Arrythmias Flashcards
How does A Fib appear on an ECG?
Irregularly irregular rhythm, no distinct P waves, narrow QRS complexes, variable R-R intervals.
What are common causes of atrial fibrillation?
Hypertension, valvular disease, heart failure, thyrotoxicosis, alcohol (“holiday heart”).
What is the most characteristic ECG finding of atrial flutter?
Sawtooth flutter waves, usually best seen in inferior leads (II, III, aVF); regular rhythm.
What is the typical atrial rate in atrial flutter?
Around 250–350 bpm, with a fixed ventricular response (e.g., 2:1 block).
How is supraventricular tachycardia (SVT) identified on ECG?
Narrow QRS complex tachycardia (>150 bpm), often no visible P waves due to overlap with T waves.
What maneuver can help diagnose or treat SVT?
Vagal maneuvers or adenosine administration (can transiently block AV node).
What ECG finding is diagnostic of ventricular tachycardia (VT)?
Wide QRS complex tachycardia (>120 ms), regular rhythm, no clear P waves.
What are some causes of VT?
Ischemic heart disease, cardiomyopathy, electrolyte imbalances (e.g., hypokalemia).
How can you distinguish VT from SVT with aberrancy?
VT has AV dissociation, capture/fusion beats, extreme axis deviation.
What does ventricular fibrillation (VF) look like on ECG?
Chaotic, disorganized electrical activity; no identifiable QRS complexes, P waves, or T waves
What is the clinical significance of VF?
Medical emergency requiring immediate defibrillation; patient is pulseless.
What is a key ECG feature of Torsades de Pointes?
Polymorphic VT with twisting QRS complexes around the isoelectric line; prolonged QT interval.
What are common causes of Torsades de Pointes
Prolonged QT (drugs, hypokalemia, hypomagnesemia, congenital long QT)
What ECG feature defines first-degree AV block?
PR interval >200 ms; every P wave followed by a QRS.
How does Mobitz type I (Wenckebach) AV block appear on ECG?
Progressive PR lengthening until a dropped QRS complex.
What is the ECG hallmark of Mobitz type II AV block?
Fixed PR interval with intermittent dropped QRS complexes; more dangerous than type I.
What characterizes a third-degree (complete) heart block?
No relationship between P waves and QRS complexes; atria and ventricles beat independently.
What is a junctional rhythm on ECG?
Bradycardia with narrow QRS, absent or inverted P waves (if present).
What is a bundle branch block pattern on ECG?
Wide QRS (>120 ms); RBBB = RSR’ in V1, wide S in V6; LBBB = broad monophasic R in I/V6, deep S in V1.
What is the defining ECG feature of pre-excitation syndromes like WPW?
Short PR interval (<120 ms), delta wave (slurred upstroke of QRS), wide QRS complex.
What arrhythmia is most associated with WPW syndrome?
Paroxysmal SVT, especially AVRT (atrioventricular reentrant tachycardia).
What rhythm is defined by irregularly irregular wide QRS complexes in a patient with WPW and AF?
Pre-excited atrial fibrillation—dangerous, can lead to VF.
What is the normal PR interval?
120–200 ms.
What is the normal QRS duration?
<120 ms (less than 3 small boxes)
What does sinus bradycardia look like on ECG?
Normal P-QRS-T morphology with rate <60 bpm
What does sinus tachycardia look like on ECG?
Normal rhythm with rate >100 bpm, P waves preceding each QRS.
