The heart, a muscular pump, tirelessly propels roughly 7192.282 liters of oxygenated blood daily, servicing the entire body by beating an average of 60-90 times per minute, totaling over 4.2 crore heartbeats each year. Roughly the size of a closed fist and weighing around half a kilogram, it resides centrally in the chest cavity, slightly leaning towards the left side.

 Structure of Heart and Circulation

The heart, structured with a dividing muscle layer known as the Septum, segregates into the right and left sides. Functionally, the right side receives deoxygenated blood from the body and propels it to the lungs for oxygenation, while the left side receives oxygen-rich blood from the lungs, circulating it throughout the body. This continuous flow of blood through the heart, lungs, and body constitutes the essential process known as “circulation.” Concurrently, the heart’s rhythmic pumping action generates a pulse, providing a direct indicator of the heart’s beats per minute. Vital to this function are the heart’s four valves, regulating unidirectional blood flow between chambers, and preventing any backward flow. These valves’ closure produces the characteristic sounds of a normal heartbeat, commonly recognized as “lub-dub.”

The Heart also needs Blood Supply.

Similar to any other muscle, the heart muscle requires oxygen to function effectively. Oxygenated blood is supplied to the heart muscle through the coronary arteries, which originate directly from the aorta (The biggest blood vessel of the body) near the heart. These arteries transport oxygen-rich blood along the heart’s surface and penetrate the muscle tissue. Among the major coronary arteries are the Right Coronary Artery (RCA), the Left Anterior Descending (LAD), and the Circumflex (CX). The LAD and CX stem from the aorta as the Left Main Division (LMD). Subsequently, these arteries branch into smaller vessels, ensuring every part of the heart muscle receives the necessary blood supply.

Coronary Artery Disease (CAD)

This disease progresses as the coronary arteries gradually narrow or get blocked due to the accumulation of fatty substances, including cholesterol and various materials, within the artery walls. This accumulation forms what is known as “atherosclerotic plaque” or simply “plaque,” causing a reduction in the artery’s diameter and consequently limiting blood flow to the heart muscle. This plaque buildup can initiate from childhood and advance over time.

This decreased blood flow to the heart muscle is termed “ischemia.” In its early stages, it might not display noticeable symptoms, particularly in individuals with diabetes. However, as the condition progresses, symptoms may manifest during exertion and eventually even at rest. Significantly reduced blood flow to the heart muscle can lead to a heart attack or disturbances in the heart’s rhythm. These serious consequences occur when the blood flow is severely compromised, affecting the heart’s normal function.

Heart Attack

A heart attack is also called a myocardial infarction (MI). Whenever these coronary arteries are unable to supply the required quantity of blood to the heart muscle due to one or more branches of these arteries being partially or completely blocked, which deprives them of essential oxygen and nourishment, can result in mild to severe degree of damage to the heart muscle. This part of the heart muscle suffers permanent damage. This is called Myocardial Infarction. This can be experienced in the form of mild to severe pain.  This is termed as ANGINA.

When individuals experience similar discomfort and pain during known levels of exertion, which subsides at rest and is managed by medication, it falls under the category of “stable angina.”

However, if the frequency and intensity of angina have escalated, occurring even at rest and proving resistant to medication, it is termed “unstable angina.” Symptoms vary among individuals, with some describing sensations of heaviness or tightness in the chest, while others experience a squeezing pain. This pain might radiate to the arm, neck, jaw, or even the back. Alongside the pain, individuals may encounter stomach discomfort, dizziness, breathing difficulties, or excessive sweating. The presence of one or more of these symptoms (fig-1) might indicate unstable angina.

What to do in Heart Attack ?

Stop whatever you are doing and take rest, relax yourself, meanwhile Contact the nearest Hospital /Doctor Call 108