Tachyarrhythmias

Question 1

what does wide QRS indicate?

Answer 1

conduction NOT thru normal system, indicates: bundle branch block , pre excitation (accessory pathway) or impulse originating in ventricle

Question 2

DDx for regular, narrow QRS

Answer 2

sinus tachy, atrial flutter, SVT (AVNRT/AVRT/AT)

Question 3

DDx for regular, wide QRS

Answer 3

V tach, SVT w/ aberrancy or pre-excitation

Question 4

DDx for irregular, narrow QRS

Answer 4

a fib, atrial flutter w/ variable conduction, multifocal atrial tachy

Question 5

DDx for irregular, wide QRS

Answer 5

v fib, polymorphic VT (Torsade), A fib w/ aberrancy or prexcitation

Question 6

sinus tachy

Answer 6

HR over 100, sinus P waves, Tx underlying cause

Question 7

atrial flutter patho

Answer 7

reentrant arrhythmia of RA (usually w/ cavo-tricuspid isthmus)- regular ventricular conduction

Question 8

atrial flutter ECG

Answer 8

regular, narrow QRS; sawtooth pattern P waves, multiple of QRS (ex. 2:1 P to QRS)

Question 9

Tx for flutter

Answer 9

anticoag for stroke prevention, rate control, ablation

Question 10

AVNRT patho

Answer 10

premature atrial beats are blocked in fast pathway of AV node, conduct thru slow pathway- causes retrograde conduction and reentry

Question 11

AVNRT ECG

Answer 11

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

Question 12

AVNRT Tx

Answer 12

acute: vagal maneuvers, adenosine- to block AV node transiently and break circuit
chronic: AV nodal block, ablation

Question 13

ECG of WPW syndrome

Answer 13

sinus rhythm, delta wave in the QRS (slurring upstroke of the R)

Question 14

WPW syndrome

Answer 14

aka ventricular preexcitation syndrome: accessory pathway b/w atria and ventricles allows for two pathways of signal transmission and potential for reentrant loop

Question 15

AVRT patho

Answer 15

tachy from reentry loop w/ accessory pathway as opposed to w/i AV node

Question 16

AVRT ECG

Answer 16

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

Question 17

AVRT Tx

Answer 17

acute: vagal maneuvers, adenosine
chronic: ablation of accessory pathway

Question 18

why adenosine for SVTs

Answer 18

hyperpolarize AV node, block the transmission for even one beat can terminate tachycardia

Question 19

a fib mechanism

Answer 19

usually initiated by automaticity or triggered activity (mostly at pulmonary venous muscle sleeves), maintained by multiple reentry circuits

Question 20

a fib ECG

Answer 20

irregularly irregular QRS, inconsistent atrial activity, varied rate

Question 21

variable conduction atrial flutter - ECG and diff b/w a fib

Answer 21

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)

Question 22

a fib Tx

Answer 22

anticoag for stroke, rate control, rhythm control when symptomatic- DC cardioversion, drug therapy to disrupt reentry/abnormal automaticity, ablation

Question 23

V tach patho

Answer 23

multi possible mechanisms: reentry around fibrosis, triggered arrhythmia from delayed afterdepolarizations

Question 24

V tach ECG

Answer 24

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

Question 25

v tach Tx

Answer 25

Acutely ACLS, chronically need ICD and/or drug therapy/ablation

Question 26

Torsade de Pointes

Answer 26

irregular wide QRS (polymorphic VT)

Question 27

distinguishing VT from SVT/aberrancy

Answer 27

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

Question 28

preconditions for torsade

Answer 28

long QTs leading to EAD triggered activity and reentry w/i ventricle

Question 29

torsade Tx

Answer 29

ACLS acutely, ICD chronically

Question 30

a fib w/ pre-excitation

Answer 30

AF conducts to ventricle rapidly thru accessory pathway, can degenerate into VF and cause death- wide irregular QRS

Question 31

Tx for a fib w/ pre-excitation

Answer 31

acutely w/ DC cardioversion, then ablation of pathway

Question 32

v fib ECG

Answer 32

wide irregular QRS, very chaotic QRS- wont get 12 lead b/c unstable

Question 33

v fib Tx

Answer 33

acutely ACLS (defibrillation) and Tx underlying cause (ischemia, electrolyte abnormality, etc)

chronically need ICD