what are we walking for? Jim Bruce dishes the dirt on the silent killer – what is heart disease? He’s not a Doctor but he is a doctor of philosophy so watch out for the long words! Oh by the way, even if we used short words, it would still be a killer….

What is Heart Failure?

Your heart is a muscle, however unlike the muscles that drive your legs on a Saints with Heart Walk, you have no control over when the heart muscle works. It’s an “involuntary” muscle which means it beats constantly from the point you develop in the womb, the day you’re born and all the way through your life. Without this remarkable muscle’s constant and unstinting work you would die, for without the heart the blood carrying the oxygen you need to live wouldn’t circulate.

It’s perhaps ironic that the heart is also dependent on oxygen carried by the blood to keep functioning and doubly so when it was discovered that heart attacks were the result of clots and blockages in the circulating blood system.

Coronary arteries are blood vessels that supply the heart muscle with blood and oxygen. Blockage of a coronary artery deprives the heart muscle of blood and oxygen, causing damage and death to the heart muscle tissue. Coronary atherosclerosis (or coronary artery disease) refers to the process that causes hardening and narrowing of the coronary arteries. This is usually caused by the build-up of plaque (deposits of fat-like substances). The plaque can burst eventually, tear or rupture, creating a "snag" where a blood clot forms and blocks the artery. Diseases caused by the reduced blood supply to the heart muscle from coronary atherosclerosis are called coronary heart diseases (CHD). Coronary heart diseases include heart attacks, sudden unexpected death, chest pain (angina), abnormal heart rhythms, and heart failure due to weakening of the heart muscle.

A heart attack occurs when the blood supply to part of the heart muscle itself is severely reduced or stopped. The medical term for heart attack is myocardial infarction. The reduction or stoppage happens when one or more of the coronary arteries supplying blood to the heart muscle is blocked and so a heart attack is also sometimes called a coronary thrombosis or coronary occlusion.
If blood flow is not restored within 20 to 40 minutes, irreversible death of the heart muscle will begin to occur. Muscle continues to die for 6-8 hours at which time the heart attack usually is "complete" and be replaced by scar tissue. This can kill or disable someone, depending on how much heart muscle is damaged as the heart muscle is damaged by the death of muscle tissue; its ability to carry out its vital function of circulating blood is impaired.

Often, this blockage can instead lead to arrhythmias (irregular heartbeat or rhythm) that cause a severe decrease in the pumping function of the heart and may bring about sudden death. This is known as Sudden Arrhythmic Death Syndrome (SADS). If the hearts rhythm is disturbed it can enter a quivering, irregularly beating state that can be fatal.

Angina is a chest pain or pressure that occurs when the blood and oxygen supply to the heart muscle cannot keep up with the needs of the muscle. When coronary arteries are narrowed by more than 50 to 70 percent, the arteries cannot increase the supply of blood to the heart muscle during exercise or other periods of high demand for oxygen. An insufficient supply of oxygen to the heart muscle causes angina. Angina can occur with exercise or exertion. In some patients, especially diabetics, the progressive decrease in blood flow to the heart may occur without any pain or with just shortness of breath or unusually early fatigue. Angina usually feels like a pressure, heaviness, squeezing, or aching across the chest. This pain may travel to the neck, jaw, arms, back, or even the teeth, and may be accompanied by shortness of breath, nausea, or a cold sweat. Angina typically lasts from 1 to 15 minutes tablet and can be eased by reducing the hearts demand for oxygen by resting or medication. Angina may be the first warning sign of advanced coronary artery disease however it should be noted that chest pains that just last a few seconds rarely are due to coronary artery disease.

Angina also can occur at rest. Angina at rest more commonly indicates that a coronary artery has narrowed to such a critical degree that the heart is not receiving enough oxygen even at rest. Angina at rest may be due to spasm of a coronary artery. When this happens the artery narrows and blood flow to part of the heart muscle decreases or stops. The causes of a spasm are not clear and it can occur in normal-appearing blood vessels as well as in vessels partly blocked by atherosclerosis. A severe spasm can cause a heart attack, however unlike a heart attack, there is no permanent muscle damage with either exertion or rest angina.

The rupture that leads to the formation of a clot in the coronary arteries is a key point in the process that leans to heart attacks and other CHDs. Its causes are largely unknown, but contributing factors may include cigarette smoking, elevated LDL cholesterol, inherited genetic conditions, high blood pressure, and other mechanical and biochemical factors

Much of the scientific research funded by the BHF is focused at understanding the processes of heart diseases and identifying the factors that can trigger them. BHF funded research was instrumental in identifying clots as being the key cause of heart attacks and heart failures. This has lead to a range of treatments to break up blood clots before they cause harm. Other research has studying the rhythm of the heart beat to understand the causes of arrhythmia and SADS.