Heart Failure - Acute Disease Background

Last updated: 08 June 2026
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Introduction

Heart failure is a clinical syndrome that is due to a structural or functional cardiac abnormality that impairs the ability of the ventricle to fill with or eject blood in order to deliver oxygen (O2) at a rate commensurate with the requirements of the metabolizing tissues in spite of normal filling pressures or only at the expense of elevated filling pressures. This is corroborated by objective evidence of cardiogenic, pulmonary, or systemic congestion and/or elevated levels of natriuretic peptides. This is characterized by either left ventricular (LV) hypertrophy or dilation or both.

Acute heart failure is a rapid or gradual onset of new or worsening signs and/or symptoms of heart failure and arises as a result of acute cardiac function deterioration in previously stable patients with heart failure or may also be the first presentation of heart failure (de novo heart failure). Acute heart failure arising from decompensation of chronic heart failure is a slow and progressive deterioration and is associated with arrhythmia, uncontrolled hypertension, infection, and non-compliance with therapy and diet. The cardiac dysfunction may be related to ischemia, arrhythmia, valvular abnormalities, pericardial disease, myocarditis, cardiomyopathy, volume overload, increased filling pressure, or elevated systemic resistance.

Epidemiology

Heart failure affects more than 60 million individuals globally. The prevalence ranges between 1-2% in the general adult population. The incidence of heart failure increases with age and is higher in males than in females.

The prevalence estimates of heart failure in Asia range between 1.3% and 6.7%. In Asia, the prevalence of heart failure with preserved ejection fraction is higher compared with the Western countries and may be due to enhanced treatment and prevention of ischemic heart disease. In Southeast Asia, the lean diabetic phenotype makes up 20% of all heart failure cases and is associated with higher rates of all-cause mortality and hospitalization. The age-standardized prevalence of heart failure per 100,000 population was highest in East Asia and lowest in South Asia.

 

Pathophysiology

Heart failure is a clinical syndrome caused by structural and/or functional cardiac abnormalities that impair ventricular filling and/or ejection, resulting from systolic dysfunction (impaired contractility) and/or diastolic dysfunction (impaired relaxation and reduced compliance).

Cardiac injury and chronic hemodynamic stress trigger cellular, structural, and neurohumoral modulations, including the activation of the sympathoadrenergic system and renin-angiotensin-aldosterone system (RAAS), which are initially adaptive but become maladaptive, causing vasoconstriction, sodium and water retention, volume overload, tachycardia, congestion and dyspnea.

Chronic catecholamine and neurohormonal activation increase intracellular calcium and myocardial O2 demand predisposing to arrhythmias, while promoting hypertrophy, fibrosis, cell death, altered gene expression, and adverse ventricular remodeling, leading to progressive deterioration of cardiac function.

Etiology

The causes of heart failure include acute coronary syndrome or its complications (eg rupture of interventricular septum, right ventricular infarction, valvular heart disease, mitral valve chordal rupture, acute mitral regurgitation), arrhythmias, aortic dissection, cardiomyopathic states (eg peripartum, hypertrophic, tachycardia-mediated or stress-related cardiomyopathy), poorly controlled hypertension (eg bilateral renal artery stenosis), and infection (eg infective endocarditis, viral myocarditis).

Precipitants of heart failure include hypertensive crisis or severe and uncontrolled hypertension; tachyarrhythmia (eg atrial fibrillation, atrial flutter, ventricular tachycardia), severe bradycardia or conduction abnormalities; pulmonary embolism; pericardial or cardiac tamponade; infection (eg pneumonia, sepsis); chronic obstructive pulmonary disease (COPD) exacerbation; cerebrovascular insult; worsening renal failure; electrolyte disturbances; high output states (eg severe anemia, thyrotoxicosis, large atrioventricular shunts/malformations, obesity, advanced liver failure, chronic lung disease, Paget’s disease); surgery and perioperative problems; non-compliance to diet or drug therapy; medications (non-steroidal anti-inflammatory drugs [NSAIDs], steroids, cardiotoxic chemotherapeutics, negative inotropic agents, drugs that increase fluid retention, Clozapine); fluid overload (eg volume overload causing pulmonary edema in acute kidney injury, iatrogenic causes); and toxic substances (recreational drugs, alcohol, radiotherapy).

Risk Factors

The risk factors for heart failure are increasing age, male sex, coronary artery disease, atherosclerotic disease, hypertension, diabetes mellitus (DM), metabolic syndrome, obesity, smoking, alcohol use, and exposure to drugs (eg cancer chemotherapies) or toxins with cardiotoxicity.  Inflammation also plays a key role in the development of heart failure. Socioeconomic status is also a risk factor for heart failure due to poor diet, smoking, physical inactivity, and non-adherence to medications.

Classification

Clinical Conditions   

Patients with acute heart failure may present in one of several categories, which are not mutually exclusive and may overlap (eg a patient with hypertensive crisis or cardiogenic shock may also develop severe pulmonary edema).

Worsening or Decompensated Heart Failure  

Worsening or decompensated heart failure is usually seen in patients with new-onset heart failure or acute decompensation of chronic heart failure. Usually, there is a gradual onset with progressive worsening despite treatment. This is characterized primarily by progressive fluid retention and associated with systemic and pulmonary congestion and increased intraventricular pressure. Hypotension on admission is associated with a poor prognosis. 

Pulmonary Edema



Heart Failure - Acute_Disease BackgroundHeart Failure - Acute_Disease Background




Patients with pulmonary edema present with severe respiratory distress, tachypnea, orthopnea, and bilateral coarse airway sounds (eg rhonchi, wheeze and rales) over the lung fields. Arterial O2 saturation is usually <90% on room air prior to O2 therapy. This diagnosis is confirmed by chest radiography. Cardiogenic pulmonary edema shows perihilar infiltrates while non-cardiogenic pulmonary edema shows peripheral infiltrates. 

Isolated Right Heart Failure  

Patients with isolated right heart failure present with symptoms and signs of right-sided volume overload. This is a low-output syndrome in the absence of pulmonary congestion with elevated jugular venous pressure, with or without hepatomegaly and low left ventricular filling pressures. Systolic blood pressure (SBP) and cardiac output are low, and right ventricular end-diastolic pressure is increased.  

Cardiogenic Shock  

ICardiogenic shock is defined as tissue hypoperfusion induced by heart failure despite adequate correction of preload and major arrhythmia. This is characterized by hypotension (SBP <90 mmHg, mean arterial pressure <60 mmHg, or a decrease of >30 mmHg from baseline SBP), diminished pulse pressure, cutaneous pallor, mental confusion, and absent or low urine output of <0.5 mL/kg/hr. Rhythm disturbance is common. Pulmonary congestion and organ hypoperfusion develop rapidly. There is a continuum from low cardiac output syndrome to cardiogenic shock. One may check lactic acid level in patients with decompensated end-stage heart failure who present with marked weakness and/or uncertain peripheral perfusion to help identify occult shock.

Hypertensive Heart Failure  

There are signs and symptoms of heart failure accompanied by high BP and preserved left ventricular function (heart failure with a preserved ejection fraction). There is evidence of increased sympathetic tone with tachycardia and vasoconstriction. They may be mildly hypervolemic or euvolemic with signs of pulmonary congestion without signs of systemic congestion. There is a rapid response to appropriate treatment and a low hospital mortality.  

Acute Coronary Syndrome and Heart Failure  

Some patients with acute coronary syndrome present with symptoms and signs of heart failure. The episodes of heart failure are associated with or precipitated by arrhythmia. Patients are managed according to the acute coronary syndrome (ACS) guidelines.  

Please see Acute Coronary Syndrome without Persistent ST-Segment Elevation disease management chart for further information.

Acute Mechanical Causes  

Acute mechanical causes are conditions that include acute incompetence of the native or prosthetic valve due to endocarditis, aortic dissection or thrombosis, cardiac intervention, chest trauma, or acute coronary syndrome complicated by the rupture of the myocardium such as acute mitral regurgitation, free wall rupture, or ventricular septal defect.