Cardiology: Cardiac Arrhythmias - Atrial flutter & AF I Flashcards
What are cardiac causes of syncope? [+]
Cardiac causes of syncope:
- Hypertrophic cardiomyopathy (HCM)
- Cardiac tampondade
- Pericardial disease
- PE
- MI
- Valvular abnormalities
- Dialted cardiomyopathy
- Aortic dissection
- Myotonic and muscular dystrophies.
- CAD
- Long QT syndrome
Cardiac syncope occurs when the source of one’s loss of consciousness stems from a problem in the heart that prevents it from supplying enough nutrients and oxygen to the brain
What is vasovagal syncope? [1]
What is it caused by? [4]
Vasovagal Syncope:
- emotional or environmental trigger (e.g. prolonged standing, fasting, dehydration) causes an activation of the PNS
- Activation of the PNS causes vasovagal reaction: bradycardia and vasodilation
- Causes a drop in BP and reduction in blood supply to brain
- Cerebral hypoperfusion and LOC
How can you differentate between cardiac and vaso-vagal syncope?
Cardiac syncope:
- preceded by exertional chest pain
- occurring during exercise or stress
- concerning cardiac history
- no prodrome
- event requiring CPR,
- abnormal physical
examination
Vasovagal syncope
- Prodromal symptoms:
- Hot or clammy
- Sweaty
- Heavy
- Dizzy or lightheaded
- Vision going blurry or dark
- Headache
What are important areas to cover in a history when someone says they’ve fainted? [4]
Precipitant/trigger:
- if situational, ask if the trigger consistently causes syncope
Warning symptoms:
- classic pre-syncopal symptoms of nausea, sweating, feeling faint
Position:
- vasovagal syncope usually happens when standing
Underlying cardiac disease?
What are key history areas for arrhythmic and structural syncope? [8]
- Palpitations
- Other cardiac symptoms (e.g. chest pain, breathlessness, oedema)
- No prodromal warning (unlike in reflex and orthostatic syncope, where there are clear pre-syncopal symptoms)
- Onset when sitting or lying down
- Onset with exercise (clarify if it is after or during exercise)
- Presence of any previous heart disease including myocardial infarctions, surgeries, and any cardiac device details (pacemakers and ICDs)
- Drug history
- Family history of sudden cardiac death
How do you manage a patient with (primary) tachycardia who is haemodynamically unstable? [+]
Assess using ABCDE
- Monitor SpO2 and give oxygen if hypoxic
- Monitor ECG and BP
- Obtain IV access
- ID and treat reversible cause (if possible)
If there are adverse features (e.g. shock, syncope, MI, HF) AND the heart is unstable:
- Deliver synchronised DC shock up to 3 times
When assessing tachycardia, if you ID that there are no adverse features, what is the next thing you are should assess? [1]
If the QRS is narrow (< 0.12s)
Describe what determines the width of the QRS complex [1]
Normal cardiac conduction uses His-purkinje system to allow R & L ventricle to depolarise within 120ms: narrow QRS complex
What does a narrow QRS complex tachycardia mean with regards to physiology? [1]
Narrow QRS complex tachycardia implies that ventricles are activated via a normal conduction system, therefore the mechansim of the tachycardia is supra ventricular.
On a normal 25 mm/sec ECG, 0.12 seconds equals [] small squares.
On a normal 25 mm/sec ECG, 0.12 seconds equals 3 small squares.
go through lectures and go through ecgs
What are the three reasons for supra-ventricular tachycardia? [4]
Atrial flutter & atrial fibrillation
AVNodal reentrant tachycardia
AV reentrant tachycardia
Describe the pathophysiology of atrial flutter [4]
Counter clockwise circuit of electrical activity goes through the right atrium due to an extra electrical pathway. Signal goes around without interruption
The signal does not usually enter the ventricles on every lap due to the long refractory period of the atrioventricular node.
Get 2:1 ratio of atrial to ventricular contractions. Usually causes atrial rate to be usually around 300 beats per minute; and the ventricles to be 150 bpm
There can be 3:1 or 4:1 or variable conduction ratios
Explain the different clinical features of atrial flutter [5]
Haemodynamic Manifestations:
- Loss of co-ordinated atrial contractions causes reduced ventricular filling and reduced CO
- Causes dyspnea; fatigue; lightheadedness; syncope
Palpitations
Chest pain
- Due to increased myocardial oxygen demand secondary to rapid ventricular rates or decreased diastolic filling time causing subendocardial ischaemia
Heart Failure Symptoms
- May get tachycardia induced cardiomyopathy
- Orthopnea; paroxysmal nocturnal dyspnea, and peripheral oedema
Thromboembolic Complications:
- predisposes patients to thrombus formation
How do you investigate for atrial flutter? [1]
ECG: Flutter waves (saw toothed morphology) with atrial rate 250/300 bpm
Describe the first line treatment algorithm for a patient with acute atrial flutter who is haemodynamically stable? [3]
What is the long term anticoagulation used? [2]
Primary option: Use an atrioventricular nodal blocking drug for rate control:
Beta blocker:
- Bisoprolol or others
OR
Non-dihydropyridine calcium-channel blockers:
- Verapamil
- Diltiazem
Secondary options:
- Digoxin
may convert atrial flutter to atrial fibrillation, which can be easier to manage.
CONSIDER:
Initial anticoagulation:
- heparin
or
- enoxaparin
Long term anticoagulation:
- 1st: apixaban or ther DOAC
- 2nd: warfarin
BMJ BP
Describe the second [1] and third line [2] treatment algorithm for a patient with acute atrial flutter who is haemodynamically stable?
2nd line:
- elective electrical cardioversion
3rd line: pharmacological cardioversion
- flecainide
OR
- amiodarone
Describe the treament regime for chronic / recurrent atrial flutter [5]
1st line:
- Catheter ablation
- Long term anticoagulation strategy (see previos)
2nd lines:
- Long term rate control
- Long term anticoagulation therapy
- Long-term anti-arrhythmic therapy
Describe the pathophysiology of atrial fibrillation [3]
- Myocytes in the atria contract largely independently of each other and in an unsynchronised pattern, leading to the macroscopic appearance of ‘fibrillation’
- This disrupts the electrical activity of the atria, with multiple groups of myocytes depolarising independently of the SAN and each other
- This results in an irregularly irregular ventricular contraction.
Wht are common causes of AF? [5]
SMITH
S – Sepsis
M – Mitral valve pathology (stenosis or regurgitation)
I – Ischaemic heart disease
T – Thyrotoxicosis
H – Hypertension
Alcohol and caffeine are lifestyle causes worth remembering.
Which endocrine pathologies are associated with AF? [2]
DM
Hyperthyroidism
Which cardiac conditions are associated with AF? [5]
HTN: most common factor
HF
CAD
Valve pathologies: In particular, mitral valve disease and rheumatic heart disease.
Atrial flutter & WPWs
Give three changeable risk factors that can cause AF [3]
Obesity
Sleep apnoea
Heavy alcohol use
Describe the different classifications of AF [3]
.1. Persistent AF:
- Experience AF at all times (sustained for more than 7 days)
.2. Paroxysmal AF:
- Experiences AF at certain times. At all other times their heart contracts in sinus rhythm
- ‘AF that terminates spontaneously within 7 days of onset’
.3. Valvular Atrial Fibrillation:
- AF with significant mitral stenosis or a mechanical heart valve.
- NB: Atrial fibrillation without valve pathology or with other valve pathologies, such as mitral regurgitation or aortic stenosis, is classed as non-valvular AF.
Describe the presentation of AF [7]
- Patients are often asymptomatic
- May be diagnosed after a stroke
- Palpitations
- SOB
- Dizziness or syncope
- irregularly irregular pulse
- Fatigue & anxiety: owing to rapid and irregular ventricular rate
Describe the presentation of AF with haemodynamic instability [4]
Acute heart failure, causing:
* Shortness of breath, due to pulmonary oedema
* Raised JVP
Cardiogenic shock, the signs of which are:
Tachycardia
Hypotension
Syncope or pre-syncope
Cardiac chest pain, including myocardial infarction
- This is most common in patients with some level of pre-existing coronary heart disease
The Ssgns of haemodynamic compromise in AF according to NICE CKS (2020) are what? [5]
- Heart Rate >150 bpm
- Blood Pressure < 90 mmHg
- Syncope or severe dizziness
- Shortness of breath
- Chest Pain
What are the two differentials for irregularly irregular pulse? [1]
Atrial fibrillation
Ventricular ectopics
Describe how you investigate AF [4]
Assessment of the radial pulse
ECG:
- Absent P waves
- Narrow QRS complex tachycardia
- Irregularly irregular ventricular rhythm
Long term electrical recordings such as 24 hour ECGs
- most commonly the case in patients with paroxysmal AF who receive ECG recordings between episodes
ECHO if presenting with AF and
- Valvular heart disease
- HF
- Planned cardioversion
Permenant AF
An elderly patient with a history of atrial fibrillation presents with a sudden painless loss of vision in one eye. Fundoscopy reveals a ‘cherry red’ spot on a pale retina is a stereotypical history of:
occlusion of central retinal artery
What is the cause of the cherry red spot? [1]
It is most frequently caused by emboli obstructing the retinal artery (e.g. stroke). Occasionally, it can be caused by vasculitis (e.g. giant cell arteritis).
Classical appearance is of a “cherry-red spot”. This occurs due to the intact reflex of the fovea standing out against a pale, ischaemic retina.
No anticoagulation:
CHA2DS2-VASc of 1 (female)
CHA2DS2-VASc of 0
First time atrial fibrillation
Describe typical histories for persistent and permenant atrial fibrillation [2]
Persistent atrial fibrillation:
- recurrent episodes of atrial fibrillation which don’t self terminate
Permanent atrial fibrillation
- treated with a beta-blocker to control his atrial fibrillation. A previous attempt to cardiovert him failed
In a patient with atrial fibrillation, which anticoagulation strategy should be followed for a patient with a CHA2DS2-VASc of 1 (male)? [1]
Consider (rather than offer) anticoagulation with warfarin or new oral anticoagulants (NOACs)
What change in JVP wave is associated with AF? [1]
Absent a wave
‘a’ wave = atrial contraction
Mesenteric ischaemia
In which of the following circumstances is it most appropriate to do cardioversion before anticoagulation ?
Onset of the current episode of AF is not clearly within 48 hours
No clot is seen on transesophageal echocardiography (TEE)
The episode of AF has been present > 48 hours
Onset of the current episode of AF is clearly within 48 h, the patient has nonvalvular AF and is not at high risk of a thromboembolic event
In which of the following circumstances is it most appropriate to do cardioversion before anticoagulation ?
Onset of the current episode of AF is not clearly within 48 hours
No clot is seen on transesophageal echocardiography (TEE)
The episode of AF has been present > 48 hours
Onset of the current episode of AF is clearly within 48 h, the patient has nonvalvular AF and is not at high risk of a thromboembolic event
According to NICE guidelines, what is the target international normalized ratio (INR) range for patients on warfarin therapy for atrial fibrillation?
A. 1.0-2.0
B. 2.0-3.0
C. 3.0-4.0
D. 4.0-5.0
According to NICE guidelines, what is the target international normalized ratio (INR) range for patients on warfarin therapy for atrial fibrillation?
A. 1.0-2.0
B. 2.0-3.0
C. 3.0-4.0
D. 4.0-5.0
According to NICE, what is the recommended anticoagulant therapy for patients with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 2 or more?
A. Aspirin
B. Warfarin
C. Dabigatran
D. Clopidogrel
According to NICE, what is the recommended anticoagulant therapy for patients with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 2 or more?
A. Aspirin
B. Warfarin
C. Dabigatran
D. Clopidogrel
NICE recommends the use of the CHA2DS2-VASc score for assessing the risk of stroke in atrial fibrillation. What does the “C” stand for in CHA2DS2-VASc?
A. Coronary artery disease
B. Congestive heart failure
C. Cardiomyopathy
D. Coagulation abnormalities
NICE recommends the use of the CHA2DS2-VASc score for assessing the risk of stroke in atrial fibrillation. What does the “C” stand for in CHA2DS2-VASc?
A. Coronary artery disease
B. Congestive heart failure
C. Cardiomyopathy
D. Coagulation abnormalities
A patient has AF, but a CHADSVASC score of 0.
What is the next investigational step? [1] Why? [1]
Remember that if a CHA2DS2-VASc score suggests no need for anticoagulation it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which in combination with AF is an absolute indication for anticoagulation.
A patient with AF + an acute stroke (not haemorrhagic) should have anticoagulation therapy started [] weeks after the event
A patient with AF + an acute stroke (not haemorrhagic) should have anticoagulation therapy started two weeks after the event
