Cardiovascular Therapeutics 3 Flashcards
(11 cards)
What is arrhythmia?
A problem with heart rate or rhythm.
Types of arrhythmia
Bradycardia - slowed heart rate (below 60 BPM)
Tachycardia - increased heart rate (over 100 BPM)
Symptoms of atrial fibrillation
Breathlessness
Chest discomfort
Syncope or dizziness
Reduced exercise tolerance
Palpitations
What are the differences will the ECG of atrial fibrillation have compared to a normal sinus rhythm?
No P-waves
Chaotic baseline
Irregular ventricular rate
The ventricular rate is often 160–180beats per minute
The ventricular complexes look normal
Role of ectopic beats in arrhythmias like atrial fibrillation.
These ectopic impulses trigger abnormal atrial depolarisations, initiating episodes of AF.
Role of re-entrant circuits in arrhythmias like atrial fibrillation
In AF, multiple micro re-entrant circuits form throughout the atria.
This leads to chaotic, disorganised atrial electrical activity, with rapid, irregular firing.
The AV node filters these signals, leading to the classic irregularly irregular ventricular response
Mechanism of action of beta blockers used for rate control in AF
Block action of noradrenaline on the heart prevents tachyarrhythmias
Mechanism of action of calcium channel blockers used for rate control in AF
Block L-Type VGCC
Types of rhythm control
Electrical
Pharmacological
What is recommended for preventing strokes in AF?
DOACS (Direct oral anticoagulants)
Factor Xa inhibitors (rivaroxaban, apixaban, edoxaban)
Factor IIa (a.k.a.a thrombin) inhibitors
Factors that contribute to thrombosis (Virchow’s triad)
Blood stasis
Endothelial Damage
Hypercoagulability