8/5- Arrhythmias Flashcards Preview

_MS2 Cardio > 8/5- Arrhythmias > Flashcards

Flashcards in 8/5- Arrhythmias Deck (62)
Loading flashcards...

What is a normal QRS complex time/width? Long?

Normal is ~120 ms, long is anything over about 140


What are the 3 steps in diagnosing any arrhythmia?

1. Determine if the QRS complexes are narrow or wide

2. Determine if the QRS complexes or regular or irregular (distance of more than 1/2 a box between complexes)

3. Determine if P waves or evidence of atrial activity are present (relation between P wave and QRS) 


What are possible arrhythmias if QRS complexes are narrow and regular?

- Sinus tachycardia

- Atrial tachycardia

- Atrial flutter




What are possible arrhythmias if QRS complexes are narrow and irregular?


- Atrial flutter with variable conduction

- Atrial fibrillation


What are possible arrythmias if QRS complexes are wide?

- SVT with BBB

- Ventricular tachycardia


What is this? Analyze 

- HR ~ 150 bpm (tachycardia)

- Positive upright (normal) P waves in front of every QRS complex (1:1 P:QRS ratio)

- QRS is nice and slim; no conduction problem down from the atrium

- Limited analysis because there's only 1 lead, but this P wave morphology may indicated sinus wave tachycardia

Most likely: sinus tachycardia

- This is just a rate problem


What is sinus tachycardia typically a response to?

Sinus tachycardia is almost always a physiologic response


What may cause sinus tachycardia?

- Hypotension

- Hypovolemia/anemia/acute bleed

- MI/depressed EF/tamponade

- Hypoxemia

- Fever

- Anxiety/pain

- Medications

- (Hyperthyroidism)


What other types of sinus tachycardia are present (rarely)?

- Sinus node reentrant tachycardia

- Non paroxysmal sinus tachycardia

- Postural orthostatic tachycardia syndrome (POTS)


What is this? 

- P wave present before every QRS complex (this is probably ~ lead II: P waves are negative)

- P wave looks a little uncharacteristic (although only 1 lead here): ectopic P waves (anything originating from any other place than the sinus node)

Ectopic atrial tachycardia


What are some common causes of atrial tachycardia?

- Structural (atrial) heart disease/diseased atria

- Sympathetic stimulation

- Toxins/drugs


What is the heart rate range for atrial tachycardia?

120-250 bpm (typically ~ 160)


T/F: Atrial tachycardia typically causes hemodynamic compromise?

False; atrial tachycardia usually does NOT cause hemodynamic compromise


Treatments for atrial tachycardia?

- Withdraw sympathetic stimuli/drugs

- Rarely (if ever) use antiarrhythmics

- Often does not respond to cardioversion


What is this? Analyze

Atrial Tachycardia with Block (PAT with Block)

- Arrows pointing at P waves (negative here)

- No 1:1 conduction here; P waves too fast and ventricles can't respond to each one. You basically see conduction every 4th P wave

- "Block" from inability of AV node to handle atrial tachycardia rate; may be protective, but bad if it causes heart rate to drop too low


What could cause atrial tachycardia with block (PAT with block)?

Digoxin toxicity


What is a common treatment for really any type of tachycardia?

Catheter ablation


What is this? Analyze

- Continuous undulation of isoelectric line; no straightish segment between P waves

- Sawtooth line pattern of isoelectric line

Atrial flutter


What does the conduction pattern look like in atrial flutter?

Depolarization is traveling continuously in an atrial circuit; there's basically no free atrial activation that would create straight isoelectric line between P waves 


What may cause atrial flutter?

Diseased or dilated atria


What is the heart rate in atrial flutter?

Usually 300 (with 2:1 AV block)


Treatment for atrial flutter?

- Unstable: synchronized cardioversion (shock the pt)

- Slow AV conduction (Metoprolol, Verapamil or diltiazem, not digoxin acutely)

- Convert back to sinus

- Recently, anticoagulate like AF (stagnant blood in parts of the atria may cause clots... -> brain)


What is this? Analyze 

- Narrow complex tachycardia; regular

- Don't see clear P wave

Narrow complex QRS tachycardia with no regular P wave; there are 2 possibilities from here:



What is AVNRT (name)? What is the conduction pathway?

AV Nodal Re-Entrant Tachycardia (AVNRT)

- Rhythm originates in AV node

- Atria and ventricles are activated almost simultaneously, thus P and QRS occur almost the same time (P waves can't be observed) 


What causes AVNRT?

"Micro-reentrant pathway"

- Usually "paroxysmal", often triggered by PAC

- Rarely correlated with any heart disease; occurs in structurally normal hearts (?)


Treatment for AVNRT?

- Unstable: cardiovert

- Block AV conduction:

---Vagal-enhancing maneuvers

---Adenosine (6 mg,12,12): almost always works

---Verapamil or Diltiazem

---Beta blockers

- Ablation


What is this? Analyze

- Cousin to AVNRT, but this AVRT

- There is a P wave (outside the QRS; commonly not seen)


What is AVRT? What is the conduction pathway?

AV Re-entrant Tachycardia (AVRT)

- Both atria and ventricle are equal participants in tachycardia

- Conduction happens in reverse from ventricle to atrium; don'c contract simultaneously (ventricles first)

- May see retrograde P wave distorting ST segment

- This is orthodromic (anti-dromic could have reversed conduction path and weird ventricle pattern) 


What causes AVRT?

"macro reentrant loop" involving bypass tract

- Usually "paroxysmal"


Orthodromic conduction (shown earlier) occurs in ___% of cases while antidromic (may resemble VT) occurs in ___%

Orthodromic: 90-95%

Antidromic: 5%