How to tell if you’re at risk of heart failure from your smart watch

A smart watch is not just a handy way to check emails — it may warn if you are at risk of developing heart failure.

Heart failure affects up to one in 50 people in the UK, with around 200,000 new cases diagnosed every year.

But the majority of people are diagnosed late, which can lead to kidney damage and complications like anaemia because the condition has been missed.

Now a study suggests there may be a telltale early warning sign of heart failure which a smart watch can detect.

People whose heartbeats are too close together, indicating a different electrical pattern in the lower chambers of the heart, have about twice the risk of heart failure, the study of more than 83,000 people found.

Importantly, this abnormality can be picked up using an ECG on a smart watch, according to the study authors.

A smart watch user simply has to watch for 15 seconds to see if any of their heartbeats – the tall vertical spikes in the ECG pattern – come too close together, with the spike consisting of two separate vertical lines like an upside down ‘V’.

Around one in 50 middle-aged people have irregular heartbeats like these every 15 seconds, the study suggests.

These are often completely normal but in some cases they may be a sign of an increased risk of heart failure.

Knowing this could allow middle-aged people to ask their GP to monitor their heart more closely.

Dr Michele Orini, from the Institute of Cardiovascular Science at University College London, led the study which looked at the ECG results of middle-aged people and their risk of developing subsequent heart problems.

He said: ‘Smart watches present an exciting future for helping people to pick up emerging heart problems early, so that those at greater risk of heart failure can take steps like exercising more and improving their diet.

‘It is so important to detect conditions early, and technology can help with that.’

The study, published in the European Heart Journal – Digital Health, looked at 83,340 people aged 50 to 70 who underwent a 15-second ECG using electrodes on their body.

However study authors say the readout is similar to what would be produced by a smart watch, which has a sensor on it to detect heartbeats.

The study results also provide further evidence that smart watches may flag up someone’s risk of an irregular heartbeat, called atrial fibrillation, which can lead to dizziness and shortness of breath.

While premature ventricular contractions – heartbeats close together in the lower chambers of the heart – were linked to heart failure, premature atrial contractions – heartbeats close together in the upper heart chambers – were linked to about twice the risk of atrial fibrillation.

Researchers know this from looking at people’s medical records for up to 11 years after their ECG to see if they developed heart problems.

Heartbeats which are abnormally close together in an ECG are clearly visible on smart watches.

While a premature ventricular contraction appears like two upside-down V’s close together, an atrial contraction shows two vertical lines close together.

However scientists want smart watch manufacturers to provide actual alerts for people so they don’t need to interpret the patterns themselves.

Heartbeats are too close together when the electrical signals which cause the beats happen in the wrong part of the heart, or take the wrong pathway through the heart.

If this happens once in 15 seconds, it can happen thousands of times a day, and experts believe this puts strain on the heart which may contribute to heart failure or atrial fibrillation.

Atrial fibrillation is linked to a fivefold increased risk of having a stroke.

Smart watches have previously been found to detect atrial fibrillation, but there was less evidence on heart failure.

The new study also found a slight extra risk, among people whose heartbeats were too close together, of a condition called life-threatening ventricular arrhythmia.

As with the other heart conditions, it is also possible that heartbeats become too close together as an early stage of more serious heart conditions.

However experts caution that their ECGs are less accurate than those taken in GP surgeries.

People with at least one premature heartbeat every 15 seconds tend to be older and more overweight.

The greater risk of heart failure and atrial fibrillation in people with this abnormality was found even when factors like these were taken into account.

The study found men with premature ventricular contractions were a third more likely to die.