Cardiology: Cardiac Arrhythmias - Atrial flutter & AF I Flashcards
How do you manage a patient with (primary) tachycardia?
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 have 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
AVN 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]
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
