Arrythmias, Conduction Blocks and EKGs Flashcards
Define parameters associated w/ bradycardia and tachycardia
brady <60
tachy >100bpm
define Symptomatic Bradycardia and compare it to sleep bradycardia
usually below 40 AND does not increase with physiological demand
•During sleep: common HR to drop below 60, even below 50 and sometimes below 40 without consequence
•most common ECG finding with PE is ____ ____
sinus tachycardia
si/ sx of sinus tachycardia
include sx in pts w CAD
Asymptomatic
Heart palpitations
Shortness of breath (especially with exertion) – feel they cannot catch their breath
CAD:
- Heart palpitations
- Shortness of breath – anginal sx
- Chest discomfort à sinus tach causes cardiac ischemia due to supply/demand mismatch
- Lightheadedness
- Fatigue
how do we tx sinus tachycardia
tx underlying cause
Si/Sx of SVT
••Sudden onset racing heart palpitations ** that fades suddenly
comes on suddenly and fades suddenly
contrast pathophysiologies of AVRT vs AVNRT
AVNRT Abnormal re-entrant loop around the AV node
AVRT -
Accessory pathway b/w atria and ventricle –> signal goes around and around causing tachycardia
defne pathophysiology for junctional rhythm
AV node is pacemaker -> depolarizing quickly and causing rapid HR
Junctional pacemakers usually 40-60bpm (ventricular rate)
•Differentiate based on junctional rate
recall treatment for stable SVT
first and second line
unstable SVT?
first - vagal maneuvers
second adenosine
unstable
vagal maneuvers
if unsuccessful - DC cardioversion
list meds that prolong QTc interval
Antiarrhythmic agents
- Amiodarone
- Flecainide
- Sotalol
- Antipsychotics
- Chlorpromazine
- Haloperidol
- Olanzapine
- Quetiapine
- Risperidone
- Antibiotics
- Macrolides – azithromycin
- Quinolones – levo, cipro
- Antidepressants
- Citalopram
- TCAs
length of QTc that puts pts at risk for ventricular arrythmias
QTc greater than 500 milliseconds (ms) puts patient at risk for ventricular arrythmias (Torsade de Pointe)
Si/Sx of Vtach
- Conscious w/ pulse – will show symptoms
- Unconscious with pulse
- Unconscious w/o pulse
- Heart palpitations
- Lightheadedness
- Chest pain
- Shortness of breath
- Diaphoresis (drenching sweat)
- Near syncope
- Syncope
- Sustained LOC
- Pulseless (death)
tx for vtach
Pulse present:
stable - amiodarone 150 mg IV followed by continuous infusion
unstable - cardioversion
long term implantable device
pulselessness:
CPR
- Defibrillation – as soon as it is available place on chest
- Epinephrine
- ICD
tx for torsade de pointe
first and second line
Stable
- First line: give Mg before you check levels
- Temporary transverse overdrive pacing if no response to Mg –> external pacer
Second line – if persistent or Unstable –> prompt defibrillation
causes of Vfib
•Myocardial ischemia / MI
- HF
- Hypoxemia or hypercapnia
- Hypotension / shock
- Electrolyte imbalances
- Stimulants (drugs, caffeine)
- Often preceded by Vtach
tx vfib
CPR
Defibrillation – IMMEDIATE (no cardiac output)
If pulse regained: coronary arteriography (cardiac catheterization) to tx CAD
Implantable cardioverter-defibrillator for long term management
describe conduction pathway of WPW
Accessory pathway (delta wave) creates preexcitation à electoral impulses arrive to ventricle early and bypass AV node
_Orthodromic AVR_T (narrow complex) – more common
•Impulse transmits anterograde down AV to ventricles and retrograde to atria up through accessory pathway
Antidromic AVRT (wide complex) - Opposite of above
complications of WPW in the setting of rapid afib
• can lead to dangerous ventricular arrythmias
standard tx for WPW
Nonpharmacologic – catheter ablation of accessory pathway
Pharmacologic – to slow ventricular heart rates / prevent arrythmias
differentiate b/w sustained vs nonsustained Vtach
Sustained ventricular tachycardia - 3 or more consecutive beats of ventricular origin
•Lead to vfib à death
Non-sustained ventricular tachycardia – less then 3 ventricular beats , <30s
•Asymptomatic
what is Torsades triggerd by?
- Hypokalemia – check levels before administration
- Hypomagnesemia – ok for emergent administration
- Drugs that prolong QTc
what type of arrythmia is associated w/ syncope and is a frequent complication of MI and dilated CM
SVT
what type of arrythmia is associated w/ severe CAD caused by acute MI
VFib
name some narrow complex rhythms
sinus tachycardia
SVT
AVNRT
AVRT
WPW - orthodromic AVRT
name some wide complex rhythms
sustained ventricular tachycardia
Torsade de pointe
Vfib
define the classes of Afib
Paroxysmal
persistent
long-standing
permanent
“Lone-AF”
refractory
- Paroxysmal (PAF) - intermittent
- Persistent - fails to self-terminate within 7 days & requires intervention in order to convert
- Long-standing - >12 months
- Permanent - >12 months & no longer pursue rhythm control
- “Lone AF” – without structural heart disease, lowest risk of complications.
- term not used much anymore
- Example is if patient underwent heart surgery and developed afib once after as heart was healing
- Refractory – not responding well to therapy/ keeps returning.
risk factors associated w/ Afib and Aflutter
- >65 y/o
- Men>women
- Whites most common
- Hypertension
- Elevated BMI
- Prolonged PR interval
- Valvular disease
- CHF
Triggers for Afib
- Sleep deprivation
- Physical illness
- Post-surgery
- Stress
- Hyperthyroidism
- Physical exercise
- Stimulant meds (Sudafed)
- Alcohol
- Caffeine
- Dehydration
workup in pt w/ newly diagnosed Afib
Hx and PE
- ECG – narrow QRS, irregular, no p wave
- Echo – look at mitral valve – if mitral valve disease put on anti-coagulation
- Stress test
- Labs: CBC, BMP, kidney function tests , TSH (new afib ALWAYS get both)
- Exercise stress test – assess for ischemic heart disease
- Heart monitors
FIRST Echo TTE –less invasive
•valvular heart disease (MS/ rheumatic heart disease )
SECOND Echo TEE – more invasive
•More sensitive for dx atrial thrombus à prior to cardioversion
describe a TEE echo vs TTE echo
FIRST Echo TTE –less invasive
•valvular heart disease (MS/ rheumatic heart disease )
SECOND Echo TEE – more invasive
•More sensitive for dx atrial thrombus à prior to cardioversion
goals of therapy w/ afib
- Rhythm control
- Reduce risk of stroke
- Prevent tachycardia mediated cardiomyopathy and ischemia (rate control)
- Alleviate symptoms
outline pharmacologic tx for Afib
first line - BBs or CCBs
metropolol and diltiazem (preferred in ED)
Adjuncts after maximizing BB or CCB
Digoxin - monior for dig tox
amiodarone (antiarrythmic) added in refractory Afib w/ RVR - lots of side effects
Most common side effect associated w/ amiodarone
- Abnormal LFTs
- Pulmonary toxicity – several months or years after initiation
- Most common is chronic interstitial pneumonitis
what are symptoms of digoxi toxicity?
what is digoxin effect?
- Symptoms: fatigue, dizziness, nausea (nonspecific)
- ECG changes – heart blocks
- Digoxin effect – normal to see on ECG of patients taking digoxin – Salvador dali mustache (nontoxic levels)
tx for aflutter w/ RVR
- Control ventricular rate - More difficult to control then afib
- FIRST LINE – BB or CCB
- Digoxin can be added, No amiodarone
- Convert to NSR / maintain NSR
•Ablation of IVC-TA area to break circuit
- Prevention of systemic embolization (stroke)
•Assess stroke risk - add anticoag if necessary
where is ablation performed
for what condition?
- Type 1 aflutter
- Ablation of macro reentrant pathway in right atrium involving obligatory pathway between inferior vena cava and tricuspid annulus (IVC-TA area)
outline tx for tachycardia in afib w/ RVR in acute and long term settings
ACUTE - FIRST line - BB or CCB in ED setting usually diltiazem drip
chronic - discharge on PO BB / CCB
- Oral metoprolol BID – long-acting Toprol dosed once daily
- Nadolol PO (liver failure pts / portal HTN)
- Carvedilol (HF pts)
consider Adjuncts:
- Digoxin – added if BB insufficient or intolerant
- Amiodarone – slow rate in refractory Afib
Cardioversion - if necessary
indications for urgent cardioversion
- Active ischemia
- Unstable hemodynamics
- Evidence of organ hypoperfusion
- Severe manifestations of heart failure (pulmonary edema)
- The presence of WPW
indications for nonurgent cardioversion
- New onset or newly recognized afib –> r/out clots!
- Pts with persistent afib who are limited by their symptoms
Reasons NOT TO cardiovert
- Known afib that is minimal symptomatic
- Multiple comorbidities
- Unlikely to maintain NSR
- Age - Benefits of cardioversion decrease after 80 years old
- Paroxysmal afib