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  • Cardio Catheters
  • Cardio Terms
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• Cardio Terms

- H -

• Haldane effect

The influence of oxygen on the affinity of hemoglobin to bind with carbon dioxide, increasing the oxygen level decreases the affinity of hemoglobin for carbon dioxide.



• Hct

Hematocrit.



• HCTZ

Hydrochlorothiazide, (type of diuretic).



• Heart

The organ responsible for pumping blood through the lungs and body. The heart is located in the chest cavity behind the breast bone, known as the sternum. The heart is divided into the right and the left side. Each side is composed of an atrium and a ventricle. The right atrium receives the blood from the body after the body�s organs have extracted the needed oxygen. The blood in the right atrium is pumped into the right ventricle, which then pumps the blood to the lungs. In the lung, the CO2 that is in the blood is removed and new oxygen is added. The blood then flows into the left atrium. The left atrium then pumps the newly oxygenated blood to the left ventricle, which then pumps this newly oxygenated blood back out to the body�s organs. The heart is controlled by the autonomic nervous system of the brain that tells the heart to speed up or slow down depending on the body�s needs. The left heart is responsible for the blood pressure measurement you hear at the doctors office. The heart is a tireless pump.



• Heart Block

A condition in which the normal electrical impulses of the heart are interrupted. The interruption causes a change in the normal heart rhythm. The heart muscle normally contracts in a regular, coordinated, rhythmic fashion. These contractions are stimulated and coordinated by tiny electrical impulses from different locations in the heart referred to as 'nodes'. These electrical impulses from the 'nodes' travel down tiny nerve fibers to the heart muscle, helping to stimulate the muscle to contract in a coordinated, synchronized sequence. Different conditions, such as a heart attack, can injure these nerve fibers leading to a blockage of the electrical energy, hence the name 'heart block' There are several different types of heart block, which can vary from no symptoms to the heart stopping or beating very slowly and irregularly. The treatment of heart block depends on the type of heart block and its severity. In some instance a pacemaker is necessary to treat heart block.



• Heart Murmur

An abnormal sound heard in the heart. A murmur results from blood flowing over or through an irregular surface. Murmurs can be classified in different ways, and different heart conditions have characteristic murmurs or sounds. Not all murmurs are associated with a condition that requires surgery, but a murmur can be used to follow any changes in a heart condition. A non-medical analogy of a heart murmur would be water flowing down a smooth stream. There would be no sound of the flow of water if the stream were perfectly smooth. However, if an irregular surface, such as a stone, is placed in the stream, the water flowing around the irregular surface would cause a sound (a babbling brook). Examples of heart conditions that cause murmurs would be mitral valve prolapse, aortic stenosis, and mitral valve stenosis.



• Heart-Lung Machine

A device used in open heart surgery to support the body during the surgical procedure while the heart is stopped. The heart-lung machine is often referred to as the 'pump', and does the work of the heart and lungs during the operation. The heart-lung machine consists of a chamber that receives the blood from the body, which is normally the responsibility of the heart�s right atrium. This blood is then pumped by the machine through an oxygenator, a function normally the responsibility of the right ventricle. The oxygenator removes the CO2 and adds oxygen, which is normally the work of the lungs. The pump then pumps this newly oxygenated blood back to the body, which is normally the work of the left heart. The heart-lung machine is connected to the patient by a series of tubes that the surgical team places. At the end of the operation, the surgeon gradually allows the patient�s heart to resume its normal function, and the heart-lung machine is 'weaned off'.



• Hematocrit

The percent of the blood which is cellular elements, normally 35 - 43 %.



• Hemo-

Referring to blood.



• Hemoconcentration

The process of removing fluid and electrolytes from the blood to increase the concentration of hemoglobin and red blood cells.



• Hemodialysis

The separation of waste products from the blood by osmosis across a semi-permeable membrane.



• Hemodilution

The decrease in the concentration of hemoglobin and red blood cells in the blood.



• Hemodynamic instability

I nstability of the blood pressure.



• Hemoglobin

A protein consisting of hematin and globin, which gives red blood cells, and therefore blood, its red color. Hemoglobin is the substance in the red blood cell that is responsible for transporting oxygen to the tissues of the body�s organs. Within the organs, the hemoglobin releases the oxygen to the tissues and takes on the carbon dioxide (CO2) from the organ�s tissues. Once the red blood cells with the CO2 is transported to the lungs, the hemoglobin allows the CO2 to exit and takes on a fresh load of oxygen. Different conditions can cause a deficit of hemoglobin, which is referred to as anemia. Part of the hemoglobin complex contains iron. Diets deficient of iron can result in insufficient hemoglobin, which is referred to as 'iron deficiency anemia'.



• Hemolysis

The freeing of hemoglobin from the inside of the red blood cell by normal breakdown or mechanical destruction.



• Hemorrhage

The loss of blood as a result of a injury to a blood vessel. Severe hemorrhage can be life threatening.



• Hemostasis

The cessation of bleeding through normal coagulation or by surgical procedure.



• Henderson - Hasselbach equation

Ph = pk + log [hco2-]/[co2d][h2co3]



• Heparin

A negatively charged polysaccharide normally found in lung or gut mucosa that naturally prolongs the time it takes blood to clot by catalyzing anti-thrombin iii.



• Hepatic

Pertaining to the liver.



• Hepatitis

Inflammation of the liver usually caused by a virus transmitted by contact or blood transfusion.



• Heterologous

Referring to a different species, or tissue coming from a different species.



• Heterothermic

Cold blooded; poikilothermic; animals whose body temperature changes with the environment.



• Hgb

Hemoglobin.



• High Blood Pressure

A condition in which the blood pressure generated by the left ventricle and the circulatory system is higher than established norms. High blood pressure can be caused by a variety of heart, circulatory system and other organ diseases. High blood pressure is often without significant symptoms but is a potentially serious problem that can lead to heart attack, stroke, kidney failure and heart failure. High blood pressure is easily detected with a routine physical exam and can be treated through a variety of medications, diet, and exercise.



• Hirudin

Coagulation inhibitor isolated from leeches, inhibits thrombin without requiring atiii.



• HLHS

Hyperplastic left heart syndrome; congenital defect characterized by atretic underdeveloped or absent left ventricle.



• HMD

Hyaline membrane disease.



• Homeostasis

The maintanence of a normal state of balance in a physiologic system.



• Homeothermic

Warm blooded; animals whose body temperature are maintained within a narrow range by its metabolic processes.



• Homologous

Referring to the same species, or tissue coming from the same species.



• Hydrogen Ions (H+)

Ion produced when hydrogen looses an electron, a proton, the ions released when an acid is placed in solution such as in water or plasma.



• Hyper

Above normal.



• Hypercapnea

A measurement of an abnormally high co2 level in the blood, pco2 >45 mmhg.



• Hypercholesterolemia

Excessive cholesterol in the blood.



• Hyperhidrosis

A condition characterized by excessive sweating of the palms, is also frequently associated with excessive perspiration involving the hands, face, and soles of the feet, as well as the armpits, chest or back.



• Hyperlipidemia

Excessive quantity of fat (cholesterol and triglycerides) in the blood.



• Hyperthermia

Temperature above normal.



• Hypertrophiccardiomyopathy

Disease of the myocardium produced by the enlargement of the cells of the myocardium; often the result of increased oxygen demand in ischemic heart disease.



• Hypertrophy

Enlargement or overgrowth of an organ or part due to increase in seze of its constituent cells.



• Hypervolemia

Blood volume increase above normal.



• Hypoperfusion

Decreased blood flow to an organ or tissue such as in shock.



• Hypoplastic Left Heart Syndrome (HLHS)

A congenital anomaly in which half (left) of the heart is not properly formed. The heart structures usually affected are; the mitral valve, the left ventricle, the aortic valve, and the aorta. Because the left side of the heart is underdeveloped, oxygenated blood cannot be pumped to the body (tissues). This condition is uniformily fatal without surgical intervention.



• Hypotension

Decrease of systolic and diastolic blood pressure below normal.



• Hypothermia

Temperature below normal.



• Hypovolemia

Decreased blood volume below normal.



• Hypoxemia

Reduction of oxygen level in the blood below normal.



• Hypoxia

Reduction of oxygen level in tissues below normal.