CVD - Cardiac arrhythmias

Question 1

What is a normal cardiac rhythm called?

What is an arrhythmia?

Answer 1

Sinus rhythm - PQRST wave

P wave - atrial depolarisation

QRS wave - ventricular depolarisation

T wave - ventricular repolarisation

Arrhythmia - abnormal cardiac rhythm

• irregular
• too fast: >100bpm at rest
• too slow: <60bpm at rest
• abnormal beat conduction

Question 2

What are the symptoms of a cardiac arrhythmia?

Answer 2

• can be no symptoms
• palpitations
• chest pain
• heart failure
• syncope

Question 3

What is atrial fibrillation?

What is it associated with and how is it managed?

What does atrial fibrillation increase risk of?

Answer 3

Instead of atria coordinating normally, blood isn’t flowing well through the atria as they are wobbling, leading to an irregular heart beat

• most comon cardiac arrhythmia - 10% of elderly
• often asymptomatic
• associated with CVD: heart failure, angina, high BP
• controlled by drugs, rarely surgery: digoxin, amiodarone, beta-blockers, calcium antagonists

Increases risk of stroke - should be on anticoagulant if no contraindications

Question 4

What is tachyarrythmias?

What is the most common type?

List symptoms of SVT:

How is SVT treated?

Answer 4

• too fast a heart beat, most common supraventricular tachyarrhythmias (above ventricles)

Symptoms of SVT:

• unpleasant
• palpitations
• chest pain
• breathlessness

SVT Treatment at time:

• vagal manoeuvres, carotid sinus massage, drugs e.g. adenosine

Prevention: drugs, surgery

Question 5

What are bradyarrhythmias?

Causes?

What is asystole?

How are bradyarrhythmias treated?

Answer 5

Bradyarrhythmias: heart rate <60bpm, problems usually if <40 –> dizziness and blackouts

Causes:

• age
• ischaemia
• drugs
• may be physiological e.g. athletes

Asystole: complete absense of electrical activity in the heart, can be seen in a cardiac arrest

Treatment

• remove underlying cause, often drugs
• may require a pace-maker

Question 6

What are some dental aspects of pacemakers?

Answer 6

• identify if patients have one
• do not require antibiotic cover for routine dental treatment
• theoretical risk of electrical interference so be ready to switch off electrical equipment, lie patient down and raise legs, ABCDE apprach if they collapse

Question 7

What are ventricular arrhythmias?

Cause?

What are the two types of ventricular arrhythmias?

Answer 7

• Always a medical emergency

Cause:

• usually ischaemic heart disease including heart attack/MI
• drugs
• congenital
• electrolyte disturbances - high blood potassium
  1. Ventricular tachycardia - breathlessness, dizziness, chestpain, palpitations - cardiorespiratory arrest
  2. Ventricular fibrillation - always cardiorespiratory arrest, needs immediate CPR

Question 8

What is the treatment for a patient with ventricular tachycardia if conscious?

If unconscious?

What is the treatment of a patient with ventricular fibrillation?

Answer 8

Ventricular Tachycardia:

• conscious: immediate hospitalisation for defibrillation/drugs
• unconscious: CPR
• longer term - drugs or sometimes implantable cardioverter defibrillator

Ventricular Fibrillation:

• Immediate CPR and rapid defibrillation
• longer term - drugs, sometimes ICD

Question 9

What are dental aspects for cardiac arrhythmias?

Answer 9

• recognise individuals at risk
• avoid treating if unstable
• treat with caution - pacemakers, ICD, CRT, arrhythmias
• caution with adrenaline containing LA in arrhythmias and heart failure - seek advice
• some patients with SVT may know how to self terminate so don’t try yourself
• recognise unwell patients: collapse, chest pain, breathlessness, sweaty, distressed

Question 10

List some signs and symptoms to recognise unwell patients due to a cardiac arrhythmia:

How would you approach this?

Answer 10

• lightheadedness/collapse
• chest pain
• breathlessness
• sweaty, distressed
• heart rate <40, >150
• history of collapse
• hypotension

ABCDE approach, hospitalisation, be prepared to manage cardiac arrest