How does heart failure develop?

How does heart failure develop?

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, creating scar tissue that does not contract along with the rest of the healthy muscle in the left ventricle. This scar tissue prevents the left ventricle from efficiently pumping blood to the rest of the body. To compensate for this inefficiency, the left ventricle becomes larger and the healthy muscle must work harder. Eventually, heart failure develops and continuously worsens, severely impairing quality of life and ultimately leading to death.

Common symptoms of heart failure.

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:

  • Fatigue and/or shortness of breath during normal activity
  • Increased swelling of feet, legs, fingers or abdomen
  • Weight gain caused by fluid retention
  • Shortness of breath and/or anxiety when lying flat, especially in bed
  • Persistent dry, hacking cough
  • Generalized weakness
  • Nausea or swelling in the abdomen
  • Frequent urination at night

Recognizing the signs and symptoms of heart failure can help you and others tell if you’re in danger and whether to notify your doctor. A good way to identify the signs of heart failure is to remember the acronym FACES:

F = Fatigue (feeling really tired and run down).

A = Activity limitation (unable to comfortably perform simple, everyday activities such as walking, gardening or climbing steps).

C = Chest congestion or cough.

E = Edema or swelling (especially in the legs and ankles).

S = Shortness of breath (including the anxious feeling that you can’t get enough air).

How doctors classify heart failure.

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.

Other therapies for treating heart failure.

Heart failure medications

Cardiologists treat heart failure (HF) with many different medications. Most of these are useful regardless of the cause of HF, and all HF patients should be on optimal dosages of these standard therapies. Each performs a special function to help patients feel better, however, they do not cure HF. Depending on symptoms, patients might take one or more of the following drugs recommended by their physicians:

  • Angiotensin-converting enzyme (ACE) inhibitors
  • Angiotensin II receptor blockers
  • Digoxin
  • Beta blockers
  • Diuretics
  • Aldosterone antagonists

Rhythm management

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, in the latter, a pacing lead is placed into both ventricles, in an attempt 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.

Ventricular Assist Device (VAD)

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 drive line 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 device is installed, the patient remains attached for life unless a heart transplant is possible.

Heart transplant

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 allow a failing heart to 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.