Arrhythmias Flashcards
Normal sinus rate and normal PR interval
sinus rate= 60-100bpm. PR= 0.12-0.20
Requirements of normal sinus rhythm
P wave preceeds each QRS, with normal PR interval, rate is 60-100bpm, QRS is regular or varies slightly
Sinus tachycardia EKG and response to carotid sinus massage
normal P and QRS, regular and fast HR (100-180BPM). Atrial rate may slow in response to massage
Causes of sinus tachycardia
Exercise, emotion, hypotension, acute lung or abdominal pathology, thyrotoxicosis
Sinus tachycardia treatment
usually none. B blockers in thyrotoxicosis
Sinus Bradycardia EKG
Regular, slow HR (<60BPM). P waves precede QRS
Causes of sinus bradycardia
Can be normal (ie. In athletes). Can produce vagotonic states (fainting, sick sinus syndrome, inferior infarct)
Treatment of sinus bradycardia
None, Atropine for vasovagal events, or pacemaker if serious
Sick sinus syndrome
syncope, lightheadedness or fatique in elderly patients with age-related dysfunction
1st degree AV block EKG
PR interval prolonged (>0.2 seconds), increased junctional delay
Causes of 1st degree AV block
Drugs (B blockers, Ca blockers, digitalis) or conduction system disease. Usually benign
2nd degree AV block EKG
Some P waves conduct, others do not
2nd degree AV block causes
Conduction system disease, high vagal tone, drugs
3rd degree AV block EKG
P waves and QRS show regular rhythm, but at different rates, with P rate> QRS rate
3rd degree AV block causes
Severe conduction system disease, drugs
3rd degree AV block treatment
pacemaker
3rd degree AV block complications
syncope or death
Atrial flutter EKG and response to carotid massage
P waves (flutter waves)are saw toothed and at rate of 180-350BPM. Pulse maay be regular or irregular. Varied ventricular rates. AV block may increase with massage
complications of atrial flutter
embolic stroke due to clot in left atrium, rapid ventricular rates
Atrial flutter treatment
Anticoag, rate control with drugs, cardioversion, ablation
Atrial fibrillation EKG
Irregularly irregular ventricular rhythm, No P waves
Atrial fibrillation causes
lone A fib, aging, post-operative, heart disease, hyperthyroidism
Complications of a fib
rapid HR (syncope, ischemia, heart failure), loss of atrial kick (HF), atrial thrombi (embolic stroke)
A fib treatment
Anticoag, rate control with drugs, cardioversion, ablation
Atrial tachycardia EKG and response to carotid sinus massage
rapid HR (atrial rate is 130-250BPM), narrow QRS, P waves present but abnormal. AV block may increase, doesn’t usually revert in response to masssage
A tach treatment
Adenosine infusion, beta blocker, verapamil, diltiazem, ablation
focal vs multifocal A tach
focal: one different P wave. Multifocal: >3 P wave shapes
Junctional rhythm EKG
regular rate, narrow QRS, no antecedant P waves (P waves are usually inverted b/c they are conducted upward from the AV node rather than down fron SA node)
What is a junctional rhythm
rhythms originating in the region surrounding the AV node
Premature atrial contraction EKG
premature beat preceded by abnormal P wave, narrow QRS
premature ventricular contraction EKG
wide, abnormal QRS with no P wave
What is the cause of premature ventricular contraction?
ectopic ventricular focus conducted by the slower fibers of myocardium instead of Purkinje. Short path length blocks can also cause re-entry. Usually benign
Ventricular tachycardia EKG
repetitive wide QRS with no P wave
What causes V tach
ectopic ventricular focus conducted by myocytes, or long path length which permits re-entry (from fibrosis, infiltrate)
Ventricular fibrillation
no visible P waves
Torsades de pointes EKG
wide QRS at very rapid rate, no P wave, sinusoidal pattern
Torsades de pointes is a form of what?
ventricular tachycardia (associated with long QT)
