Exam 2 Flashcards
Atrium vs ventricle walls
Atrium have thin walls, easy to stretch
LV has thick wall
Dysrhythmias
disorders of the formation or conduction (or both) of the electrical impulse within the heart
Atrium contracts first, then ventricle to maximize blood flow
If not in sync, arrhythmia and low CO
2 possible problems that can arise in conduction disorders
Pacemaker doesnt put a signal regularly (generation of signal
Or blockage in conduction pathway
ECG
A voltmeter that records the electrical voltages (potentials) generated by depolarization of the heart’s cells
12 lead ecg reflects electrical activity in LV
Right sided heart damage
flip ECG leads
QRS
depolarization of ventricle
Atrial repolarization hides in here
Wide is considered >3 squares (0.06-0.12 seconds is normal)
T wave
Repolarization of ventricle
Usually the same deflection (direction) as QRS
P wave
Depolarization of atrium
<0.2 seconds (<3 small boxes wide)
<1.5-2.5 small boxes tall (for chest and limb leads respectively)
What delays time for filling of the ventricles
AV node
V1
4th intercostal at right border of sternum
V2
4th intercostal at left border of sternum
V3
Midway between V2 and V4
V4
Mid-clav line in 5th intercostal
V5
Anterior axillary line on the same horizontal level as V4
V6
Midaxillary line on same horizontal level as V4 and V5
Shouldn’t see this if looking straight at patient
LL and RL
Above ankle and below torso
AVR, AVL, and AVF
Augmented view limb leads
Calculated
Last line of ecg
lead 2, used to check rhythm issues (patterns)
Why multiple leads?
If we see ST elevation or depression in one lead, we want to be able to confirm and check with other leads
EKG changes in one lead and not another could be due to artifact, so we want at least two
Frontal plane leads
View the heart from the front of the body as if it were flat
Six leads view the heart in the frontal plane
Leads I, II, and III: standard limb leads
Leads aVR, aVL, and aVF: augmented limb leads
Which leads look inferior
II, III, aVF
Which leads look septal
V1 and V2
Which leads look anterior
V3, V4
Which leads look lateral
I, aVL, V5, V6
5 lead ecg
White on top right
Green on bottom right
Brown on tummy
Black on top left (smoke)
Red on bottom left (fire)
SA node
60-100 BPM
Primary pacemaker
If SA node fails to send out signals—Caused by cardiac arrest/infarction, muscles die and SA node is killed so it can’t send signal
AV node
secondary pacemaker
40-60 BPM
Ventricular pacemaker
30-40 BPM
Too slow to provide cardiac output, get them a pacemaker!
How many boxes in 6 second strip
30
Formula for HR
1500/number of small boxes
Directions of p waves
Positive in lead I and II in NSR (points up)
Negative in lead aVR in NSR
Biphasic in lead V1
PR interval
Indicates AV conduction time
Beginning of the P wave to the QRS complex
Measures 0.12-0.20 seconds (3-5 small boxes)
Prolonged PR interval=1st degree heart block
QRS breakdown
Q wave: the first negative deflection after the P wave
R wave: the first positive deflection after the P wave
S wave: first negative deflection after the R wave
Small box on ecg
0.04 seconds
U wave
small rounded wave follows T wave. Less prominent than the P, QRS, and T waves. Only sometimes present.
Causes of sinus brady
lower metabolic rate: sleep, athletic training, hypothyroidism
Vagal stimulation: vomiting, suctioning, severe pain, bearing down
TAKE COLACE STOOL SOFTENER
Idiopathic sinus node dysfunction
Increased intracranial pressure
Coronary artery disease (e.g. MI of the interior wall)
Women’s cycle
Resolving the causative factors might be the only treatment needed.
Medications that cause sinus brady
calcium channel blockers, amiodarone, beta-blockers
Atropine for sinus brady
If the bradycardia produces signs and symptoms of clinical instability (e.g., acute alternative of mental status, chest discomfort, syncope, or hypotension): Atropine: 0.5 mg given rapidly as an IV bolus every 3-5 minutes to a max dose of 3 mg
Causes of sinus tachy
Physiologic or psychological stress
Varies depending on menstrual cycle
Medications that stimulate the sympathetic response; stimulants; and illicit drugs
ALCOHOL INCREASES HR BECAUSE BP GOES DOWN
Enhanced automaticity of the SA node/or excessive sympathetic tone with reduced parasympathetic tone (to improve stress level and increase influence of parasympathetic, deep breathing, meditation
Autonomic dysfunction: POTS-increase in heart rate greater than 30 bpm without hypotension when moving to a standing position
Prolonged sinus tachy can cause
Tired heart
Low myocardial supply → myocardial ischemia → possible heart attack
Persistent sinus tachy treatment
synchronized cardioversion is the treatment of choice (reset the heart)
Vagal maneuvers: carotid sinus massage, gagging, bearing down, forceful and sustained coughing, and applying a cold stimulus to the face.
Administration of adenosine (narrows the QRS)
Wide QRS: procainamide, amiodarone, and sotalol
Catheter ablation (done in EP lab)
Sinus dysrhythmia
HR changes based on respirations (faster on inspiration, slower on expiration)
Does not cause any significant hemodynamic effect and not typically treated
Pattern! Irregular but there’s a pattern
Defined as regularly irregular
Atrial dysrhythmia: PAC causes
caffeine, alcohol, nicotine, stretched atrial myocardium, anxiety, hypokalemia, hypermetabolic states, or atrial ischemia, injury, or infarction
QRS comes earlier than it’s supposed to
Atrial dysrhythmia: PAC treatment
treat the underlying cause (potassium levels, anxiety, etc)
Atrial dysrhythmia: aflutter treatment
vagal maneuvers, adenosine.
Treated with antithrombotic therapy, rate control, and rhythm control in the same manner as afib
How is aflutter described
Described with atrial to ventricular ratio (how many p waves per r wave)
Afib
Most common heart dysrhythmias
uncoordinated atrial electrical activation: rapid, disorganized, and uncoordinated twitching of atrial musculature.
Irregular
Causes of afib
Older people with structural heart disease, inflammatory or infiltrative disease, coronary artery disease, hypertension, congenital disorder, and heart failure.
DM, obesity, hyperthyroidism, pheochromocytoma (a rare, usually non cancerous (benign) tumor that develops in cells in the center of an adrenal gland.), pulmonary hypertension and embolism, obstructive sleep apnea, and acute moderate to heavy ingestion of alcohol
Symptoms of afib
Symptoms of heart failure
Hemodynamic collapse
Pulse deficit (hard to find)
Myocardial ischemia
Thrombi
Treatment of afib (meds)
Antithrombotic: aspirin, warfarin (not given as much, new ones given so they don’t have to get levels checked so much), Pradaxa, Xarelto, Eliquis, Savaysa.
Heart rate control medications: goal→ resting heart rate is less than 80 bpm. Beta-blocker or verapamil, diltiazem
Pharmacologic cardioversion: amiodarone.
Cardioversion for afib
Electrical cardioversion: for those hemodynamically unstable (e.g., acute alteration in mental status, chest discomfort, hypotension) and does not respond to medications
Old people have small brains so be careful when they fall
Junctional dysrhythmias
40-60 beats/min (above is junctional tachycardia)
AV node as the pacemaker
Components of ECG with junctional dysrhythmia (AV node is pacemaker)
Location of P wave varies
P waves may be:
Inverted and before, during, or after QRS
Absent (hiding in QRS)
PR interval: short
QRS: normal
Treatment of junctional dysrhythmia
May produce s/s of reduced cardiac output
Treatment same as sinus bradycardia
(Atropine, dopamine, epi)
PJC treatment
Treat underlying conditions (CAD or other abnormalities)
Catheter ablation
Meds and lifestyle mods
PJC meds
beta-blockers, calcium channel blockers, and other antiarrhythmics
Lifestyle mods for PJC
reducing or eliminating triggers (avoiding caffeine, alcohol, and nicotine, as well as managing stress and getting adequate sleep)
Junctional tachy
60-120 BPM
SVT
P waves not clear
Afib, a flutter, or junctional tachycardia can all be called SVT
QRS: normal (tight and narrow, once it’s wide, that means something is wrong with the ventricles)
Treatment for SVT
Adenosine–6mg rapidly: always follow with NS bolus
Warn patient: chest pressure, feeling faint
PVC
Initiated by Purkinje fibers–“skipped beat” and felt as palpitations in the chest (irregular pulsations)
Bigeminy: every other complex
Trigeminy: every third complex
If persistent what do we give for PVC
Amiodarone
Vtach
three or more PVCs in a row, occurring at a rate exceeding 100 bpm.
Assess the patient!!
Emergency: unresponsive and pulseless
Patients with larger MIs and lower ejection fractions are at higher risk of lethal VT.
Types of VT
stable monomorphic VT (do not have acute MI or severe HF): continuing assessment
Symptomatic monomorphic VT: cardioversion
Pulseless VT: defibrillation
Treatment of vtach
ejection fraction <35%: implantable cardioverter defibrillator
ejection fraction>35%: amiodarone
vfib
most common dysrhythmia in patients with cardiac arrest
rapid disorganized ventricular rhythm>300/min
Heartbeat and treatment of vfib
no atrial activity is seen
absence of an audible heartbeat, a palpable pulse, and respirations
cardiac arrest and death are imminent if not corrected
early defibrillation is critical to survival
Treatment of asystole
high quality CPR with minimal interruptions and identifying underlying and contributing factor (do not shock the patient)
Heart block
AV block
delayed or failed conduction of supraventricular impulses through the AV node (atrium) to the ventricles (atrium contracts, ventricles don’t contract appropriately)
PR interval is a measure of conduction between the initial stimulation of the atria and the initial stimulation of the ventricles
PR interval is used to identifying the degree (type) of block present
1st degree heart block
Long
PR interval >0.2 seconds (5 small boxes)
PR interval measurement is constant (all same length!)
Not so serious, you can get by
Second degree type 1 heart block
Wenckebach
Atrial contractions but no ventricular, can’t stimulate the QRS contraction
PR interval becomes longer with each succeeding ECG complex until there is a P wave not followed by a QRS. The changes in the PR interval are repeated between each “dropped” QRS
Atrium takes longer and longer to communicate, eventually the ventricle doesn’t receive a signal (QRS drops)
This pattern repeats itself
Regularly irregular!
2nd degree type 2 heart block
Second degree type II:
PR interval constant (length varies can be less than 0.2 or longer than that)) for those P waves just before QRS complexes
Third degree heart block
Complete
Two impulses (pacemakers!!) stimulate the heart.
PR interval: very irregular
More P waves
Than QRS complexes
Ps and Rs on their own, no coordination
PP is the same, and so is RR
P wave to R wave ratio is off: More p waves
Pacemaker for ventricles is intrinsically much slower, which is why there’s fewer R waves
Medical management of heart blocks
increase HR and maintain CO
Stable, no symptoms: no treatment (usually 1st degree, treatment in third degree)
The initial treatment of choice is an IV bolus of atropine, although it is not effective in second-degree AV block, type II, or third-degree AV block.
Acute dysrhythmias may be treated with medications or with external electrical therapy (emergency defibrillation, cardioversion, or pacing).
Chronic management of heart block
pacemaker for bradycardias and ICDs for chronic tachydysrhythmias [vtach or vfib])
Adjunctive modalities and management of heart block
cardioversion and defibrillation: to depolarizes myocardial cells (to terminate a tachydysrhythmia)
Indications of a successful response are conversion to sinus rhythm with adequate perfusion
Cardioversion vs defibrillation
cardioversion: deliver SYNCHRONIZED current (50 jules, aligns with patient’s rhythm, meaning they need to have a rhythm)
defibrillation: the delivery of the current is immediate and UNSYNCHRONIZED (VT/VF, irregular rhythms)
Defibrillation
Used in emergency
treatment of choice for v fib and pulseless VT
not for those who are conscious or have a pulse
use more voltage than used in cardioversion
give epinephrine or vasopressin after defibrillation
Synchronized cardioversion
a shock is timed to delivered during ventricular depolarization (QRS complex, when ventricles contract)
not to delivery the shock during vulnerable period of the T wave repolarization (when heart is relaxed)
is used to treat rhythms that have a clearly identifiable QRS complex and a rapid ventricular rate (SVT, monomorphic VT)
not for disorganized rhythms (polymorphic VT, VF)
Instructions for elective cardioversion
May need to take anticoagulants for a few weeks before the procedure.
Digoxin withheld for 48 hours before the procedure (to ensure the resumption of sinus rhythm with normal conduction)
No food or drinks at least 4 hours before the procedure
Can be chosen to be done to correct afib
Transcutaneous pacing
use electrical stimulation through pacing pads positioned on a patient’s torso to stimulate contraction of the heart
=temporary external pacing or noninvasive pacing
indication: symptomatic bradycardia unresponsive to atropine therapy or atropine is not available
painful, skin burns, tissue damage
Get put on a sedative because it’s painful
Indications of pacemaker
Symptomatic bradycardia (slow ventricular rate)
Symptomatic heart block (also slow rate)
Two components of pacemaker
Electronic pulse generator (intrinsic/house pacemaker)
Pacemaker electrodes (conduction pathway)
Pacemaker is externally programmable
Single chamber (unipolar) pacemaker:
One lead placed in atrium or ventricle
Produce large spic on the ECG
Sensing and pacing in the chamber where the lead is located
More likely to be affected by electromechanical interference
Dual-chamber (bipolar) pacemaker
One lead located in the atrium and one in the ventricle
Sensing and pacing in both chambers mimicking the normal heart function
Less affected by electromechanical interference
This is the one we see more
NASPE-BPEG code (first)
Paced
A: atrium
V: ventricle
D: dual
NASPE-BPEG (second)
Sensed
A: atrium
V: ventricle
D: dual
NASPE-BPEG (third)
Response to pt’s HR
I: inhibited (when heart beats normally, the pacemaker does not function)
T: triggered
D: dual
AAI pacemaker
sinus node dysfunction–no conduction disturbance in the AV node, atrium to ventricle is fine so we can only use one lead since this conduction is fine
DDD pacemaker
AV conduction disturbance
With complete heart block, we use DDD because it needs to sense both chambers
Pacing
Stimulation of the chamber–mimic normal heart conduction
Produce a spic on ECG
Inhibited response on pacemaker
response of the pacemaker is controlled by the activity of the patient’s heart. only function when pt’s heart not beat up to programmed rate (usually below 60)
Triggered response with pacemaker
response when it sense intrinsic heart activity (triggered by each p wave)
Capture with pacemaker
the heart has responded to the stimulus by producing an appropriate complex
Failure to capture
may occur with a low battery or poor connection, doesn’t send out impulse strong enough for contraction. The pacemaker is discharging the impulse; however, there is no responding cardiac contraction
Pacemaker says hey heart! Contract! And heart says nope
Pacemaker therapy prep
Check pt has a patent IV, and that the defibrillator, emergency cart and appropriate medications are available
Obtain consent–make sure patient is capable to make decision and witness the signature, doctor’s job to educate and answer questions
Obtain vital signs and ECG rhythm strips prior to insertion. connect to 12 lead ECG and continuously monitor before, during, and after
Anesthetize the area locally
Portable chest x-ray is required to confirm placement
Nursing management of pacemaker insertion
monitor the insertion site for bleeding, hematoma, and infection
Complications of pacemaker insertion
Movement and dislocation of the lead (don’t lift arms or heavy objects for a while)
Bleeding and hematoma
Ventricular ectopy or VT from wall stimulation
Infection leading to cardiac tamponade
Hemothorax, pneumothorax
Hiccups: may indicate that the generator is pacing the diaphragm
Pacemaker syndrome
Pacemaker syndrome
most common in VVI–pacemaker is only in ventricle
Fatigue, chest discomfort, SOB, activity intolerance, and postural hypotension, they feel worse than before. Teach pt to report this to the doctor
Electromagnetic interference with pacemaker
Never exposed to MRI because it may alter and erase the program memory
At security gates at airports, government buildings, or other secured areas request a hand search (no wand detection device directly over the pacemaker)
Household appliances (eg, microwave ovens) should not cause any concern
AICD
Detects and terminates life-threatening episodes of tachycardia or fibrillation, especially those that are ventricular in origin, so vtach and vfib
Risks that make you candidates for AICD
Dilated cardiomyopathy
Hypertrophic cardiomyopathy
Arrhythmogenic right ventricular dysfunction
Idiopathic prolonged QT syndrome
Vtach and vfib are huge risks in these so get an AICD!
CPR with AICD
Normal to feel tingling if you are touching patient when AICD delivers a shock
Not to place defibrillator paddles directly over the device
Patient with a permanent pacemaker with defibrillator or AICD should have the device checked after defibrillation
(check battery or if rate changed, needs to be replaced if so)
EP study
invasive cardiac catheterization
Evaluates and treats dysrhythmias
Includes cardiac cath and catheter ablation
Take fluid out and bring it to lab to check for bacteria, treats bc we’re removing fluid and also diagnoses
Patient is conscious but lightly sedated
Cardiac cath
performed in a specially equipped cardiac catheterization lab by an electrophysiologist
Catheter ablation
destruction of the causative cells
Radiofrequency–thermal injury and cellular changes
Extremely cold temperature
EP study nursing care
Similar to those associated with cardiac catheterization:
Restriction of activity
Duration 2-6 hours (if treatment is indicated)
Procedure is not painful but can be tiring. It may also cause feelings that were experienced when the dysrhythmia occurred in the past
Which valves are similar
Tricuspid and mitral are similar in terms of location (in between atrium and ventricles
Aortic and pulmonic are also similar because they both send blood out of the heart
Chordae Tendineae
fibrous tissue that anchor valve leaflets to papillary muscles of the ventricles, white stringy thingies
Holds onto the valves
Heart muscle can die or chordae tendineae can rupture
Regurgitation
when valves do not close completely when they are supposed to close.
Stenosis
when valves do not open completely when they are supposed to open (something is stuck)
Anterior vs posterior leaflet
anterior leaflet: longer
posterior leaflet: shorter
Mitral valve prolapse
Enlargement of one or both of the leaflets of mitral valve.
When leaflet is too long it can buckle onto ventricle itself, can’t close completely (regurgitation issue)
annulus often dilates; chordae tendineae and papillary muscles may elongate or rupture.
A portion of one or both mitral valve leaflets balloons back into the atrium during systole–blood regurgitates from the left ventricle back into the left atrium
Needs to close during systole (systolic murmur)
Clinical manifestations of MVP
Most never have symptoms
A few have fatigue, SOB, lightheadedness, dizziness, syncope, palpitations, chest pain, or anxiety
Assessment and diagnostics of MVP
Extra heart sound–mitral click
A murmur of mitral regurgitation may be heard if the valve opens during systole (systolic murmur) and blood flows back into the left atrium.
Echocardiography for structure problems is used to diagnose and monitor progression of MVP
Controlling symptoms of MVP
Eliminate caffeine and alcohol, stop using tobacco products.
Antiarrhythmic medications
Chest pain: nitrates or calcium channel blockers or beta-blockers
HF management
Severe: mitral valve repair or replacement
Endocarditis r/t MVP
At risk for endocarditis because of the extra long tissue (bacteria on it)
Women diagnosed with mitral valve prolapse without mitral regurgitation or other complications may complete pregnancies with vaginal deliveries
Antibiotic prophylaxis is recommended for high-risk patients before and after dental procedures–Amoxicillin, not everyone needs it, just depends on condition
Mitral regurgitation
By itself, this is a pathology
Blood flowing back from the left ventricle into the left atrium during systole.
Due to the thickness and fibrosis of the chordae tendineae pulls on to leaflets so they can’t close tightly
systolic murmur
Causes of mitral regurgitation
Developing countries: rheumatic heart disease
Developed countries: degenerative changes of the mitral valve as people get older
Clinical manifestations of mitral regurgitation
Often asymptomatic
Acute mitral regurgitation: usually from a MI–manifests as severe CHF (heart failure management can be used here as well as with MVP)
Most common: Dyspnea, fatigue, and weakness, not enough blood pumped to body because it flows back into the left atrium
S/s are similar to MVP
Big risk for clots!!