Sudden cardiac arrest: Signs, risk factors, causes, and treatment – Steps to perform CPR

Heart failure: When your heart suddenly stops beating, it is called Sudden Cardiac Arrest. If there is an electrical problem, your heart will stop pumping blood. As a result your cells do not get the oxygen they need. Because your cells are not getting enough oxygen, sudden cardiac arrest can quickly turn fatal. The chances of survival are greatest when help is provided immediately.

In an interview with Zee English, Dr. Saikat Kanjilal, Consultant Interventional Cardiologist, Manipal Hospital talks about the causes, symptoms and treatment options for sudden cardiac arrest.

What is sudden cardiac arrest?

Sudden cardiac arrest (SCA) is a medical emergency and potentially fatal condition that occurs when the heart suddenly stops beating. Failure to start immediate treatment can result in death and is called “sudden cardiac death” or SCD.

The heart has a powerful electrical system that controls the normal rhythmic beating of the heart. Abnormal functioning of this electrical system can trigger arrhythmias (abnormal heart rhythms) and lead to SCA.

Heart Attack vs Sudden Cardiac Arrest: What’s the Difference

SCA is different from a heart attack. In a heart attack, the heart fails to pump efficiently because one or more of the arteries that bring blood to the heart are blocked by cholesterol deposits. Damage to the heart from a heart attack can lead to SCA. Whereas SCA is a pre-terminal electrical event caused by various cardiac and non-cardiac disorders.

What causes sudden cardiac arrest (SCA)?

People with known or unknown pre-existing heart problems and certain non-cardiac causes are most likely to have an SCA.

Cardiovascular causes of SCA include:

– coronary heart disease

– heart attack

Thickening/enlargement/weakening of the heart muscle

Abnormalities in the electrical system of the heart such as long QT syndrome and Brugada syndrome

– heart failure

– heart valve disease

– congenital heart disease.

– genetic disorders

Non-cardiac causes of SCA include:

Certain lung problems such as pulmonary embolism (clots in the arteries of the lungs)

Drowning, electric shock, or severe trauma

– substance abuse (cocaine, heroin or meth)

– electrolyte imbalance

– intracranial bleed

– sepsis

Are there any risk factors for sudden cardiac arrest?

– Personal or family history of CAD or other heart diseases such as arrhythmia, congenital heart disease etc.

– Previous medical history of heart attack or SCA

Lifestyle factors and habits, mainly including smoking, sedentary lifestyle, overweight and obesity

Co-morbidities like high blood pressure, high blood cholesterol, and uncontrolled diabetes

– growing old

– obstructive sleep apnea

– chronic kidney disease

Although

Sudden cardiac arrest: Symptoms

In the vast majority of cases, SCA occurs without any “warning” symptoms. But in symptomatic cases, the symptoms commonly experienced include:

– Pain in chest

Difficulty breathing or shortness of breath

– high-speed heart

Feeling weak, dizzy or vomiting

fainting or loss of consciousness

How to Diagnose Cardiac Arrest?

SCA is diagnosed clinically without major tests. Because SCA is a fatal condition, most cases of SCA are often diagnosed post-mortem. Diagnostic tests are done to look at the cause of SCA and if it can be treated, it is treated. The tests usually include:

– Electrocardiogram (ECG)

– chest X-ray

– blood tests to determine chemical markers of various diseases

– echocardiogram (or “echo”)

Other imaging tests, such as cardiac MRI

– electrophysiological studies

Family screening and genetic testing to determine risk for SCA

– cardiac catheterization

How is sudden cardiac arrest treated?

SCAs need immediate intervention:

– Cardiopulmonary resuscitation (CPR) to revive and facilitate blood and oxygen circulation.

– Treatment strategies to maintain blood pressure, respiration, and oxygenation (including measures such as ventilation and ECMO).

– Defibrillation

Once the heart starts beating and blood circulation resumes, further tests and treatment can be initiated based on the patient’s history and findings

Dr. Saikat says, “Doctors sometimes recommend body cooling in unresponsive patients after successful resuscitation from SCA (usually 33-36°C) for 1 to 2 days to reduce the risk of brain injury.” Let’s start a treatment called “Hypothermia. One of the most common causes of death after SCA.”

Specific treatments can be given after resuscitation such as:

– Coronary Angioplasty

– Correction of electrolyte and metabolic imbalances

– Treatment of infection and sepsis

– Treatment of specific electrical disorders

– Implantable Cardioverter-Defibrillator (ICD)

Life After Surviving SCA

This partly depends on what caused the SCA and how quickly it was treated. Some people may recover without any long-term problems. Most of the survivors generally report with long-term neurological problems.

How to do CPR?

If the victim is not breathing, perform CPR. Push hard and fast on the person’s chest – about 100 to 120 pushes a minute. Check the person’s airway if you are proficient in CPR. Then give rescue breath after every 30 compressions.

If you are untrained then keep pressing the chest. Allow the chest to rise completely between compressions. Keep doing this until help is available or emergency services arrive.

Finally, most people (about 90%) who have an SCA outside the hospital do not survive due to lack of immediate intervention. The ready availability of automated external defibrillators (AEDs) in public places, as well as general public awareness and training in basic cardio-pulmonary resuscitation until medical help arrives, is critical in saving lives.