Diagnosis of Heart Failure
The diagnosis of heart failure involves a comprehensive clinical assessment, including the evaluation of symptoms, a detailed medical history, physical examination, and a combination of laboratory and imaging tests. Because the symptoms of heart failure can overlap with those of other common medical conditions, an accurate and early diagnosis of heart failure is essential for effective treatment and better long-term outcomes.
A thorough history is usually the starting point. Patients often report fatigue, shortness of breath (especially on exertion or when lying down), leg swelling, weight gain, and reduced ability to exercise. Some may also mention waking up at night with difficulty breathing, needing extra pillows to sleep comfortably, or noticing a persistent cough that worsens when lying flat. These symptoms may be gradual or sudden and are key red flags prompting further investigation.
The clinician will review past and present medical conditions that may contribute to heart failure, such as coronary artery disease, hypertension, diabetes, valvular disorders, arrhythmias, kidney disease, or previous heart attacks. Family history is also relevant, as genetic predispositions can play a role in certain types of cardiomyopathy.
Diagnosis of Heart Failure
A detailed physical examination is critical. Doctors will assess heart rate and rhythm, check blood pressure, listen to the heart and lungs with a stethoscope, and look for signs of fluid retention—such as jugular vein distension, ankle or leg swelling, and crackling sounds in the lungs. Cool extremities, delayed capillary refill, and low blood pressure can indicate poor perfusion in advanced cases.
After the initial clinical assessment, the next step in the diagnosis of heart failure is a series of investigations that confirm the presence of the disease and help determine its underlying cause and severity.
One of the first and most useful blood tests is measurement of natriuretic peptides, including B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP). These biomarkers are released by the heart in response to increased pressure and volume overload. Elevated levels strongly suggest heart failure, especially in patients presenting with shortness of breath.
Other important blood tests include:
Full blood count – to rule out anaemia or infection.
Kidney function tests – since renal impairment can both mimic and exacerbate heart failure.
Liver function tests – to assess for hepatic congestion in advanced heart failure.
Thyroid function tests – as both hypo- and hyperthyroidism can influence cardiac output.
Lipid profile and HbA1c – to evaluate cardiovascular risk and screen for diabetes.
Diagnosis of Heart Failure
The electrocardiogram (ECG) is an essential tool for evaluating heart rhythm, previous myocardial infarction, and evidence of left ventricular hypertrophy or conduction abnormalities. While not diagnostic on its own, the ECG can reveal clues that point towards underlying pathology contributing to heart failure.
The cornerstone of structural assessment is the echocardiogram, a non-invasive ultrasound test that visualises the heart in real-time. This test can evaluate:
Left and right ventricular size and function
Ejection fraction (EF), which helps classify heart failure as HFrEF (EF <40%) or HFpEF (EF ≥50%)
Valve structure and performance
Wall motion abnormalities suggesting previous infarction
Presence of pericardial effusion or intracardiac masses
In some cases, more advanced imaging may be required. Cardiac MRI provides detailed information about heart muscle structure, function, and scarring. It is particularly useful in assessing cardiomyopathies and distinguishing between different types of myocardial disease. Cardiac CT is useful for evaluating coronary anatomy, particularly in patients unable to undergo invasive coronary angiography.
Chest X-rays are commonly performed in patients suspected of heart failure. They can show signs of pulmonary congestion, cardiomegaly (enlarged heart), pleural effusions, or alternative causes of respiratory symptoms such as pneumonia or lung disease.
Diagnosis of Heart Failure
For patients with suspected coronary artery disease, a key contributor to heart failure, a stress test may be used. This can be an exercise ECG or a nuclear perfusion scan that evaluates blood flow to the heart under stress. If the results are concerning, coronary angiography—an invasive procedure—may be performed to identify and potentially treat blockages in the coronary arteries.
Right heart catheterisation is sometimes used in complex cases, particularly where pulmonary hypertension or advanced heart failure is suspected. This procedure measures pressures in the heart chambers and pulmonary arteries, providing valuable haemodynamic data to guide treatment decisions.
Holter monitoring or event recorders may be employed when arrhythmias are suspected as a cause or complication of heart failure. These portable devices record the heart’s rhythm continuously over a day or more, helping detect intermittent disturbances such as atrial fibrillation or ventricular tachycardia.
In some patients, especially younger individuals or those with a family history, genetic testing may be recommended to evaluate for inherited forms of cardiomyopathy. This can also help inform family screening and guide therapy.
The diagnosis of heart failure does not end with confirmation of the disease. It extends to determining its subtype, cause, and stage. For this reason, clinical guidelines often recommend using validated classification systems such as the New York Heart Association (NYHA) functional class. The American College of Cardiology/American Heart Association (ACC/AHA) stages. Furthermore, the European Society of Cardiology (ESC) algorithms. These systems support treatment decisions and help predict prognosis.
Diagnosis of Heart Failure
Importantly, diagnosing heart failure early—even in patients without obvious symptoms—can change the course of the disease. Timely intervention may prevent progression, reduce hospitalisations, and improve quality of life.
In conclusion, the diagnosis of heart failure requires a multi-pronged approach that combines careful clinical evaluation with targeted testing. The aim is not only to confirm the condition, but to understand its cause, guide treatment, and anticipate complications. Accurate and timely diagnosis is the cornerstone of effective heart failure management.
