What is Pulseless Electrical Activity?
Pulseless electrical activity (PEA), also known as electromechanical dissociation, happens when a person shows no response and has no detectable pulse, despite the heart’s electrical system functioning adequately. Just because your heart’s electrical system is working, doesn’t necessarily mean your heart is contracting as it should. This can be the case during a cardiac arrest, where there’s normal electrical activity in the heart, but the heart’s ventricles don’t respond as they should, meaning they’re not pumping blood sufficiently to produce a noticeable pulse.
However, it’s vital to note that a lack of detectable pulse doesn’t always indicate pulseless electrical activity. In rare situations, the heart can still be contracting and producing adequate pressure in the main artery (aorta) – a condition sometimes called pseudo-PEA.
True pulseless electrical activity is when no heart contractions are taking place, even though the electrical signals in the heart are coordinated. This condition can involve various heart rhythms, which might originate from different parts of the heart. Exhaustive, deep pulse checks shouldn’t always be viewed as pulseless electrical activity because this could alternatively be due to severe problems with the extremity blood vessels.
What Causes Pulseless Electrical Activity?
Pulseless electrical activity is a condition where the heart shows electrical activity, but there is no pulse. This condition can be caused by primary (heart-related) or secondary (non-heart-related) factors.
Primary pulseless electrical activity usually happens due to a heart-related disease or problem. It often arises because the heart runs low on energy. This type of pulseless electrical activity usually doesn’t respond well to treatment.
Secondary pulseless electrical activity, on the other hand, can be caused by many different factors. These factors are often described as the “5 Hs and 5 Ts”.
The 5 Hs are:
1. Hypovolemia – This is when you have a low volume of blood in your body.
2. Hypoxia – This is when your body or a region of your body is not getting enough oxygen.
3. Hydrogen ion (acidosis) – This is when your body has too many hydrogen ions, and it becomes too acidic.
4. Hypo/hyperkalemia – This is when the level of potassium in your blood is either too low or too high.
5. Hypothermia – This is when your body temperature falls below the normal range.
The 5 Ts are:
1. Tension pneumothorax – This is a severe condition where air accumulates in the space around the lungs, which can lead to lung collapse.
2. Trauma – This is any injury or damage caused to the body.
3. Tamponade – This is when fluid builds up around the heart, restricting its ability to pump blood.
4. Thrombosis, pulmonary – This is when a blood clot blocks one or more arteries in your lungs.
5. Thrombosis, coronary – This is when a blood clot forms in the blood vessels of the heart.
Risk Factors and Frequency for Pulseless Electrical Activity
Pulseless electrical activity is a condition that varies in how often it occurs among different groups of people in the United States. It’s responsible for about 20% of sudden cardiac deaths that occur outside a hospital. A significant investigation found that this condition accounted for 68% of recorded deaths in hospitals and 10% of all deaths within hospitals. Hospitalized patients are more at risk of experiencing complications like a pulmonary embolism.
- Pulseless electrical activity is the first rhythm noted in 30 to 38% of adults who experience a cardiac arrest within a hospital.
- Drugs like Beta-blockers and calcium channel blockers may alter the heart’s squeezing action, making a person more vulnerable to this condition and more resistance to its treatment.
- Women are at higher risk of developing pulseless electrical activity compared to men.
- The risk of developing this condition increases in people aged over 70, particularly in women.
Signs and Symptoms of Pulseless Electrical Activity
When medical professionals deal with a patient, they need to quickly yet thoroughly check their medical history. There are several key factors they look for:
- Risk of heart attack or lung blood clot
- Any kind of physical injury
- Significant fluid loss
- Exposure to cold temperatures
- Chance of metabolic disorders
Physical findings primarily include the absence of detectable pulses. Depending on what caused the situation, the following might also be observed:
- Deviated windpipe
- Loss of skin elasticity
- Physical damage to the chest
- Cold arms and legs
- Rapid heart rate
- Bluish-colored skin caused by inadequate oxygen
Testing for Pulseless Electrical Activity
Your doctor will likely order several tests when trying to diagnose your condition. These tests may include an electrocardiogram (EKG), which is a test that measures your heart’s electrical activity to check if it’s working correctly. An arterial blood gas analysis is another test that might be conducted; this involves measuring the amounts of certain gases in your blood to assess how well your lungs are working.
A serum electrolytes test may also be done to check the balance of minerals in your blood. These minerals, such as potassium and sodium, are essential for normal body function. Additionally, they might measure your core body temperature, which can help assess if you have a fever or other medical condition affecting your body’s temperature.
Additional tests may include a chest radiograph and an echocardiogram. A chest radiograph, also known as a chest X-ray, can display images of your heart, lungs, and chest structures to help determine if there are any abnormalities. An echocardiogram uses sound waves to create detailed images of your heart’s structure and function.
These tests help your doctor understand better what might be causing your symptoms and how best to treat your condition.
Treatment Options for Pulseless Electrical Activity
If someone’s heart isn’t beating but there’s still electrical activity – a condition known as pulseless electrical activity – it has to be managed quickly. The initial step is to start chest compressions, which mimics the heart’s function of pumping blood around the body. While this is happening, treatment is also given to the patient to address any underlying causes that could have triggered the heart problem. For example, if the person’s lung has collapsed (known as pneumothorax), they will work to reinflate it. If the fluid has built-up around the heart (known as tamponade), they will drain it. If the patient is dehydrated (severe lack of fluid, or hypovolemia), they will provide fluids.
The medical team might also adjust the patient’s body temperature if they’re too cold (hypothermia) or administer medicine if the heart problem was caused by a blockage in the arteries or a blood clot in the lungs (myocardial infarction or pulmonary embolism). The team will take blood samples during this process to keep track of body’s gases and salts, which could give clues about why the heart problem occurred.
While the rescuers are performing chest compressions, they will also inject a medicine called epinephrine into the patient’s vein or bone. This medication helps get the heart beating again. After each dose, they will inject 20 ml of additional liquid to make sure the epinephrine travels through the bloodstream and reaches the heart. Then, they lift the patient’s arm for up to 20 seconds to help improve the flow of the medicine to the heart. Higher doses of epinephrine are generally no more effective than normal doses and can have harmful side effects.
If the heartbeat is abnormally slow and the patient’s blood pressure is low, a medicine called atropine is administered. This can speed up the heart rate and improve blood pressure. Doctors most often give three doses of atropine, but no more, because additional doses have not been proven to help. Notice that atropine may cause larger pupils, so you cannot judge consciousness by eye appearance if this medicine has been used.
A medicine called sodium bicarbonate may only be used in severe cases where the patient’s body is too acidic (severe acidosis) or has too much potassium (hyperkalemia). Routine use of sodium bicarbonate isn’t usually recommended because it can make acid build up inside the body’s cells and worsen certain health conditions.
If the heart continues not to beat, other life-saving procedures might be necessary like drainage of fluid from around the heart, or even emergency surgery. Or sometimes the patient might need mechanical help to improve blood circulation. This could involve the use of devices like a balloon pump which is inserted into the aorta (the main artery), or even a machine that can take over the heart and lungs’ functions.
What’s most important in these situations is that everyone involved in the resuscitation process works together as a team, with each person responsible for a specific task. This teamwork is key to increasing the chances of a successful outcome for the patient.
What else can Pulseless Electrical Activity be?
These are the potential health conditions that could be related to abnormal heartbeat or other heart problems:
- Accelerated idioventricular rhythm (a type of heart rhythm)
- Acidosis (too much acid in the body fluids)
- Cardiac tamponade (pressure on the heart caused by fluid accumulation)
- Drug overdose
- Hypokalemia (too low potassium levels in the blood)
- Hypothermia (abnormally low body temperature)
- Hypovolemia (decrease in blood volume)
- Hypoxemia (low oxygen levels in the blood)
- Myocardial ischemia (reduced blood flow to the heart)
- Pulmonary embolism (a blocked blood vessel in the lungs)
- Syncope (fainting or sudden loss of consciousness)
- Tension pneumothorax (a life-threatening condition where air builds up between the chest wall and the lungs)
- Ventricular fibrillation (a heart rhythm problem that can be serious)
What to expect with Pulseless Electrical Activity
People who experience sudden cardiac arrest due to a condition called pulseless electrical activity often face challenging outcomes. In one research study that looked at 150 such patients, only 23% were able to be revived and lived until they reached the hospital, and even fewer, just 11%, were still alive when discharged from the hospital.
Regrettably, even with the best of emergency heart and lung (cardiopulmonary) resuscitation efforts, pulseless electrical activity is often a fatal condition.
Possible Complications When Diagnosed with Pulseless Electrical Activity
The complications that can occur from pulseless electrical activity include:
- A broken rib from chest compression
- Poor blood flow leading to lack of oxygen in the limbs
- Brain injury due to lack of oxygen
Preventing Pulseless Electrical Activity
Most heart attacks occur after changes in vital signs, such as a rapid heart rate (tachycardia), low oxygen levels (hypoxia), and rapid breathing (tachypnea). Medical professionals need to spot these changes and investigate their causes. This way, they can intervene and treat these conditions to potentially prevent a heart attack caused by PEA (Pulseless Electrical Activity), a condition where the heart’s electrical rhythm is regular but the heart isn’t pumping blood.
