Lecture 6: Cardiac Rhythm Disturbances (Atrial, Junctional, Ventricular) Flashcards
What is your interpretation?
Sinus Arrhythmia
What is Sinus Arrythmia due to?
Normal, but minimal, increase in HR during inspiration and decrease in HR during exhalation
Bile salt accumulation in obstructive jaundice can have an affect on the SA node and lead to what type of HR?
Bradycardia
What is the effect of hyperkalemia on HR?
Bradycardia
List some drugs that can cause bradycardia?
- Quinidine
- Digitalis
- HTN drugs –> clonidine, methyldop, and reserpine
- Beta-blockers —> propranolol and metoprolol
Sinus bradycardia is a common finding with what type of MI?
Acute inferior MI (increased vagal tone, N/V)
Sick sinus syndrome has what effect on HR?
Bradycardia
Which HR is considered bradycardia?
HR < 60/min
What are characteristic ECG findings of someone with Sick Sinus Syndrome?
- Periods of inappropriate, and often, severe bradycardia
- Sinus pauses, arrest, and sinoatrial (SA) exit block with, and often without, appropriate atrial and junctional escape rhythms
- Alternating bradycardia and atrial tachyarrhythmias
For each of these parameters, pO2, pCO2, pH, and BP, use (↑↓) to describe which is associated with bradycardia
- ↓pO2
- ↑pCO2
- ↓pH
- ↑BP
What is the most common cause of unexplained pause on an EKG tracing?
Nonconducted PAC
What is the tx of choice for pt with sinus bradycardia, if HR <45-50 with hemodynamic compromise/unstable acute situations?
Use caution in which pt’s?
- Atropine
- Use caution in glaucoma –> can ↑ IOP
If atropine is given to someone with hemodynamically unstable sinus bradycardia and fails to work, what are the next 3 options for tx?
- Epinephrine
- Isoproterenol
- Pacemaker
Define automaticity in regards to cardiac cells
Property of cardiac cells to depolarize spontaneously during phase 4 of AP/leads to generation of an impulse
What characteristics are used to determine if a PAB is present and to help differentiate it from something more serious?
- Appears early in the cycle
- Morphologically distinct from the previous P waves
What is the characteristic finding on an EKG of a PAB with aberrant ventricular conduction?
Wide QRS following PAB
What is this known as?
Atrial Bigeminy
Interpret the tracing in A and B
- A) 1st degree AV block w/ non-conducted PAC
- B) 1st degree AV block w/ non-conducted PAC occurring in trigeminal rhythm
Interpret this EKG
Non-conducted PAC in Bigeminal rhythm
What is the tx for PAC’s if symptomatic?
- Reverse causes (i.e., coffee, alcohol, other contributors)
- Beta-blocker —> Metoprolol
Paroxysmal atrial tachycardia has a sudden onset and what is the HR?
Rate = 150-250/min
What are the criteria for paroxysmal atrial tachycardia with AV block?
What should you suspect as underlying cause?
- Greater than one P’ wave per QRS complex; 2 P’ waves for each QRS
- Rapid rate with spike P’ waves
- Suspect digitalis toxicitiy
Interpret this EKG
Atrial Tachycardia with 2:1 AV block
Interpret this EKG
Atrial Tachycardia w/ 2:1 AV block
What are the criteria for Multifocal Atrial Tachycardia (i.e., morphology, rate/rhythm, intervals)?
- 3 or more DIFFERENT P waves
- P-R interval varies
- Irregular ventricular rhythm
- Atrial rate >100
List 5 etiologies for Multifocal Atrial Tachycardia?
- Lung disease (COPD, pneumonia, ventilator theophylline)
- Beta agonists
- Electrolyte abnormalities (↓K+ and ↓Mg)
- Digitialis toxicitiy
- Sepsis
Which EKG abnormality will almost exclusively been seen in COPD patients on ventilator theophylline?
Multifocal Atrial Tachycardia
Interpret this EKG
Multifocal Atrial Tachycardia
Interpret this EKG
Multifocal Atrial Tachycardia
Interpret this pt’s EKG
Multifocal Atrial Tachycardia
What are the Tx options for Multifocal Atrial Tachycardia?
- CCB –> nondihydropyridine = Dilitiazem or Verapamil via IV
- MgSO4 via IV then Amiodarone/Adenosine
What is the atrial rate in Atrial Fibrillation and what are the other characteristics on the EKG (baseline, rhythm, and intervals)?
- Atrial rate >350-600/min
- Undulating baseline w/ no discernible P waves
- Irregular RR interval; “irregularly irregular” ventricular rhythm
Interpret this EKG
Atrial Fibrillation w/ Complete AV block
Interpret this EKG
Atrial Fibrillation
What is the diagnosis based on this EKG?
Atrial Fibrillation w/ controlled ventricular response
What is the characteristic appearance of Atrial Flutter and in which leads is it seen best?
- “Saw tooth appearance”
- Leads II, III, and aVF
Interpret this EKG
Atrial Flutter
Interpret this EKG
- Acute Pericarditis w/ Atrial Flutter
- Pericardiits will show diffuse ST elevations in multiple leads
- Atrial flutter is best seen in leads II, III, and aVF
Interpret this EKG
Atrial Flutter w/ 2:1 AV block
Interpret this EKG
- Atrial flutter with 2:1 AV block
- Notice every other p wave is NOT followed by a QRS
If you see a premature QRS complex that is slightly widened you should consider that it may be due to what?
Premature Junctional (or atrial) beat with aberrant ventricular conduction