Asystole (Heart Attack)

What is Asystole (Heart Attack)?

Asystole, commonly known as “flatline,” is a condition where the heart stops its electrical and mechanical functioning entirely. It often starts as a dysfunctional heart rhythm that does not allow blood flow. This might occur through serious disturbances like ventricular fibrillation or pulseless ventricular tachycardia (pVT). Pulseless electrical activity (PEA) might also evolve into asystole. Patients suffering a sudden cardiac arrest with asystole as the first detected rhythm have extremely low chances of survival. If after an out-of-hospital cardiac arrest (OHCA), the first rhythm identified is asystole, it’s less likely that the heart will naturally restart. Patients in this scenario usually have less chance of survival after 30 days compared to those with other initial rhythms.

In the case of a long-lasting asystole in an OHCA victim, continuing the resuscitation efforts are usually not medically beneficial. It might be advisable to stop resuscitation in these instances, after consulting with online medical direction, considering local protocols. Both the American College of Emergency Physicians and the National Association of Emergency Medical Services Physicians endorse protocols which allow medical providers to stop resuscitation efforts in scenarios when there is no hope of patient survival.

The electrical system of the heart works like a sophisticated circuit, controlling the spread of electrical pulses that cause muscle contractions and drive the flow of blood. The starting point of this electrical impulse is the sinoatrial node in the right atrium, which acts as the heart’s natural pacemaker. This impulse travels through pathways to reach the atrioventricular node, sandwiched between the atria and ventricles. The node delays the signal for a coordinated contraction between the atria and ventricles. This impulse then crosses the His bundle, a muscle bridge which divides into right and left bundle branches. These branches further split to spread the electrical waves throughout the ventricles, triggering the synchronized contraction of the heart chambers and pushing out the blood.

The heart’s rhythm depends on voltage-gated channels that include sodium, potassium, and calcium channels. Sodium channels start the process where the cardiac muscle cells are electrically charged, which equals to the contraction of ventricles and the QRS complex on the electrocardiogram (ECG). Potassium channels help reverse this electrical charge, restoring the resting potential, and this corresponds to the relaxation of ventricles and the T wave on the ECG. Calcium channels play a role in producing the electrical charge and reversing it in the muscles, and they also regulate the levels of calcium within the cells, all of which are vital for contraction of the heart muscle. The activity of the ventricular calcium channels contributes to the QRS complex. The atria also has similar voltage channels. The electrical activation of the atria results in the P wave on the ECG.

The electrical system of the heart can be disturbed due to various factors such as severe lack of blood supply leading to death of heart tissues, electrolyte imbalances obstructing the flow of electricity, or direct injury to the heart from physical trauma or toxins. The result is that the electrical waves fail to traverse the system, leaving the heart in a state of complete electrical and mechanical silence.

What Causes Asystole (Heart Attack)?

Asystole, a type of cardiac arrest where the heart stops, can have many different causes. It’s often a result of a severe case of ventricular fibrillation arrest where the heart quivers instead of pumping blood. Using a defibrillator to shock a heart that is beating too fast or irregularly can also cause asystole. But, basically, any reason for cardiac arrest, if not treated quickly, may eventually lead to asystole.

When the heart first stops (asystole is the initial cardiac rhythm), it’s important to consider if the cause is something that can be fixed. That’s where the “Hs and Ts” come into play. This is a memory device taught in advanced heart resuscitation training to quickly recall the possible treatable causes of cardiac arrest.

The ‘Hs’ stand for issues with fluid levels in the body (hypovolemia), lack of oxygen (hypoxia), acidity in the blood (acidosis), levels of potassium that are too low or too high (hypokalemia or hyperkalemia), and body temperature that’s too low (hypothermia).

The ‘Ts’ stand for a buildup of air pressure in the chest (tension pneumothorax), blood filling the sac around the heart (cardiac tamponade), poisons (toxins), and blood clots in the lung or heart (pulmonary or coronary thrombosis). These conditions, once identified, should be treated immediately.

Risk Factors and Frequency for Asystole (Heart Attack)

Every year, there are more than 350,000 cases of cardiac arrest occurring outside hospitals (called out-of-hospital cardiac arrests or OHCAs) in the United States, and many of these cases result in death. The statistics vary across different regions of the country and different studies. Unfortunately, less than 23% of people with an OHCA make it to the hospital and only 10% survive until discharge. From 2015 to 2019, a study conducted by the Cardiac Arrest Registry to Enhance Survival (CARES) found 258,342 OHCAs. The most common initial rhythm of the heart during these OHCAs was asystole, occurring in 51.6% of cases. The 2022 data from CARES revealed that of all the arrest rhythms, asystole had the worst survival rate, both for getting to the hospital (16%) and for surviving until discharge (2%).

On the other hand, there are around 300,000 in-hospital cardiac arrests (IHCAs) each year in the United States. The heart rhythms that can be treated with an electric shock accounted for just 15.3% of these cases, with the rest being rhythms that couldn’t be treated this way, including asystole. However, survival after an IHCA increased from 21.3% to 32.7% between 1999 and 2018. This increase is largely due to improvements in survival after asystole and a rhythm called pulseless electrical activity (PEA) – these increased from 18.9% to 30.2%. There was also a slight increase in survival after a shockable rhythm, rising from 29.8% to 39.7%. Since 2014, survival after a shockable rhythm stayed about the same, but survival after PEA-asystole continued to increase slightly. This progress is believed to be due to better resuscitation techniques, more use of recommendations-guided treatments, quick treatment of blocked arteries when necessary, special cardiac arrest teams, and systematic strategies for resuscitative care.

Signs and Symptoms of Asystole (Heart Attack)

Asystole usually leads to a condition called cardiac arrest. In simple terms, when someone has cardiac arrest, they do not respond to anything, stop breathing naturally, and do not have a detectable pulse. The American Heart Association suggests doing a quick check if you think someone might be in cardiac arrest. This includes looking for anything blocking the airway, seeing if the person is breathing normally (they may be gasping for air instead, which is called “agonal breathing”), and checking their pulse for, at most, 10 seconds – if there’s no pulse, start doing chest compressions and breaths which is the first step in CPR.

Trying to rescue someone from cardiac arrest requires a sum of the efforts of several people. While some team members are doing CPR, others should investigate causes that we might be able to correct. Even though heart problems are most common in older people, up to 40% of cases of “Out of Hospital Cardiac Arrests (OHCAs)” could be caused by other things. When assessing such situations, we should keep in mind conditions like diabetes, lung disease, drug poisoning, imbalance of body salts (electrolytes), or blood clots.

In younger patients, heart problems are less common. Instead, common causes of cardiac arrest may include blocked airways, drowning, severe injuries, heavy bleeding, poisoning, drug overdose, electrocution or serious water loss from the body. In addition, conditions that change the structure of the heart and its electrical signals, like thickened heart muscles or irregular heart rhythms, can cause sudden cardiac arrest in young individuals who are genetically predisposed.

Getting information from their family, friends or people who were with them may help us figure out what could have caused someone’s cardiac arrest. For instance, someone with longstanding, uncontrolled diabetes or lupus could have a medical condition called metabolic acidosis. If someone has been diving deep underwater, flying in an aircraft without cabin pressure, or travelling in space recently, although rare, they can have a condition called decompression sickness.

Even while rescue efforts are ongoing, a quick physical check of the person’s body could be done to look for additional clues. Signs of conditions like an overactive thyroid, brain injury, a severe type of collapsed lung, or choking could be found when examining the head and neck. Diseases like liver damage, methanol poisoning, and diabetes can be associated with specific smells in a person’s breath. An inspection of the chest could reveal clues like a characteristic puffiness that suggests trapped air under the skin or shape of the chest that indicate ongoing lung problems. Conditions that cause abdominal distension, or presence of any wounds or infections from recent operations could be discovered from inspecting the person’s abdomen. Problems related to urinary system obstruction, blood disorders, cancer, blood clots, drug-related issues or injury could be indicated by certain signs on the skin or the limbs of a suspected cardiac arrest patient.

Testing for Asystole (Heart Attack)

Asystole is a condition that can be identified on a heart monitor. On the monitor screen, instead of displaying the usual wave patterns that indicate a regular heartbeat (P, QRS, and T waves), it will look like a flat line. Some people, who briefly respond to certain medications used in resuscitation, may show small amounts of electrical activity on the monitor. But, most of the time, their heart monitor will show a flatline. During resuscitation, the patient should be connected to a machine that measures the oxygen level in their blood and a heart monitor to keep track of their vital signs and to detect whether normal heart function has resumed.

There a number of quick tests that can be very helpful in figuring out why the asystole happened and maybe even fix it:

• Echocardiogram: This test can find heart rhythm problems, electrolyte imbalances, and any heart disease that might have caused the cardiac arrest.
• Capillary blood glucose test: This is a simple test to check for abnormal blood sugar levels.
• Complete blood count: This test can find signs of serious infections, bleeding, or malignancies in the blood that may cause asystole.
• Complete metabolic panel: This test is used to examine your electrolyte levels and check how your kidneys and liver are working.
• Coagulation profile: This tests for blood clotting problems that might be contributing to the asystole.
• Arterial blood gases: This test is used to detect and classify cases of acidosis, which is when your blood is too acidic.
• Chest and abdominal ultrasound: These tests can identify issues with the heart, lungs, and abdomen. In cases of trauma, a specialized ultrasound test called “focused assessment with sonography in trauma” (FAST) may be used.

Most of these tests can be run on blood samples taken when an IV line is placed. A quick finger prick can be used to check blood sugar levels. Finding and treating the underlying cause of asystole as fast as possible may give the patient the best chance of survival.

Treatment Options for Asystole (Heart Attack)

If someone goes into cardiac arrest, meaning that their heart suddenly stops beating, it’s essential to act quickly and follow the up-to-date guidelines from the American Heart Association. The key to successful treatment is high-quality CPR, or chest compressions and rescue breaths. Here is a step-by-step procedure based on 2020 guidelines to manage cardiac arrest:

• Quickly look for any signs that it might be unsafe to begin resuscitation.
• Test the individual for responsiveness and call for help if they don’t respond.
• Call the emergency services and start chest compressions right away.
• Ask for a defibrillator, a machine that can help assess the heart’s rhythm and potentially restore it to normal.
• Check how the individual is breathing and look for a pulse.

If there’s a pulse, you need to open the airway using simple methods and give rescue breaths once every 6 seconds. If there’s no pulse, high-quality chest compressions should be initiated, aiming for 5 cm deep at a rate of 100-120 times per minute in adults. One cycle of CPR involves 30 compressions followed by two breaths. This process should continue until a defibrillator is available, or the patient is revived.

In the case of ‘asystole,’ where the heart shows no electrical activity, defibrillation isn’t suitable. In this instance, keep performing chest compressions until advanced life support arrives, the patient starts moving, or signs of circulation return. There should be minimal interruption to chest compressions, even during the process of intubation, or inserting a tube into the airway to assist with breathing.

According to the advanced life support guidelines, if CPR doesn’t revive the patient after two minutes, IV or intraosseous (directly into the bone marrow) access should be established, and adrenaline should be given every 3-5 minutes. It’s crucial to check for and treat any reversible causes. If the rhythm changes to a shockable rhythm, electrical shocks should be given. Certain medications like amiodarone or lidocaine could be considered if defibrillation doesn’t work.

If the patient recovers and shows signs of sustained circulation, they should be closely watched in the ICU. Doctors might consider inducing hypothermia, a medical treatment that cools the body to help protect the brain and other organs after a cardiac arrest. Finally, in cases of asystole, it’s important to note that this is often a terminal condition, and stopping the resuscitation efforts might have to be considered, depending on local protocols.

What else can Asystole (Heart Attack) be?

When your heart rhythm stops, or goes into “asystole,” a few potential diagnoses include PEA (pulseless electrical activity), ventricular fibrillation, and pVT (polymorphic ventricular tachycardia). All these conditions are treated according to BLS (Basic Life Support) and ACLS (Advanced Cardiac Life Support) guidelines, and the underlying cause should be addressed as swiftly as possible.

The cause for this cardiac event could be any number of things, including but not limited to:

• Heart issues, like blocked blood flow (coronary thrombosis) or damage to the heart muscle (myocardial infarction).
• Blood-related problems or “Hs and Ts:” dehydration (hypovolemia), lack of oxygen (hypoxia), too much acid in the blood (acidosis), issues with potassium levels (hypokalemia/hyperkalemia), low body temperature (hypothermia), chest injury causing pressure build-up (tension pneumothorax), fluid build-up in the heart (cardiac tamponade), poison/toxicity, or blood clot in the lung (pulmonary thrombosis).
• Lung conditions, such as COPD (chronic obstructive pulmonary disease) or asthma.
• Different hormonal conditions: adrenal insufficiency, high blood sugar (diabetic ketoacidosis), or thyroid disease (thyrotoxicosis).
• Trauma, including head trauma or major bleeding.
• Severe stomach issues like perforated ulcers or obstruction.
• Drug abuse or adverse reaction to certain medications.
• Advanced stage cancers or immune disorders
• Severe infections such as pneumonia or urinary tract infections.
• Neuromuscular disorders or mental health issues.

Being conscious of these possible conditions, and conducting proper tests can help medical teams accurately diagnose asystole, differentiate it from other conditions and adequately treat its root cause.

What to expect with Asystole (Heart Attack)

The outlook for asystole, or a flatline on the heart monitor, varies depending on several factors. The most crucial of these are the quality and speed of the revival efforts. The root cause of the flatline also plays a significant role in determining the outcome. For instance, causes that are not related to heart issues often have a better outlook, especially if treated quickly.

Age and overall heart health also influence the outcome, with younger individuals with strong hearts usually faring better in the long term than older individuals with pre-existing heart conditions. Because of this, it’s important to ensure that revival efforts are robust for patients who are expected to have good outcomes.

Another factor to consider is the resources available during revival. For example, if the rescuer becomes tired, the quality of CPR can significantly decrease. Additionally, if the drug epinephrine is not available, patients who can’t be treated with a defibrillator will lose an opportunity for improved survival.

Possible Complications When Diagnosed with Asystole (Heart Attack)

If CPR isn’t administered promptly or if it fails during a cardiac arrest, the worst-case scenario is death. For those who do survive, they might experience neurological problems or various complications from the CPR itself. These complications could range from a punctured lung or air bubbles entering the blood vessels to damage to the spleen, stomach, colon, and liver. It can also cause a buildup of blood in the chest, muscle breakdown, and broken ribs.

Common complications following a rescue:

• Neurological problems
• Punctured lung
• Air bubbles entering the blood vessels
• Damage to the spleen
• Damage to the stomach
• Damage to the colon
• Liver damage
• A buildup of blood in the chest
• Muscle breakdown (rhabdomyolysis)
• Broken ribs

Preventing Asystole (Heart Attack)

The best way to prevent a heart rhythm disorder called asystole is to identify and address any risk factors and diseases that could potentially lead to a sudden cardiac arrest. This can be accomplished by leading a healthy lifestyle, quitting smoking, limiting alcohol consumption, and undergoing regular health screenings. These screenings can detect cardiovascular risks like high blood pressure, high cholesterol, and diabetes early, allowing for timely intervention and management. Additionally, public education about the signs and symptoms of heart disease is crucial, and individuals should be encouraged to promptly seek medical help if they experience such symptoms.

Safety practices should also be prioritized in various environments such as homes, schools, workplaces, and on the road. This includes keeping medications and household chemicals away from young children, protecting vulnerable individuals from potential hazards inside the home, wearing appropriate clothing for work and sports, and practicing safe driving. Installing barriers in places where accidents might occur, such as fall-prone areas or pools, is also recommended.

An additional prevention strategy, especially for those already at high risk such as those with a history of heart disease or irregular heart rhythms, is early recognition and intervention. This can be done through regular heart monitoring using tools like an electrocardiogram or portable heart monitors to facilitate quick detection of abnormal heart rhythms and intervention. The adoption of proven treatments such as medication, implantable devices that normalize heart rhythms, and therapy to improve heart function can also help reduce the risk of asystole. Lastly, the general public needs to be aware of the life-saving importance of bystander CPR in case someone goes into cardiac arrest. Healthcare professionals should also be continually trained in Basic Life Support and Advanced Cardiac Life Support techniques. These actions can help decrease the number of deaths caused by asystole.