Arrhythmias Flashcards
What is step 1 in identifying arrhythmias? Next?
Cherchez la P wave! Then find out who she has been hanging out with (hopefully her QRS) = sinus rhythm
Sinus tachycardia
Signs?
Tx?
Is a regular, fast HR (>100)
P waves precede each QRS
Arises due to sympathetic activation
Treatment: Usually none, B-blockers in thyrotoxicosis
Sinus Bradycardia
Signs?
Tx?
Regular, slow HR (<60) P waves precede each QRS Common in athletes Vagotonic states: situations where parasympathetic NS is turned on (faint, sick sinus syndrome, inferior infarct) Treatment: none, atropine, pacemaker
1st degree A-V block
Signs?
Tx?
PR interval prolonged - increased junctional delay
Caused by: drugs (beta blockers, digitalis)
“A P wave before every QRS and a QRS after every P wave”
2nd degree AV block
Some P waves conduct but some do not
What’s Mobitz I or Wenckebach
Sequence upon which PR interval gradually lengthens, followed by a nonconducting P wave. This is a 2nd degree AV block
Complete heart block
Signs?
Tx?
no relationship to slower ventricular rate. P waves faster than QRS rate
Tx: pacing if ventricular rate or BP too low
What do ectopic beats look like?
Sometimes an early beat that looks like the others (sometimes can see P wave, sometimes can’t)
Premature ventricular contractions
Signs?
Tx?
Wide QRS, no P wave
Common in normal subjects, acute myocardial infarct, HF
Tx: Usually none required, B-blockers
*note: junctional/nodal rhythm has narrow QRS with no p waves
Atrial flutter
signs?
tx?
Re-entry in atrium P wave rate 240-320/min Causes a classical "sawtooth" pattern Tx: Anticoagulation, Rate control with drugs, Cardioversion, Ablation - same tx as afib
Atrial tachycardia
Signs?
Tx?
Rapid HR > 150 bpm
Narrow QRS complexes
P waves present but abnormal
Tx: adenosine, vagal maneuver, B-blocker, verapamil or dilatiazem
Atrial fibrillation
Signs?
Tx?
No P waves at all, but irregular QRS waves @ 350 bpm “squiggles”
“Irregularly irregular”
Problems: Rapid HR - ischemia, HF; Loss of atrial kick - HF; Atrial thrombi - embolic stroke
Tx: “5 Cs” Anticoagulation, rate control with drugs, cardioversion, ablation
Junctional rhythm
Signs?
Tx?
Regular, narrow QRS, no antecedent P waves (sometimes can see negative P wave after QRS)
Tx: usually unnecessary
Ventricular fibrillation
No consistent P or QRS complexes or coordinated contraction
Atropine
muscarinic M2 antagonist
increases heart rate
bc m2 activates Gi
