What is the Megacode?

In this lesson, we'll provide you with a brief overview of the megacode. And at the end of the lesson, we'll provide you with an additional Word on the approach to unstable tachycardias, that you learned about in the last two lessons.

Back in the day, megacodes were known to cause mega stress, and were widely considered one of the most fearful things that healthcare providers could imagine doing as it relates to their ACLS certification course.

Why, you might ask? Because megacodes are so dynamic, much like a difficult word problem or riddle that you've been tasked with solving. And since not everyone loves word problems or riddles, think of megacodes like you would a puzzle, if that helps.

Unlike an IRS audit or a colonoscopy, we're going to try to make megacodes as enjoyable as possible, and as simple as possible. And by the time you've completed and mastered your ACLS training at ProACLS, you'll feel confident that you'll be able to make a difference in your community, as in saving lives.

Megacode testing scenarios combine knowledge and protocols of multiple ACLS algorithms. These can include any of the following:

• Acute coronary syndrome
• Acute stroke
• Cardiac arrest
• Pulseless VFib or V-tach
• Asystole
• Pulseless electrical activity (PEA)
• Bradycardia
• Tachycardia, whether stable or unstable

To be a successful ACLS provider, you need to know about:

• Appropriate therapies
• Appropriate drugs
• Drug doses used in each ACLS algorithm
• When to use which drug based on the situation and patient

And you need to know how to identify and interpret basic arrest and pre-arrest cardiac rhythms so you can know their proper treatments as well, related to the ECG.

By gaining and building upon this knowledge base, you'll be able to increase the rate of survival for those people you help, which may mean returning loved ones back to family and friends once again.

A Word About the Approach to Unstable Tachycardia

A tachyarrhythmia, as in a rhythm with a heart rate greater than 100 beats per minute, has many potential causes and can be either symptomatic or asymptomatic. The key to managing a patient with any tachycardia is to determine whether pulses are present.

If pulses are present, you should first determine whether the patient is stable or unstable and then provide treatment based on the patient's condition and their rhythm.

If the tachyarrhythmia is sinus tachycardia, you should conduct a diligent search for the cause of the tachycardia. Treatment and correction of this cause will usually improve the signs and symptoms.

Unstable tachycardia exists when the heart rate is too fast for the patient's clinical condition and the excessive heart rate causes symptoms or an unstable condition because the heart is:

• Beating so fast that cardiac output is reduced; this can cause pulmonary edema, coronary ischemia, and hypotension with reduced blood flow to vital organs, such as the brain or the kidneys.
• Beating ineffectively so that coordination between the atrium and ventricles, or the ventricles themselves, reduces cardiac output.

Signs and Symptoms

Unstable tachycardia leads to serious signs and symptoms that include the following:

• Hypotension
• Acutely altered mental status
• Signs of shock
• Ischemic chest discomfort
• AHF

Rapid Recognition

The two keys to managing patients with unstable tachycardia are:

1. Rapid recognition that the patient is significantly symptomatic or even unstable.
2. Rapid recognition that the signs and symptoms are caused by the tachycardia.

The first step is to quickly determine whether the patient's tachycardia is producing hemodynamic instability and serious signs and symptoms or whether the signs and symptoms are producing the tachycardia.

Making this determination can be difficult. Many experts suggest that when a heart rate is less than 150 beats per minute, it's unlikely that the symptoms of instability are caused primarily by the tachycardia unless there is impaired ventricular function. While a heart rate greater than 150 beats per minute is usually an inappropriate response to physiologic stress, such as fever and dehydration, or other underlying conditions.

Indications for Cardioversion

Rapid identification of symptomatic tachycardia will help you determine whether you should prepare for immediate cardioversion. For example:

• Sinus tachycardia is a physiologic response to extrinsic factors, such as fever, anemia, or hypotension/shock, which create the need for a compensatory and physiological increase in heart rate. There is usually a high degree of sympathetic tone and neurohormonal factors in these settings. Sinus tachycardia will not respond to cardioversion. In fact, if a shock is delivered, the heart rate often increases.
• If the patient with tachycardia is stable, patients may await expert consultation because treatment has the potential for harm.
• Atrial flutter typically produces a heart rate of approximately 150 beats per minute. Atrial flutter at this rate is often stable in the patient without heart or serious systemic disease.
• At rates greater than 150 beats per minute, symptoms are often present, and cardioversion is often required if the patient is unstable.
• If the patient is seriously ill or has underlying cardiovascular disease, symptoms may be present at lower rates.

It's important to know when cardioversion is indicated, how to prepare the patient for it, and how to switch the defibrillator/monitor to operate as a cardioverter.