying cardiac disease, long standing HTN, CAD, hypoxia, HF…

what can occor due to lack of atrial contraction during a flutter

blood stasis and thromboembolisms

tx for A Flutter ****

control heart rate, convert to normal sinus rhythm, (amiodarone, cardioversion) vagal maneuvers, anticoagulation

examples of vagal maneuvers for A Flutter

carotid sinus massage, cough

what meds can help control HR for A Flutter

diltiazem, beta blockers, digitalis

what is this

A Flutter

A Fib

uncoordinated atrial electrical activation from multiple areas in the atria. Results in a rapid, disorganized, quivering, fibrillating atria

A Fib charateristics

• no p waves!!

• EKG baseline is irregular and undulating

  • irregularly irregular

clinical significance of A Fib

loss of atrial systolic volume “atrial kick”

loss of AV synchrony

reduced cardiac output (blood clots)

increased potential for thromboembolism

causes of A Fib

HTN long term, MI, HF, pulmonary disease…

t/f: A fib rarely occurs in those with no functional heart disease

true

A Fib tx

convert to NSR, decrease ventreicular raate, prevent clots, rate control meds: (calcium channel blockers, beta blockers, digoxin) conversion meds: amiodarone, dofetilide, flecanide

antiplatelet agent

aspirin

antithrombotic meds

anticoagulant: warfarin

factor Xa inhibitors: dabigatran, rivaroxaban, apixaban

A Fib tx

cardioversion if unstable

t/f: some pts remain chronically in A Fib

true

what is cardioversion

synchronized defibrillation

what is this

A Fib

ventricular dysrhythmias

premature ventricular contraction, ventricular tachycardia, ventricular fibrillation, PEA

premature ventricular contraction (PVC)

premature ectopic impulse that originates in the ventricle. conducted through the ventricles before the next normal sinus impulse

can PVCs occur in healthy ppl

yes

characteristics of PVC

ventricular complex that comes in early

QRS is wide, shape is bizzare and there are ST and T wave changes

QRS and T tend to go in opposite directions

causes of PVC

caffine, nicotine, alc, cardiac ischemia, hypoxia…

tx for PVC

if infrequent- none needed

remove causing agent

amiodarone, lidocaine

what is this

sinus with PVC

V tach

3 or more PVCs in a row with a rate exceeding 100bpm

t/f: v tach is an emergency situation and can be a life-threatening dysrhythmias

true

characteristics of v tach

ventricular rate greater thhan 100, rhythm is usually regular, QRS complexes r wide, no P waves present

causes of V Tach

MI, ischemia, hypoxia, electrolyte imbalence, CAD, acidosis, HF…

treatment for v tach with a pulse (stable)

antiarrhythmic drugs, amiodarone

treatment for v tach with a pulse (unstable but conscious)

sedate, cardioversion, antiarrhythmic drugs

Cardioversion

uses quick, low-energy shocks to restore a regular heart rhythm

treatment for v tach without a pulse

defibrillate

T/F: you can get someone out of this rhythm with just CPR

false, early defibrillation is VERY important

what is this

v tach

torsades de pointes

type of polymorphic VT that is preceded by a long QT interval

T/F: torsades de pointes is a life threatening dysrhythmia with no P waves

true

causes of torsades

long QT interval, electrolyte imbalance, coronary vasospasm and meds

tx for torades

IV magnesium, treat the cause, defibrillate if pt is pulseless

what is this

torsades de pointes

V Fib

rapid, disorganized ventricular rhythm that causes ineffective quivering and pumping of the ventricles

characteristics of V Fib

no atrial activity seen, ventricular rhythm is extremely irregular and chaotic with no pattern. QRS shape is irregular

most common cause of cardiac arrest

V Fib

tx of V Fib

CPR, defibrillation, epi, amiodarone, vasopressin, lidocaine, sodium bicarb

what is this?

V Fib

Asystole

cardiac arrest, cardiac standstill

Asystole charaterisitcs

no electrical activity on EKG, no cardiac output

tx for Asystole

CPR, epi

T/F: Asystole has a poor prognosis

true

What is pulseless electrical activity

the monitor shows an identifiable electrical rhythm but no pulse is detected

what is this?

asystole

what is this (its pulseless)

PEA

1st degree AV heart block

occurs when all the atrial impulses are conducted through the AV node into the ventricles at a slower rate than normal