Question # 1 (Multiple Answer) Consequences of reduced sodium activation because of reduced membrane potential (less negative):

A) decreased upstroke velocity
B) reduced excitability
C) decreased conduction velocity
D) decreased effective refractory period

Question # 2 (Multiple Choice) In the cardiac Purkinje fiber action potential: the major current-carrying ion for phase 0 is:

A) potassium
B) sodium
C) calcium

Question # 3 (Multiple Choice) A polymorphic ventricular arrhythmia, especially associated with prolonged QT intervals; possibly induced by early afterdepolarizations

A) supraventricular tachyarrhythmia
B) Torsades de Pointes
C) both
D) neither

Question # 4 (Multiple Answer) Cardiac membrane ionic gate state(s) is/are controlled by:

A) ionic conditions
B) metabolic conditions
C) transmembrane potential (voltage)

Question # 5 (Multiple Answer) Cardiac cells tie in which the resting membrane potential drifts towards threshold:

A) normal His-Purkinje cells
B) normal ventricular muscle cells
C) SA nodal cells
D) ischemic ventricular muscle cells

Question # 6 (Multiple Answer) Factors that increase phase 4 depolarization:

A) mechanical cardiac muscle fiber stretch
B) increased vagal tone
C) beta-adrenergic stimulation
D) hypokalemia

Question # 7 (Multiple Choice) The primary repolarization phase of the Purkinje fiber or ventricular muscle cell action potential:

A) Phase 0
B) Phase 1
C) Phase 2
D) Phase 3
E) Phase for

Question # 8 (Multiple Choice) Triggered automaticity: associated with significant prolongation of the action potential duration:

A) delayed afterdepolarization (DAD)
B) early afterdepolarization (EAD)
C) both
D) neither

Question # 9 (Multiple Choice) Phase of the Purkinje fiber action potential composed of the combination of inward, depolarizing calcium current balanced by an outward, repolarizing potassium current (delayed rectifier):

A) phase 0
B) phase 1
C) phase 2
D) phase 3
E) phase 4

Question # 10 (Multiple Choice) Factors reducing cardiac membrane resting potential and could reduce conduction velocity:

A) hyperkalemia
B) sodium pump blockade
C) ischemic cell damage
D) B & C
E) A, B & C

Question # 11 (Multiple Answer) Effective in treating Wolff-Parkinson-White-based arrhythmias:

A) antimuscarinic drugs
B) beta-adrenergic blockers
C) digitalis glycosides
D) beta-adrenergic agonists
E) calcium channel blockers

Question # 12 (True/False) Most common cardiac induction abnormality leading to arrhythmias -- reentry

A) true
B) false

Question # 13 (Multiple Choice) Primary inward, depolarizing current carrying ion in SA nodal and AV nodal tissues:

A) sodium
B) calcium
C) potassium

Question # 14 (Multiple Choice) Less intense sodium current flow upon depolarization:

A) membrane potential = -80 mV
B) membrane potential = -50 mV

Question # 15 (Multiple Answer) Increases slope of phase 4 depolarization:

A) edrophonium
B) atropine
C) isoproterenol
D) propranolol
E) physostigmine

Question # 16 (Multiple Answer) Factors which may precipitate or worsen arrhythmias:

A) ischemia
B) acidosis
C) alkalosis
D) cardiac fiber stretch
E) drug action

Question # 17 (Multiple Choice) The cardiac cell membrane potential is closest to the equilibrium potential of this ion:

A) sodium
B) potassium
C) chloride
D) calcium
E) inorganic anions

Question # 18 (Multiple Answer) Principal mechanism(s) associated with many tachyarrhythmias:

A) suppressed automaticity
B) reentry
C) triggered automaticity

Question # 19 (Multiple Answer) Cardiac transmembrane potential: mainly determined by these ionic gradients:

A) chloride
B) sodium
C) potassium
D) calcium
E) magnesium

Question # 20 (Multiple Answer) Cardiac membrane permeability -- resting state:

A) sodium-- relatively impermeable
B) potassium -- relatively impermeable
C) sodium -- relatively permeable
D) potassium -- relatively permeable

Question # 21 (Multiple Answer) Cardiac resting membrane potential is mainly determined by:

A) sodium concentration
B) extracellular potassium concentration
C) inward potassium rectifier channel state
D) chloride conductance

Question # 22 (Multiple Choice) Phase for depolarization (spontaneous depolarization) may occur because of:

A) gradual increase in membrane permeability to sodium or calcium
B) decrease in repolarizing potassium currents (decreasing membrane potassium permeability)
C) both
D) neither

Question # 23 (Multiple Answer) Arrhythmias may be caused or characterized by:

A) abnormal rate
B) abnormal regularity
C) abnormal impulse origination
D) abnormal conduction