Cardiac Arrhythmias Flashcards
What does the QRS represent on an ECG?
Ventricular depolarisation (contraction)
What does the p-wave represent on a ECG?
Atrial depolarisation (contraction)
What does the S-T segment represent on an ECG?
Early part of ventricular repolarisation (relaxation)
What does the T wave represent on an ECG?
Repolarisation (relaxation) of the ventricles
What does the QT interval represent on an ECG?
The time of ventricular activity (repolarisation + depolarisation)
What is Torsades de Pointes?
,earns twisting about the points (is a VT), the QRS complex deflect above and below the baseline
What is a cardiac tamponade?
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
Explain Pulseless electrical activity (PEA)
Cardiac contraction absent in presence of coordinated electrical activity
Manifestations: weakened cardiac contractions, situation exacerbated by worsening acidosis, hypoxia and increasing vagal tone
Describe a normal sinus rhythm
Rate: 60-100 bpm
Rhythm: regular
Describe asystole
Rate: no rate
Rhythm: no rhythm
P-wave: no discernible p wave
QRS complex: no QRS
What are the causes, diagnosis and treatment of asystole
Causes: hypovolaemia, hypoxia, hyperkalaemia/hypokalaemia, hypothermia (4Hs), acidosis, toxins, cardiac tamponade, pneumothorax, pulmonary emboli, myocardial infarction
Possible diagnosis: cardiac arrest, death
Treatment: CPR
Describe ventricular tachycardia
Rate: > 100 bpm
Rhythm: regular or slightly irregular
P wave: unidentifiable
QRS complex: prolonged duration
Why can you not shock in non-shockable VT and what do we do instead?
Because the pt is still conscious
Administer amiodarone
What are the causes, diagnosis and treatment of ventricular tachycardia?
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)
Describe a third degree AV block
Rate: 40-60 bpm (bradycardic)
Rhythm: regular
P-wave: unrelated
QRS: regular, can be widened
What are the causes, diagnosis and treatment for a third degree AV block?
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
Describe ventricular fibrillation
Rate: undeterminable
Rhythm: irregular
P-wave: unidentifiable
QRS: unidentifiable
What are the causes, diagnosis and treatment of ventricular fibrillation?
Causes: myocardial ischaemia, untreated VT, electrolyte imbalances, medications and electrocution
Diagnosis: can deteriorate into asystole
Treatment: defibrillation
Describe the symptoms of a third degree AV block
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
What are the diagnostic studies performed for a person with a throw degree AV block? Provide rationales.
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
Identify complications associated with third degree AV block
Syncope, hypotension, cardiovascular collapse, death, dizziness, weakness, malaise
Pacemaker complications: arterial injury, haemothorax, pneumothorax or cardiac tamponade
Describe amiodarone
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
Describe sotalol
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
