Very often, one comes across terms such as heart failure, heart attack, and cardiac arrest being used interchangeably. This is perhaps the result of indiscriminate usage of these terminologies by popular media, including movies and television.
However, the three are very distinct conditions, caused by specific faults in the cardiovascular system, also referred to simply as the circulatory system, which comprises the heart, a muscular pumping device, and a closed system of vessels that includes arteries, veins, and capillaries.
Let us take a closer look at these two phenomena to understand them better.
What is a heart attack?
A heart attack, also termed myocardial infarction, is caused by the narrowing of the coronary artery from the build-up of fat, cholesterol, and other substances, such as cellular waste, that together are termed plaque.
As small, thin pieces of this plaque detach or break off, they are carried by the bloodstream and eventually begin obstructing the flow of blood to the heart.
Plaque also leads to the formation of a blood clot. This contributes to depriving the heart muscles of blood supply, oxygen and other nutrients. Further, plaque build-up also leads to the thickening of the arteries, narrowing the channel available for blood flow and restricting the blood supply reaching the heart.
Heart muscles need oxygen to survive. When the blood supply and oxygen supply to these heart muscles are restricted or completely cut off, one is at risk of experiencing a heart attack.
What is heart failure?
To understand what heart failure is, also known as congestive heart failure, we need to know certain facts about the functioning of the heart. The human heart has four chambers, two atria and two ventricles. The atria form the upper part of the heart, while the ventricles comprise the lower portion.
Four valves—the tricuspid valve, aortic valve, bicuspid valve, and the pulmonary valve help regulate the flow of blood among the four chambers of the heart.
The valves work like gates, opening to allow blood to flow through and then tightly closing to prevent the backward flow of blood.
According to Dr Pavan Rasalkar, Consultant—Interventional Cardiology, Fortis Hospital, Nagarbhavi, “in layman's language, heart failure refers to a state in which the pumping efficiency of the heart is compromised. In other words, the heart is not pumping to its efficiency, in the condition referred to as heart failure.”
"Heart failure could result from a malfunctioning of the heart valves, a heart attack, and weak heart muscles, a heart health condition that is a manifestation of one’s genes,” he added.
A heart attack could result in heart failure, where an individual has to live with impaired efficiency as regards pumping of the heart, or have it rectified by undergoing an appropriate medical intervention. In the words of Nature Magazine, “Heart failure is a pathological condition in which the heart is unable to pump enough blood to the rest of the body, because it is either unable to fill with a sufficient volume of blood or unable to generate sufficient force to pump out enough blood; it is not a condition in which the heart has stopped pumping.”
Then what is a cardiac arrest?
When the heart ceases to function, the episode is termed a cardiac arrest. During cardiac arrest, the blood flow to vital organs is completely cut off. This is why cardiac arrest outside of a medical facility can often result in death within minutes. Cardiac arrest (or sudden cardiac arrest) could be due to a heart attack or heart failure or arrhythmia (irregular heart rhythm).
“Heart failure is a state that could go on as long as one lives. One needn’t necessarily die of heart failure. However, if one succumbs to a prolonged state of heart failure, the episode is termed a cardiac arrest. Death due to a heart attack is also termed cardiac arrest. Ultimately, the stopping of the functioning of the heart and the ensuing death is called cardiac arrest," explained Dr Rasalkar.
This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS.