Arrhythmias - An Overview Flashcards
What are arrhythmias?
Anything that deviates from a normal rhythmic ECG - regular pulse, within normal range of rate, p waves, normal QRS, etc…
They are common and often benign.
They are also often intermittent which can make them difficult to diagnose, this means that the patient might report symptoms that they have at home but when they come to see you, they might be fine.
Cardiac causes of arrhythmia.
Ischaemic heart disease
Structural changes like left atrial dilation.
Cardiomyopathy
Pericarditis
Myocarditis
Aberrant conduction pathways
Non-cardiac causes of arrhythmias.
Caffeine
Smoking
Alcohol
Pneumonia
Drugs
Metabolic imbalance
Phaemochromocytoma
Drugs that can cause arrhythmia
B2 agonists
Digoxin
L-dopa
Tricyclics
Doxorubicin
Metabolic imbalance that can cause arrhythmia.
K+
Ca2+
Mg2+
Hypoxia
Hypercapnia
Metabolic acidosis
Thyroid disease
Clinical features of arrhythmia.
May be asymptomatic - may be an incidental finding
Palpitations
Chest pain
Presyncope/syncope
Hypotension
Pulmonary oedema
A good history of arrhythmias:
Detalied history of palpatations
Precipitating factors
Duration
Associated symptoms like chest pain, dyspnoea and collapse.
Drug history
PMH
FH of cardiac disease and sudden death
Syncope during exercise?
Explain a detailed history of palpitations.
Ever aware of own heart beat?
When and how did it start/stop?
Duration?
Onset sudden or gradual?
Associated with blackout?
Chest pain?
Dyspnoea?
Food related?
Regular or irregular?
Dropping beats?
Regular pounding? (anxiety)
Slow palpitations?
Investigations done in arrhythmias.
Bloods - FBC, U&Es, glucose, Ca2+, Mg2+, TSH, cardiac enzymes
ECG
Continuous ECG monitoring
Some arrhythmias can be paroxysmal meaning it can come and go.
If the patient is asymptomatic at time of appointment, what can be done?
Continuous ECG monitoring.
Give examples of continuous ECG monitoring.
Telemetry
Exercise ECGs
Holter monitors
Loop recorders
Pacemakers and ICDs (can also monitor activity)
What is telemetry?
An inpatient ECG recording.
Signals are shown on screen and watched by staff.
This means that if a dangerous arrhythmia occurs immediate intervention can be done.
Only done in high risk of dangerous arrhythmias like post-STEMI.
What is exercise ECG?
Patient exercises according to a standard protocol.
BP and ECG are monitored at the time of exercise.
It is looking for ischaemic changes, arrhythmias, and features of suggestive arrhythmia risk such as delta waves.
What is holter monitors?
Patient wears an ECG monitor which records their rhythm for 24h, 72h or 7 days.
This is an outpatient monitoring which is then later analysed.
This can pick up any irregularities on ECG that was not present at time of consultation.
What are loop recorders?
Record only when activated by patient.
They save a small amount of ECG data before an event.
This means that is can be useful if the arrhythmia causes loss of consciousness as the patient can press the button when they wake up.
The loop recorders may be implanted or even injected.
They are especially useful in pateints with infrequent episodes as they can continually monitor for months or years awaiting an event.
Explain the Bradycardia algorithm of classification.
Explain the tachycardia algorithm of classification.
Non-shockable rhythms.
Pulseless electrical activity
Asystole
