ch 35 dysrhythmias Flashcards
what does the P wave represent
depolarization of atria
what does the QRS wave represent
depolarization of ventricles
what does the T wave represent
repolarization of ventricles (refractory period)
cardiac output = ? x ?
heart rate x stroke volume
what happens to K, Na, and Ca during depolarization
K moves out
Na and Ca move in
contraction
what happens to K, Na, and Ca during repolarization
K moves in
Na and Ca move out
what are the steps to rhythm analysis (5)
- what is heart rate?
- is rhythm regular/irregular?
- is there a P for every QRS?
- is there a QRS for every P?
- measure intervals (PR, QRS)
what is considered a normal QRS interval
<0.12 seconds (3 small boxes)
what is considered a normal PR interval
0.12-0.2 seconds (1 big box)
what can cause artifact
bad adherence to chest
movement
S+S sinus bradycardia
- hypotension
- pale cool skin
- weakness
- angina
- dizziness/fainting
- SOB
- confusion
causes of abnormal sinus bradycardia (6)
- hypothyroidism
- hypoglycemia
- increased intracranial pressure
- hypothermia
- b blocker or calcium channel blocker
- vagal stimulation
atropine toxicity S+S
- “hot as a hare” = increased temp
- “mad as a hatter” = confused
- “red as a beet” = flushed
- “dry as a bone” = thirst
treatment for symptomatic sinus bradycardia (3)
- atropine: 0.5 IVP and flush with NS fast
- pacemaker
- stop offending drugs
max dose in 24 hr for atropine
3 mg
how to calculate max sinus tachycardia
220 - person’s age
what is the HR for sinus bradycardia
<60 bpm
what is the HR for sinus tachycardia
101-180 bpm
what is the HR for paroxysmal supraventricular tachycardia
151-220 bpm
what is the HR for atrial flutter
200-350 bpm
what is the HR for atrial fibrillation
350-600 bpm
what is the HR for ventricular tachycardia
150-250 bpm
S+S sinus tachycardia
- dizziness
- dyspnea
- hypotension
- chest pain
- decreased cardiac output
causes sinus tachycardia (2)
- vagal inhibition
- sympathetic stimulation
what meds can cause sinus tachycardia (3)
- atropine
- epinephrine
- albuterol
treatment for sinus tachycardia (3)
- vagal maneuver
- meds: B blockers, adenosine, or calcium channel blockers
- synchronized cardioversion
what is the minimum amount of time you should give an IVP of B blocker over
atleast 5 mins
causes premature atrial contractions (PAC)
- stress
- fatigue
- caffeine
- alcohol
- tobacco
- hypoxia
- electrolyte imbalance
- disease states
S+S premature atrial contractions
palpitations
treatment premature atrial contractions (2)
- remove offending agent
- b blocker
S+S paroxysmal supraventricular tachycardia (PSVT) (3)
- hypotension
- dyspnea
- angina
causes PSVT (6)
(abrupt onset and ending)
- overexertion
- stimulants
- disease
- digitalis toxicity
- deep inspiration
- stress
1st priority for PSVT treatment
call a code!
treatment PSVT
- vagal stimulation
- IV adenosine rapid push with NS flush
- IV b blocker
- synchronized cardioversion if adenosine not effective
ECG characteristic of PSVT
- can’t distinguish P from T waves
- change occurs suddenly
- HR 150-220
risks with atrial flutter and atrial fibrillation
- blood clot in atrium
- stroke
ECG characteristics of atrial flutter
- sawtooth pattern
- irregular rhythm
treatment A flutter and A fib (4)
- O2
- if HR > 100 = digoxin, calcium channel blockers, b blockers, amiodarone
- stroke prevention = enoxaparin, warfarin, or factor 10a inhibitor
- radiofrequency ablation or cardioversion if amiodarone didn’t work
toxicity S+S digoxin (5)
- fatigue
- dysrhythmias
- visual disturbances **
- anorexia
- hypokalemia
how do you give amiodarone
through a filter
ECG characteristics of atrial fibrillation
- irregular rhythm
- wavy baseline
causes atrial flutter and fibrillation (2)
- ectopic pacemakers in atria
- decreased cardiac output, blood pools in atria
what endocrine imbalance can long term use of amiodarone lead to
hypothyroidism
most common dysrhythmia after heart attack
1st degree AV block
ECG characteristics of 1st degree AVB
long PR interval (>0.2)
-HR can be brady, normal, or tachy
treatment for 1st degree AVB
none
continue to monitor
ECG characteristics of 2nd degree AVB type 1
- irregular rhythm
- dropped beats **
- not QRS for every P
- PR intervals increasingly prolonged across ECG strip
treatment 2nd degree AVB (types 1 and 2)
if symptomatic:
- atropine
- temporary pacemaker
ECG characteristics of 2nd degree AVB type 2
- irregular rhythm
- not QRS for every P
- P waves are punctual and normal **
- same PR interval *
- dropped beats
what could be indicated by T wave not beginning at baseline
MI
S+S 3rd degree AVB
- hypotensive
- unconscious
ECG characteristics of 3rd degree AVB
- regular rhythm with dropped beats
- not QRS for every P
- wide QRS (>0.12)
- PR intervals all different
treatment 3rd degree AVB (2)
- dopamine or epinephrine
- emergency pacemaker
causes premature ventricular contractions (PVC)
- stress
- fatigue
- caffeine
- electrolyte imbalance
ECG characteristics premature ventricular contractions
- wide QRS
- early beats
what does multifocal PVC mean
PVCs don’t look the same
what is a couplet
2 PVCs in a row
what is bigeminy
PVC q2nd beat
what is trigeminy
PVC q3rd beat
treatment PVC (2)
- address underlying condition (maybe O2 or electrolyte replacement)
- amioderone
2 shockable pulse rhythms
vtach and vfib
causes V Tach (3)
- head injuries
- MI
- electrolyte imbalances
S+S V Tach
- severe hyperthermia
- “R on T phenomenon” next beat starts before ventricles are repolarized
ECG characteristics V Tach
- regular rhythm
- QRS >0.2
- HR 150-250 bpm
what can sustained V Tach lead to
- hypotension
- pulmonary edema
- decreased cerebral blood flow
- cardiopulmonary arrest
treatment for V Tach with pulse
-antidysrhythmics or cardioversion
treatment for V Tach without a pulse
- CPR and rapid defibrillation
- amiodarone can prevent going back into V Tach
what is torsades de pointes
occurs with V Tach
next beat starts before ventricles are repolarized, varying heights of R waves
1 cause of MI
v fib
ECG characteristics V Fib
- wavy baseline
- extremely irregular rhythm
treatment for V Fib
CPR and debrillation
causes v fib
- MI
- HF
- electrolyte imbalances
- severe alkalosis
- drug toxicity
- hypoxia
ECG characteristics of asystole
- absence of electrical impulses
- pt unresponsive and pulseless
treatment asystole (5)
- CPR
- epinephrine 1 mg IVP q3-5 mins
- intubation
- temporary pacemaker
- treat 5 Hs and 5 Ts
5 (6) Hs with asystole
- hypovolemia
- hypoxia
- hydrogen ion (acidosis)
- hyper/hypokalemia
- hypoglycemia
- hypothermia
5 Ts with asystole
- toxins
- tamponade
- thrombosis (MI + pulmonary)
- tension pneumothorax
- trauma
ECG characteristic of pulseless electrical activity (PEA)
any electrical pattern without pulse
treatment PEA
- CPR
- epi IVP q3-5 mins
- intubation
how to use cardioversion
- 50-100 J
- sync to R wave
- for supraventricular tach, a fib, a flutter, 2nd degree type 2 avb
how to use defibrillation
- 120-200 J
- don’t sync to R wave
- shock when clear
what to tell pts about ICDs
- don’t lift arm until cleared
- avoid large magnets and MRIs
- if fires once, call hcp; if once and sick or twice, call 911*
- keep incision dry for several days after implant
- avoid direct blows to site
emergency management of dysrhythmias (6)
- monitor ABCs
- apply O2
- take VS
- 12 lead ECG
- identify dysrhythmia
- IV access
what effect can b blockers and calcium channel blockers have on ECG strips (3)
- bradycardia
- prolonged PR interval
- AV block
who might need a pacemaker (6)
- AV block
- A fib
- cardiomyopathy
- HF
- symptomatic bradycardia
- tachydysrhythmias (V tach)
who might need a temporary pacemaker (5)
- maintaining HR and rhythm during surgery, cardiac cath, before permanent implant, drug therapy that may cause bradycardia
- prophylaxis after open heart surgery
- acute MI with 2nd or 3rd degree AVB
- acute MI with symptomatic bradycardia
- to evaluate pt with brady/tachydysrhythmias
