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Tachycardia Algorithm

Tachycardia, also known as, tachyarrhythmia is defined as a heart rate greater than 100 bpm.  Tachycardias may be stable or unstable.  An unstable tachycardia results when the heart is beating so fast that the cardiac output is reduced and this causes serious signs and symptoms such as:  chest pain, SOB, signs of shock, change in LOC, weakness or severe fatigue, syncope, or hypotension.

The healthcare provider must first determine if the signs and symptoms are being caused by the tachycardia or if the tachycardia is being caused by an underlying condition.  For instance, a fever can cause tachycardia that may cause serious symptoms.  The treatment, however, is not to treat the tachycardia but to treat the fever which will result in the tachycardia resolving itself.  While providing patient support such as oxygen for hypoxia and SOB, it is always important to identify and treat reversible causes of tachycardias.  The most common reversible causes of tachycardias are:  sepsis, fever, dehydration, and hypoxia.  Administration of oxygen and IV infusion of normal saline are the two most common initial therapies for tachycardia.  If the serious signs and symptoms persist after treating the reversible underlying causes the Tachycardia Algorithm should be started.

There are several arrhythmias that may be associated with tachycardia.  These include:

• Supraventricular Tachycardia (SVT)
• Atrial Flutter
• Atrial Fibrillation
• Wide Complex Tachycardia both Monomorphic Ventricular Tachycardia (VT) and Polymorphic Ventricular Tachycardia (VT)

Note:  Both monomorphic VT and polymorphic VT may or may not be perfusing.  If they are not perfusing go to the Cardiac Arrest Algorithm.  The Tachycardia Algorithm is only for perfusing rhythms.  You can click on the links above to read more about each type of tachycardia.   Click on this link to see the flow chart for Adult Tachycardia With a Pulse Flow Chart.

The first question a healthcare provider always needs to ask is, “Is the patient stable or unstable?”  This determine which pathway on the Adult Tachycardia with a Pulse Flow Chart to use.

Stable Tachycardia

Stable narrow-complex tachycardia (SVT) is treated with:

1. Vagal maneuvers
2. Calcium Channel Blockers (or beta blockers but watch the Blood Pressure)
3. Adenosine
4. Expert Consultation

Stable wide-complex tachycardia is treated with:

1. Adenosine
2. Antiarrhythmic Infusion (amiodarone, magnesium, or lidocaine)
3. Expert Consultation

Beta blockers, calcium channel blockers, and AV nodal blocking agents may cause severe bradycardia in patients with irregular tachycardias and should be used only with great caution.

Unstable Tachycardia

If the patient is unstable they should be treated immediately with Synchronized Cardioversion or Defibrillation based on whether the perfusing tachycardia is regular or irregular.  Unstable, irregular, wide-complex tachycardias are defibrillated at the manufacturer’s recommended dose for the defibrillator being used.  Unstable, regular wide-complex tachycardias are synchronized cardioverted at 100 Joules.  Unstable, narrow-comlex regular tachycardias are synchronized cardioverted at 50-100 Joules.  Unstable, narrow-complex irregular tachycardias are synchronized cardioverted at 120-200 Joules.