Tachyarrhythmias Flashcards
what does wide QRS indicate?
conduction NOT thru normal system, indicates: bundle branch block , pre excitation (accessory pathway) or impulse originating in ventricle
DDx for regular, narrow QRS
sinus tachy, atrial flutter, SVT (AVNRT/AVRT/AT)
DDx for regular, wide QRS
V tach, SVT w/ aberrancy or pre-excitation
DDx for irregular, narrow QRS
a fib, atrial flutter w/ variable conduction, multifocal atrial tachy
DDx for irregular, wide QRS
v fib, polymorphic VT (Torsade), A fib w/ aberrancy or prexcitation
sinus tachy
HR over 100, sinus P waves, Tx underlying cause
atrial flutter patho
reentrant arrhythmia of RA (usually w/ cavo-tricuspid isthmus)- regular ventricular conduction
atrial flutter ECG
regular, narrow QRS; sawtooth pattern P waves, multiple of QRS (ex. 2:1 P to QRS)
Tx for flutter
anticoag for stroke prevention, rate control, ablation
AVNRT patho
premature atrial beats are blocked in fast pathway of AV node, conduct thru slow pathway- causes retrograde conduction and reentry
AVNRT ECG
regular, narrow QRS; P wave immediately after or buried inside QRS (atrial conduction from reentry right after ventricular conduction)
if regular, narrow tachy w/ no visible P waves, think SVT
AVNRT Tx
acute: vagal maneuvers, adenosine- to block AV node transiently and break circuit
chronic: AV nodal block, ablation
ECG of WPW syndrome
sinus rhythm, delta wave in the QRS (slurring upstroke of the R)
WPW syndrome
aka ventricular preexcitation syndrome: accessory pathway b/w atria and ventricles allows for two pathways of signal transmission and potential for reentrant loop
AVRT patho
tachy from reentry loop w/ accessory pathway as opposed to w/i AV node
AVRT ECG
regular, narrow QRS w/ P wave right after QRS-can look like a sharp notch in the T wave, no more delta wave in QRS
AVRT Tx
acute: vagal maneuvers, adenosine
chronic: ablation of accessory pathway
why adenosine for SVTs
hyperpolarize AV node, block the transmission for even one beat can terminate tachycardia
a fib mechanism
usually initiated by automaticity or triggered activity (mostly at pulmonary venous muscle sleeves), maintained by multiple reentry circuits
a fib ECG
irregularly irregular QRS, inconsistent atrial activity, varied rate
variable conduction atrial flutter - ECG and diff b/w a fib
regularly irregular QRS (unlike a fib), alternating pattern of P to QRS (like 2:1, 4:1, 2:1, etc), consistent atrial activity (unlike a fib)
a fib Tx
anticoag for stroke, rate control, rhythm control when symptomatic- DC cardioversion, drug therapy to disrupt reentry/abnormal automaticity, ablation
V tach patho
multi possible mechanisms: reentry around fibrosis, triggered arrhythmia from delayed afterdepolarizations
V tach ECG
wide, regular tachycardia distinguished from SVT w/ aberrancy by P waves: VT has no P waves and SVT/aberrancy would have P wave associated w/ QRS
v tach Tx
Acutely ACLS, chronically need ICD and/or drug therapy/ablation
Torsade de Pointes
irregular wide QRS (polymorphic VT)
distinguishing VT from SVT/aberrancy
w/ ECG: VT has no relationship b/w P waves and QRS and V1-6 all have similar appearance; and SVT/aberrancy would have same QRS in sinus vs SVT
clinically: history of heart disease makes VT more likely, response to vagal maneuvers makes SVT more likely
preconditions for torsade
long QTs leading to EAD triggered activity and reentry w/i ventricle
torsade Tx
ACLS acutely, ICD chronically
a fib w/ pre-excitation
AF conducts to ventricle rapidly thru accessory pathway, can degenerate into VF and cause death- wide irregular QRS
Tx for a fib w/ pre-excitation
acutely w/ DC cardioversion, then ablation of pathway
v fib ECG
wide irregular QRS, very chaotic QRS- wont get 12 lead b/c unstable
v fib Tx
acutely ACLS (defibrillation) and Tx underlying cause (ischemia, electrolyte abnormality, etc)
chronically need ICD
