Generality
Heart failure is the inability of the heart to supply an adequate amount of blood compared to the normal needs of the body. In fact, for a number of causes, the heart muscle can weaken and generate less contractile force.
The most common causes of heart failure include severe health conditions that damage the heart, including myocardial infarction and other forms of ischemic heart disease, hypertension, valvular heart disease and cardiomyopathy. Heart failure can involve the left, right or both sides of the heart. In general, the onset of the condition affects the left side (in particular, the left ventricle), but the effects can also affect the other side.
The condition is diagnosed by physical examination of the patient, supported by blood tests and confirmed by echocardiography.
Often, it is not possible to reverse the conditions that induce heart failure, but this can be treated with good results. Depending on the etiology and severity of the clinical picture, the disorder can be managed with drug therapy, pacemaker implantation, ventricular assist devices or, in the most severe cases, with a heart transplant. The best way to prevent heart failure is to control the risk factors and conditions that contribute to determining its onset, such as hypertension, high cholesterol, diabetes and obesity.
Causes
In most cases, heart failure is not a consequence of a single cause, but develops due to the overlapping of multiple predisposing conditions. In the presence of these disorders, the heart muscle can become progressively too weak to function properly, until it loses its ability to pump blood at the right pressure and efficiently through the body. In similar circumstances, heart failure is due to chronic alteration of ventricular contractility (ability to generate a force starting from a given diastolic volume). Also a dysfunction of an atrioventricular valve can induce the slowing of the ventricular filling, therefore the reduction of the ejection volume during diastole. Furthermore, any of the following pathological conditions can damage or weaken the heart and contribute to causing heart failure:
- High blood pressure (hypertension) : if the pressure is high, the heart muscle must increase its activity to circulate blood throughout the body. Over time, hypertension can induce a compensatory increase in myocardial thickness (hypertrophy). As a result, the heart muscle can reduce its ability to relax during the alternation of contractions and relaxations, and decrease the amount of blood housed in its cavities (whose walls become thicker). High blood pressure can therefore interfere with the heart's ability to maintain correct cardiac output and, over time, cause heart failure;
- Coronary artery disease : arteries that supply blood to the heart muscle can reduce their lumen due to the progressive accumulation of fat deposits and scar tissue (a process called coronary arteriosclerosis). As a result, blood moves slowly through the arteries, leaving some areas of the heart muscle weak and chronically devoid of oxygen-rich blood. This imbalance contributes to the onset of angina or other cardiac disorders;
- Ischemic heart disease: a blood clot in one of the coronary arteries can cause irreversible damage and injuries to the heart muscle, usually during an acute heart attack. However, blood flow obstruction can also occur gradually, progressively weakening the ability to maintain adequate cardiac output: it is the case of atherosclerosis. For this reason, it is important to note this phenomenon, as a therapeutic intervention on blocked blood vessels can lead to an improvement in cardiac function.
- Cardiomyopathy : it is recognized as one of the most common causes of heart failure. Etiology is often unclear, but may include genetic factors, infections, alcohol abuse and the toxic effect of drugs (such as cocaine) or some drugs used for chemotherapy;
- Cardiac rhythm anomalies ( cardiac arrhythmias ): they can worsen heart failure or contribute to causing the condition. An irregular heart rhythm (atrial fibrillation is the most common irregularity) increases the risk of developing a blood clot (thrombosis), which can cause a stroke. In some people, this alteration can also cause heart failure, particularly in cases of tachycardia (if the CF is above 140 beats per minute). If the heart beats too fast, it may not have enough time to fill and empty properly, and over time, the heart muscle may weaken. In these cases, treating heart rhythm disorder can reverse the pathological condition. Even a very slow heartbeat (less than 40 beats per minute) can reduce the efficiency of the heart and lead to symptoms of heart failure;
- Heart valve disorders: the heart contains four one-way valves to ensure that blood flows proceed in the right direction. A damaged valve, due to a heart defect, a coronary heart disease or a local infection, forces the heart to increase its activity to maintain the correct blood supply to the body. Progressively, this extra work can weaken the heart. Defective heart valves, if detected in time, can be effectively treated by repair or replacement.
- Myocarditis: consists of an inflammation of the heart muscle. Myocarditis is usually caused by a viral infection and can induce heart failure.
- Congenital heart conditions: some people suffering from heart failure have structural heart defects since birth. Some children, for example, are born with an abnormal connection between the right and left sides of the heart (Botallo's oval hole), which allows blood to flow from one side to the other (usually, from left to right).
- Other diseases: chronic diseases such as diabetes, severe anemia, hyperthyroidism, hypothyroidism, pulmonary emphysema, systemic lupus erythematosus and an accumulation of iron (hemochromatosis), proteins ‹‹ (amyloidosis) or inflammatory cells ( sarcoidosis) can help increase the risk of developing heart failure. Causes of acute heart failure include myocardial infarction, infections that attack the heart muscle, allergic reactions and taking certain medications (chemotherapy or diabetes management).
Symptoms
To learn more: Symptoms of Heart Failure and Symptoms of Heart Failure
The main symptoms of heart failure are dyspnea, extreme tiredness and ankle swelling, which can extend to the legs. However, these symptoms can also be caused by other conditions and, for this reason, the doctor may suggest some investigations to ascertain a heart failure or to exclude it as a cause of the symptoms.
Other symptoms that are associated with heart failure include:
- Persistent cough;
- Inappetence or nausea;
- Weight loss;
- Tachycardia (fast heart rate).
The symptoms of heart failure can arise rapidly (acute heart failure), while in other cases they may develop gradually over the long term (chronic heart failure).
Chronic heart failure - signs and symptoms
- Shortness of breath (dyspnea), during a physical activity or if the patient assumes a lying position;
- Fatigue and weakness;
- edema in legs, ankles and feet;
- Accelerated or irregular heart beat;
- Persistent cough or breathlessness;
- Swelling of the abdomen (ascites);
- Sudden weight gain due to fluid retention;
- Lack of appetite and nausea;
- Difficulty concentrating or decreasing vigilance.
Acute heart failure - signs and symptoms
- Symptoms similar to those of chronic but more serious heart failure, onset or sudden worsening;
- Fluid retention;
- Rapid or irregular heart beat (palpitations);
- Sudden and severe shortness of breath;
- Chest pain, if heart failure is caused by a heart attack.
The onset of symptoms is also influenced by the affected part of the heart.
Left heart failure - signs and symptoms
If the condition affects the left heart, the symptoms include weakening of the wrist, fatigue and cyanosis (indicates inadequate oxygenation). Another sign of left ventricular failure is pulmonary edema (fluid accumulation in the lungs), due to increased pressure in the venous district of the pulmonary circulation. The insufficiency of the left ventricle induces an increase in the pressure in the pulmonary veins, which carry the oxygenated blood to the left side of the heart.
Other signs and symptoms of left heart failure are:
- Shortness of breath: if present during rest, markedly worsens, in particular if the patient is lying in bed during night rest;
- In less severe cases, breathing problems begin only under stress;
- Persistent dry cough;
- Fatigue and muscle weakness;
- Weight loss, usually only in advanced cases.
Right heart failure - signs and symptoms
- In the case of right ventricular failure, however, the pressure in the vena cava and in the systemic veins increases. This causes excessive accumulation of fluids in the body (water retention), especially in the legs and abdominal organs, which are more likely to be affected by complications.
Symptoms of right heart failure (and biventricular insufficiency ) are:
- Swelling of the legs (edema);
- Dry skin in the lower part of the legs, as a result of the edema and due to the pressure inside the tissue;
- Eczematous rash on the legs, which can be complicated by ulcers that do not heal (venous ulcers);
- Possible accumulation of fluid in the abdominal cavity and at the level of organs, such as the liver and kidneys. The organs swell and the abdominal wall may expand.
When the diagnosis of heart failure is overt, it is necessary to monitor the symptoms carefully. If the weight increases more than 2 kg in a few days, it can be a sign of fluid retention; this evidence could therefore indicate the need to reduce the amount of salt introduced with the diet or to take diuretics. You should also tell your doctor if you develop new clinical signs or if an existing symptom suddenly worsens.
Complications
If you suffer from heart failure, the possibility of a series of complications being triggered depends on the cause and severity of the disorder, general health conditions and other factors, such as age.
Complications may include:
- Damage or kidney failure. Heart failure can reduce blood flow to the kidneys and, if neglected, can cause kidney failure. Renal damage resulting from heart failure may require dialysis for treatment.
- Valvulopathies, heart attack and stroke.
- Liver injury. Heart failure can lead to an accumulation of fluid , which, if it exerts too much pressure on the liver, makes normal liver function more difficult.
Symptoms and cardiac function may improve with proper treatment. However, heart failure is a life-threatening condition and can lead to sudden death.
Continue: Heart Failure - Diagnosis and Treatment »
