13 Drugs and CVS Flashcards
What’s the difference between atrial fibrillation and atrial flutter?
Atrial fibrillation- atria beat irregularly
Atrial flutter- atria beat regularly but faster than usual and often more than the verticles (eg 4 atrial beats per 1 ventricular)
`What (in general terms) causes arrhythmias?
- Disturbance in impulse generation
- Disturbance in impulse conduction
- Both
Give some examples of causes of arrhythmias.
- Ectopic pacemaker activity (damaged area of myocardium
- Conduction problem- causing re-entry loop
- Mitral valve stenosis (extra pressure and stretch on atria)
Name 3 conditions which antiarrhythmic drugs can be used to treat?
- Supraventricular tachycardia
- Ventricular tachycardia
- Atrial fibrillation
Why must antiarrhythmic drugs be used with caution?
Have potential to cause arrhythmias
What are the 4 classes of antiarrhythmic drugs?
- Voltage-sensitive sodium channel blockers
- ß-adrenoreceptor antagonists
- Potassium channel blockers
- Calcium channel blockers
Name an anti-arrhythmic drug that acts of sodium, potassium and calcium channels as well as ß-adrenoreceptors.
Amiodarone
What do inotropic drugs do?
affect the force of contraction
Name 3 types of inotropic drugs and give an example of each.
- Cardiac glycosides (Increase contraction force)
- Digoxin
- Selective ß1 agonists (Increase contraction force)
- Adrenaline
- Dobutamine
- ß-adrenoblockers (Decrease contraction force)
- Propanolol
How do cardiac glycosides work to increase the force of heart contraction in a patient with heart failure with atrial fibrillation?
-
Increase cardiac output
- Inhibit Sodium/Potassium ATPase
- Increase intracellular Sodium
- Lose Sodium gradient- NCX doesn’t work as well
- Rise in intracellular Calcium
When would a cardiac glycoside be given to a patient?
If patient has heart failure w./ atrial fibrillation (not good in long term
When might a patient be given a selective beta-1 agonist?
- Cardiogenic shock
- Acute reversible heart failure
When and why might a patient be given a beta-adrenoreceptor blocker?
- After MI- increase sympathetic response
- Reduce HR and prevent arrhythmia
- Treat angina
How do beta-adrenoreceptor blockers work?
Reduce contraction force
Lower workload
Prevent action of sympathetic noradrenaline
What are vasodilators used to treat? (2)
- Chronic heart failure
- Hypertension (to avoid CVD/stroke)
What are the 3 main categories of vasoldilators?
- Alpha 1-adrenoreceptor antagonists
- Hypertension
- Calcium channel blockers
- Hypertension
- ACE Inhibitors and Diuretics
- Chronic heart failure
ACE= Angiotensin converting enzyme
How do ACE inhibitors work to decrease the workload of the heart to treat chronic heart failure? (2)
- ACE= Inhibited- can’t form Angiotensin II
- Promotes Vasodilation as angiotensin II= vasoconstrictor
- Decrease afterload and preload on heart
-
Diuretic effect
- Angiotensin II- promotes aldosterone release from adrenal cortex
- Decrease blood volume
- Promotes Vasodilation as angiotensin II= vasoconstrictor
What are organic nitrates used to treat?
Angina
What do organic nitrates release and why are they effective?
Nitric oxide:
Powerful vasodilator (produced naturally- in the endothelial lining of blood vessels)
What vessels does nitric oxide act on?
- Primarily Veins
- Decrease preload and work for heart
- May dilate collacteral coronary arteries
- NOT ARTERIOLES
- Improve blood supply to heart
Antithrombotic drugs may be prescribed to patients with which conditions? (4)
- Atrial fibrillation
- Valve disease
- After MI
- Coronary artery disease
Give examples of 3 antithrombotic drugs.
- Warfarin
- Dabigatran (direct thrombin inhibitor)
- Aspirin (anti-platelet drug)
What do you give a patient having an MI?
