Recently we have had a lot of enquiries from patients who have been concerned about abnormal heart rate notifications from their wrist-based heart monitors. These are monitors intrinsically built into the device. The commonly available ones are those in the Apple Watch or Fitbit. These devices can usually be programmed to notify the wearer of a low or high heart rate. The specific heart rate at which an alert is issued can be pre-specified and varies from 40-50 beats per minute (ie heart rates falling below this). Similarly, high heart rate notifications can be specified from 100-150 beats per minute. The latest Apple Watch now has FDA approval as a medical device and potentially has a lot of use for patients who suffer with arrhythmia to enable them to monitor their condition.
However, our Birmingham Cardiology clinic has seen an increased number of referrals from people who have received low or high heart rate alerts from their devices. They are concerned they might have an arrhythmia or other heart condition and often this leads to a considerable amount of anxiety. In the vast majority of cases, we are able to reassure our patients that their heart is completely normal. Younger people will receive a low heart rate notification because they wear their wrist monitor at night. In younger people (usually under the age of 40) the heart rate will drop below 40 whilst they are asleep. This is completely normal and in no way indicative of any sort of heart condition. The medical term for this low heart rate at night is ‘nocturnal bradycardia’. To confirm this, diagnosis patients may require additional heart tests for reassurance. This would usually be in the form of a 24 hour ECG monitor which can show the patient’s ECG and heart rate accurately during the day and night and confirm the presence of nocturnal bradycardia.
Elevated heart rates can also be a concern for some of our patients. We often hear patients saying that their usual heart rate is low but when they check it the rate is different from their normal resting heart rate. What is important to remember is that a healthy person’s heart rate will vary and fluctuate throughout the day. It would be unusual and even abnormal for a heart rate to be at a fixed number throughout a normal day. In a healthy individual, the heart rate may fluctuate between 60 and 100 beats per minute if they are in a sedentary job. For more physical daily activities or jobs that require walking long distances or flights of stairs there may be even more variation in heart rate and this may trigger a high heart rate notification.
In most cases, we can provide reassurance to our patients with additional heart tests. We usually recommend portable ECG monitoring and this can be arranged from 24 hours up to 14 days. In most of our patients, the ECG monitoring will show a normal heart rhythm with no detectable arrhythmia. We can also show the times when heart rates are particularly fast or slow. If the patient diary accompanying the monitor has been completed we can provide an explanation for any slow or fast heart rates. Occasionally we do diagnose other heart rhythm disturbances such as atrial fibrillation, supraventricular tachycardia or frequent ectopic beats. If this is diagnosed then further heart tests may be required (usually an echocardiogram/heart ultrasound scan).
The development of wrist-based heart monitors in portable devices such as the Apple Watch and Fitbit is a useful new innovation and can offer patients who suffer from arrhythmia with a great way to monitor their condition. It may be useful for healthy people to understand the variations in their natural heart rate and how to rule out arrhythmia should the heart rate alerts be triggered. If people have any concerns we are happy to arrange a consultation with Dr Ali Hamaad and arrange further heart tests for reassurance and peace of mind.
