Heart Failure: Definition, Symptoms, Classification, Causes and Diagnosis

Heart failure is a major cause of morbidity and  cardiovascular mortality worldwide.It often develops as a consequence of maladaptive cardiac remodeling in response to severe stress, exposure to toxins or injury. Early diagnosis and treatment of causes are essential to prevent progression to more severe symptoms

Heart failure is a clinical syndrome that can result from any disorder that compromises the ability of the ventricle to fill or expel blood, making the heart unable  to pump blood and deliver the body's metabolic needs. Heart failure is the last common route for many heart conditions, including those affecting the pericardium, heart valves and myocardium. Diseases that adversely affect the ventricular diastole (filling), ventricular systole (contraction) or both can cause heart failure

Heart Failure Definition

Heart failure (HF), also called congestive heart failure (CHF), is a common condition that occurs when the heart is unable to pump enough blood to meet the oxygen and nutrient needs of the tissues. It can be the result of impaired myocardial contraction during systole (systolic dysfunction), relaxation and filling of compromised ventricles during diastole (diastolic dysfunction) or a combination of systolic and diastolic dysfunction

Heart Failure Symptoms

The key symptoms of heart failure are respiratory distress (DISNEA) and fluid retention (edema). Since symptoms gradually appear with the progression of heart failure, many people do not notice until they notice fatigue, weakness with exertion, rapid or unexplained weight gain and frequent urination

The primary symptoms of heart failure are fatigue and shortness of breath. Although fatigue has traditionally been attributed to low cardiac output in heart failure, abnormalities of skeletal muscle and other non-cardiac comorbidities (eg Anemia) can also contribute to this symptom. Right heart failure tends to cause peripheral edema (swelling of legs, ankles and feet). Left heart failure tends to cause central edema (fluid build-up in the lungs), also known as congestive heart failure

The most important mechanism is pulmonary congestion with accumulation of interstitial or intraalveolar fluid, which activates the juxtacapillary J receptors, which in turn stimulate the rapid and superficial breathing characteristic of cardiac dyspnea. Heart failure patients may also have gastrointestinal symptoms such as anorexia, nausea and early satiety associated with abdominal pain and fullness are common cases and may be related to edema of the intestinal wall and / or a congested liver. In patients with severe HF, especially elderly patients with cerebral arteriosclerosis and reduced brain perfusion show them Brain symptoms such as confusion, disorientation and sleep and mood disturbances

ORTHOPNEA: orthopnea, defined as dyspnea that occurs in a reclining position, is usually a subsequent manifestation of heart failure compared to exertional dyspnea. It is the result of the redistribution of the fluid from the splanchnic and lower limb circulation into the central circulation during reclining, with a consequent increase in pulmonary capillary pressure

PAROXISMAL NIGHT DYSPNEA (PND) This term refers to acute episodes of severe respiratory distress and cough that usually occur at night and wake the patient from sleep, usually 1 to 3 hours after the patient has withdrawn

Classification of Acute Heart Failure

I Patients with heart disease but without limits of physical activity. Ordinary physical activity does not cause fatigue, dyspnoea or undue palpitations

II Patients with heart disease involving slight limitations of physical activity. Ordinary physical activity produces fatigue, palpitations, dyspnea or angina

III Patients with heart disease who produce a marked limitation of physical activity. Although patients feel comfortable at rest, fewer than normal activities will cause symptoms

IV Patients with heart disease with consequent inability to perform physical activity without discomfort. Symptoms of congestive heart failure are also present at rest. With any physical activity, you experience greater discomfort

Heart Failure Causes 

Heart failure is a progressive disorder according to mechanisms that are responsible for the symptoms and disease progression wich, starts with a myocardial injury. In response to the injury, various compensatory responses are activated in an attempt to maintain adequate cardiac output, including the sympathetic nervous system, increased preload, vasoconstriction and ventricular hypertrophy / remodeling

At the cellular level, heart failure is due to the dysfunction of the contractile myocardial cells and the endothelial cells that line the heart and blood vessels. The vital functions of the endothelium include maintaining the balance between vasodilation and vasoconstriction, coagulation and anticoagulation and the promotion and inhibition of cell growth

Endothelial dysfunction allows processes that narrow the lumen of blood vessels (e.g. atherosclerotic plaque buildup, cell growth, inflammation, platelet activation) and lead to the formation of blood clots and vasoconstriction that further narrow the lumen of blood vessels. blood vessels. These are important factors in coronary heart disease and hypertension, the most common conditions that lead to heart failure

• A heart attack

• Heart valve disease

• Certain types of arrhythmias

• High blood pressure/hypertension

• Cardiomyopathy, a disorder of the heart muscle that causes the heart to become weak

• A congenital heart defect

• Lung disease, such as emphysema

• Diabetes

• An hyper-active or hypo-active thyroid

• HIV

• Severe types of anemia

• Certain cancer therapies, such as chemotherapy

• Drug or alcohol abuse

Systolic dysfunction (reduced contractility)

• Reduction of muscle mass (eg myocardial infarction)
• Dilated cardiomyopathies
• Ventricular hypertrophy
• Pressure overload (eg, systemic or pulmonary hypertension, aortic or pulmonary valve stenosis)
• Volume overload (eg valve regurgitation, shunts, high performance states)

Diastolic dysfunction (restriction in ventricular filling)

• Greater ventricular stiffness
• Ventricular hypertrophy (eg, hypertrophic cardiomyopathy, other previous examples)
• Infiltrative diseases of the myocardium such as amyloidosis, sarcoidosis, endomyocardial fibrosis
• Ischemia and myocardial infarction
• Mitral or tricuspid valve stenosis
• Pericardial disease (eg, pericarditis, pericardial tamponade)

Heart Failure Diagnosis

Heart failure is a clinical diagnosis grounded on the basis of symptoms, physical findings and chest radiography. Symptoms generally include a combination of wheezing, fatigue and water retention. Dyspnea can be exercised or reclined

There is no single test available to confirm the diagnosis of heart failure. Since heart failure syndrome can be caused or aggravated by multiple cardiac and non-cardiac ailments, an accurate diagnosis is essential for the development of therapeutic strategies

It is often recognized to heart failure disease in a patient based on symptoms. However, it should be emphasized that the signs and symptoms lack sensitivity to diagnose heart failure because these symptoms are frequently found with other ailments such as lung disease. Even in patients with known heart failure, there is little correlation between the presence or severity of symptoms and the hemodynamic abnormality

• Laboratory tests to identify disorders that can cause or worsen heart failure include competitive blood count; serum electrolytes (including calcium and magnesium); kidney, liver and thyroid function tests; urine analysis; lipid profile; and hemoglobin A1C. Selected patients should be screened for diabetes mellitus (serum glucose tolerance test or fasting oral glucose), dyslipidemia (fasting lipid panel) and thyroid abnormalities (thyroid stimulating hormone level)

• An echocardiogram is the most useful assessment procedure because it can identify abnormalities of the pericardium, myocardium or cardiac values ​​and quantify the left ventricular ejection fraction (LVEF) to determine if there is systolic or diastolic dysfunction. The main importance of the ECG is to evaluate the heart rhythm and determine the presence of VS hypertrophy or a previous myocardial infarction (presence or absence of Q waves), as well as determine the amplitude of the QRS to determine if the patient can benefit from the therapy. resynchronization.A normal ECG virtually rules out systolic dysfunction

• A chest X-ray provides useful information about the size and shape of the heart, as well as the status of the pulmonary vascular system and can identify the non-cardiac causes of the patient's symptoms

A complete medical history and physical examination are essential in the initial assessment of a patient suspected of having heart failure. Particular attention should be paid to cardiovascular risk factors and other ailments that can cause or exacerbate heart failure

Framingham Criteria for Clinical Diagnosis of Congestive Heart Failure

Major criteria

• PND (paroxysmal nocturnal dyspnea)
• Orthopnea
• Increased JVP (jugular venous pressure)
• Rales
• S3
• Chest X-ray
• Cardiomegaly
• Pulmonary edema

Minor criteria

• Peripheral edema
• Night cough
• DOE (exertional dyspnea)
• Hepatomegaly
• Pleural effusion
• Heart rate> 120 beats / min
• Weight loss ³4.5 kg in 5 days with diuretic