Medical Pharmacology Practice Questions: Antiarrhythmic Drugs

Classifications of antiarrhythmic drugs:
1. sodium channel blockers
2. calcium channel blockers
3. potassium channel blockers
4. beta-blockers
5. all of the above
Antiarrhythmic drug classification: class II
1. sodium channel blocker
2. calcium channel blocker
3. beta adrenergic receptor blocker
4. potassium channel blocker
Factors that may precipitate or exacerbate arrhythmias:
1. ischemia
2. cardiac fiber stretching
3. alkalosis
4. A & C
5. A, B & C
Factors that precipitate or exacerbate arrhythmias:
1. abnormal electrolytes
2. excess vagal tone
3. antiarrhythmic drugs
4. A & C
5. A, B & C
Normal cardiac impulse propagation sequence:
1. AV node, His-Purkinje, ventricle, SA node
2. SA node, His-Purkinje, AV node, ventricle
3. SA node, AV node, His-Purkinje, ventricle
4. AV node, SA node, His-Purkinje, ventricle
5. none of the above
Possible cause(s)/characteristic(s) of arrhythmias:
1. Improper site of origination
2. abnormal rate
3. abnormal conduction characteristics
4. A & B
5. A & C
Principal ions involved in determining the cardiac transmembrane potential:
1. chloride, sodium, potassium
2. potassium, calcium, chloride
3. sodium, calcium, large organic anions
4. sodium, calcium, potassium
5. sodium, potassium, large organic anions
Factors controlling membrane ionic "gates":
1. ionic conditions
2. metabolic conditions
3. membrane potential
4. A & B
5. A, B & C
In reference to ionic gradients, the term "electrogenic" means:
1. that a large membrane capacitance is present
2. that the membrane is relatively permeable to potassium
3. that net current flows as a result of ionic transport
4. that current flows independent of membrane voltage
5. none of the above
Concerning the ionic permeability state of the resting membrane:
1. the membrane is relatively impermeable to potassium
2. the membrane is relatively impermeable to sodium
3. both
4. neither
Cardiac cell permeability and conductance:
1. conductance -- determined by characteristics of ion channel proteins
2. current flow = voltage X conductance
3. both
4. neither
Cardiac cell membranes: "driving forces" acting on ions--
1. Tendency for sodium to be driven out of the cell
2. Limited tendency for potassium movement because of the balance between the potassium concentration and membrane electrical gradients
3. The concentration gradient for potassium tends to drive potassium out
4. B & C
5. A, B & C
Principal determinant(s) of cardiac resting membrane potential:
1. external potassium concentration
2. inward potassium rectifier channel state
3. both
4. neither
Rapid upstroke characteristic of phase 0 depolarization in Purkinje and ventricular muscle cells:
1. due to rapid increase in calcium permeability
2. due to rapid decrease in potassium conductance
3. due to rapid increase in sodium conductance
4. due to significant outward chloride currents
Phase of the cardiac action potential (in SA nodal cells, for example) that is associated with "diastolic depolarization":
1. phase 0
2. phase 1
3. phase 2
4. phase 3
5. phase 4
Factors which promotes ectopic pacemaker development:
1. reduced autonomic, sympathetic activity
2. reduced serum potassium
3. both
4. neither
Sequence of cardiac Purkinje fiber ion channel activation:
1. calcium, potassium, sodium
2. potassium, calcium, sodium
3. sodium, calcium, potassium
Activation of this ion channel mainly associated with cardiac cell repolarization:
1. calcium
2. potassium
3. sodium
Relationship between membrane resting potential when depolarization occurs and conduction velocities:
1. increased membrane potential: reduced conduction velocity
2. increased membrane potential: increased conduction velocity
Consequences of reduced sodium channel activation due to the reduced membrane potential (less negative) at the time and depolarization
1. reduced of upstroke velocity (phase 0); i.e., reduced maximum rate of membrane potential change
2. reduced conduction velocity
3. increased of effective refractory period (prolongation of recovery)
4. B & C
5. A, B & C