Cardio-arrhythmia Flashcards
What are the specialized cells of the heart conduction system?
Cardiomyocytes (contractile cells) and pacemaker cells (automaticity cells)
What are the key pacemaker cells in the heart?
SA node, AV node, His bundle, Purkinje fibers.
What is the role of the funny sodium channel (If)?
It is found only in the SA node and is responsible for spontaneous depolarization of pacemaker cells
How does ivabradine work in arrhythmia management?
Blocks the funny sodium channel, slowing heart rate without affecting contractility.
What drug is commonly used for symptomatic sinus bradycardia?
Atropine
What are the different types of AV blocks?
First-degree AV block → PR interval >200 ms, no dropped beats.
Second-degree AV block (Mobitz I – Wenckebach) → Progressive PR prolongation until a beat is dropped.
Second-degree AV block (Mobitz II) → Fixed PR interval with unpredictable dropped QRS complexes.
Third-degree (Complete) AV block → No communication between atria and ventricles, with independent P and QRS rhythms.
What is the usual site of disease in Mobitz I vs. Mobitz II AV block?
Mobitz I (Wenckebach) → AV node level.
Mobitz II → Below AV node (His-Purkinje system).
What is the management for symptomatic AV block?
Acute: Atropine, dopamine, epinephrine, transcutaneous pacing.
Definitive: Permanent pacemaker (PPM) if persistent or severe block.
What are common causes of atrial fibrillation (AF)?
CAD, MI, hypertension, valvular disease, hyperthyroidism, cardiac surgery, stimulants (caffeine, alcohol).
What are the key ECG features of AF?
Irregularly irregular rhythm.
No distinct P waves, fibrillatory waves instead.
What are the three key pillars of AF management?
Rate control, rhythm control, stroke prevention.
What medications are used for rate control in AF?
Beta-blockers, calcium channel blockers (verapamil, diltiazem), digoxin.
What are the rhythm control options in AF?
Pharmacologic cardioversion: Amiodarone, sotalol, flecainide.
Electrical cardioversion.
Catheter ablation (for recurrent AF).
How do you assess stroke risk in AF?
CHADS₂-VASc score (Congestive HF, Hypertension, Age ≥75, Diabetes, Stroke, Vascular disease, Age 65-74, Sex category).
What are the anticoagulation options for stroke prevention in AF?
Warfarin (INR 2-3), Direct Oral Anticoagulants (DOACs) - Dabigatran, Rivaroxaban, Apixaban.
What are the key ECG features of atrial flutter?
Sawtooth “F” waves, usually in lead II.
What are the three main types of SVT?
AV nodal re-entrant tachycardia (AVNRT)
Atrioventricular re-entrant tachycardia (AVRT, e.g., WPW syndrome)
Atrial tachycardia
What is the first-line treatment for SVT?
Vagal maneuvers (Valsalva, carotid massage)
What is the drug of choice for acute SVT termination?
Adenosine (rapid IV push)
What is the key ECG finding in AVNRT?
Narrow complex tachycardia with pseudo R’ wave in V1 and pseudo S wave in II
What are the ECG findings of AVRT (WPW syndrome)?
Short PR interval, delta wave, wide QRS.
What are the two types of VT?
Monomorphic VT → Regular, wide QRS (>120 ms).
Polymorphic VT (e.g., Torsades de Pointes) → Irregular QRS morphology.
What is the common cause of monomorphic VT?
Scar-related reentry (e.g., post-MI, cardiomyopathy)
What is the first-line treatment for stable monomorphic VT?
Amiodarone, procainamide, sotalol
What is the first-line treatment for unstable VT?
Synchronized cardioversion
What is Torsades de Pointes?
A form of polymorphic VT associated with QT prolongation
What are common causes of Torsades de Pointes?
Electrolyte imbalances (hypokalemia, hypomagnesemia).
QT-prolonging drugs (antiarrhythmics, antibiotics, antipsychotics).
Congenital Long QT syndrome.
What is the first-line treatment for Torsades de Pointes?
IV Magnesium sulfate.
What ECG phenomenon can lead to Torsades de Pointes?
R-on-T phenomenon (ventricular depolarization during the T wave)
