EKG lecture 4 pt 1 highlights Flashcards
through slide 53
What are the 4 questions you need to answer to figure out rhythm?
Are normal P waves present?
Are QRS complexes narrow or wide?
What is the Relationship of P waves & QRS complexes?
Is the rhythm regular or irregular?
What are the 5 types of arrythmias?
1) Sinus arrhythmias
2) Ectopic rhythms
3) Re-entrant rhythms
4) Conduction blocks
5) Preexcitation syndromes
Define:
1) Sinus arrhythmias
2) Ectopic rhythms
1) Sinus origin, follow normal conduction pathways (narrow QRS)
-Brady, Tachy, Irregular, sinus exit block or arrest, junctional escape rhythm
2) Electrical origin other than SA node
Define:
1) Re-entrant rhythms
2) Conduction blocks
1) Electrical activity trapped within an electrical racetrack or circuit
2) Sinus origin. but electrical impulse encounters delay or block between atria and ventricles
Define preexcitation syndromes
Electrical activity follows an anomalous accessory pathway that bypasses the normal conduction system (short circuit)
Name one important differential for sinus bradycardia
Myocardial ischemia
True or false: SA node depolarization does not show up on ECG
True
Name 2 situations where there’s no P-wave or any electrical activity (unless an escape beat emerges….atrial, junctional, ventricular).
1) Sinus arrest
2) Sinus exit block
What is the most common ectopic pacemaker?
Junctional pacemakers (at or near AV node) ~ 40-60/minute
Ectopic rhythms are essentially disorder of ___________ formation
impulse
Reentry rhythms are a disorder of __________ transmission
impulse
Explain the 4 questions to assess any rhythm d/o
1) Are NORMAL P-waves present? i.e. normal shaped P waves and normal P wave axis (0-70 degrees therefore + in lead II, - in lead aVR.)
2) Are QRS complexes narrow (< 0.12 sec or 3 small boxes) or wide (>0.12 sec)?
3) What is the relationship between the P waves and the QRS complexes?
4) Is the rhythm regular or irregular (look at rhythm strip)?
“Are NORMAL P-waves present?”
What are the 3 potential answers to this question?
1) YES … present and normal axis
2) YES … present, abnormal axis or appearance
3) NO … no P waves present
What does a narrow QRS complex imply?
Ventricular depolarization is proceeding along usual pathway and the origin to be above the ventricles – at the AV node or atria … spreads quickly via the electrical conduction system
What does a wide QRS complex usually imply?
Depolarization origin from within the ventricle myocardium and not traveling through the conduction system … spreads more slowly
Which 2 questions can help determine the important distinction as to whether an arrhythmia is supraventricular (atrial or junctional) or ventricular in origin?
1) Are NORMAL P-waves present?
2) Are QRS complexes narrow (< 0.12 sec or 3 small boxes) or wide (>0.12 sec)?
Usually, P waves and QRS complexes are associated 1:1; explain what this means
1) Each P wave is followed by a QRS
2) Each QRS is preceded by a P wave
= sinus or other atrial origin
True or false: Atrial & junctional Premature beats May initiate more sustained arrhythmias
True
AV Nodal Reentrant Tach (AVNRT): Describe the onset and termination. What usually initiates it?
1) Sudden onset - usually initiated by premature supraventricular beat (atrial or jct)
2) Abrupt termination
AVNRT:
1) Is the rhythm normal?
2) Most often driven by reentrant circuit within ___________ (carotid massage may terminate rhythm).
3) May see retrograde P waves in lead II or III and __________________, most buried in QRS complex
1) Yes
2) AV node
3) V1 pseudo-R’
AVNRT terminated by carotid massage since originates in _______________
AV node
Atrial flutter:
1) Is the rhythm normal?
2) ______________ increases AV nodal block (slows ventricular rate)
1) Regular rhythm
2) Carotid massage
AFIB:
1) What do the P waves look like?
2) AV node only allows periodic impulses thru generating __________________ Rhythm usually between _________/min (rapid ventricular response)
1) No true P waves
2) Irregularly Irregular; 120-180
