Heart failure module 2: diagnosis

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Introduction

Patients with symptoms and signs of heart failure and previous myocardial infarction should be urgently referred for transthoracic 2D Doppler echocardiogram and specialist assessment within two weeks. The same is true for patients with a very high BNP or NT-proBNP.

Without a history of myocardial infarction, or with only modestly raised natriuretic peptides, imaging and specialist assessment should be offered to patients with suspected heart failure within six weeks.1

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Essential initial investigations include a 12-lead electrocardiogram (ECG) and laboratory tests.2 The use of natriuretic peptides is gaining importance as a screening, prognostic and diagnostic tool for heart failure particularly in primary care where access to ECG and imaging may be limited. Biochemical and haematological investigations (see below) are also important. Other diagnostic tests are generally only required if the diagnosis remains unclear.

It is important to note that because the signs and symptoms of heart failure are non-specific, many patients with suspected HF referred for echocardiography may not have any important cardiac abnormality. A normal NT-proBNP excludes the diagnosis without the need for an echocardiogram.

The distinction between acute and chronic HF is often not understood correctly. The word ‘acute’ is often taken, wrongly, to mean ‘severe’, and should be used to mean ‘presenting suddenly’. Acute HF generally refers to patients presenting as emergencies to hospital, usually with either pulmonary oedema or with fluid retention. Such patients are often presenting for the first time, but may be patients having an exacerbation of their chronic, previously stable, HF. They have acutely abnormal haemodynamics.

In contrast, most patients with chronic HF have been treated medically and will usually have few, if any, symptoms or signs at rest. The term ‘congestive’ HF, often used to describe patients in this condition (particularly in North America), is inappropriate: patients with treated chronic HF should not be congested.3,4