Heart failure that occurs as a result of a previous heart attack can lead to a condition called ischemic cardiomyopathy. During a heart attack a portion of the left ventricle muscle - the main pumping chamber of the heart - is deprived of blood and dies, creating a scar that does not contract along with the rest of the healthy tissue in the left ventricle. This scar prevents the left ventricle from efficiently pumping blood to the rest of the body and it becomes volume overloaded. The left ventricle becomes larger and eventually heart failure develops and worsens, severely impairing quality of life and ultimately leading to death.
Without normal blood flow from the left ventricle, patients feel fatigued and short of breath, unable to comfortably conduct even simple everyday activities. Common symptoms of heart failure can include the following:
Doctors typically classify heart failure according to the severity of the patient's symptoms. The most common classification system comes from the New York Heart Association (NYHA), and it uses four categories to classify heart failure.
Class I: no symptoms and no limitation in ordinary physical activity (e.g., shortness of breath when walking, climbing stairs, etc.)
Class II (mild): mild symptoms (mild shortness of breath and/or angina) and slight limitation during ordinary physical activity.
Class III (moderate): marked limitation in activity due to symptoms, even during less-than-ordinary activity (e.g., walking short distances such as 20-100m).
Class IV (severe): severe limitations, experiences symptoms while at rest, mostly bedbound patients.
Heart failure medications
A consistent heart rhythm is important for maintaining proper blood flow to the brain, organs and all parts of the body. Rhythm management is how doctors make sure the heart keeps a regular beating pattern and does not miss any beats.
Cardiac Rhythm Management (CRM) takes two forms; one is to shock the heart back into a regular rhythm if it becomes erratic, (a high risk in patients with HF), and the other is to try to synchronize the two ventricles if they do not beat simultaneously. Both require implantation of a device into the body with leads extending through the vessels and into the heart. In the first instance, electricity is delivered to the heart to reorganize the rhythm back to regularity, and in the latter, a pacer lead is placed into both ventricles, and an attempt made to adjust the timing of contraction in each chamber to become more coordinated. The two forms can be used in combination, and placement of these devices works in over half the cases. Doctors may also use a non-surgical procedure known as ablation, which uses radiofrequency (RF) waves to eliminate the source of the irregular rhythm.
A VAD is a mechanical pump that is surgically placed in the heart failure patient’s chest to help distribute blood throughout the body. All current devices require a “drive line” placed outside the body that extends through the skin and to the VAD. The patient has to be continuously connected to a power source, although battery packs do allow temporary freedom to move about. The procedure may take 4 to 8 hours and require a 2 to 4 week hospital stay to recover. A VAD is considered invasive because doctors must cut the chest open to implant the device. Also, there is a higher risk for infection with VADs than with other less invasive treatment options because of the connection between the driveline and the VAD. Even the best devices ultimately require replacement, though some have lasted over a year. In general, while VADs have extended many lives, it is a one-way street; once a machine is installed, the patient remains attached for life unless a transplant is possible.
A heart transplant involves surgically replacing a failing heart with a healthier heart donated from a person who recently passed away. The most common reason for a receiving heart transplant is that one or both ventricles are not functioning well enough to help a failing heart pump properly. Heart transplantation is a very complicated procedure that carries many risks, including long wait times for a donor and the body’s possible rejection of the new heart. Transplant patients can expect a lifetime of heavy medications and close monitoring by a physician. The primary limitation, however, comes down to supply and demand. Throughout the world, far more patients need a heart transplant than there are heart donors. As a result, many patients die waiting for a new heart.
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3Gheorghiade, M; Bonow, R. Chronic heart failure in the United States: A manifestation of coronary artery disease. Circulation. 1998:97:282-289.