Tough Dysrhythmias (Amal Mattu, MD)

These are notes highlighting important points made whilst I was watching The Centre for Medicla. Education videos on Tough Dysrhythmias by Amal Mattu, MD, the legend.

Starting from sinus rhythm which is defined as:

• Upright P waves in I, II, III, aVF
• inverted in aVR.

V1 is the money lead in which to view the P waves as it sits directly over the R atrium.

Bradycardias

HR 40-60 = Junctional Bradycardia. Narrow. No p-waves as they are usually buried in the QRS.

HR 20-60 = Ventricular Escape Rhythm / Idioventricular Escape Rhythm. Wide.

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AV Blocks

1st Degree

PR interval longer than 0.20. No treatment as it’s a normal part of aging. Can be seen in things like HyperK+, but you don’t treat the rhythm (1st degree) you treat the cause (tooooo much potassium).

2nd Degree Type I

aka Mobitz I aka Wenckebach. P’s on the run, Mobitz Type 1.

2nd Degree Type II

P’s stay true, Mobitz Type II. If you have 3p’s for every 2 QRS’s this is 3:2 bloc. If you have 2:1 you may not know if it’s even type 1 or 2 as there’s no 2nd pr for comparison with he first.

3rd Degree

Random PR interval. Lots of P’s.

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Tachycardias

We need to know three things:

• Wide or Narrow?
• Regular or Irregular?
• Is there Atrial Activity (aka p or flutter waves?)

Narrow & Regular

Sinus Tachycardia: Most common. Never shock it. There’s a P for every QRS. The P is sometimes half-buried in the T wave appearing like a ‘camel-hump’.

Up to 220HR minus age. So a baby can be 2 and have a heart rate of up to 218 and still be called sinus tachycardia.

Supraventricular Tachycardia

Not ‘superventricular’. P’s are normally buried or follow the QRS aka a retrograde P wave, one that pops out after the QRS.

Atrial Flutter (2:1)

Normally 2 P waves for every QRS. Solid regular conduction.

Narrow & Irregular

Atrial Fibrillation

The old classic. Differing R-wave heights. Super fast is offically called Atrial Fibrillation wih Rapid Ventricular Rate (AF+RVR)

Atrial Flutter with Variable Conduction

Instead of regular like above, it conducts in various ratios: 2:1, 3:1, 2:1, 5:1, 4:1, 5:1, 2:1….

Multifocal Atrial Tachycardia (MAT)

These have more than three morphologies of P wave (inverted, biphasic, flat, tall). Never shock this badboy. Normally associated with pulmonary diseases like COPD, asthma, peumonia).

Wide and Irregular

Sinus Tachycardia with Abberent Conduction

This is tachycardia with a bundle branch block (BBB), normally P-wave present and wide QRS.

Ventricular Fibrillation

• P-waves hidden / occasionally seen
• AA/V disassociation
• Must be >120/130. If not, maybe a mimic:
  • HyperK+
  • Tricyclic Acid OD
  • Accerlated Idioventricular Rhythm

Supraventricular Tachycardia with Bundle Branch Block

P waves are often hidden

Atrial Fibrillation with Bundle Branch Block

Ths is rare to see >200HR. Also have identical QRS.

Atrial Fibrillation and Wolff-Parkinson White

Rate is normally around 300HR. QRS would vary morphology. Appears regular at very rapid rates.

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Other Tachycardias

Polymorphic VT

• Regular
• Rapid
• Distinction between Poly VT and TdeP n ot made by looking at QRS complexes during arrhythmia.
• Shock it!
• Polymorphic VT
  • No prolonged QT prior
  • Caused by Acute Cardiac Ischaemia
  • Treated with Amioderone / Procainamide
• Torsades de Pointe
  • Prolonged QT prior
  • Caused by Drugs or Hypoelectrolytes
  • Treated With Magnesium, Amioderone, Procainamide

Accelerated Idioventricular Escape Rhythm (AIVR)

HR 40-120, normally a reperfusion arrhythmia that looks like VT and lasts 5-10 seconds. Seen lots in cath labs when restoring blood flow to vessels.

4 Cardinal Sins of Instability

Hypotension
Confusion
Ischaemic Chest Pain
Acute Heart Failure