Atrial Fibrillation

1. Photoplethysmography and
the detection of atrial
fibrillation
Natalie Kanis

2. Case Study

3. A 67-year-old Caucasian male presents to his PCP for a routine well-
visit. He has a history of HTN and HLD on atorvastatin 10 mg daily and
lisinopril 10 mg daily. He weighs 220 lbs. and is 69 in. tall (BMI 32.5 kg/m2). He
is a non-smoker and only drinks alcoholic beverages on special occasions. At
this visit he denies SOB, palpitations, dizziness, fatigue, and chest pain. His BP
is 124/80 mmHg and his HR is 115. His physical exam is benign except for an
irregularly irregular heart rhythm.
An EKG reveals atrial fibrillation with a rapid ventricular response. An
echo is performed showing “mild concentric left ventricular hypertrophy and
mild left atrial enlargement.” His echo is otherwise normal. His lab values are
all unremarkable. His CHA2DS2-VASc score is a 2; he is moderate-high risk for
stroke. His HAS-BLED score is also a 2; he is at moderate risk for major
bleeding. Anticoagulation should be considered.

4. Technology
Photoplethysmography (PPG)

5. PPG
Previously only detectable on EKGs, wearable patches, and
implantable recorders, new technology on smartwatches and
other portable devices may allow for detection of atrial fibrillation
before adverse events via a non-invasive, cost-effective, portable
technology.
This technology is called photoplethysmography (PPG). PPG
measures light transmission to a sensor placed on the skin near an
artery. A pulse is detected by shining a light onto the skin and
measuring the difference in light reflected to the sensor.

6. Use of Technology

7. PPG is present in some smartwatches, some applications on smartphones
(utilizing the camera flash as the light source), and some handheld EKG devices.
These devices and applications are available to consumers without provider
prescription. While EKG is necessary for definitive diagnosis of atrial fibrillation, use
of PPG can clue patients into heart rhythm abnormalities so they might seek medical
attention.
Devices such as the Apple Watch and Kardia Band are continuously worn,
and the user is issue notifications if an irregular or fast heart rate is captured.
Devices such as applications using a smartphone’s camera as a PPG sensor
(Cardiio Rhythm App) and the portable single-lead EKG monitoring devices
(MyDiagnostick and AliveCor Kardia Mobile Heart Monitor) are used by patients
intermittently to check for arrythmias at the specific time of use.
The FDA has approved the AliveCor Heart Monitor, the Apple Watch, and the
Kardia Band for detection of rhythm abnormalities.

8. Cont.
This table is from a review conducted
by Raja et al. (2019). It discusses
sensitivity and specificity of these
heart monitoring devices in detecting
atrial fibrillation.
According to Rajakariar et al. (2018)
98% of patients preferred wearable
technology to an event monitor while
90% stated they would use the
technology to determine cardiac
abnormalities.

9. Apple Watch

10. Kardia Band

11. Cardiio
Rhythm
Application

12. My Diagnostick

13. AliveCor
Kardia Mobile
EKG Monitor

14. Special Precautions

15. • False positives may induce anxiety and worry in patients and
may also increase number of unnecessary ER visits.
• Intermittent EKG monitoring is more sensitive than use of PPG
for atrial fibrillation detection. Four times more cases of atrial
fibrillation are diagnosed with EKG than PPG.
• Wearable technologies are less often worn by older patients
who could benefit more from technology than younger
patients.
• Should not be used as the sole diagnostic tool, but as a starting
point for patients to seek medical help.

16. Expected Outcomes

17. The use of these monitoring devices should give the healthcare
provider more insight into a patient’s cardiovascular health and lead to more
prompt diagnosis of cardiovascular conditions. Patients should seek medical
attention with notifications of irregular heart rates. It is expected that with
more universal use of wearable/portable PPG monitoring devices patients
should have earlier treatment of atrial fibrillation and other cardiovascular
abnormalities and thus earlier implementation of stroke reduction strategies.
The use of PPG is relatively new to healthcare and thus controversial as
a diagnostic tool. More research needs to be conducted to garner more
evidence into the clinical usefulness of portable PPG monitors. These
devices/applications have the potential to lead to better patient outcomes
and to become a useful tool for healthcare providers to monitor patients over
a longer period.

18. Final Thoughts
A patient like the one described in our case
presentation could have been treated for his new atrial
fibrillation sooner had he owned a device with a PPG
sensor. A patient with numerous risk factors for atrial
fibrillation could have been advised by a healthcare
provider to invest in a wearable or portable heart
monitor so that he could be alerted of an irregular or
fast heart rate.

19. References
Castaneda, D., Esparza, A,. Ghamari, M., Soltanpur, C. & Nazeran, H. (2019). A review on wearable
photoplethysmography sensors and their potential future applications in health care.
International Journal of Biosensors & Bioelectronics, 4(4). Retrieved from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6426305/
Nelson, B.W. & Allen, N.B. (2019). Accuracy of consumer wearable heart rate measurement during
an ecologically valid 24-hour period: intraindividual validation study. JMIR MHealth uHealth, 7(3).
DOI 10.2196/10828
Raja, J.M., Elsakr, C., Roman, S., Cave, B., Pour-Ghaz, I., Nanda, A., Maturana, M., & Khouzam, R.N.
(2019). Apple watch, wearables, and heart rhythm: where do we stand? Annals of Translational
Medicine, 7(17). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6787392/
Rajakariarlow, K., Koshy, A., Sajeev, J., Roberts, L. & Teh, A. (2018). Increased preference of
wearable devices compared with conventional cardiac monitoring. Heart Lung and Circulation, 27.
Retrieved from https://doi.org/10.1016/j.hlc.2018.06.288
Vega, C.P. (2019, April 1). Case clinic: a 67-year-old white male patient with atrial fibrillation risk
factors. Clinical Advisor. https://www.clinicaladvisor.com/home/topics/cardiovascular-disease-
information-center/case-clinic-a-67-year-old-white-male-patient-with-atrial-fibrillation-risk-factors/