Key terms + definitions

Question 1

What is a positive and negative inotrope?

Answer 1

Inotrope = Capable of altering the FORCE of energy of a muscle contraction

(1. ) Positive = Makes contraction stronger, increase the force of contraction e.g. NO, digoxin
(2. ) Negative = Decrease the force of a muscle contraction e.g. beta-blockers, CCB

Question 2

What is a positive and negative chronotrope?

Answer 2

Chronotrope = A agent capable of altering the RATE of muscle contraction

(1. ) Positive
- Inc rate of muscle contraction i.e. makes heart beat quicker e.g. NA, atropine
- Atropine inhibits parasymp systems, i.e. removes brakes on heart so speeds up rate

(2. ) Negative
- Dec rate of muscle contraction e.g. Ach, beta-blocker, CCB