Arrhythmias Flashcards
What are Arrhytmias ( how do they happen )
Abnormal heart rhythms that result from an interruption of normal electrical signals that coordinate heart contraction
What are the four possible rhythms seen in pulses unresponsive patients and what categories are they divided into
Shockable ( defibrillation may work ) 1 -Ventricular Tachycardia 2- Ventricular fibrillation Non-shockable ( defibrillation won't work ) 3- Pulseless electrical activity 4- Asystole
What is a pulseless electrical activity rhythm
All electrical activity is there except VF/VT. There is also sinus rhythm but no pulse.
ECG will show a heart rhythm that should produce a pulse but doesn’t.
What is an Systole rhythm
when there is no significant electrical activity shown.
What is the Tachycardia treatment for unstable patient
Consider up to 3 synchronized shocks and amiodarone infusion.
What is the narrow complex Tachycardia treatment for a stable patient ( Hint: 3 possible scenarios ) and what does the QRS have to be
QRS should be less than 0.12s
- Atrial fibrillation: beta blocker or diltiazem ( calcium channel blocker )
- Atrial flutter: beta blocker
- Supraventricular Tachycardias : vagal manoeuvres and adenosine
What is the broad complex Tachycardia treatment for a stable patient ( Hint: 3 possible scenarios ) and what does the QRS have to be
QRS should be greater than 0.12s
- Ventricular Tachycardia or unclear : amiodarone infusion
- SVT with bundle branch block : treat as normal SVT
- irregular : may be an AF variation seek expert help
What is an Atrial Flutter and explain what happens and how is this different from normal.
A re-entrant rhythm in either atrium. Electrical signal re-circulates in a self-perpetuating loop due to an extra electrical pathway, signal goes round atrium without interruption.
Normally electrical signal passes through atria once to stimulate contraction then disappears through AV node.
What happens when there is an atrial flutter ( explain in terms of atrial vs ventricle bmp)
Atrial contraction is stimulated at 300 bpm and the signal makes its way to the ventricle every second lap due to long refractory period of AV node. Ventricular contraction is at 15o bmp .
How does an atrial flutter present on an ECG
Repeated P wave
Name the conditions associated with Atrial flutters ( Hint: 4 )
1- Hypertension
2- Ischaemic heart disease
3- Cardiomyopathy
4- Thyrotoxicosis
What is the treatment for Atrial Flutters
1- beta blockers or cardio version to control rate and rhythm
2- treat reversible underlying condition
3- radio frequency ablation of re-entrant rhythm
4- Anticoagulation based on CHA2DS2VACc score
What is Supra ventricular Tachycardias ( SVT) and explain what happens
When the electric signal re-enters the atria from the ventricles. Once signal is brought back to atria it travels again through AV node and contracts the ventricles.
What is the result SVT and how does it show on ECG
A narrow complex tachycardia with QRS less than 0.12.
QRS complex followed immediately by T wave and repeated
What is Paroxysmal SVT
SVT reoccurs and remits in the same patient over time
What are the types of SVT ( Hint: 3 ) and explain their differences
1- Atrioventricular nodal re-entrant tachycardia : re-entry through AV node
2- Atrioventricular re-entrant tachycardia : re-entry point is accessory pathway
3- Atrial tachycardia : electrical signal originates in atria instead of sinoatrial node
Is atrial tachycardia SVT caused by signal re-entering from ventricles ?
No. the electric signal is abnormally generated in atria
Explain the Acute Management of Stable Patients with SVT (Hint: 4 steps )
1- Valsalva manoeuvre : patient blows hard against resistance
2- Carotid sinus massage
3- Adenosine or the alternative verapamil
4- Direct current cardioversion is above treatment fails
What is the MOA of adenosine
Slows cardiac conduction by interrupting AV ( or accessory pathway ) during SVT and resets it back to sinus rhythm.
How does adenosine need to be given and why. Explain dosage used.
Given as rapid IV bolus to ensure it reaches heart with enough impact to interrupt pathway.
Start with 6 mg then 12 mg then another 12 mg if there is no improvement.
What are the side effects of adenosine
Can briefly cause systole or bradycardia.
When should adenosine be avoided
Patient with asthma, COPD , heart failure , heart block , and severe hypotension should not be given adenosine.
What should you warn a patient of when they are about to be injected with adenosine
They might feel like dying or impending doom
Explain the long term management of patients with Paroxysmal SVT
Medications such as beta blockers, calcium channel blockers and amiodarone are given. Radiofrequency ablation is used.
What is Wolff-Parkinson White Syndrome
When there is an extra electrical pathway connecting the atria and ventricles. Pathway is called Bundle of Kent.
What is the treatment fro Wolff-Parkinson White Syndrome
Radiofrequency ablation of accessory pathway.
How would Wolff-Parkinson White Syndrome present on ECG ( Hint: 3 changes )
1- Short PR intervals
2- Wide QRS complex
3- Delta wave ( slurred upstroke of QRS )
Explain the situation of a patient with Atrial fibrillation or atrial flutter and WPW
There is a risk that the chaotic electrical signal activity can pass through accessory pathway into ventricles causing polymorphic wide complex tachycardia.
Antiarrhythmic medications such as beta blockers, calcium channel blockers and adenosine increase risk of this happening since they reduce conduction through AV node and promote conduction through accessory pathway.
Describe the radio frequency ablation done through catheter ablation procedure
A catheter us inserted into the femoral veins and a wire is fed through it to the heart under Xray guidance. Once wire is in the heart it is placed against different areas to test electrical signals, this is done to find location of abnormal electrical pathways. Once abnormality is identified RFA is applied to burn area and remove source of arrhythmia.
What can be cured by RFA (Hint: 3 conditions )
1- Atrial Fibrillation
2- Atrial Flutter
3- SVT
4- WPW
What is Torsades de pointes
A type of polymorphic ventricular tachycardia.
How does Torsades de pointes present on ECG
It looks like normal ventricular tachycardia on ECG but the QRS complex is shown to be twisting around baseline. Height of WRS progressively gets smaller then larger and so on.
What patients experience Torsades de pointes
Patients with prolonged QT interval can get Torsades de pointes.
What is a prolonged QT interval and what can it progress into.
A prolonged QT interval means there is prolonged depolarization of muscle cells in heart after contraction. Waiting for repolarisation can result in random spontaneous depolarisation. Random depolarization will continue to contract ventricles before proper repolarisation. Can progress to ventricular tachycardia if it doesn’t spontaneously revert back to normal sinus rhythm.
What are causes of Prolonged QT ( Hint : 3 )
1- Long QT syndrome ( inherited )
2- Medications
3- Electrolyte Disturbance
What’s the Acute Management of Torsades de pointes ( Hint : 3 )
1- correct the cause
2- magnesium infusion
3- defibrillation if VT occurs
What’s the long term management of prolonged QT syndrome
1- avoid medication prolonging QT interval
2- correct electrolyte disturbances
3- beta blockers
4- pacemaker or implantable defibrillator
What are Ventricular ectopics
Premature ventricular beats
What causes Ventricular ectopics
Random electrical discharged from outside the atria
How does a patient with ventricular ectopics present
Random brief palpitations
In who are ventricular ectopics most common
patients with pre-existing heart conditions
How are ventricular ectopics diagnosed and how does it present.
Diagnosed by ECG. Can appear as individual random, broad or abnormal QRS complexes.
What is Bigeminy
When ventricular ectopics are occurring so frequently that they happen after every sinus beat.
How does Bigeminy present on an ECG
Presents as normal sinus beat followed immediately by ectopic then normal beat and so on.
What is the management of Ventricular ectopics ( Hint: 3 steps )
1- check blood for anaemia, electrolyte disturbance and thyroid abnormalities
2- no treatment in healthy. people
3- seek help with patients with heart conditions background or concerning findings
What is first degree heart block
When there is delayed atrioventricular conduction through AV node.
How does First degree heart block present on ECG
Every P wave results in QRS complex. But PR interval is greater than 0.2 seconds
What is second degree heart block
When some of the atrial impulses do not make it through AV node to ventricles
How does Second degree heart block present on ECG
no every P wave results in QRS complex.
What are the three different patterns of second degree heart block
1- Wenckebach’s Phenomenon ( Mobitz Type 1)
2- Mobitz Type 2
3- 2:1 Block
What is Wenckebach’s Phenomenon ( Mobitz Type 1)
Atrial imputes become gradually weaker until it doesn’t pass through AV node. Once ventricular contractions is failed to be stimulated the atrial impulse becomes strong again and then the cycle repeats.
How does Wenckebach’s Phenomenon ( Mobitz Type 1) present on ECG
Increasing PR interval until P wave no longer conducts to ventricles and there is an absent QRS complex. PR interval will return to normal and then cycle repeats.
What is Mobitz Type 2
Intermitted failure or interruption of AV conduction.
How does Mobitz Type 2 present on ECG
There is missing QRS complexes. Ex: for every 3 P waves there’s 1 QRS.
PR interval remains normal
What is the risk with Mobitz Type 2
Asystole
What is 2:1 Block
When there are 2 P waves for every QRS complex since second P wave is not strong enough to stimulate QRS complex.
What are the causes of 2:1 Block ( Hint: 2 )
1- Mobitz T1
2- Mobitz T2
What is third degree heart block
A complete heart block where there is no relationship between P wave and QRS complex.
What is a significant risk with third degree heart block
Asystole
What is the treatment for a sable patient with Bradycardia / AV node blocks
Observe
What is the treatment for unstable or asystole risk patients with Bradycardia/ AV node block
First line: Atropine
2nd line: repeated Atropine IV, inotropes , Transcutaneous cardiac pacing
What is the treatment for patients with high risk of asystole with Bradycardia/AV node block
1- Temporary transvenous cardiac pacing
2- Permanent implantable pacemaker
What is temporary transvenous cardiac pacing
An electrode is placed on end of wire which is inserted into vein and fed through venous system to right atrium or ventricle to stimulate directly
What is Atropine
A antimuscuranic medication that inhibits the PNS
What are the side effects of Atropine ( Hint: 4 )
1- pupil dilation
2- urinary retention
3- dry eyes
4- constipation
