Tachyarrhythmias Flashcards Preview

Cardiovascular > Tachyarrhythmias > Flashcards

Flashcards in Tachyarrhythmias Deck (36):
1

non-sustained ventricular tachycardias

≥ 3 consecutive beats of ventricular origin at a rate > 100 beats per minute lasting less than 30 seconds and not associated with hemodynamic collapse

2

sustained monomorphic ventricular tachycardia

consecutive ventricular beats of a single electrocardiographic morphology lasting greater than 30 seconds with a rate > 100 beats per minute or associated with hemodynamic collapse

3

ventricular fibrillation

chaotic ventricular activation associated with hemodynamic collapse and death. Most likely a reentrant (functional) tachyarrhythmia

4

polymorphic ventricular tachycardia

ventricular tachycardia with beat-to-beat changes in morphology on the surface electrocardiographic recordings

5

drugs that cause torsades de pointes

Type IA, IC, and III antiarrhythmic agents

phenothiazines

tricyclic antidepressants

Certain antibiotics (i.e. pentamidine)

drug combinations (erythromycin or ketoconazole with Seldane)

6

idiopathic ventricular tachycardia

patients have normal hearts, rarely associated with sudden death

usually a triggered rhythm

can be a reentrant rhythm utilizing the purkinje system

7

isthmus

a channel that is critical for formation of reentrant rhythms

8

long QT syndrome

congenital or drug-induced

patients at risk of sudden cardiac death due to polymorphic ventricular tachycardia such as Torsades

mostly due to defects in potassium channels

sodium and calcium have also been implicated

9

Brugada Syndrome

patients have ST elevation and T wave inversion in leads V1-V3 and an incomplete right bundle branch block pattern

due to sodium channel mutation in the epicardium in the right ventricular outflow tract, allowing for reentry

patients are susceptible to dying from ventricular fibrillation

10

treatment for ventricular fibrillation and tachycardia

treat underlying condition if reversible

antiarrhythmic drugs

implantable cardioverter defibrillator

11

tachyarrhythmia mechanisms

abnormality in impulse formation due to abnormal automaticity or triggered activity

abnormality in impulse formation due to reentry

12

triggered activity

increased calcium leads to afterdepolarizations

if these are large enough, these can cause an action potential to form

focal source arrhythmia

13

early afterdepolarization (EAD)

occurs in phase 3

14

delayed afterdepolarization (DAD)

occurs in phase 4

15

reentry

requires two pathways:

one with slow conduction and rapid recovery

another with fast conduction and prolonged recovery

16

atrioventricular nodal reentrant tachycardia (AVNRT)

slow pathway and fast pathway in and around the AV node

17

paroxysmal supraventricular tachycardia

regular, narrow-QRS tachycardia

includes AVNRT, AVRT, and ectopic atrial tachycardia (AT)

**AVNRT is the most common

18

possible symptoms of SVT

none

heart racing

chest discomfort

dyspnea

syncope

heart failure

aborted sudden death

19

atrioventricular reentrant tachycardia (AVRT)

uses atrioventricular accessory pathways

muscle bundles that connect the atrium and ventricle across the valves

known as bypass tracts or Kent bundles

congenital but may lose conduction with age

can sometimes be seen as a delta wave

20

orthodromic vs antidromic tachycardia

orthodromic goes through accessory pathway last

antidromic goes through accessory pathway first

othrodromic is more common

21

atrial tachycardia

focal tachycardia confined to the atrium

does not require the AV node

can be sustained, paroxysmal, or incessant

22

mechanisms of atrial tachycardia

triggered, automatic, or micro-reentry (small circuit that appears focal)

23

atrial fibrillation

most common arrhythmia

appears as disorganized atrial activity usually with an irregularly irregular ventricular response

350-450 depolarizations/min in the atrium

24

atrial flutter

fixed reentrant circuite around the tricuspid annulus

organized, rapid, and regular atrial rate

often regular ventricular rate

25

categories of ventricular tachycardia

monomorphic and polymorphic

26

monomorphic VT

a single consistent QRS morphology

27

polymorphic VT

morphology changes beat-to-beat between 100 and 300 bpm

setting of a normal QT interval

setting of a long QT interval - Torsade de Pointes

28

substrates, triggers, and modulating factors of VT

substrate - MI, myofiber disarray, dispersion of refractoriness

triggers - PVCs

modulating factors - electrolyte imbalance, ischemia, autonomic tone

29

idiopathic ventricular tachycardia

structurally normal hearts

not associated with sudden death

most commonly triggered by focal rhytms

right ventricular outflow tract is an important pathway

reentry using the Purkinje system - usually the posterior fascicle

30

cardiomyopathies that can cause VT

chronic MI

dilated cardiomyopathy

sarcoid

hypertrophic cardiomyopathy

31

treatments for VT

implantable cardioverter defibrillator

antiarrhythmics

ablation for reccurent VT

32

What defines a long QT?

a normal QT is about 1/2 the length of the RR interval

33

long QT syndrome

can be due to congenital causes because of LQT gene mutations

drugs, electrolyte imbalances, and idiotpathic reasons can also cause long QT syndrome

34

ventricular fibrillation

primary - non-reversible causes such as cardiomyopathies

secondary - acute MI, ischemia, electrocution, severe electrolyte disturbances, drugs

35

symptoms and treatments of ventricular fibrillation

symptoms - syncope and sudden death

treatment - treat cause if any, ICD, agents to control recurrences

usually does not self-terminate

36

mechanism of ventricular fibrillation

depends on substrate

cardiomyopathy - scarring causes reentry

primary electrical abnormalities - functional reentry