arryhthmia Flashcards
what is a brady arrhythmia?
abnormally slow rhythm of the heart, below 60 bpm and it includes AV block
whats tachy arrhymia ?
are abnormally fast rhythm of the heart above 100 bpm
what are the 2 types of tachyarrhythmia ?
1- Supraventricular originate from SA , AV node ,atrium myocardium
HAS REGULAR QRS COMPLEX
2- Ventricular originate from bundle of his or purkinje system or the myocardium WIDE QRS complex
describe sinus bradycardia?
heart rate less than 60 bpm
has normal P wave before every QRS complex
what could cause sinus bradycardia?
-Athletes
- Sinus node dysfunction
3- drugs BB, CCB
describe AV block
arrhythmia with delayed or blocked conduction
what are the 3 degrees of AV block
1st degree –> NO block –> only delay and its constant delya
2nd degree :
Mobitz 1 –> theres delay and the delay increased until it blocks and rest
Mobitz 2 —> random block without a warning , js randomly the signal will not go through
3rd degree –> complete block and theres no connection between atrium and ventricle
describe sinus tachycardia
normal rhythm but its fast . normal p wave, but NARROW QRS COMPLEX
max rate is 180 bpm
what could cause Sinus tachycardia
1- increased sympathetic activities
2- withdrawal of parasympathetic
describe the atrial flutter?
regular and organized but extremely fast and it gives SAWTOOTH APPEARANCE ON ECG,
Multiple P waves with narrow QRS complexes
Atrium rate is 250-400
whats happening in atrial flutter?
ONE SINGLE –> reentrant circuit
describe atrial fibrillation?
chaos in the atriuam with multiple reentry circuits
400-600 bpm in atrium
NO DESTINCT P WAVES
has irregularly regular rhythm
whats the reason behind atrial fribrillation?
not understood.
Describe paroxysmal supraventricular tachycardia PSVT
Sudden and abrupt tachycardia
Narrow QRS complex with regular rhythm that lead to dysnpea , dizziness , chest pain, syncope
what could cause PSVT
defect in AV conduction
what are the 2 types of PSVT
1- Unifocal/multifocal atrial tachycardia due to ECTOPIC FOCUS STIMULATING AV not SA NODE, its similar to sinus tachycardia but not SA node and similar to flutter but its not SA node
2- AV reentrant tachycardia AVRT –> one signal spins around the AV node leading to multiple stimulations
In PSVT THE P IS NOT VISIVBLE
describe premature ventricular beats?
premature contractions caused by ectopic focus in the ventricle
on ecg you see WIDE QRS COMPLEX THAT ARE NOT AFTER A P WAVE
causes of premature ventricular tachycardia?
1- hypoxia
2-Hyperthyrodism
3- electrolytes abnormalities
describe ventricular tachycardia
life threating arrhytmia originating from the ventricle due to multiple ectopic focus which lead to :
1- palpitation
2- syncope
3- cardiogenic shock
4-sudden cardiac death
on ecg you see RAPID WIDE QRS COMPLEX
what are the causes of ventricular tachycardia ?
coronary artery block
MI
structural heart damage
describe ventricular fibrillation
life threating arrhythmia caused by disorganized high frequency
more than 300 BPM of the ventricles
DIMINISH CO –> hemodynamic collapse
on ECG you will see rapid fast QRS and NO P WAVES THEY ARE INVISIBLE BECAUSE THEY ARE HIDDEN BY THE VENTRICULAR DEPOLARIZATION
so what are the QRS CHARACTESTICS IN SVT AND VENTICULAR?
1- in SVT the QRS IS NARROW
2- in Ventricular the QRS IS WIDE
Normal width is less than 0.12 seconds like less than one large square or 3 small squares
what could be narrow QRS WITH REGULAR RHYTHM
Regular rhythm mean constant rr intervals
1- Sinus tachycardia
2- focal atrial tachycarida ( uni )
3- SVT ( AVRT. AVRNT
4- atrial flutter
narrow QRS with irreguglar rhythm and rr intervals are not constant
1- Atrial fibrillation
2- multi focal atrium tachy
wide QRS and regular rhythm
1- ventricular tachycardia
wide QRS with irregular rhythm
1- ventricular fibrillation
2- torsade de point
what could cause arrhythmia?
1- Altered impulse formation
2- Altered impulse conduction
how altered impulse formation is formed?
1- Enhanced automacity –> tachy
2- triggered activity ( increased firing ) –> tachy
3 - reduced automacity —> brady
whats are the 3 types of enhanced automacity
1- increased SA node automacity –
2- increased automacity of other pacemakers
3- abnormal automacity
what are the 2 types of altered impulse formation?
1- Conduction block –> brady
2- unidirectional block and reentry –> tachy
what could cause enhanced SA node automaticity
sympathetic via b1 ( recall how it work )
what could decrease Sa node automaticity
parasym via m2 ( recall what it does it do )
what is triggered activity and why its caused?
abnormal automaticity in injured cardiac tissue due to LEAKY MEMBRANE
whats the abnormal depolarization and whats are its two types
action potential will trigger an abnormal depolarization and its named according where it is
1- Early afterdepolarization –> in the plateau phase ( phase 2 )
2- delayed after depolarization –> in phase 4
what could cause early depolarization
1- Inherited long QT syndrome
2- Certain drugs
what could early depol lead to?
TORSADE DE POINTES
what could cause a delayed afterdepo?
HIGH INTRACELLULAR CALCIUM
LIKE DIGOXIN TOXICITY
- Catecholamine stimulation
what could delayed afterdo lead to?
ventricular tachy
what are the 2 types of impulse conduction?
1- Heart block –> conduction block
2- Reentry mechanism
whats a reentry mechanism
self perpetuating circuit of excitation ( continuous circulation )
what is a unidirectional block and reentry?
electric pulse circulates repeatedly around a path causing multiple depolarizations - tachy
Also called LOCAL REENTRY
what are the 3 criteria for reentry to happen?
1- presence of unidirectional block with conduction pathway
2- critical timing
3- length of effective refractoy period of normal tissue ( remember in ERP it can depo but it wont conduct )
what could a local reentry circuit in atria lead to?
atrial tachycardia
what could a local reentry circuit in ventricle lead to?
ventricular tachycardia
local reentry circuit with AV node
AVNRT –> PSVT , signal circulates around AV node stimulating it multiple times
describe what happens in WPW?
theres an accessory pathway that the signal from sa node can go through and skip the AV node pathway –> abnormal
you will se it as delta wave in ecg
whats the name of the accessory pathway?
bundle of kent
WPW is an example of what?
Global reentry
whats long QT syndome?
congenital or acquired heart condition where theres prolonged QT interval
what are the 2 types?
1- congenital
2- acquired
in congenital whats the chromosome affecteD?
11p
what gene is mutated
KCNQ1 gene
what happens in congenital ?
defect in the voltage potassium gates, leading to slow repolarization and prolonged AP - torasde de points
how is acquired LQTS acquired?
any drugs that increase AP duration will increase QT -> torsade de point
1- na channel blocks
2- K channel blocks
3- cc
what could trigger torsade de pointe?
early afterdepolar
- prolonged QT
- prolonged AP duration
- electrolyte abnormality
whats the ecg finding of torsade de pointe?
twisted QRS complexes that appear on isoelectric line
