Cardiac Arrhythmia Drugs Flashcards
List the following for: Class 1B agents
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
Cardiac arrhythmia:
- Ventricular tachycardia (especially during ischaemia)
Lidocaine
Mexiletine
Class 1B agents
Lidocaine affects normal tissue and ischaemic tissue
Blocks Na channels responsible for activating late phase 2 of AP
Increase Na threshold
Shortens APD slightly
- Dizziness
- Drowsiness
- Abdominal upset / metallic taste
Can cause arrhythmias themselves!
Atrial arrhythmias
AV functional arrhythmias
List the following for: Class 1C agents
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
Cardiac arrhythmia – wide spectrum!
- Supraventricular arrhythmias (fibrillation and flutter)
- Premature ventricular contractions
- Wolff-Parkinson-White syndrome
Flecainide
Class 1C agents
Powerful fast Na channel blockers - markedly depress phase 1 depolarisation
Increase APD and refractory period
Proarrhythmic and sudden death, especially with chronic use / structural heart disease
Increase ventricular response to supraventricular arrhythmias
- CNS effects e.g. dizziness, blurred vision
- GI effects e.g. nausea
Can cause arrhythmias themselves!
List the following for: Class 2 agents
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
Cardiac arrhythmia:
- Sinus / catecholamine dependent tachycardia
- Convert re-entry arrhythmias at AVN
- Protect ventricles from high atrial firing
Propranolol
Bisoprolol
Metoprolol
Esmolol
Class 2 agents - beta blockers
Increase APD and refractory period in AVN to slow AVN conductivity
Decreases phase 4 repolarisation
- Bronchospasm (X asthma)
- Hypotension
- Asthma!
- Partial AV block
- Acute heart failure
List the following for: Class 3 agent - Amiodarone
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Important drug reactions
Cardiac arrhythmia - wide spectrum:
- Useful for most arrhythmias
- But SELECTIVE use due to serious side effects
Amiodarone
Class 3 agent - Amiodarone
Main action: Block K channels responsible for phase 4 repolarisation
- Increase APD and refractory period
- Also blocks Na channels and Ca channels
LOTS!!
- Pulmonary fibrosis
- Thyroid disease (hypo or hyper)
- Hepatic injury
- Photosensitivity
- Optic neuritis (transient blindness)
- Increase LDL cholesterol
- Digoxin (monitor)
- Warfarin (monitor)
List the following for: Class 3 agent - Sotalol
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
Cardiac arrhythmia
- Supraventricular tachycardia
- Ventricular tachycardia
Sotalol
Class 3 agent - Sotalol
- Increase APD and refractory period
- Slows phase 4 repolarisation
- Slows AVN conduction
- Proarrhythmic
- Fatigue
- Insomnia
List the following for: Class 4 agents
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
- Important drug reactions
Cardiac arrhythmia:
- Supraventricular tachycardia – control ventricles and convert
Verapamil
Diltiazem
Class 4 agents
Non-dihydropyridine calcium channel blockers – selective for myocardium
- Block Ca channels during depolarisation - slows conduction through AVN and reduced contractility
- Increase refractory period in ANV
- Increase slope of phase 4 – slow HR
- GI problems e.g., constipation
- Partial AV block
- Hypotension
- Decreased cardiac output
- Sick sinus syndrome
- B-blockers
List the following for: Miscellaneous (Adenosine)
- Use
- Example drugs
- Drug class
- Mechanism of action
- Warnings / contraindications
Cardiac arrhythmia
- Convert re-entry supraventricular arrythmias
- Diagnosis of coronary artery disease
Adenosine
Miscellaneous - A1 receptor blocker
- Blocks A1 receptor (nucleoside), prevents adenylyl cyclase from binding
- Reduces cAMP
- Activates K current in SAN and AVN causing hyperpolarisation, reducing HR
- Reduced Ca currents, increase refractory period in AVN
Can completely stop the heart (very short t1/2) = feeling of impending doom - Asthma
List the following for: Miscellaneous (Ivabradine)
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
Cardiac arrhythmia
- Reduce inappropriate sinus tachycardia (POTS)
- Reduce HR in HF and angina
Ivabradine
Miscellaneous – Selective beta blocker
- Blocks If (funny) channel in SAN
Doesn’t affect blood pressure! - Flashing lights
- Teratogenicity not known (avoid in pregnancy)
- Pregnancy
List the following for: Miscellaneous (Digoxin)
- Use
- Example drugs
- Drug class
- Mechanism of action
- Warnings / contraindications
Cardiac arrhythmia
- Reduce ventricular rates in AF and flutter
Digoxin
Miscellaneous – Cardiac Glycoside
- Enhances vagal activity (increase K and Ca currents and increases refractory period)
- Slows AVN conduction
- Slows HR
- Renal failure (caution)
List the following for: Miscellaneous (Atropine)
- Use
- Example drugs
- Drug class
- Mechanism of action
- Adverse effects
- Warnings / contraindications
- Important drug reactions
Cardiac arrhythmia
- Acute IV administration for patients feeling faint (vagal bradycardia)
Atropine
Miscellaneous – Selective muscarinic antagonist
- Block vagal activity
- Speed up AVN conduction and increase HR
List all of the Cardiac Anti-arrhythmic drugs
- Class 1B agents
- Class 1C agents
- Class 2 agents
- Class 3 agents
- Class 4 agents
Plus miscellaneous: Adenosine, Ivabradine, Digoxin and Atropine
