Never miss a beat27 October 2023
Arrhythmias aren’t that uncommon and usually don’t present a grave health threat. But in places like the ICU, where even slight variations in cardiac output can be symptomatic of pathology, or even threaten the life of a patient, keeping tabs is vital for a quick response with treatment. There are established methods to monitor cardiac output of course, but as technology advances, medical researchers can push the envelope of what’s possible. Sarah Harris speaks to Dr Alexandra Kharazi, cardiothoracic surgeon at CVTS Medical Group, and Dr Subasit Acharji, interventional cardiologist at MetroWest Medical Center, to find out about some of the latest methods that could improve cardiac monitoring both in and out of the clinic.
It’s safe to say that the healthcare industry has witnessed remarkable technological advancements in recent years: robotic arms frequently perform surgery under the control of practitioners; specialised cells genetically engineered to take on cancer in CAR T cell therapy have saved lives when all other treatments failed; and in the context of the current pandemic, we witnessed the development of vaccines using mRNA technology for which the pioneers were recently given the 2023 Nobel Prize in Medicine.
There’s one area of medicine that’s ripe for improvement though, and it’s arriving in the form of apps connected to monitors in personal gadgets like our smartphones and watches. These technologies have not only led to significant improvements in early diagnosis and prevention of cardiac disease, but also revolutionised the way patients receive cardiac care, explains Dr Alexandra Kharazi, a board-certified cardiothoracic surgeon, and member of the American College of Surgeons.
“The most significant advances that I have seen in cardiac monitoring technology in recent years are devices which link vital signs to our electronic devices,” she says.
While we were once only able to monitor our heart rate during routine check ups at our local general practices, this is far from the case now. Almost everyone is easily able to track their own health data, whether it be their daily step count, or in the case of those with cardiac issues, monitor their heart rate.
“An example of this type of device is the Fitbit,” shares Kharazi. “Other devices include ECG monitors for at-home use and continuous glucose monitoring.” For those patients who don’t have to worry about their cardiac health, these technological advances may seem miniscule, but for those who live in constant fear of cardiac issues, access to such precise information can be potentially lifesaving.
In particular, these devices can be especially convenient in the aftercare of patients who have had heart surgery, Dr Kharazi explains. “For example, if they feel palpitations, and monitoring confirms a high heart rate, this information can be used to adjust existing medications between clinic visits,” she says.
In a time when most medical specialities are overworked and struggling, these innovations have the potential to not only save the time of healthcare professionals, but also the lives of their patients. “I only do this when I have recently examined the patient and the information makes sense in their clinical scenario,” Kharazi clarifies. “If there are any concerns or discrepancies however, I schedule them for a clinic visit or send them to the ER.”
The advantages of wearable devices have also begun to be more widely noticed by the medical community, with a 2021 article published in the Journal of Clinical Medicine stating there is a growing body of evidence that supports the clinical benefits of this technology in the management of patients who have previously experienced heart failure. A more recent 2023 paper authored by 16 physicians active in medical research concluded that cardiovascular data collected by wearables has the potential to improve individual patient care and lead to healthier populations.
The challenges of remote monitoring
While the advances being made in this field hold great promise, challenges do persist. Data security and privacy concerns being the major one, as personal health data is transmitted and stored electronically.
But according to popular studies, these risks are minimal, explains Dr Subasit Acharji, an interventional cardiologist and vascular specialist. “There appears to be little regulatory or privacy concerns with using arrhythmia detection monitoring in clinical practice,” he says. “In both the 2019 Apple Heart Study and the 2022 Fitbit Heart Study, participants’ arrhythmia detection were de-identified and individual-level data were unavailable.” However, since these studies were published, the wearable devices industry has seen a huge boom, and not all suppliers are as careful with their data as Apple or Fitbit.
“The most significant advances that I have seen in cardiac monitoring technology in recent years are devices which link vital signs to our electronic devices.”
Dr Alexandra Kharazi
In 2021, news was released surrounding a huge breach in data that had been collected from major wearable device providers. It was suggested that nearly 61 million records had been exposed, which included basic personal information such as display names, dates of birth and GPS logs. While in the US, where the FDA regulates medical devices, there is still little regulation on the personal data these devices store and disperse.
A fundamental ethical consideration is the issue of informed patient consent when it comes to wearable devices. Whilst many users of this technology may not be paying particular attention to how their data will be used and who will have access to it, they need to consider the potential risks of this and maybe involuntarily participating in remote monitoring programmes.
Another huge issue highlighted by the adoption of these advanced cardiac monitoring devices is the inadvertent creation of a digital divide. While we would like to assume that most patients have access to a smartphone or reliable internet connection, this is far from the case and therefore not all patients are candidates for remote monitoring.
In a day and age where technology should be making healthcare more accessible and fairer for all patients, the rise in wearable devices is doing the opposite. Especially when research has continued to consistently highlight that those who fall under the low socioeconomic status bracket are more likely to develop cardiovascular disease.
“There appears to be little regulatory or privacy concerns with using arrhythmia detection monitoring in clinical practice.”
Dr Subasit Acharji
The future of cardiac monitoring
Cardiac monitoring devices have already come a long way from the bulky machines of the past to the affordable and accessible smart devices of today, but the journey of innovation is far from over.
The future of cardiac monitoring devices is huge and with the ongoing growth of telehealth services, patients will continue to have the ability to remotely connect with their various healthcare providers, sharing real-time data from their monitoring devices. These remote consultationps will be especially valuable for those individuals who live in remote areas, have mobility issues, or simply prefer the convenience of virtual healthcare.
We can also expect to see an increase in the development of user-friendly interfaces and mobile apps that allow patients to easily access and, importantly, understand their cardiac health data. Advanced data visualisation techniques, including 3D representations of the heart’s electrical activity, will make it easier for patients to grasp the status of their cardiovascular health.
“Asymptomatic atrial fibrillation detection as risk factors for first-time stroke patients is also a developing area of investigation,” says Acharji. While screening for atrial fabulation in the general population has been a heavily debated issue among the medical community for some time now, technological advances have made screening within high-risk populations easier.
“Detection of heart block as a cause of syncope or seizures,” is also a promising area for advancement suggests Acharji. The presence of heart disease in patients with syncope has been identified as the most important factor in prognosis and risk stratification, according to the American Heart Association Journals.
While research in this area is still ongoing, several studies have identified permanent pacemakers in patients with severe syncope showed an 85% relative risk reduction during a tilt test. The use of pacemakers to treat syncope could potentially be a huge advancement in the field of cardiac health research.
The ultimate goal of the future of cardiac monitoring devices is to facilitate more in the way of early intervention and proactive care. Devices will not only be able to alert patients to potential health issues, but also automatically connect with healthcare providers in case of critical anomalies arising. This real-time collaboration between patients and physicians will save lives and reduce the burden on healthcare systems by preventing emergencies and costly hospitalisations. At the same time, “tracking our health information makes us more mindful and conscious of our body and our health choices”, says Kharazi, which can also lead to heart-healthy behaviours. These advances are revolutionising patient care and bridging the gap between patients and healthcare providers, by promoting proactive and individualised care. And undoubtedly, future advancements being made in the field will continue to strengthen patient experiences – and their hearts.
Detecting arrhythmias using wearables
Prolonged ECG monitoring devices such as Holter monitors are cumbersome, can only be worn for short periods, and might miss paroxysmal arrhythmias. Furthermore, implantable devices (loop recorders) are invasive and require specialist training to insert and analyse. Wearable technology can be advantageous for arrhythmia detection; several modern smartwatches use photoplethysmography sensors, and more recently ECG technology, to detect heart rate and rhythm.
Photoplethysmography sensors can detect atrial fibrillation, the most common significant arrhythmia, with a sensitivity and specificity of 91–100% in comparison with ECG. The Apple Heart study investigated the use of smartwatchbased arrhythmia detection in 419 297 participants. Through the watch’s photoplethysmography sensor, if an irregular cardiac rhythm was detected, a notification advised a telemedicine consultation and to wear an ECG recording patch for 7 days.
Within a median monitoring period of 117 days, 2,161 participants received an irregular pulse notification (0.52%). After exclusions, 450 participants returned usable ECG data, 34% of which were confirmed to have atrial fibrillation. Although undergoing simultaneous ECG monitoring, the positive predictive value of subsequent irregular pulse notifications was 84%.
In a similar study performed across China, 246,541 people downloaded a mobile atrial fibrillation app that used data from a photoplethysmography wristband or watch. Of these, 187 912 people used the app via their smartphone and 0.23% received a notification of a suspected atrial fibrillation. After follow-up, the positive predictive value of the photoplethysmography detected signal was 91.6%.
These studies were the first demonstration of a general population-wide approach to arrhythmia screening using a commercially available wearable device with telemedicine. Given that atrial fibrillation was diagnosed in asymptomatic participants, future research should consider whether major sequelae such as the incidence of stroke can be reduced by this approach in adequately powered prospective controlled trials.