2 min read - Tachyarrhythmias

A 32 years old previously healthy male patient admitted with a history of palpitations for 1 hour duration. He had experienced a similar episode a few months back which lasted only for few minutes.

What are your concerns?
  • First priority is to make sure that the patient is stable.
  • Who is unstable?
    • Hypotensive patient (Systolic BP < 90mmHg)
    • Coronary ischemia (Ischemic chest pain)
    • Cardiac failure (Patient has SOB)
    • Patient with brain hypoperfusion (reduced conscious level)
IF ANY OF ABOVE ARE PRESENT IRRESPECTIVE OF THE TYPE OF ARRHYTHMIA YOU WILL HAVE TO PERFORM DC CARDIOVERSION (SHOCK)

ECG
  • Analysing tachyarrhythmias is a long topic, which might bore you.
  • Let's learn a few short cuts to diagnose common arrhythmias.
  • Look at the QRS
    • Is it narrow or broad?
    • Narrow complex tachycardias we usually encounter are
      • SVT (Read and understand the proper nomenclature. SVT is a wrong term!)
      • Atrial fibrillation/ flutter
        • In most patients both are managed the same way.
    • READ ABOUT THE OTHER NARROW COMPLEX TACHYCARDIAS.
    • Broad complex tachycardias UNLESS PROVEN OTHERWISE ARE VENTRICULAR TACHYCARDIAS
    • However some 'supra' ventricular tachycardias can mimic ventricular tachycardias
      • Eg: SVT with a bundle branch block.
  • Is it regular or irregular
    • Regular narrow complex tachycardia = SVT
    • Irregular narrow complex tachycardia = Atrial Fibrillation/ flutter
    • Regular broad complex tachycardia = VT
    • Irregular broad complex tachycardia = Ventricular Fibrillation
    • However, as you start to learn more and more about ECGs you will realize that this is oversimplified and there are so many other arrhythmias in each category.
    • REMEMBER, THIS IS ONLY A SURVIVAL GUIDE!
Diagnosis??

Diagnosis??
Diagnosis??

Diagnosis??

Now you've made a diagnosis what have you got to do?
  • I repeat, irrespective of the type of arrhythmia if the patient is unstable - SHOCK 
  • If the patient is stable
    • SVT
      • Perform vagal manouvers
      • Medications
        • Drug of choice is adenosine
        • Contraindication is ASTHMA
        • Give IV 6mg bolus (FAST) followed by a 10-20ml saline flush.
          • patient will respond in a few seconds
        • If it fails, you may try about two boluses of 12mg.
      • However in the case of a SVT, even if the patient is unstable you may try adenosine as it's response is very very fast!
See the response to adenosine!

    • ATRIAL FIBRILLATION
      • This is kind of complicated!
      • We shall discuss it on a separate day.
    • VENTRICULAR TACHYCARDIA
      • Most patients will require SHOCK
      • If the patient is stable you may try medications
        • Amiadarone
          • 150mg over 10 minutes
          • Followed by 1mg/min infusion
        • Lidocaine
          • 1-1.5mg/kg bolus
          • you may repeat up to a total cumulative dose of 3mg/kg every 5-10 minutes
    • VENTRICULAR FIBRILLATION
      • Homework
        • What medications can you give for a patient who is hemodynamically stable with a VF??
Few facts about SHOCK
  • Don't EVER shock yourself or your colleagues while attempting to shock the patient!
  • Sedate the patient!
    • Widely used medication is midazolam given as a bolus of 1-2.5mg
  • Most of the defibrillators available are Biphasic
  • Press the SYNC button for
    • SVT
    • VT
    • AF
    • NEVER FOR VF
  • Energy level
    • SVT 50-100 
    • AF 120-200
    • VT 100
    • VF - well, I guess you know what to give.
Vagal manouvers
  • Avoid carotid massage in older patients
    • You might give them a stroke!
  • Modified valsalva manouver 
    • Read and check on youtube!
  • Diving reflex
What if there is no response?
  • Consider following 
  • Metabolic causes such as
    • Electrolyte abnormalities
    • Thyrotoxicosis
    • Acidosis
    • Hypo/Hyperglycemia
  • Hypo/hyperthermia
  • Toxins
  • MI/ Pulmonary embolism
Isn't it too much for a day? Let's take a break.

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