Arrhythmias Flashcards
First degree AV block
-ECG, associations, treatment
ECG: PR > 200
a/w increased vagal tone or B-block/CCB use
Tx: none
List of bradyarrhythmias
Sinus bradycardia
AV block: first degree, second degree Mobitz I (aka Wenckebach), second degree Mobitz II, third degree
Sick sinus syndrome (aka tachy-brady syndrome)
Wenckebach
Second degree AV block, Mobitz I
Etiologies of Mobitz I AV block
Drug effects: digoxin, B-blockers, CCB
Increased vagal tone
Right coronary ischemia or infarction -> RCA is blood supply for AV node
Mobitz I vs Mobitz II
I: progressive PR lengthening until a dropped beat occurs
II: unexpected dropped beats without a change in PR interval
I is intranodal while II is below AV node
Only tx for I is atropine while II needs pacemaker placement
EKG of third degree AV block
No relationship between P waves and QRS complexes
Si/sx of third degree AV block and tx
Syncope, dizziness, acute heart failure, hypotension, cannon A waves
Tx: pacemaker placement
cannon A waves
Third degree AV block
List of supraventricular tachyarrhythmias
Sinus tachycardia, atrial fibrillation, atrial flutter, multifocal atrial tachycardia, AVNRT, AVRT, and paroxysmal atrial tachycardia
Etiology of acute and chronic atrial fibrillation
Acute: PIRATES
-pulmonary dz, ischemia, rheumatic heart disease, anemia/atrial myxoma, thyrotoxicosis (classic step 2 question), ethanol, sepsis
Chronic: HTN, CHF
Tx of a-fib
A-fib < 48 hours can just be cardioverted
A-fib > 48 hours requires an echo or 3-6 weeks of anticoagulation
CHADS2 score
CHF HTN Age > 75 Diabetes Stroke = 2 points
2 or more points = requires warfarin
Digoxin and a-fib
Rate control > rhythm control
Digoxin is used to slow the resting heart rate and is rarely given by itself
-usually with CCB or b-blocker
DKG of a-flutter
Sawtooth pattern: multiple P waves before every QRS
Can calculate what percentage is
Multifocal atrial tachycardia
-etiology, EKG, Tx
Etiology: multiple atrial pacemakers or reentrant pathways; COPD; hypoxemia
EKG: at least 3 different P wave morphologies; each P wave from different foci
- more than 3 P waves w/ HR< 100 = wandering pacemaker
- more than 3 P waves w/ HR < 60 multifocal atrial bradycardia
Multifocal atrial tachyardia treatment
Underlying disorder
Rate control: verapamil or B-blockers
AVNRT definition
A reentrant circuit in the AV node
-you have a slow and a fast pathway in the AV node which will lead to a re-entrant circuit in the node itself
Rate: 150-200 bpm, P waves often get buried in QRS complex
Tx: cardiovert if unstable; carotid massage; valsalva, adenosine
AVRT definition
Reentrant circuit of the heart outside the AV node
most common ex: Wolff-Parkinson-White syndrome
ECG: retrograde P wave after a normal QRS
-preexcitation delta is common in WPW (upstroke just before QRS starts)
Tx: cardiovert
-note: cannot give adenosine for WPW syndrome (since it’s not a nodal problem); use amiodarone or procainamide instead
Definite therapy: catheter ablation
Paroxysmal atrial tachycardia
Rapid ectopic pacemaker in the atrium (not the SA nose)
Rate > 200 bpm; P wave with an unusual axis before each normal QRS
Never pathologica, no tx needed
List of ventricular tachyarrhythmias
PVC
ventricular tachycardia
ventricular fibrillation
TdP
PVC associations
hypoxia, electrolyte abnormalities, hyperthyroidism, caffine
V-tach definition
> 3 PVCs in a row is considered v-tach
Ventricular tachycardia associations
CAD, MI, structural heart disease; wide QRS in a regular rapid rhythm
Tx for v-tach
Can progress to v-fib if untreated
Cardiovert and antiarrhythmics, namely procainamide, lidocaine, and amiodarone
