Arrhythmias Flashcards
a fib
rapid, irregular, atrial activation (atria quiver instead of contracting properly, causes blood to pool & form a clot –> increased r/o stroke)
-very common
-increased risk w/ age
a fib sx
-may be asx
-palpitations (all arrhythmias), tachycardia (100-200 bpm), fatigue, weakness, mild dyspnea
-irregularly irregular pulse
others: stroke, thromboembolism
Dx studies for a fib
EKG: no p waves, ventricular rhythm lacks a repetitive pattern
ECHO: should be done on all pts w/ new onset a. fib to look for clots
Labs: CBC, electrolytes, renal fxn
a fib tx (address rhythm)
-cardiac ablation: better than drugs but higher r/o stroke (ex. atrioventricular junction ablation w/ cardiac resynchronization therapy - destroys link btwn LA and LV, f/b pacemaker implantation)
-drugs: AMIODARONE has least cardiotoxic AEs & is more effective than sotalol, donedarone, propafenone, flecainide; start in hosp to closely monitor!
-cardioversion: must be on AC for 3 wks and have TEE prior
A fib: tx of rate vs rhythm
-for decades, rate control was deemed most important d/t AEs of anti-arrhythmics and “noninferiority” of rate control agents
-recent studies, lean towards prioritizing rhythm control
-there are times when both are important
a fib tx (address rate)
-indications: asx, elderly, long-standing afib, markedly enlarged left atrium
-1st line: B-blockers and non-DHP (CCB) ***avoid CCB in pts w/ CHF
-less aggressive rate control (<110bpm) is preferred over more intense rate control (<80bpm)
a fib tx (address stroke risk)
Calc CHA2DS2-VASc score –>
-start oral AC if 2+ in men or 3+ in women
-may consider LAA closure (i.e. WATCHMAN device) depending on score
What does CHA2DS-VASc score stand for/consider
CHF
HTN
Age 75+ (doubled)
DM
Stroke (prior stroke, TIA, or thromboembolism) (doubled)
Vascular dz
Age 65-74
Sex category
*each is worth 1 pt unless it says “doubled”
Stroke risk AC: new oral AC (NOACs) that are now recommended over warfarin
-Dabigatran (Pradaxa)
-Apixaban (Eliquis)
-Rivaroxaban (Xarelto)
-Edoxaban
When is warfarin still recommended over other NOACs
if pt has moderate/severe mitral stenosis, advanced kidney dz, or if pt has an artificial heart valve
Supraventricular tachycardias
-caused by premature signaling in atria
-often paroxysmal (PSVT)
Supraventricular tachycardia S/S
- > 100 bmp (often 150-200)
-narrow QRS
-palpitations, dyspnea, dizziness, chest discomfort, syncope
3 types of supraventricular tachycardia (most to least common) and their changes on EKG
- AVNRT (atrioventricular node reentry): retrograde p wave falls w/in or just after QRS
- AVRT: reentry involving an accessory pathway (i.e. WPW - short PR interval)
- Focal & Multifocal Atrial tachycardia: p waves immediately in from of QRS complex
*supraventricular –> think above ventricles, which lies the atria; on EKG the p wave represents the atria, therefore these will have p wave abnormalities
AVNRT (AV nodal reentrant tachycardia)
-MC type of PSVT
-reentry circuit involving the AV node & nearby atrial tissue –> leads to separate pathways w/in the AV node, resulting in tachycardia d/t premature beats
-usu presents after age 20
Dx of AVNRT (s/s, dx test results)
-HR of 150-250 bpm
-palpitations, lightheadedness, dizziness, dyspnea
-neck pounding secondary to CANNON WAVES is pathognomonic
-EKG (PAC w/ prolonged PR at beginning, p wave in or just after QRS - may be superimposed (“pseudo-r”))
*pathognomonic = specifically typical of that disease
*cannon waves are d/t atria & ventricles contracting simultaneously causing waves in the blood
what are cannon waves and what condition is this associated with?
cannon waves are d/t atria & ventricles contracting simultaneously causing waves in the blood
associated with AVNRT
AVNRT: acute management tx
-if hemodynamically stable, try vagal maneuvers (Valsalva)
-if Valsalva doesn’t work, give IV adenosine
-If adenosine is ineffective, give IV verapamil or IV metoprolol
-If all fails, OR if pt is hypotensive, has angina pectoris, or has CHF, then cardioversion is performed
*if refractory (resistant to tx) then perform advanced CV life support (ACLS)
how does the Valsalva maneuver work
holding your breath and bearing down decreases blood return to the heart –> stim symNS –> increased HR and contractility –> stim parasymNS to compensate for overstim of symNS –> decreased HR and contractility
AVNRT: preventative therapy
depends on frequency of arrhythmia, severity, pt preference, etc.
Tx for recurrent AVNRT (Cure rate)
catheter ablation
-95% cure rate
*if pt can’t undergo ablation, then use B-blockers, non-DHP (CCB), anti-arrhythmics
WPW
<1% of population
-accessory pathways connect the atria and ventricles; AV node is bypassed
-dx in teenager/early adulthood
Sx of WPW
dizziness
syncope
SOB
weakness
chest pain
EKG findings w/ WPW
short PR interval
delta wave
WPW: Tx
-Goals: reduce sx and prevent life-threatening arrhythmia
-urgent cardioversion if hemodynamically unstable (low BP, elevated HR)
-Vagal maneuvers
-Adenosine 1st choice if vagal maneuvers fail; Verapamil 2nd line
-Long-term management: catheter ablation
Focal Atrial Tachycardia (what is it, what causes it, EKG findings, long-term therapy)
-small area in atria generates impulses that override SA node
-can be d/t meds, caffeine, alcohol, or idiopathic
-EKG: abnormal p wave morphology, QRS is normal
-Long-term therapy: uncertain, drugs (???), catheter ablation may be effective in 70-90%
Multifocal Atrial Tachycardia (MAT)
100-130bpm
-3+ morphologically distinct p waves
-irregular
-multiple areas of the atria are sending electrical impulse randomly
(same sx as other arrhythmias)
what diseases are MAT associated with
respiratory dz (MAT is secondary to COPD, hypoxia, pulm HTN)
CHF
MAT: Tx
tx underlying problems (oxygen)
rate control w/ Metoprolol or Verapamil