Cardiovascular Toxidromes Flashcards
Cardiac Action Potential Stages
(5)
0 - Rapid Depolarisation (systole)
1 - Notch
2 - Plateau
3 - Rapid Repolarisation
4 - Baseline (diastole)
Cardiovascular Drugs
Class 1
Type
Sodium Blockers
Cardiovascular Drugs
Class 2
Type
Beta Blockers
Cardiovascular Drugs
Class 3
Type
Potassium Blockers
Cardiovascular Drugs
Class 4
Type
Calcium Blockers
Cardiovascular Drugs
Class 5 (OTHER)
Type
Cardiac Glycosides
Cardiovascular Drugs
Class 1 Effects
drop rate of repolarisation (drug dependent)
Cardiovascular Drugs
Class 2 Effects
- decrease SA node rate
- decrease AV conductivity
- increase refractory period
Cardiovascular Drugs
Class 3 Effects
- increase refractory period
- increase action potential duration
Cardiovascular Drugs
Class 4 Effects
- decrease action potential duration
- decrease AV conduction & contractility
Cardiovascular Drugs
Class 5 Effects
- increase in chronotropic
- decrease in inotropic
Cardiovascular Drugs
Class 1 Pharmocodynamics
- sodium channel blockers slow NA+ influx during stage 0
Sodium Blockade Toxicity
Neuro Symptoms
(5)
- ALOC
- agitation
- tremors/twitching
- seizures
- coma
Sodium Blockade Toxicity
Respiratory Symptoms
- tachypnoea
- bradypnoea (terminal sign)
Sodium Blockade Toxicity
Cardio Symptoms
- hypotension
- bradycardia or tachycardia (tachy = bad)
- AV or bundle branch blocks
- QRS widening
- R axis deviation
- VT or VF
Diagnosis
Sodium Blockade Toxicity
Cardiovascular Drugs
Class 2 pharmacodynamics
beta receptors blunt chronotropic, intotropic and metablic effect of catecholamines
Beta Blockers
Common Effects
(4)
- reduce arrythmias, particularly tachyarrythmias
- reduce blood pressure
- manage psychological stress
- reduce workload for angina or following MI infarction
Common drug class for -lol
class 2 beta blockers
Beta Blocker Toxicity
Neuro Symptoms
- ALOC
- seizures
- coma (seen with propranolol)
Beta Blocker Toxicty
Respiratory Symptoms
- bronchospasm
- pulmonary oedema
Beta Blocker Toxicity
Cardio Symptoms
- hypotension
- bradycardia
- AV blocks, complete dissociation
- QRS widening
- R axis deviation
Beta Blocker Toxicity
Peripheral Symptoms
- hypoglycaemia
- hyperkalaemia
Diagnosis
Beta Blocker Toxicity
Cardiovascular Drugs
Class 3 pharmacodynamics
(3)
- K+ prolong overall action potential by reducing K+ efflux out of cells
-prolongs effective refractory & QT - blunts myocytes ability to respond to ectopic stimuli
Potassium Toxicity
Neuro Symptoms
- ALOC
- tremors
- seizures
- coma
Potassium Toxicity
Respiratory Symptoms
- depression at high doses
Potassium Toxicity
Cardio Symptoms
- hypotension
- bradycardia
- AV blocks
- QT prolongation
- risk of TdP
- VF
Potassium Toxicity
Peripheral Symptoms
- nausea
- sweating
- hypoglycaemia
- hypokalaemia
Diagnosis
Potassium Toxicity
Cardiovascular Drugs
Class 4 pharmacodynamics
calcium channel blockers restrict calcium ingress slowing cardiac conduction and contractiility
Cardiovascular Drugs
Calcium Blockers Effects
- reduce tachyarrythmias
- antihypertensive
- reduce cardiac workload for angina or following MI infarction
Cardiovascular Drugs
Calcium Channel Blockers
3 Types
- phenylalkylamines
- benzothiazepines
- dihydropyridines
Cardiovascular Drugs
Calcium Blockers
Phenylalkylamines
cardiac vs peripheral
- decrease in AV conduction
- decrease inotropic effect
- moderate peripheral vasodilation
Cardiovascular Drugs
Calcium Blockers
Benzothiazepines
cardiac vs peripheral
- milder cardiac effects
- moderate peripheral vasodilation
Cardiovascular Drugs
Calcium Blockers
Dihydropyridines
cardiac vs peripheral
- peripheral vasodilation only
Cardiovascular Drugs
Calcium Toxicity
Neuro Symptoms
- headache
- ALOC
- seizures/coma, rare and show late stage
Cardiovascular Drugs
Calcium Toxicity
Respiratory Symptoms
- depression progressing to failure
Cardiovascular Drugs
Calcium Toxicity
Cardio Symptoms
- peripheral vasodilation
- refractory hypotension
- bradycardia
- AV block
- complete block
Cardiovascular Drugs
Calcium Toxicity
Peripheral Symptoms
- hyperglycaemia
- ketoacidosis
- renal failure
Diagnosis
Calcium Toxicity
Cardiovascular Drugs
Class 5 - Digoxin
Pharmocodynamics
inhibits function of the NA/K pump increasing intracellular sodium and restricting calcium loss
Cardiovascular Drugs
Class 5 - Digoxin
Effects
- contractility increases improving CO
- decreased automaticity decreasing HR
- increased refractory period decreases arrythmia risk
Cardiovascular Drugs
Class 5 - Digoxin
Neuro Symptoms
- headache
- visual disturbances
- agitation
- ALOC
- fatigue
Cardiovascular Drugs
Class 5 - Digoxin
Respiratory Symptoms
(1)
- dependent on CNS status
Cardiovascular Drugs
Class 5 - Digoxin
Cardio Symptoms
(4)
- dysrhythmias & heart blocks (vary by pt)
- high risk of PVCs
- high risk of VT
- high risk of VF
