Cardiac Arrhythmias

Question 0

What does the QRS represent on an ECG?

Answer 0

Ventricular depolarisation (contraction)

Question 1

What does the p-wave represent on a ECG?

Answer 1

Atrial depolarisation (contraction)

Question 2

What does the S-T segment represent on an ECG?

Answer 2

Early part of ventricular repolarisation (relaxation)

Question 3

What does the T wave represent on an ECG?

Answer 3

Repolarisation (relaxation) of the ventricles

Question 4

What does the QT interval represent on an ECG?

Answer 4

The time of ventricular activity (repolarisation + depolarisation)

Question 5

What is Torsades de Pointes?

Answer 5

,earns twisting about the points (is a VT), the QRS complex deflect above and below the baseline

Question 6

What is a cardiac tamponade?

Answer 6

Clinical syndrome caused by accumulation of fluid in the pericardial space
Results in: reduced ventricular filling and subsequent haemodynamic compromise
Complications: pulmonary oedema, shock and death

Question 7

Explain Pulseless electrical activity (PEA)

Answer 7

Cardiac contraction absent in presence of coordinated electrical activity
Manifestations: weakened cardiac contractions, situation exacerbated by worsening acidosis, hypoxia and increasing vagal tone

Question 8

Describe a normal sinus rhythm

Answer 8

Rate: 60-100 bpm
Rhythm: regular

Question 9

Describe asystole

Answer 9

Rate: no rate
Rhythm: no rhythm
P-wave: no discernible p wave
QRS complex: no QRS

Question 10

What are the causes, diagnosis and treatment of asystole

Answer 10

Causes: hypovolaemia, hypoxia, hyperkalaemia/hypokalaemia, hypothermia (4Hs), acidosis, toxins, cardiac tamponade, pneumothorax, pulmonary emboli, myocardial infarction
Possible diagnosis: cardiac arrest, death
Treatment: CPR

Question 11

Describe ventricular tachycardia

Answer 11

Rate: > 100 bpm
Rhythm: regular or slightly irregular
P wave: unidentifiable
QRS complex: prolonged duration

Question 12

Why can you not shock in non-shockable VT and what do we do instead?

Answer 12

Because the pt is still conscious

Administer amiodarone

Question 13

What are the causes, diagnosis and treatment of ventricular tachycardia?

Answer 13

Causes: heart disease, drug toxicity trauma, electrolyte imbalance, acid-base imbalance
Diagnosis: decreased CO, haemodynamic instability, ineffective tissue perfusion, cardiopulmonary, peripheral, altered consciousness, potential cardiac arrest
Treatment: amiodarone (non-shoackable), defibrillation (shockable)

Question 14

Describe a third degree AV block

Answer 14

Rate: 40-60 bpm (bradycardic)
Rhythm: regular
P-wave: unrelated
QRS: regular, can be widened

Question 15

What are the causes, diagnosis and treatment for a third degree AV block?

Answer 15

Causes: myocardial infarction, congenital conditions, acute or degenerative cardiac disease, drugs, electrolyte imbalance
Diagnosis: decreased CO, ineffective tissue perfusion: cerebral, peripheral, cardiopulmonary; altered consciousness, potential cardiac arrest
Treatment: permanent pacemaker

Question 16

Describe ventricular fibrillation

Answer 16

Rate: undeterminable
Rhythm: irregular
P-wave: unidentifiable
QRS: unidentifiable

Question 17

What are the causes, diagnosis and treatment of ventricular fibrillation?

Answer 17

Causes: myocardial ischaemia, untreated VT, electrolyte imbalances, medications and electrocution
Diagnosis: can deteriorate into asystole
Treatment: defibrillation

Question 18

Describe the symptoms of a third degree AV block

Answer 18

Fatigue, dizziness, impaired exercise intolerance, chest pain, syncope, confusion, dyspnoea, severe chest pain, sudden death
Associated symptoms from MI: chest pain, dyspnoea, nausea/vomiting and diaphoresis

Question 19

What are the diagnostic studies performed for a person with a throw degree AV block? Provide rationales.

Answer 19

FBC (anaemia, infection), WBC (endocarditis), U&Es (metabolic imbalance, renal insufficiency, severe hyperkalaemia), APTT, digoxin level (if pt taking drug), myocarditis related studies (Lyme titres, HIV serologies, enterovirus polymerase chain reaction (PCR), adenovirus PCR), chest radiograph and ECG

Question 20

Identify complications associated with third degree AV block

Answer 20

Syncope, hypotension, cardiovascular collapse, death, dizziness, weakness, malaise
Pacemaker complications: arterial injury, haemothorax, pneumothorax or cardiac tamponade

Question 21

Describe amiodarone

Answer 21

Action: class III anti-arrhythmic agent, used for VF, VT, atrial flutter and atrial fibrillation
Dose: 100/200mg tablets and 150mg ampoules
Contraindications: monitor serum conc, don't give with drugs that may prolong the QT interval
Side effects: bradycardia, VT, VF arrest, severe hypotension, nausea, anorexia, hair loss, insomnia, dizziness, thyroid and liver dysfunctions, sweating/hot flushes

Question 22

Describe sotalol

Answer 22

Action: class III anti-arrhythmic and non-selective beta adrenergic receptor block. Used for ventricular arrhythmias
Dosage: 80/160mg tabs and 40mg/mL ampoules
Contraindications: use w/ other anti-arrhythmics
Side-effects: nausea, sweating, bradycardia, fatigue, sleep disturbance, anxiety and depression, fever, dyspnoea, rash, diarrhoea, abdo pain/flatulence, hearing disturbance, sexual disfunction