Heart and Vessels Archives - Healthhype

Coronary Artery | Blood Supply to the Heart

Dr. Chris — Sat, 18 Dec 2010 20:55:56 +0000

The heart is a muscular pump located in the thoracic (chest) cavity. It is constantly working to circulate blood throughout the body. During times of physical exertion or emotional stress, the activity of the heart increases. Due to its constant action, the heart needs a good supply of oxygen and nutrient rich blood to sustain the muscle tissue. This is supplied to the heart via the coronary arteries. The coronary arteries branch off from the major artery of the heart – the aorta. There are two main coronary arteries, namely the right and left coronary artery. It arises from the aortic sinuses above the aortic valve just as the ascending aorta leaves the heart. Each coronary artery gives off a number of branches that supply the entire heart. The coronary artery distribution may vary, sometimes slightly or at other times significantly, among people. Coronary Arteries Right Coronary Artery This artery arises from the right aortic sinus and supplies the following parts of the heart : Right atrium Most of the right ventricle Diaphragmatic surface of the left ventricle Part of the IV septum Sinoatrial and atrioventricular nodes The right coronary artery is able to supply all these parts of the [...]

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Heart Valves (Mitral, Tricuspid, Aortic, Pulmonary) Function

Dr. Chris — Sat, 15 Jan 2011 23:47:48 +0000

The heart has four chambers – two atria (right and left) and two ventricles (right and left). Blood from the rest of the body or the lungs enters the right and left atrium respectively. The atria then pushes the blood into the ventricles. The more muscular ventricle wall contracts sending the blood into the pulmonary artery or aorta. Blood exits the right ventricle and travels to the lungs (pulmonary artery ~ pulmonary circulation) and out of the left ventricle to the rest of the body (via aorta ~ peripheral circulation). What are the Heart Valves? The heart valves are sets of flaps (leaflets or cusps) that prevents the movement of blood against the direction of flow – from an atrium into a ventricle and then out into the artery (pulmonary artery or aorta). There are two sets of valves : Valves between the atria and ventricles known as the atrioventricular (AV) valves Valves between the ventricles and blood vessels exiting in (pulmonary artery or aorta) known as the semilunar valves. There are two atrioventricular valves and two semilunar valves : Atrioventricular Valves Tricuspid valve between the right atrium and right ventricle Mitral valve between the left atrium and left ventricle [...]

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Sudden Cardiac Death (SCD) Meaning, Process and Causes

Dr. Chris — Sat, 09 Jul 2011 21:57:03 +0000

The hearts has its own electrical system to control the rate and rhythm of the heart beat. Impulses are generated in the sinoatrial node (SA node) and immediately cause the muscles of the atria to contract. This pushes blood into the ventricles. The impulse travels along the internodal pathways to the atrioventricular node (AV) node where it is delayed. This ensures that the ventricles do not contract at the same time as the atria. After a few milliseconds, the impulses leave the AV node and dissipate to the muscles of the ventricles thereby causing it to contract. Blood is then pushed out of the ventricles and into the pulmonary or systemic circulation. The electrical system can increase or decrease the heart rate as needed throughout the day. The rhythm, however, stays the same – atria contract and then the ventricles a short while later. This process is continuous throughout life. Sometimes heart disease and other conditions may change the rate and rhythm of the heart activity and this causes various disturbances in circulation. These abnormal alterations of the rate and rhythm is known as an arrhythmia. Some arrhythmias are life-threatening and can disrupt heart activity to such a degree that [...]

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Heart Damage With A Heart Attack (Permanent and Irreversible)

Dr. Chris — Wed, 13 Jul 2011 23:51:17 +0000

A heart attack, or myocardial infarction (MI), is the death of a portion of the heart wall when there is an interruption in its blood supply. The heart wall is composed of three layers – the inner lining (endocardium), middle muscle layer (myocardium) and outer lining (epicardium) – and has its own supply of oxygen and nutrient-rich blood via the coronary arteries. There is usually underlying disease of the coronary artery, like atherosclerosis, where fatty plaques build up in the arterial wall. This is known as coronary artery disease and reduces the blood flow to portions of the heart wall. It is often asymptomatic if the extent of occlusion is less than 75% of the diameter of the arterial lumen. However, once there is a severe blockage or total occlusion then there is a wide range of symptoms that arise particularly when the heart muscle needs increased blood flow like during physical activity. This interruption in the blood supply causes muscle injury known as myocardial ischemia but the tissue does not die. It may persist for months or years without a heart attack and is known as ischemic heart disease. Eventually, the fatty plaque may become unstable and possibly rupture. [...]

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Hypotension – Abnormally Low Blood Pressure Problems

Dr. Chris — Thu, 23 Jun 2011 22:37:38 +0000

Blood pressure is the force that blood exerts against the walls of the vessels it travels through it. Arterial pressure, that is the pressure within arteries which are the blood vessels that carry oxygen and nutrient-rich blood through the body, and it is higher than venous pressure (pressure in the veins). There are several mechanisms in the body to regulate blood pressure which involves major organs and even individual tissues in the body. It is a combination of water volume, size of the blood vessel lumen and rate and force of heart contraction. When one or more of these systems are disturbed, the blood pressure is also affected leading to a rise or fall in blood pressure. If these changes are sustained, a person is said to have high blood pressure (hypertension) or low blood pressure (hypotension). Given the prevalence and often disastrous consequences of high blood pressure, most of us consider low blood pressure to be a benign condition. However, low blood pressure can have equally devastating effects on the body and even lead to death in severe cases. What is hypotension? Hypotension is an abnormally low blood pressure that hampers the oxygen supply to various parts of the [...]

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Heart Murmurs (Abnormal Heart Sounds) Types, Causes, Symptoms

Dr. Chris — Mon, 27 Jun 2011 15:42:46 +0000

The heart is a muscular pump that fills with blood when the muscle relaxes (diastole) and forces blood out during contraction (systole). The heart sounds are normally a ‘lub dub’ sound when heard with the aid of a stethoscope. It is a result of the closing or snapping back of the heart valves and the flow of blood through the heart and blood vessels. Sound is created by reverberation and the heart sounds area normal phenomenon. Sometimes, additional or abnormal sounds may be heard when the normal flow of blood is affected or heart valves are diseased. What is a heart murmur? Heart murmurs are extra and abnormal heart sounds that may be an indication of a problem in the cardiac cycle. Murmurs sound like clicks, knocks, snaps or whooshing. The four normal heart sounds are a consequence of vibration of the flow of blood and closure of the heart valves. Similarly heart murmurs are a result of vibration caused by turbulent flow or abnormal closure of the heart valves. A murmur is not always an indication of a problem though and most are benign or innocent murmurs. Although there are four heart sounds, only two can be clearly heard [...]

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Left-to-Right Cardiac Shunts (Heart) Types and Symptoms

Dr. Chris — Thu, 30 Jun 2011 23:49:50 +0000

Congenital heart defects arise in the fetal stage in life when the development of the heart and/or great blood vessels is disrupted in some manner. This leads to a structural abnormality in the heart or vessels which depending on the type and extent may case mild to severe symptoms or can even be life threatening. The heart is a a muscular pump with four chambers – two atria that receive blood and two ventricles that push out blood. The atrium and ventricle on each side are separated by heart valves which open and close at different stages of the cardiac cycle. Similarly the ventricles and arteries communicating it are separated by valves. However, the atria and ventricles are kept separate from each other by the atrioventricular (AV) septum. This means that the blood from the right atrium or ventricle cannot mix with the blood in the left atrium or ventricle. The septum is essential to keep oxygen deficient blood in the right chambers of the heart separate from the oxygen rich blood in the left chambers. In certain types of congenital heart defects, the septum is compromised thereby allowing for a mixing of the blood. What is a cardiac shunt? [...]

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Congenital Heart Disease and Defects Causes and Symptoms

Dr. Chris — Thu, 30 Jun 2011 20:29:35 +0000

The terms congenital and acquired are frequently used in medicine to describe a disorder, disease or defect that is either present from birth (congenital) or develops during the course of life (acquired). Congenital defects stem from fetal development but is often only obvious after birth once the baby’s body has to sustain life independent of the mother. However, with modern investigative techniques, many congenital disorders can be detected during fetal life and the appropriate measures taken prior to birth in certain cases. Congenital diseases or defects can affect any part of the body or organ and the heart and great blood vessels are no exception. These diseases and defects can be life-threatening and require intervention in fetal life or immediately after birth while in some cases it may only manifest later in life or adulthood. What is congenital heart disease? Congenital heart disease or defect is any type of structural abnormality of the heart and/or great blood vessels that arises in fetal life. It is a broad term to describe a number of abnormalities most of which occur during the formation of the heart and blood vessels around week 3 to 8 of fetal life. Congenital heart diseases and defects [...]

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Irregular Heart Beat Rhythm and Rate (Arrhythmia)

Dr. Chris — Wed, 29 Jun 2011 23:52:16 +0000

The heart is a muscular pump with its own electrical system to keep it functioning independently. Electrical impulses are generated in the sinoatrial node (SA node) in the atrial wall, passes directly to the muscles of the atria, is delayed in the atrioventricular node (AV node) and then transmitted to the muscles of the ventricles. The impulses travel in only one direction and ensures that the atria contract first and then the ventricles. In this manner blood received in the atria, pushed into the ventricles and then pumped out to the lungs and rest of the body.The heart beat has to maintain a constant rate and rhythm to ensure that blood is being pumped out in manner that is sufficient for the body’s needs. What is an arrhythmia? An arrhythmia, or dysrhythmia, is a disturbance in the electrical system of the heart leading to an irregular heart beat. The rhythm is usually affected and in some cases there is also a disruption in the rate meaning that the heart beats faster or slower than normal. There are several different types of arrhythmias which arise with a variety of disturbances in the natural pacemaker and conduction system of the heart. The [...]

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Electrical Conduction System and Activity of the Human Heart

Dr. Chris — Wed, 29 Jun 2011 01:44:59 +0000

The heart has a complex electrical system which regulates the contraction and relaxation of its muscular wall. This enables the heart to function by receiving blood during relaxation and pumping it out with force to the lungs and other parts of the body. The rhythm of the heart beat is controlled by a natural pacemaker known as the sinoatrial node (SA node) which generates the electrical impulse. To prevent simultaneous contraction of the atria and ventricles, the atrioventricular node (AV node) delays the conduction of the impulse to the ventricle. Fibers from the SA node to the AV node (internodal pathways) and then from the AV node to the rest of the ventricles (Purkinje fibers) serves as the electrical ‘cables’ of the heart. Sinoatrial Node (SA Node) The Natural Pacemaker The sinoatrial node, or SA node, is known as the natural pacemaker of the heart. It regulates the rhythm of the heart beat by generating an impulse that causes the heart muscle to contract. The faster these impulses are generated, the faster the heart will beat. In order to carry out is function, the SA node has a specialized structure with unique characteristics that ensures it keeps the electrical activity [...]

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