Big Picture Overciew Of Anti Arrhythmias

Question 1

What phase do class 1A drugs effect, what specific cardiac tissue, what is the effect, and what is the effect on action potential duration?

Answer 1

Slows phase 0 of ventricular muscle fibers. Prolong action potential duration because of their potassium blocking action.

Question 2

What phase and cardiac cells do 1b drugs effect, what is the effect and what effect does it have on the action potential duration?

Answer 2

Slows phase 0 but also shortens phase 3 of the ventricle. Shortens the action potential.

Question 3

What is the phase effected by class 1c drugs, what is the effect, what is the cardiac tissue involved, and what is the effect on the duration of action potential?

Answer 3

Phase 0. Marked slowing of the phase. Ventricle muscle. Normal duration.

Question 4

What phase do class 2 drugs effect, what is the effect, what tissue is involved, and what effect does it have on action potential duration?

Answer 4

Phase 4 automaticity. Diminish/inhibit. SA and AV node. Decreases HR and AV conductance.

Question 5

What phase is effected with class 3 drugs, what is the effect, what is the tissue involved, and what is the effect on action potential duration?

Answer 5

Phase 3. Prolongs phase 3 repolarization. Ventricle muscle. Longer.

Question 6

What phase is effected by class 4 drugs, what is the effect, what tissue is involved, and is the effect on action potential duration?

Answer 6

Phase 0 and 3. Slow phase 0 and prolong phase 3. SA and AV node. Longer action potential because of longer refractory period.