Chaper 2: Cardiovascular - Arrythmia Flashcards
What is an arrhythmia?
A problem with the rate or the rhythm of the heartbeat
What are the general symptoms of an arrhythmia?
Palpitations SOB Dizziness Fainting Chest pain Fatigue
What are the three types of supraventricular arrhythmias?
Atrial fibrillation
Atrial flutter
Paroxysmal supraventricular arrhythmia
What are the two types of ventricular arrhythmia
Ventricular tachycardia (e.g. torsades de pointes) Ventricular fibrillation
What are ectopic beats and how are they managed?
They are extra heartbeats that occur just before a regular heartbeat
They usually don’t require treatment
But if they are troublesome beta-blockers may help
What is atrial fibrillation?
An abnormally fast rhythm arising from or above the AV node
It is triggered by rapidly firing electrical impulses
When the AV node receives more impulses that it can conduct, an irregular ventricular rhythm results
What are the causes of atrial fibrillation?
Cardiovascular: CHF
Non-cardiovascular: infection, cancer, PE
Lifestyle: alcohol abuse, obesity
What is the main complication of atrial fibrillation and how is this managed?
Stroke
Managed using anticoagulants
E.g. warfarin, apixaban, rivaroxaban, dabigatran, edoxaban
But before initiating consider a patients risk of stroke vs risk of bleeding
Assessment tools can help with this
What are the three broad categories for managing atrial fibrillation?
Cardioversion
Rate control
Rhythm control
What is the first-line treatment for reversible atrial fibrillation?
Cardioversion
What drugs are used for pharmaceutical cardioversion?
Oral or IV amiodarone (preferred if there is structural heart disease)
Oral or IV flecainide
When is electrical cardioversion preferred?
When atrial fibrillation has been present for more than 48 hours
Anticoagulation and electrical cardioversion?
Patients should be anticoagulated for at least 3 weeks before electrical cardioversion
If this is not possible, use parenteral anticoagulation before cardioversion, then oral anticoagulation for at least 4 weeks afterwards
What are the two types of electrical cardioversion?
Direct current
Cardiac pacing
What drugs can be used for rate control?
Beta-blocker (not sotolol)
Rate-limiting CCB e.g. diltiazem, verapamil
Digoxin
When can digoxin be used in atrial fibrillation?
When the patient is predominantly sedentary (it is only effective when at controlling the ventricular rate when the heart is at rest)
For non-paroxysmal atrial fibrillation
For atrial fibrillation and heart failure
In atrial fibrillation, when mono therapy with one of the rate control drugs fails to control the ventricular rate, what do you do?
Consider cardioversion
Or use a combination of 2 drugs (beta-blocker, diltiazem or digoxin)
In atrial fibrillation, how to you select which beta-blocker to use
First choice is atenolol (cheapest)
Acebutolol, metoprolol, nadolol, oxprendolol and propranolol are also indicated in AF
In atrial fibrillation, when is rhythm control used
Post-cardioversion
In atrial fibrillation, what drugs can be used for rhythm control?
First line - standard beta-blocker
Other options include anti-arrhythmics e.g. amiodarone, flecainide, sotolol, propane ones
What do you do in the acute presentation of atrial fibrillation?
Life-threatening haemodynamic instability:
Electrical cardioversion
Non-life-threatening haemodynamic instability:
Consider cardioversion (remember to anticoagulate the patient for 3 weeks, prior to cardioversion offer rate control)
Less than 48 hours - rate or rhythm control
Over 48 hours - rhythm control
What is paroxysmal atrial fibrillation and how is it managed?
Intermittent AF - it begins suddenly and stops on its own within 7 days
Manage with a standard beta-blocker
Or consider an oral anti-arrhythmic e.g. amiodarone, flecainide, sotolol, dronedarone, propafenone
In some patients, the ‘pill in pocket’ approach may be considered
What is the pill in pocket approach and when can it be used in atrial fibrillation?
It is when patients can self-treat when an episode occurs
It can be used in paroxysmal atrial fibrillation, where there are infrequent episodes
Drug options include oral flecainide or propafenone
What are the risk factors for stroke in atrial fibrillation?
Prior ischaemic stroke, TIA or thromboembolic events
Other heart conditions e.g. HF, LVSD
Other CV conditions e.g. diabetes, hypertension
Patient factors e.g. over the age of 65, female
What are the signs of haemodynamic instability?
Rapid pulse (>150 beats per minimum) Low blood pressure (systolic BP <90mmHg Ongoing chest pain Increasing breathlessness Severe dizziness
Describe the two screening tools to determine whether anticoagulation should be initiated in atrial fibrillation
CHADSVAS - stroke risk C - CHF/LVSD (1) H - Hypertension (1) A - Age >75 (2) D - Diabetes (1) S - Stroke/TIA/systemic arterial embolism (2) V - Vascular disease (precious MI, aortic plague (1) A - Age 65-74 (1) S - Sex, male 0, female 1
HASBLED H -Hypertension (1) A - Abnormal liver function (1) A - Abnormal renal function (1) S - Stroke (1) (Major) Bleeding history (1) L - Labile INR E - Elderly (>65) Drugs and alcohol (Drugs includes anticoagulants and NSAIDS (1), alcohol abuse (1))
What oral anticoagulants can be used for stroke prevention in atrial fibrillation?
Vitamin K antagonists:
Warfarin
Apixaban, rivaroxaban, edoxaban, dabigatran
What is atrial flutter and how does this differ from atrial fibrillation?
Atrial flutter is when the atria beat faster than the ventricles, causing for the heart rhythm to be out of sync
In atrial fibrillation, the atria beat irregularly. In atrial flutter that beat regularly but faster than usual and more often than the ventricles
How is atrial flutter managed?
First, rate control
Beta-blockers, rate-limiting CCB, digoxin
Note, IV is preferred if a rapid rate control is required
Then conversion of sinus rhythm by:
Electrical cardioversion (preferred if the atrial flutter has been present for more than 48 hours)
Pharmacological cardioversion
Catheter ablation
Remember, fully anticoagulate for 3 weeks prior to cardioversion
How do you manage paroxysmal supraventricular tachycardia?
First, reflex vagal stimulation
If this is not adequate or if symptoms are severe, use IV adenosine
IV verapamil is an alternative to IV adenosine, but avoid in patients recently treated with beta-blockers
In patients who are haemodynamically unstable or do not respond to either of the above do electrical cardioversion
Prophylaxis can include verapamil, diltiazem, beta-blockers, flecainide, propafenone
What can be used to treat an arrhythmia after an MI?
Lidocaine
Disopyramide
How do you manage ventricular tachycardias?
Pulseless patients:
Defibrillation
Sustained ventricular tachycardia and haemodynamically unstable: Electrical cardioversion (direct current)
Sustained ventricular tachycardia and haemodynamically stable:
IV anti-arrhythmics e.g. amiodarone
Non-sustained ventricular tachycardia and haemodynamically stable:
Beta-blocker
Most patients will require maintenance therapy, e.g. beta-blocker, or beta-blocker and amiodarone
What is torsades de pointes?
A form of ventricular tachycardia that is associated with a long QT interval syndrome
How is torsades de pointes managed?
IV magnesium sulfate
Beta-blocker
Avoid anti-arrhythmics as these also prolong the QT interval and so can worsen the condition