What is the definition of chronic heart failure in adults, particularly those with a history of hypertension, coronary artery disease, or diabetes?

Definition of Chronic Heart Failure

Chronic heart failure is a complex clinical syndrome resulting from any structural or functional cardiac disorder that impairs the ventricle's ability to fill with or eject blood, characterized by the cardinal manifestations of dyspnea, fatigue (which limit exercise tolerance), and fluid retention (which leads to pulmonary and peripheral edema). 1, 2

Core Diagnostic Components

Heart failure is fundamentally a clinical diagnosis requiring three essential elements to be present simultaneously 3:

• Typical symptoms: Breathlessness at rest or on exertion, fatigue, tiredness, or ankle swelling 3
• Physical signs: Elevated jugular venous pressure, pulmonary crackles, peripheral edema, tachycardia, pleural effusion, or hepatomegaly 3
• Objective cardiac abnormality: Demonstrated by echocardiography (reduced ejection fraction, left ventricular hypertrophy, diastolic dysfunction, valvular disease) OR elevated natriuretic peptides (BNP/NT-proBNP) 3

Critical distinction: Heart failure is not equivalent to cardiomyopathy or left ventricular dysfunction—these latter terms describe possible structural or functional reasons for developing heart failure, but the syndrome itself requires the presence of symptoms and signs. 1

Pathophysiologic Understanding

The syndrome arises from a progressive disease process that typically follows this sequence 1:

• Initial myocardial injury: From ischemia, hypertension, toxins, or other insults 4
• Ventricular remodeling: The chamber dilates, hypertrophies, and becomes more spherical as a homeostatic attempt to decrease wall stress 1, 4
• Progressive dysfunction: This remodeling process continues even without new identifiable insults, often preceding symptoms by months or years 1
• Clinical manifestation: Eventually resulting in the symptomatic syndrome with impaired functional capacity and quality of life 1

Common Etiologies in At-Risk Populations

In adults with hypertension, coronary artery disease, or diabetes—the populations specified in your question—the following etiologic patterns predominate:

• Coronary artery disease: Accounts for approximately two-thirds of cases with left ventricular systolic dysfunction and represents the single most common etiology globally (approximately 40% of all heart failure cases) 1, 2, 4
• Hypertension: Represents the underlying cause in 17-31% of heart failure cases, with higher prevalence in heart failure with preserved ejection fraction phenotypes 2
• Diabetes mellitus: Contributes through multiple mechanisms including coronary atherosclerosis, hypertension, and specific diabetic cardiomyopathy that occurs independently of coronary disease 5

Functional Classification

The New York Heart Association (NYHA) functional classification quantifies symptom severity 1:

• Class I: Symptoms only at levels that would limit normal individuals 1
• Class II: Symptoms on ordinary exertion 1
• Class III: Symptoms on less-than-ordinary exertion 1
• Class IV: Symptoms at rest 1

Important Clinical Caveats

Poor correlation between ejection fraction and symptoms: Patients with very low ejection fractions may be asymptomatic, while those with preserved left ventricular systolic function may have severe disability—this discordance remains poorly understood despite extensive investigation. 1, 4

Progressive nature: Heart failure is a progressive disorder where left ventricular dysfunction continues to worsen even in the absence of new identifiable insults to the myocardium, with remodeling continuing after symptom onset and contributing to worsening despite treatment. 1, 4

No single diagnostic test exists: Because heart failure is largely a clinical diagnosis based on careful history and physical examination, accuracy of clinical diagnosis alone is inadequate (particularly in women, elderly, and obese patients), making objective testing mandatory. 1, 3