Four Heart Chambers
The heart has two upper chambers called the left and right atria, and two lower chambers called the left and right ventricles. Blood returns to the heart through a system of veins which get larger as they approach closer to the heart, until only one large vein is left to enter the heart, called the Vena Cava. This is venous blood, full of waste products.
The Circular Blood Movement
• The venous blood enters the right atrium and travels downwards through a valve into the right ventricle.
• The heart pumps it into the pulmonary artery (the only artery in the body which carries venous blood). Thus the blood enters the lungs, where our indrawn air absorbs the waste (chiefly carbon dioxide) and fills it with oxygen.
• From the lungs it travels in the pulmonary vein to the left atrium of the heart.
• It moves downwards through another valve into the left ventricle.
• The heart pumps it out into the Aorta, the biggest artery, which allows it into all the other arteries, getting smaller and smaller.
• This blood gives up its oxygen, takes on waste products, and thus is now venous blood, returned to the heart for cleansing.
What is Fibrillation?
Our heartbeats are directed by the brain via nerves. In a diseased heart, information (nerve impulses) may not arrive intact or may not be interpreted and acted upon properly. The heart would then lose its steady rhythm and beat in a random, weak way, not effectively pumping blood. This is fibrillation.
If the brain does not receive enough oxygen for several minutes, it becomes damaged. Then it may cease to direct the heart to beat. Ventricular fibrillation is life-threatening. (There is also atrial fibrillation, which is a more minor problem.) If a person goes into ventricular fibrillation, time is of the essence. That is why an ICD is often implanted in the person"s chest, to immediately detect any arrhythmia in the heartbeats and correct it before fibrillation becomes dangerous.
How Does the ICD Work?
The ICD lead is attached in two places to the heart: to the right atrium and the right ventricle. From here the blood should be pumped into the lungs to be oxygenated. If the heart"s rhythm falters, these leads notice right away and the ICD sends an electrical shock through these leads to the heart. It jolts the heart back into a regular rhythm.
You may have seen the same thing done on some television programs about medical emergencies. Several nurses and doctors stand around the endangered patient with large electrodes on his chest, and the shock they deliver makes the patient jerk.
An ICD works more subtly but just as effectively. It protects a person from ventricular tachycardia (a heartbeat that"s too fast to be effective as well as from fibrillation.
Defective Defibrillator Leads
The leads are insulated with silicone. But in some cases, the insulation fails. Sometimes the lead fractures. Sometimes the lead does not detect an arrhythmia and thus fails to deliver the electrical jolt that would restore normal heart beats.
Some ICDs have been recalled because of such defects, for example, those made by Medtronic, Guidant and St. Jude Medical.
If you have lost a loved one because of the failure of an ICD, you might have a valid legal claim. Lawsuits involving defective medical appliances can be very complex and require time-consuming medical investigation. The sooner you contact an experienced defibrillator attorney, the sooner he or she can begin looking into your situation and gathering information.