Managing tachycardia – effective 2021 update

As part of your ACLS training, you’ll be asked to manage Tachycardia in skill stations. Let’s learn about tachycardia.

What is tachycardia?

When the heart rate goes over 100 beats per minute, we can label it as tachycardia.
Tachyarrythmias have a rate of over 150 beats per minute usually.
Tachycardia can be a supraventricular or ventricular.
Regardless of the types, the management is similar. Firs step is identifying if the tachycardia patient is stable or unstable.

Tachycardia evaluation (ABC)

• Airway – Check the patency
• Breathing – Assist as necessary and apply Oxygen if hypoxemic
• Circulation – Attach a cardiac monitor to identify rhythm;
  Check blood pressure
  Get IV access and give fluids if needed
  Get a 12-Lead ECG (if available) If ECG is not available, proceed with therapy
• Consider probable causes such as anxiety, fever, hypotension, pain and intoxication.

Stable Vs Unstable tachycardia

Use the following signs to differentiate stable or unstable (Similar signs are used in tachycardia as well to differentiate stable and unstable bradycardia.)
If the patient does not have any of the 5 signs listed below, it is a case of Stable tachycardia.
If the patient happens to have even one of the 5 listed signs, label it as Unstable tachycardia.

Stable tachycardia – Medical therapy

For stable tachyarrythmias, we can choose to give medical therapy.
First we need to see if it’s a narrow complex ( less than 3 small boxes / 0.12 seconds) or broad complex ( more than 3 small boxes / 0.12 seconds) rhythm on ECG.

Narrow complex

Narrow–QRS-complex tachycardias (QRS <0.12 second), in order of frequency ( Even if you cannot identify the exact name of the rhythm, you should be able to identify whether it’s narrow or wide – regular or irregular, which will help you treat the patient).
– Sinus tachycardia
– Atrial fibrillation
– Atrial flutter
– AV nodal reentry
– Accessory pathway–mediated tachycardia
– Atrial tachycardia (including automatic and reentry forms)
– Multifocal atrial tachycardia (MAT)
– Junctional tachycardia (rare in adults)
– Wide–QRS-complex tachycardias (QRS ≥0.12 second)
– Ventricular tachycardia (VT) and ventricular fibrillation (VF)
– SVT with aberrancy
– Pre-excited tachycardias (Wolff-Parkinson-White [WPW] syndrome)
– Ventricular paced rhythms

Management

1. Attempt Vagal maneuvers ( Valsalva maneuver or carotid sinus massage ), which can help in 25% of cases.
2. In case the rhythm persists and it is narrow regular, you may choose Adenosine 6mg RAPID IV PUSH followed by flush. We can escalate the dose to 12mg and another 12mg if 6mg doesn’t help. (More details on how to deliver in pharmacology module)
3. If adenosine fails, or discloses a different form of SVT (such as atrial fibrillation or flutter), it is reasonable to use longer-acting AV nodal blocking agents, such as the nondihydropyridine calcium channel blockers (verapamil and diltiazem) or β-blockers (metoprolol, atenolol, propranolol, esmolol, and labetolol). (Dosing details in pharmocology module)
4. Involve an expert.

Wide complex

Wide QRS complex stable tachycardias (QRS >0.12 second)
The most common forms of wide-complex tachycardia are:
VT or VF
SVT with aberrancy
Pre-excited tachycardias (associated with or mediated by an accessory pathway)
Ventricular paced rhythms

If you see VT on monitor, first check PULSE. (VT with pulse and without pulse are managed differently

Don’t miss the shockable rhythm.

Management

Adenosine can be considered if regular and monomorphic.
Start an anti-arhythmic infusion and speak to an expert.
Choices of anti-arrhythmics:

• Procainamide : 20-50mg/min until resolution of arrhythmia or hypotension occurs or QRS prolongs >50%, or Max doe of 17mg/kg is given. Infusion dose : 1-5mg/min
  Avoid in QT prolongation or CHF (Heart failure)
• Amiodarone : 150mg over 10min, repeat if VT recurs. Continue infusion dose of 1mg/min for 6hrs then 0.5mg/min for 18hrs
• Sotalol: 100mg (1.5mg/kg) over 5min. Avoided in patients with prolonged QT.

If one of these antiarrhythmic agents is given, a second agent should not be given without expert consultation. 
If antiarrhythmic therapy is unsuccessful, cardioversion or expert consultation should be considered. Look for underlying cause.

Unstable tachycardia – Synchronized cardioversion

As detailed in the beginning, if it turns out to be an unstable tachyarrhythmia, immediate synchronized cardioversion is recommended.
Before the procedure, consider explaining to the patient and obtaining consent if time permits.
Apart from consent, to prevent discomfort to the patient, consider sedating.
Now, choose the right energy on the defibrillator and press the SYNC button.

Energy requirements (device specific):
Narrow – regular rhythms – 50-100J (start at 50, escalate as needed)
Narrow – irregular – 120-200J
Wide – regular – 100J (escalate to 150 or 200 if needed)
Wide – irregular – 200J (or maximum energy available on machine without SYNC mode)

Charge the machine and announce CLEAR (loudly) before pressing the SHOCK button.

For any shock, this is mandatory.

After delivering a shock, you should immediately check the monitor for a change in rhythm and check patient’s pulse.