What is cardiac arrest?
Cardiac arrest is the sudden loss of heart function in a person who may or may not have had a heart disease. It is an electrical malfunctioning of the heart that causes the heart to stop beating and, therefore, blood cannot be pumped to the brain, the lungs and other parts of the body. It is very deadly because if left unattended to, it can result in death within a few minutes.
Is it related to sudden death syndrome?
Yes, cardiac arrest is related to sudden death syndrome. Sudden death syndrome is an umbrella term which includes many causes of cardiac arrest, especially in children and young adults.
Ventricular and atrial fibrillation are said to be significant factors that cause sudden cardiac arrest. Can you please explain them briefly?
In the functioning of the heart, electrical activation precedes mechanical action. Blood flows from the atria (the thin upper heart chambers) to the ventricles (the muscular lower heart chambers) to the entire body and back to the atria. Both ventricular and atrial fibrillations are examples of abnormal electrical activities of the heart which occur rapidly, irregularly and result in ineffective pump action of the heart.
Atrial fibrillation is one of the most commonly sustained irregular heart rhythms. In this instance, the atria beat very rapidly in an uncoordinated and ineffective pattern. This can result in the ventricle not receiving enough blood from the atrium. By extension, the body’s blood supply from the heart may be compromised with resultant heart failure. Ventricular fibrillation is a grave condition but thankfully not as common as atrial fibrillation. In this instance, the ventricle is rapidly and irregularly activated but with no resultant mechanical effect, thus, resulting in cardiac arrest.
Are there certain heart conditions that increase the risk of cardiac arrest?
Yes, there are. Diseases affecting different parts of the heart can put an individual at risk of cardiac arrest as these conditions are potential causes of ventricular fibrillation. Examples include hypertensive heart disease, heart attacks (coronary heart disease), heart muscle disease (e.g. hypertrophic cardiomyopathy), heart valve disease, arrhythmias (irregular heartbeats) and conduction abnormalities (e.g. Long QT syndromes), and inflammation of heart muscle (acute myocarditis, one of the cardiac complications of COVID-19).
Risk factors for heart diseases, and by extension cardiac arrest, include hypertension, diabetes, obesity, high cholesterol (dyslipidemia), sedentary lifestyle, cigarette smoking, excessive alcohol consumption, and psychosocial factors such as depression, anxiety and high-stress level. A person with a family history of heart attacks or sudden death is at risk. Other risk factors for cardiac arrest include massive blood loss, blunt chest injury, asphyxia, drowning, electrocution and drug abuse, especially the use of recreational drugs like cocaine.
Are certain age groups prone to cardiac arrest than others?
The occurrence of cardiac arrest increases with age as the risk of heart disease increases with age. Although persons in all age groups can suffer cardiac arrest, those aged between 40 and 70 years are more prone.
What is the prevalence rate in Nigeria?
The exact prevalence rate in Nigeria is not known. However, more cases are being recorded in Nigeria, both in and out of hospital. A study in Lagos showed that one out of two brought-in-dead deaths was due to a heart disease. In another study in Ile-Ife, Osun State, over 80 per cent of the cases of sudden cardiac death were due to hypertension. One in every four adult Nigerians currently has hypertension, and many unfortunately are not aware of their blood pressure status.
What are the early and recognisable signs of cardiac arrest?
A person who suffers cardiac arrest will suddenly become unresponsive (unconscious); the pulse cannot be felt and the person is either not breathing at all or breathing abnormally.
What are the signs that show that a person requires emergency medical care to avoid cardiac arrest?
Half of the cases of sudden death have prior symptoms that are either ignored or explained away. The symptoms include chest pain or discomfort (especially if it is related to exercise or other physical activities), shortness of breath, palpitations (awareness of the heartbeats), fast or irregular heartbeats, dizziness or lightheadedness, fainting or near fainting, and nausea or vomiting.
How can a diagnosis be done?
Diagnosis of cardiac arrest is based on the clinical state of the victim – sudden collapse, no pulse, and no breathing. Clinical history, physical examination and imaging test, e.g. chest x-ray, electrocardiogram or ECG, echo and laboratory tests such as blood glucose, blood electrolytes, especially potassium, are important contributors that help to identify the cause of the arrest. There are different forms of cardiac arrest, with differences in their advanced care. The specific type of cardiac arrest is detected by ECG. Ventricular fibrillation is the most common form of cardiac arrest. Other forms of cardiac arrest are pulseless ventricular tachycardia, pulseless electrical activity and asystole.