Cardiac Arrest

Cardiac arrest or sudden cardiac arrest is a heart condition that occurs due to abrupt loss of heart function and sudden stop of a heartbeat. The dysfunction of the heart’s electrical impulse system is the most common cause of cardiac arrest, leading to a lack of blood supply to the brain and other body organs. In short, cardiac arrest results in an inability to breathe, unconsciousness, and failure of the liver and kidneys in some cases. If patients cannot receive immediate treatment through cardiopulmonary resuscitation (CPR), they may die before the emergency team arrives.

Highlights

• Cardiac arrest or sudden cardiac arrest is a heart condition that occurs due to abrupt loss of heart function and sudden stop of a heartbeat.
• The dysfunction of the heart’s electrical impulse system is the most common cause of cardiac arrest, leading to a lack of blood supply to the brain and other body organs.
• Common signs and symptoms of sudden cardiac arrest include no pulse, loss of consciousness, breathing, weakness, tachycardia and sudden collapse.
• Treatment of cardiac arrest include anti-arrhythmic drugs, such as angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers, and implantable cardioverter-defibrillator devices.

What is cardiac arrest?

A cardiac arrest occurs when the heart suddenly stops circulating blood throughout the body. As a result, your brain runs out of oxygen, and you lose consciousness and stop breathing—gasping for air. Cardiac arrest is a sudden heart failure to pump blood to body organs, so the body collapses within minutes (Figure 1). However, cardiac arrest is more related to dysfunction of the heart’s natural electrical system, also known as sinoatrial nodes. This may lead to ventricular fibrillation (inefficient heart rhythms in the heart’s ventricles) and dangerously fast heart beating. In contrast, a heart attack is quite a different condition due to obstruction of the heart arteries, causing blockage of blood flow to the heart. Although cardiac arrest occurs suddenly and can affect anyone, patients with heart attacks are more prone to cardiac arrest.

Causes of cardiac arrest

In general, cardiac arrest occurs due to irregular heart rhythms (arrhythmia) resulting from dysfunction of the heart’s sinoatrial nodes. Because sinoatrial nodes continuously produce and give the heart mild electric impulses to beat normally. Sometimes, if sinoatrial nodes are suddenly dysfunctional, they cause too fast (tachycardia) or too slow (bradycardia) heart beating. So, heart chambers could not receive normal electrical impulses to pump blood to the body, and the heart collapsed. In tachycardia, the heart’s ventricles shiver uselessly without pumping the blood. This condition is called ventricular fibrillation.

Heart conditions that can cause cardiac arrest include:

• Coronary heart disease refers to narrow heart arteries that can easily clog with fat deposits, including cholesterol, and is the most frequent cause of cardiac arrest.
• Heart attack is a condition in which heart arteries block and leave scar tissue in your heart, disrupting normal electrical impulses and leading to ventricular fibrillation, one of the most common causes of cardiac arrest.
• Cardiomyopathy, or abnormal heart muscles, is a condition in which muscular walls of the heart stretch and enlarge or thicken, resulting in arrhythmia and, after that, cardiac arrest.
• Heart valve disease is characterized by leakage and narrowing of the heart valves that exert pressure on heart chambers and enlarge and weaken them. So weakened chambers cannot respond to electrical impulses and cannot do blood pumping properly, leading to cardiac arrest.
• Congenital heart defects that occur by birth may play a role in sudden cardiac arrest in kids or teenagers. The risk of sudden cardiac arrest is higher in adults who have undergone corrective surgery for a congenital heart defect.
• Issues in sinoatrial nodes of the heart include conditions such as Brugada syndrome and long QT syndrome. These conditions affect the production of electrical impulses from the sinoatrial nodes, leading to sudden cardiac arrest.

Symptoms

Common signs and symptoms of sudden cardiac arrest include no pulse, loss of consciousness, breathing, weakness, tachycardia and sudden collapse.

Diagnoses

If you survive a cardiac arrest, your healthcare provider will order:

Electrocardiogram (ECG) to measure your heart rhythms and prolonged QT interval.

Blood tests such as tests to measure potassium, magnesium and other chemicals that are critical to the heart’s normal functioning.

Imaging tests such as X-rays, echocardiogram, MRI and nuclear scans. All tests except X-rays can detect blood flow to your heart, abnormalities in heart valves, and blood pumping rate from a filled heart ventricle.

Another test known as coronary catheterization involves injecting a dye through a thin tube or catheter from your arm to your heart. Once dye fills the heart arteries, the arteries become visible on an X-ray or video visualizing monitor to reveal the blockage of the heart. So, surgeons perform an angioplasty procedure to open the blocked artery and insert a stent to keep it open.

Treatment

Suppose a person nearby you suddenly fall and collapse. In that case, you should do cardiopulmonary resuscitation or CPR through an automated external defibrillator (AED) or compressing the person’s chest to return the electrical impulses. Simultaneously, call an emergency to ensure the patient reaches the hospital as soon as possible.

Once you recover from a cardiac arrest, your doctor will diagnose the reasons for the condition and prescribe various anti-arrhythmic drugs, such as angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers. In rare cases, if your survival is at the edge, your doctor advises surgery to implant an implantable cardioverter-defibrillator (ICD) device in your collarbone that continuously measures heartbeat and gives mild electric impulses to keep heart rhythms regular.