What is heart failure?
Heart failure, also called congestive heart failure, is a condition in which the heart cannot pump enough oxygenated blood to meet the needs of the body's other organs. The heart keeps pumping, but not as efficiently as a healthy heart. Usually, the loss in the heart's pumping action is a symptom of an underlying heart problem. Heart failure affects nearly 5 million adults in the United States. It is on the rise with an estimated 400,000 to 700,000 new cases each year.
What causes heart failure?
Heart failure may result from any/all of the following:
- coronary artery disease - narrowed arteries that supply blood to the heart muscle
- previous heart attack(s) (myocardial infarction) - scar tissue from previous attacks may interfere with the heart muscle's ability to work normally
- high blood pressure (hypertension)
- heart valve disease - caused by past rheumatic fever or other infections
- infections of the heart valves and/or heart muscle (i.e., endocarditis)
- congenital heart disease/defects (present at birth)
- cardiomyopathy - or another primary disease of the heart muscle
- inflammation of infection of heart muscle (myocarditis)
- cardiac arrhythmias (irregular heartbeats)
- drug-induced heart failure
- excessive sodium intake
- chronic lung disease and pulmonary embolism
- hemorrhage and anemia
How does heart failure affect the body?
Heart failure interferes with the kidney's normal function of eliminating excess sodium and waste from the body. In heart failure, the body retains more fluid - resulting in swelling of the ankles and legs. Fluid also collects in the lungs - resulting in shortness of breath.
What are the symptoms of heart failure?
The following are the most common symptoms of heart failure. However, each individual may experience symptoms differently. Symptoms may include:
- shortness of breath during rest, exercise, or lying flat
- weight gain
- visible swelling of the legs and ankles (due to a build-up of fluid), and, occasionally, the abdomen
- fatigue and weakness
- loss of appetite and nausea
- persistent cough - often produces mucus or blood-tinged sputum
- reduced urination
The severity of the condition and symptoms depends on how much of the heart's pumping capacity has been lost.
The symptoms of heart failure may resemble other conditions or medical problems. Always consult your physician for a diagnosis.
How is heart failure diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for heart failure may include any, or a combination of, the following:
- chest x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- echocardiogram (Also called echo.) - a noninvasive test that uses sound waves to produce a study of the motion of the heart's muscle and valves. The echo sound waves create an image on the monitor as an ultrasound transducer is passed over the heart.
- electrocardiogram (ECG or EKG) - a test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias), and detects heart muscle damage.
- BNP testing - B-type natriuretic peptide (BNP) is a hormone released from the ventricles in response to increased wall tension (stress) that occurs with heart failure. BNP levels rise as wall stress increases. BNP levels are useful in the rapid evaluation of heart failure.
Treatment for heart failure:
Specific treatment for heart failure will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the disease
- your tolerance for specific medications, procedures, or therapies
- expectations for the course of the disease
- your opinion or preference
The cause of the heart failure will dictate the treatment protocol established. If the heart failure is caused by a valve disorder, then surgery is usually performed. If the heart failure is caused by a disease, such as anemia, then the disease is treated. And, although there is no cure for heart failure due to a damaged heart muscle, many forms of treatment have proven to be successful.
The goal of treatment is to improve a person's quality of life by making the appropriate lifestyle changes and implementing drug or surgery.
- controlling risk factors:
- losing weight (if overweight)
- restricting salt and fat from the diet
- stop smoking
- abstaining from alcohol
- proper rest
- controlling blood sugar if diabetic
- Medication, such as:
- beta-blockers - reduce the heart's tendency to beat faster by blocking specific receptors on the cells that make up the heart
- angiotensin converting enzyme (ACE) inhibitors - to decrease the pressure inside the blood vessels, or angiotensin II receptor blockers if ACE inhibitors are not tolerated
- diuretics - to reduce the amount of fluid in the body
- vasodilators - to dilate the blood vessels and reduce workload on the heart
- digitalis - to increase heart strength and control rhythm problems
- inotropes - increase the pumping action of the heart
- antiarrhythmia medications - keep the rhythm regular and prevent sudden cardiac death
- aldosterone blockers - block the effects of aldosterone which causes sodium and water retention.
Mechanical Circulation Support - Ventricular Assist Devices:
Mechanical circulatory support (MCS) is the practice of using mechanical devices, or blood pumps, to support failing heart function. MCS is employed when the forward pumping function of the heart cannot pump blood to vital organs. This “low flow” situation, combined with increased congestion in the lungs and other organs in spite of maximal therapy with medications, is ultimately fatal if left untreated. Mechanical circulatory support is most often provided by ventricular assist devices (VADs), specifically designed blood pumps that take over the pumping function of the heart.
These, devices, while they do not replace the heart, work by receiving blood that enters the ventricles and is routed to the VAD instead of the heart. The VAD then pumps the blood to the body or to the lungs, assuring adequate flow and relieving congestion in the lungs and other organs.
A VAD is used to assist the right (RVAD) or left (LVAD) ventricle, though the majority of patients have primary left ventricular failure and can be supported with an LVAD alone. In some patients, both ventricles fail and require support simultaneously (BiVAD). Rarely, a patient may have isolated right heart failure, requiring only RVAD support.
All assist devices consist of a pump with an inflow attachment that connects to and receives blood from the right or left ventricle and directs blood to the VAD pumping chamber. Blood is then pumped through an outflow graft that returns the blood to the aorta (for an LVAD) or the pulmonary artery (for an RVAD) with the appropriate amount of pressure and flow. The pumps are driven pneumatically, using air, or electrically. All pumps require a control system to maintain regulated pumping function. The energy supplies for the devices and the controllers are located outside of the patient and are connected to the pump by a driveline.
Some pumps are placed inside of the patient, while others are external. When the pump is external, the inflow and outflow connections to the pump traverse the skin, bringing blood from the heart and back to the body through conduits connecting the ventricles and arteries. The earliest LVADs and RVADs were external (paracorporeal). Currently, the majority of VADs used for right ventricular support are paracorporeal. When biventricular support is required, a paracorporeal system for right and left heart support is often used.
The majority of left ventricular assist devices (LVADs) currently in use are internal (intracorporeal) and are connected to external power sources and controllers. This offers the patient the possibility of leaving the hospital with a portable or wearable power source and controller. The power sources with rechargeable batteries allow patient mobility as well, which can improve quality of life and lead to a relatively normal lifestyle.
Originally, VADs were used for only short-term emergency support. The intent was to allow the heart muscle time to recover. Such support, which was most frequently used after open heart surgery (post-cardiotomy) is commonly called bridge-to-recovery and is still employed for periods of time lasting from several days to several weeks.
Currently available devices that allow patients to go home can also be used for bridge-to-recovery in patients with certain types of diseases that lead to heart failure from which patients can recover. In this case, after a period of resting the heart for up to several months, the device may be able to be removed.
VADs are also used for patients with very advanced or “end stage” heart failure who have been evaluated and found suitable for heart transplantation, and are awaiting a suitable donor heart. Some patients deteriorate to the point where survival is not possible without a mechanical circulatory support using a VAD. This use is known as a bridge-to-transplant (BTT), and currently many potential heart transplant recipients require this type of surgery prior to transplant. Bridge-to-transplantation with VADs has been successfully used for more than two decades.
More recently, one VAD was approved for use as an alternative to transplant, called destination therapy (DT) and is the use of mechanical circulatory support for patients who are not suitable candidates for cardiac transplantation for a variety of reasons. This device was approved after a large randomized trial comparing best medical therapy to LVAD therapy in patients not suitable for cardiac transplantation. This study showed a definite survival advantage with LVAD use. It is anticipated that many more patients will eventually be supported with LVADs rather than heart transplants because of the finite and limited supply of suitable donor hearts.
Currently, there are smaller and more advanced second and third generation devices under investigation for both bridge-to-transplant and destination therapy. These devices are continuous flow pumps using either axial or centrifugal flow to support the circulation. These devices are not only smaller but likely more durable than first generation devices. All such DT devices are portable with wearable controllers and energy supplies. The initial experience with these devices at Inova Fairfax Hospital has been extremely favorable and looks very promising for the future.