Arrhythmias Flashcards
What are arrhythmias?
Abnormal heart rhythms due to electrical conduction disturbances in the heart, leading to bradycardia, tachycardia, or irregular rhythms.
What is Atrial Fibrillation (AF)?
Disorganized electrical impulses in the atria cause rapid, uncoordinated contraction, leading to an irregularly irregular ventricular rhythm.
What are the clinical features of Atrial Fibrillation?
Palpitations, dyspnea, fatigue, stroke risk due to atrial thrombus formation.
What is Atrial Flutter?
Reentrant circuit in the right atrium causes rapid but regular atrial contractions, often resulting in a ventricular response at 150 bpm.
What are the clinical features of Atrial Flutter?
Palpitations, breathlessness, dizziness; can progress to AF.
What is Supraventricular Tachycardia (SVT)?
Abnormal reentry circuit involving the AV node or an accessory pathway, leading to sudden onset rapid palpitations.
What are the clinical features of Supraventricular Tachycardia (SVT)?
Sudden onset rapid palpitations, lightheadedness, chest discomfort.
What is Ventricular Tachycardia (VT)?
Reentry circuits or abnormal automaticity in the ventricles lead to rapid ventricular depolarization (>100 bpm).
What are the clinical features of Ventricular Tachycardia (VT)?
Palpitations, dizziness, syncope; risk of deteriorating into VF.
What is Ventricular Fibrillation (VF)?
Multiple chaotic electrical impulses in the ventricles prevent coordinated contraction, leading to cardiac arrest.
What are the clinical features of Ventricular Fibrillation (VF)?
Immediate loss of consciousness, pulseless electrical activity, sudden death if not treated.
What is Torsades de Pointes?
Polymorphic VT associated with prolonged QT interval, often due to electrolyte disturbances or medications.
What are the clinical features of Torsades de Pointes?
Palpitations, syncope, risk of degeneration into VF.
What is Sinus Bradycardia?
Reduced SA node firing, commonly due to high vagal tone, beta-blockers, or hypothyroidism.
What are the clinical features of Sinus Bradycardia?
Fatigue, dizziness, syncope if severe.
What is First-degree heart block?
Prolonged PR interval (>200 ms) but all impulses reach ventricles.
What is Second-degree Mobitz I (Wenckebach)?
Progressive PR lengthening until a beat is dropped.
What is Second-degree Mobitz II?
Sudden dropped beats without PR lengthening.
What is Third-degree (Complete) Heart Block?
No atrial impulses reach the ventricles, requiring pacemaker implantation.
What is the mechanism of action of Beta-Blockers?
Blocks beta-adrenergic receptors, reducing heart rate and myocardial oxygen demand.
What are the side effects of Beta-Blockers?
Fatigue, bradycardia, hypotension, erectile dysfunction.
What is the mechanism of action of Calcium Channel Blockers?
Inhibits calcium influx, reducing conduction at AV node.
What are the side effects of Calcium Channel Blockers?
Bradycardia, constipation (verapamil), peripheral edema.
What is the mechanism of action of Digoxin?
Inhibits Na+/K+ ATPase, increasing vagal tone to slow AV node conduction.
What are the side effects of Digoxin?
Nausea, vomiting, confusion, visual disturbances.
What is the mechanism of action of Amiodarone?
Blocks multiple ion channels, prolonging action potential duration.
What are the side effects of Amiodarone?
Pulmonary fibrosis, thyroid dysfunction, liver toxicity, skin discoloration.
What is the mechanism of action of Adenosine?
Transiently blocks AV node conduction.
What are the side effects of Adenosine?
Flushing, chest pain, shortness of breath.
True or False: DOACs are preferred for anticoagulation in AF according to recent NICE guidance.
True
What monitoring is recommended before initiating antiarrhythmic drugs?
ECG monitoring.
Fill in the blank: Rate control is preferred in most AF patients unless _______ is strongly indicated.
rhythm control
What is the risk associated with using beta-blockers and calcium channel blockers together?
Risk of complete heart block.
