What is Congestive Heart Failure?

Damaged heart muscle can become so weak that it can no longer pump effectively, leading to cardiomyopathy and CHF.

Coronary artery disease and heart attacks are the most frequent causes of CHF, but inherited disorders, viral infections and toxins, such as alcohol, also can cause heart muscle damage. Symptoms of CHF typically include shortness of breath, swelling of the feet and legs, abdominal swelling, fatigue, exercise intolerance, diminished appetite and depression.

Most often, medications aim to control CHF symptoms, such as the buildup of excess fluid that causes leg swelling and makes it difficult to breath. Medications can reduce fluid retention, strengthen the heart’s squeezing ability and relax blood vessels, thereby reducing the resistance to blood flow and easing the heart’s workload.

In addition, lifestyle changes, such as low-salt diets and exercise, can help control symptoms.

Overview of a Heart Beat

The heart is comprised of four chambers: two upper atria, and two lower ventricles. An electrical system controls the synchronized pumping action of these chambers.

The normal heartbeat originates in a section of the right atrium known as the sinoatrial, or SA node. The electrical signal from the sinoatrial node spreads through both atria causing them to contract and squeeze blood into the ventricles. The electrical signal then passes through an electrical bridge known as the atrioventricular or AV node. After a split second delay, the signal continues to the ventricles by way of a specialized network known as the left and right bundle branches.

The bundle branches separate to the left and right ventricles, which enables the electrical signal to stimulate both ventricles simultaneously. This coordinated contraction, or squeezing, of the ventricles is necessary for optimal pumping of blood to the body and lungs.

Uncoordinated Contractions

When there is a delay in electrical signal transmission through the left bundle branch, this causes left bundle branch block (LBBB). Because the electrical signal to the left ventricle is delayed, the right ventricle begins to contract a fraction of a second before the left ventricle, instead of simultaneously. The result is an asynchronous, or uncoordinated contraction of the ventricles and a mis-timing in the contraction pattern of the left atrium and ventricle. Other conduction abnormalities, such as right bundle branch block (RBBB), also may contribute to less efficient contraction of the heart. This further reduces the pumping ability of the already weakened heart muscle.

Cardiac Resynchronization treatment

Cardiac resynchronization relies on electric leads to correct an arrhythmia commonly diagnosed in patients experiencing heart failure. The leads electrically stimulate heart muscle to synchronized the contractions of the heart’s two lower chambers, or ventricles. Only when the lower chambers beat in harmony can they contract with enough force to push blood carrying oxygen through the body.

More than 22 million people worldwide suffer from congestive heart failure (CHF), a potentially debilitating disease.

Until recently, lifestyle changes, medication and, sometimes, heart surgery were the only treatment options. Patients with severe symptoms, however, received little, if any, relief from such approaches. To make matters worse, up to 40 percent of patients with CHF also have an arrhythmia that further reduces the heart’s ability to beat properly.

Cardiac resynchronization therapy (CRT) is an innovative new therapy that can relieve CHF symptoms by improving the coordination of the heart’s contractions.CRT builds on the technology used in pacemakers and implantable cardioverter devices. CRT devices also can protect the patient from slow and fast heart rhythms.