The Healthy Heart
Anatomy of the Heart
The heart is a muscle located in the middle of the chest and behind the breastbone (sternum) that is approximately the size of a fist. It is "powered" by an "electrical system" that signals the heart muscle to beat rhythmically approximately 72 times per minute.
If you were to slice it down the middle, you would find that it has three layers, the endocardium (the smooth inside lining of the heart); the myocardium (the muscle layer of the heart); and the epicardium (the outside lining of the heart). The pericardium is the tough, fluid-filled sac that surrounds the heart itself, this pseudo-fourth layer provides protection and minimizes the friction created by the heart beat.
The Heart is divided into four chambers: The Right Atrium (RA), the Right Ventricle(RV), the Left Atrium(LA) and the Left Ventricle (LV). The electraical signal for each heartbeat begins in the Right Atrium in an area called the sinus node (aka the heart's natural pacemaker). Each chamber has a one-way valve at its exit that prevents blood from flowing backwards. When each chamber receives an electrical pulse, it contracts, and the valve at its exit opens pumping blood through it and when it is finished contracting the valve closes. As the lower chambers fill with blood, the electrical signal travels along special conduction tissues to the AV node, where it pauses for a few seconds, allowing the chambers to finish filling.
There are four valves in the heart including the Tricuspid Valve, which is at the exit of the Right Atrium, the Pulmonary Valve, which is at the exit of the Right Ventricle, the Mitral Valve, which is at the exit of the Left Atrium and the Aortic Valve, which is at the exit of the Left Ventricle.
When the heart muscle contracts (or beats) it pumps blood out of the lower chambers of the heart. The heart contracts in two stages. In the first stage the Right and Left Atria contract at the same time, pumping blood to the Right and Left Ventricles. Then the Ventricles contract together (called systole) to propel blood out of the heart. After this second stage, the heart muscle relaxes (called diastole) before the next heartbeat. During this time, the muscle resets itself for contraction and blood fills the atria.
Functions of the Heart
The right side of the heart collects oxygen-poor blood from the body and pumps it to the lungs where it picks up oxygen and releases carbon dioxide while the left side collects oxygen rich blood from the lungs and pumps it to the body so that the cells throughout your body have the oxygen they need to function properly.
All blood enters the right side of the heart through two veins, the Superior Vena Cava(SVC), which collects blood from the upper half of the body and the Inferior Vena Cava (IVC), which collects blood from the lower half of the body.
When the heart is pumping, blood flows from the body to the Superior and Inferior Vena Cava then to the Right Atrium through the Tricuspid Valve. It flows to the Right Ventricle through the Pulmonary Valve through the Pulmonary Artery to the Lungs.
There, the blood picks up oxygen and drops off carbon dioxide in the lungs, and then flows from the lungs through the Pulmonary Veins to the Left Atriumthrough Mitral Valve to the Left Ventriclethrough the Aortic Valve to the Aorta through the two main coronary arteries -- the Left Coronary Artery (which divides into two - the Left Anterior Descending Artery and the Circumflex Artery) and the Right Coronary Artery. From here blood flows the arterial system to the body.
The heart, just like any other organ, requires blood to supply it with oxygen and other nutrients so that it can do its work. The heart does not extract oxygen and other nutrients from the blood flowing inside it. The heart gets its blood from coronary arteries, located on the outside surface of the heart, that eventually carry blood within the heart muscle through a network of branches.
Heart Failure does not mean your heart has stopped beating. It means that the heartbeat is not sufficient to supply an adequate volume of blood and oxygen to the brain and other parts of the body. When this occurs, a variety of compensatory changes will take place in an effort to pump an adequate amount of blood:
-the walls of the heart will stretch to increase volume capacity
-the walls of the heart will thicken to squeeze more forcefully
-the kidneys cause the body to retain sodium and water thereby increasing the amount of circulating blood
-hormones are released to make the heart squeeze more forcefully
Over time, these compensatory mechanisms will not be adequate to maintain sufficient circulation. The blood will not flow through the heart efficiently and as a result the heart becomes congested causing a backup of pressure in the circulatory system. This is known as Congestive Heart Failure (CHF) An associated build up of fluids occurs in the tissues, especially the lungs, causing peripheral swelling, fatigue and shortness of breath.
Two to three million Americans live with congestive heart failure. It is one of the most common reasons people 65 and older are admitted to the hospital. It can take years to develop.
Symptomatology; blood tests; electrocardiography and echocardiography; x-rays, angiography.
Treatment of chronic heart failure includes the use of multiple medications including: vasodilators (drugs that dilate blood vessels); ACE inhibitors (drugs that block vasoconstriction); inotropes (drugs that increase the heart's ability to contract), and diuretics (drugs to reduce fluid). These medications are used alone and in combination.
In a healthy heart, both upper chambers (atria) beat together as do both lower chambers (ventricles). Electrical impulses are delivered to the left ventricle in a highly organized pattern of contractions that efficiently pump blood out of the ventricle. In about one-third of patients with congestive heart failure (CHF), the electrical coordination is lost and the right and left ventricles do not beat together. This uncoordinated heart muscle function leads to inefficient ejection of blood from the ventricles and poses the risk of abnormal heart rhythms (arrhythmias). The biventricular pacemaker has leads implanted in the right atria, the right ventricle and the coronary sinus to sense and pace the left ventricle. This three-lead system allows the pacemaker to sense both ventricles and stimulate in a way that causes them to contract together. This resynchronization can help alleviate symptoms of CHF such as fatigue, shortness of breath and exercise intolerance thereby improving the patient's overall quality of life.
Correction of underlying problem
Early diagnosis and corrective treatment of an underlying problem may minimize the risk of congestive heart failure. Medicines may be described to increase cardiac output and others to reduce volume overload.
Careful monitoring of the diet can help to keep symptoms of heart failure from flaring up. Heart failure patients eat a healthy diet that is low in salt and monitor their fluid intake.
Corrective surgery is an option to treat underlying conditions to prevent them from leading to congestive heart failure. Surgery may also be done in some instances for the patient with congestive heart failure.
Severe coronary artery disease (CAD) or valve disease may lead to CHF. Patients with CAD may benefit from angioplasty or bypass surgery. Patients with faulty heart valves can have valve replacement surgery. For severe CHF, a heart transplant may be needed.
Heart Failure Program - Multi-faceted Treatment:
The Congestive Heart Failure program at The University Hospital is designed to minimize the length of hospital stay for heart failure patients and to reduce admissions and readmissions. At the same time, the program also focuses on improving the patient's ability to accomplish the routines of daily living as well as to reduce the number of medical complications associated with congestive heart failure.
The reduction of length of stay is accomplished through early and aggressive therapy for patients admitted with heart failure. Echocardiography is used in the Emergency department to make an immediate diagnosis so that therapy can start without delay. Admissions and re-admissions to the hospital are reduced because of a committed clinical staff who ensure that patients are seen frequently, adjustments to medications are made as needed, and will regularly re-enforce with patients the need for medical and dietary compliance.
The clinical staff help patients increase their ability to accomplish the routines of daily living by aggressively following up to be sure they take their medicines, and participate in a nutritional counseling and exercise rehab program. Patients who remain symptomatic despite receiving the best of conventional care are encouraged to participate in clinical trials.
The Program serves both hospitalized patients and as well as providing outpatient services by appointment at the NACC and Doctors Office Center (DOC).