Table 1.

Characteristics of included studies.

Author, year, and country	Sample size and age (range or mean [SD])	Smartphone	Control	Duration and conditions measurement	Outcome measure
Bolkhovsky et al, 2012, United States [68]	22 subjects, age not specified	Motorola Droid, iPhone 4S	ECGa	2 × 2 min: supine and sitting up in tilt position (iPhone 4S, n=9); 2 × 5 min: supine and sitting up in tilt position (Motorola Droid, n=13)	Heart rate, heart rate variability
Drijkoningen et al, 2014, Belgium [70]	28 adults with sinus rhythm during electrophysiological examination, age not specified	Samsung Galaxy S4	ECG	60 s	Heart rate, premature atrial ectopic beats identification
Gregoski et al, 2012, United States [73]	14 adults, 18-59 years	Motorola Droid	ECG, pulse oximeter	3 × 5 min: sitting, at rest, reading, and playing a video game	Heart rate
Ho et al, 2014, Taiwan [75]	40 children undergoing ECG monitoring, 3 days to 15 years	iPhone 4S	ECG	3 × 20 s at finger (or toe) and earlobe	Heart rate
Koenig et al, 2016, Germany [78]	68 adults (45 patients from a cardiologic outpatient ambulance and 23 healthy controls), 51.7 (18.83) years	iPhone 4S	ECG	5 min: at rest 2 min: after 3 min of physical exercise (only controls)	Heart rate, heart rate variability
Kurylyak et al, 2012, Italy [91]	10 adults, 26-60 years	HTC HD2, iPhone 4, Nokia 5800, Samsung Galaxy S i9000	Pulse oximeter	2 × 60 s (per smartphone): at rest and after 60 s squatting	Heart rate
Lagido et al, 2014, Portugal [79]	43 heart failure patients, age not specified	Sony Xperia S	ECG	At rest	Heart rate, heart rate variability
Losa-Iglesias et al, 2016, Spain [80]	46 healthy adults, 39.3 (7.35) years	Samsung Galaxy Note	Radial pulse, pulse oximeter	3 × 10-30 s: at rest (resting 10 min before measurements)	Heart rate
Matsumara et al, 2013, Japan [82]	12 students, 21-24 years	iPhone 4S	ECG	3 × 3 min: at rest (resting 7 min before measurement), during mental arithmetic, and during mirror tracing	Heart rate, normalize pulse volume
Nam et al, 2016, United States [85]	11 healthy nonsmoking adults, 20-40 years	HTC One M8	ECG	3 × 2 min: breathing at frequencies from 0.1 to 0.5 Hz at increments of 0.1 Hz, breathing at 1 Hz and spontaneous breathing	Heart rate and breathing rate
Pelegris et al, 2010, UK [87]	50 adults, 21-55 years	HTC Tattoo	Pulse oximeter	2 × 9 s: well-lit room and average lit room	Heart rate
Po et al, 2015, China [88]	10 subjects, age not specified	Samsung Galaxy Nexus, LG Optimus P920, Samsung Galaxy S2, Samsung Galaxy Tablet 7.0, Motorala Atrix	Pulse oximeter	1 × 20 s	Heart rate and root mean square distortion of heart rate
Scully et al, 2012, United States [89]	1 subject, age not specified	Motorola Droid	ECG	1 × ?: spontaneous breathing 3 × 2 min: breathing at 0.2, 0.3, and 0.4 Hz	Heart rate, respiration rate, oxygen saturation
Wackel et al, 2014, United States [90]	26 children undergoing an electrophysiology study under general anesthesia, 5-17 years	iPhone 5	ECG	2 × ?: during baseline heart rate (34 measurements in 17 children) 2 × ?: during sustained supraventricular tachycardia (38 measurements during 21 supraventricular tachycardia in 18 children)	Heart rate

^aECG: electrocardiogram.