Many heart scans fail to provide clear diagnostic results

Thousands of patients sent for vital heart scans may be undergoing unnecessary first-line tests that fail to deliver clear answers - according to new research from the University of East Anglia.

A new study finds that more than one in three heart ultrasounds are either unclear or cannot diagnose the patient's disease requiring doctors to repeat tests or send patients for more invasive - and expensive - follow‑up scans.

Researchers analysed results from more than 70,000 patients and found that scans are more likely to fail for certain patient groups - including those with lung disease, heart failure or irregular heart rhythms.

They say that a simple check before the scan could help speed up diagnosis and reduce unnecessary repeat imaging as well as saving the NHS time and money.

The problem with routine heart scans

Lead researcher Dr Pankaj Garg, from UEA's Norwich Medical School and a consultant cardiologist at the Norfolk and Norwich University Hospital, said: "Heart ultrasound scans - known as echocardiograms - are one of the most common and most valuable tests used in the NHS. They use ultrasound waves through the chest wall to assess heart structure and function.

"They are quick, painless, and widely available. And they are usually the first test doctors order when someone has breathlessness, suspected heart failure or valve disease.

"But in everyday clinical practice, many of these scans fail because they don't produce clear images. Doctors are then forced to repeat the test or order more expensive scans, delaying diagnosis and increasing costs.

"This is not because the test is poor, but because real patients don't resemble textbook patients. The ultrasound beam must travel through the chest wall and lungs before it reaches the heart, and many common clinical factors interfere with that process.

"But until now, there has been little evidence to explain how often scans fail, which patients are most affected and whether this could be anticipated before the scan takes place."

How the research happened

Researchers analysed 70,597 heart scans taken over a decade at the Norfolk and Norwich University Hospital to understand why so many produce unclear results.

Dr Garg said: "We looked at routine scans and patients weren't selected or screened - everyone was included. Image quality was judged by sonographers at the time, just as it is in day‑to‑day practice.

"This means the results reflect real‑world NHS conditions."

Using these existing clinical records, the team examined scan quality alongside patient medical details. The data was split into two groups to develop and then test a prediction model.

Researchers also modelled NHS costs to compare standard practice with a triage approach that directs higher‑risk patients to enhanced imaging first.

"We found that 34 per cent of the scans were limited or non‑diagnostic, particularly in patients with lung disease, heart failure, irregular heart rhythms or previous cardiac surgery," said Prof Garg.

"This means that thousands of patients leave appointments without clear answers - despite having undergone what is supposed to be the NHS's frontline heart test.

"Our research shows that in the NHS, it may be possible to predict, before a patient even enters the heart-scanning room, whether a routine heart ultrasound is likely to produce clear or difficult-to-read images.

"By combining simple patient information with smart computer analysis, we uncovered hidden clues linked to scan quality. This could help NHS teams plan scans more effectively, reduce repeat appointments, speed up diagnosis, and make heart imaging more reliable for patients."

Lung disease doubles the risk of a 'failed' scan

The strongest predictor of a poor‑quality scan was lung disease, which more than doubled the risk of failure, the test not providing any useful information.

Patients were also more likely to get unclear results if they were being scanned as hospital inpatients, had suspected heart failure, had an irregular heartbeat, had undergone previous heart surgery or had a pacemaker.

Dr Garg said: "Inpatients had a particularly high risk, which is likely because they are often more sick and harder to position correctly.

"Interestingly, body weight and sex made little difference, which goes against common assumptions that obesity is the main obstacle to clear cardiac imaging."

NHS savings hiding in plain sight

The researchers found the real cost isn't just clinical - it's financial.

"When scans are unclear, doctors often have no option but to repeat the ultrasound with contrast dye or refer patients for expensive cardiac MRI scans," said Dr Garg.

"We modelled what would happen if patients most likely to have poor scans were sent straight to contrast ultrasound or alternative imaging instead.

"And we found that £317,331 would have been saved across this study alone, simply by getting the right test first."

This study was led by UEA in collaboration with the Norfolk and Norwich University Hospitals Foundation Trust, the University of Sheffield, Sheffield Biomedical Research Centre, and the University of Leeds.

It was funded by the Wellcome Trust and supported in part by the National Institute for Health and Care Research (NIHR) Sheffield Biomedical Research Centre.

'Determinants of image quality in transthoracic echocardiography: a retrospective cohort study' is published in the journal JRSM Cardiovascular Disease.