Pharmacology - Anti-Arrhythmic Drugs Flashcards
Resting HR is ___________ correlated to life expectancy
inversely
Why is having a fast heartbeat bad?
- Heart works harder (higher O2 demand)
- Diastole gets shorter (less O2 supply)
- Risk of ischemia (higher O2 demand + less O2 supply)
- Prone to arrhythmias
Irregular heartbeat
Arrhythmia
Your heart beats too fast, too slow, or with an irregular pattern
Arrhythmia
> 100 bpm (too fast)
Tachycardia
<60 bpm (too slow)
Bradycardia
Which is the more frequent issue: tachycardia or bradycardia
Tachycardia
What three things can cause arrhythmia?
Ischemia
Muscle death
Heart failure
Which drugs are specific to arrhymthia?
Na+ blockers
K+ blockers
Difference in electrical potential between inferior and exterior of a cell
Membrane potential
Which part of the cell is more negative?
Inside
Rapid rise and fall of membrane potential upon stimulus; occurs in excitable cells like neurons and muscle cells
Action potential
Resting membrane potential
-90 mV
Negative membrane potential starts becoming more positive
Depolarization
Positive membrane potential starts becoming more negative again
Repolarization
Which lead in EKG is most commonly used?
Lead II
What is “P” on an EKG?
Atrial depolarization
What is “R” on an EKG?
Ventricular depolarization
What is “T” on an EKG?
Ventricular repolarization
Where is atrial repolarization on an EKG?
Hidden between “P” and “R” in the PR segment
Explain the electrochemical gradient
Outside membrane: positive, more Na+, less K+, more Ca2+
Inside membrane: negative, less Na+, more K+, less Ca2+
Voltage gated channels are also called what?
Ion channels
What are voltage gated channels NOT activated by?
Ligands
What are voltage gated channels activated by?
Changes in membrane potential
T/F voltage gated ion channels are transmembrane
True
What are the 2 types of action potentials?
- Nodal
- Non-nodal
What is nodal action potential made by?
Pacemaker cells
SA/AV nodes
What is non-nodal action potential made by?
Myocytes
What 3 things regulate HR?
- Automaticity
- Refractoriness
- Conduction velocity
Spontaneous impulse generation
Automaticity
What controls automaticity?
SA node
AV node