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Now let’s take a closer look at asystole. Asystole is a term that means no ventricular activity. In most cases this is a lethal arrhythmia which has no electrical or mechanical activity. But let’s take a closer look at the EKG. Is the rhythm regular or irregular? There is no rhythm. So what is the rate? Well there is no rate and no other rate findings apply. Next we evaluate the P-wave: Are they present? In some cases, a small P-wave can sometimes be seen but is not followed by any other wave forms. This can mean that in rare cases the atrial pacemaker may be trying to send an impulse but has no ventricular reaction. No other P-wave findings will apply. Regarding the PR interval, there is no P-wave, therefore there isn’t a PR interval. Is the QRS interval less than 0.12 seconds? There are no QRS complexes and therefore no other QRS questions apply. So what is our cardiac interpretation? Because there is no myocardial electrical or mechanical activity, there is no pulse and no circulation of blood. This is most commonly seen after a time of untreated or unconverted ventricular fibrillation. Though asystole is most commonly seen after extended untreated and sudden cardiac arrest, it can also be caused by hypothermia, hyper or hypokalemia, hypoxia, hydrogen ions which mean acidosis, toxins, cardiac tamponade, tension pneumothorax, pulmonary or coronary thrombosis.
The term asystole simply refers to an absence of ventricular activity, which means the patient will exhibit no discernible electrical activity on an ECG readout. In most cases, asystole is a lethal arrhythmia and survival is extremely rare.
In this lesson, we'll look at an ECG readout for a patient in asystole, tackle those H's and T's and provide some corresponding information about their diagnostic use, and at the end of the lesson, provide some information on asystole and technical problems.
Asystole is a cardiac standstill where there is no discernable electrical activity. It Is represented by a straight flat, or almost flat, line on an ECG.
Warning: However, do not rely on an ECG alone for your diagnosis of a patient in cardiac arrest. It's a good idea to always confirm it clinically, because what appears to be a flat line on the ECG can also be caused by a loose ECG lead.
Now let's take a look at an ECG for a patient in asystole.
*Asystole ECG for Adult Patient
The first thing you'll want to look at is the heart rhythm. Does the heart rhythm look regular? Or does it look irregular? In the ECG above, there is no heart rhythm.
Next, you'll want to look at the heart rate of the patient. What is the patient's heart rate? Is it normal? Or is it too slow or too fast? In this case, there is no rate and no pulse.
After looking at the heart rate, check to see if the patient's P-waves look normal by asking yourself the following few questions.
Pro Tip #1: If you notice these small P-waves on the ECG that aren't followed by any other waveforms, this can mean that, in rare cases, the atrial pacemaker may be trying to send an impulse but has no ventricular reaction.
Next, look at the PR interval on the patient's ECG readout and ask yourself the following questions:
The last thing you should look at to determine if the sinus rhythm is normal or not is the QRS complex and ask yourself these questions while you do:
So, what is your cardiac interpretation? Based on these questions and on the findings from the ECG readout above, it would appear that this patient is in asystole. Because there is no myocardial, electrical, or mechanical activity, there is no pulse and no circulation of blood and oxygen.
Pro Tip #2: Asystole is most commonly seen following a period of unconverted ventricular fibrillations or ventricular tachycardia. And while asystole is most commonly seen after extended, untreated, and sudden cardiac arrest, it can also be caused by reversible conditions outlined below.
The most common reversible causes of asystole can best be remembered by keeping in mind the H's and T's.
The following H's and T's are designed to help you identify (and easily remember) potentially reversible causes of cardiac arrest or factors that may be complicating your resuscitative efforts.
Asystole is a specific diagnosis. However, a flat line is not. The term flat line is nonspecific and can be the result of several possible conditions, including the absence of cardiac electrical activity, lead or other equipment failure, and/or operator error.
Some defibrillators and monitors will signal the operator when a lead or other equipment failure occurs. However, some of these problems do not apply to all defibrillators.
For a patient with cardiac arrest and asystole, you should quickly rule out any other causes of an isoelectric ECG, such as: