Antiarrhythmics deck Flashcards
What are the normal steps in heart electrical activity? (4)
- SA node discharge
- Spread through atria
- AV node discharge
- Propagation through Purkinje fibres
The process of cardiac muscle contraction is called ________.
It is called excitation-contraction coupling
Membrane potential is maintained by __ , __ & __ on either side of the cell membrane.
Sodium (Na+)
Calcium (Ca2+)
Potassium (K+)
At rest, intracellular __ is low.
This is maintained by ______.
At rest, intracellular sodium (Na+) is low
This is maintained by Na+/K+ ATPase
What are the 3 action potential phases?
Rapid depolarization
Plateau phase
Repolarization
What is the rapid depolarization phase of the action potential phases
Na+ influx through rapidly opening Na+ channels
Sodium enters the cell rapidly
What happens in the plateau phase of the action potential phases?
Ca+2 influx through slowly opening Ca2+ channels
What is the first step of the excitation-contraction coupling?
Action potential leads to increased calcium levels
What is the second step of the excitation-contraction coupling?
The Calcium binds to troponin C and uncovers myosin binding site for actin
What is the third step of the excitation-contraction coupling?
The actin and myosin cross-linkages form, triggering the contraction
What is a normal heart rate?
60-80 bpm
What are arrhythmias?
Arrhythmias are abnormal heart rhythms due to electrical issues
What is bradycardia?
Slow heart rate <60 bpm
What is tachycardia?
Fast heart rate > 100bpm
What is automaticity?
The ability of some cardiac cells, mainly the SA node, to generate their own impulses
What is the order of the electrical signal through the heart?
SA node fires -> spreads through atria causing coordinated contraction
Next AV node -> his bundle -> Purkinje fibers -> coordinated contraction
What is a reentrant in arrhythmia?
When a signal reenters or circulates through tissue instead of following its normal path
can lead to abnormal rhythms
What are atrial flutters?
arrhythmia of 200-350bpm
what are atrial fibrillations?
300-500 bpm arrhythmia
Are atrial flutters/fibrillations dangerous?
They don’t always impact cardiac output but can become serious. Treated if symptoms develop or patient is at risk
Ventricular tachycardia is…
when the lower chambers of the heart beat too fast
Is Ventricular tachycardia dangerous?
It can occur occasionally and be fine but if its consistent it requires quick treatment
What is ventricular fibrillation?
When the lower chambers begin to beat rapidly AND irregularly
Is ventricular fibrillation dangerous?
It’s incredibly fatal.
