Therapeutics 2 Flashcards
Give examples of conditions of bradycardia
- Sinus node disease
- AV nodal disease (heart block)
What could cause sinus bradycardia
- age related, loss of pacemaker cells
- hypothyroidism
- ischaemia
- pharmacological therapy
What could cause AV nodal disease
- ischaemia
- pharmacological therapy
Give examples of drugs that could induce bradycardia
amiodarone, verapamil, diltiazem, digoxin, donepezil, carbamazepine, lithium
Describe what an ECG would show for sinus bradycardia
- impulses originate at SA node at slow rate
- all complexes normal and evenly spaced
- rate less than 60bpm
Describe what an ECG would show for first degree AV block
- atrioventricular conduction lengthened
- P wave precedes each QRS complex
Describe what an ECG would show for a second degree AV block
- sudden dropped QRS complex
- intermittently skipped ventricular beat
Describe what an ECG would show for a third degree AV block
- impulses originate at AV node and proceed to ventricles
- atrial and ventricular activities are not synchronous
- P-P interval normal and constant
- QRS complexes normal
Describe the treatment of bradycardia
- withdraw/correct the cause
- atropine IV/ isoprenaline infusion (unlicensed in UK)
- Temporary pacemaker- AV node often recovers
- permanent pacemaker
What factors should a pharmacist think about when considering pacemakers
- infection risk- antibiotics choice and timing
- bleeding risk- care if anticoagulated
- lead placement- movement, analgesia
- for patients with tachy-brady syndrome
- will allows patient to be prescribed rate lowering drugs
Give examples of conditions of tachycardia
- sinus tachycardia
- supraventricular tachycardia (atrial)
- AF
- atrial flutter
- re-entry/junctional tachycardias (WPW) - ventricular tachycardia
- monomorphic/polymorphic
- ventricular fibrillation
what would an ECG of sinus tachycardia show
- impulses originate at SA node at rapid rate
- all complexes normal and evenly spaced
- rate greater than 100bpm
what can sinus tachycardia be caused by
thyrotoxicosis, hypotension, pulmonary emboli, stress, caffeine, cocaine, alcohol, pain
- may be self terminating
- treat underlying cause
what would an ECG of ventricular tachycardia show
- impulses originate at ventricular pacemaker
- wide ventricular complexes
- rate greater than 120bpm
what is ventricular tachycardia defines as
3 or more consecutive ventricular beats
- broad complex
- 2 types: monomorphic and polymorphic
Outline the presenting complaints of ventricular tachycardia
- dizziness, syncope, palpitations
- reduced cardiac output
- often self terminating
What could ventricular tachycardia lead to
may lead to ventricular fibrillation which could lead to death
What can ventricular tachycardia be caused by
- AMI (infarcted area)
- often drug induced: antiarrhythmics, amiodarone, sotalol
- low potassium and magnesium
- cardiomyopathies
- congenital defect (TDP)
What are the treatments of ventricular tachycardia
- precordial thump
- IV amiodarone
- IV lidocaine
- DCCV once anaesthetised
- atenolol (non sustained )
- correct potassium and magnesium
- may require ICD
What are the characteristics of polymorphic ventricular tachycardia (TDP)
- twisting axis
- long QT
What is the treatment of polymorphic ventricular tachycardia
- reduce/treat the cause and correct electrolytes
- magnesium
- beta blockers to reduce QT
- temporary pacing
what would an ECG of ventricular fibrillation show
- chaotic ventricular depolarisation
- irregular, rapid and no organised contraction of the ventricle
- no cardiac output so no pulse
What does ventricular fibrillation cause
rapidly causes LOC and sudden cardiac death
what is ventricular fibrillation caused by
commonly caused by AMI
