GPs say the app could increase pressure on doctors having to deal with patients alerted by their phone to possible heart issues.
Users of the new series of Apple Watch will be able to take their own electrocardiogram to test if their heart is working normally.
The ECG app, which carries out a simple version of the check until now confined to hospitals, has been cleared by regulators for use across the UK and Europe.
But GPs have raised concerns it could increase pressure on already stretched doctors having to deal with patients alerted by their phone to possible heart abnormalities.
The ECG app takes a reading of the heart rhythm via electrodes on the crown of the watch and sensors on the back, creating a loop across the chest and monitoring electrical activity. It then sends a PDF of the chart to the user’s phone.
The company says it has high degree of accuracy and can identify irregularities in rhythm.
The development was headed Apple’s vice-president of health Sumbul Desai, herself a practicing physician, and she says it is intended to be shared between patient and doctor.
She told Sky News: “This product is really meant to augment your relationship with your physician, not at all replace it, and that’s really important.
“From everything from the results and how they are conveyed to the consumer, throughout the process, we thought through how to make this a conversation starter between the patient and the physician.”
Sky News was given rare access to Apple’s secret fitness lab close to its Silicon Valley HQ. Company employees volunteer to exercise in a gym, swimming pool or yoga studio as data readings of oxygen use are taken. The aim is to use the information to improve Apple’s health offerings.
The tech industry has always hoped that the growth of so-called wearables for health and fitness would ease the burden on doctors.
But Professor Helen Stokes-Lampard, chair of the Royal College of GPs, has concerns the ECG could have the opposite effect.
She said: “As a busy general practitioner my worry is that this new technology is going to cause anxiety in fit, healthy patients and it is going to cause them to come and see their GP at a time that it’s not really necessary.
“Of course, we want people to be responsible about their health and if anyone feels they have an irregular heartbeat they should seek medical advice.
“But just because your phone tells you you have an irregular heartbeat it’s not necessarily the case.”