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.