Shining a new light on Left Ventricular Function
At the recent AHA meeting in New Orleans, Niema M. Pahlevan (1), a post doctoral fellow at Cal Tech in Pasadena presented preliminary trial results on using the flashlight component on the Apple iPhone 5S to calculate the ejection fraction. His method is based on the ability of the smartphone light beam in conjunction with a custom derived application to assess carotid waveform fluctuations during the cardiac cycle. The underlying application analysis is based on the concept that the ventricular-arterial system is coupled and applying a mathematical method called intrinsic frequency, it is possible to non-invasively calculate Left Ventricular Ejection Fraction (LVEF).
The authors reported a comparison of a standard cardiac MRI LVEF analysis to a temporarily obtained non-invasive iPhone derived carotid LVEF based on the developed app. A total of 72 subjects, ages 20-92 years of age were analyzed. The correlation between the MRI and the iPhone was 0.74 (r=0.74, P<0.0001). A subgroup analysis of 11 patients clinically diagnosed as having heart failure by a cardiologist with a reduced LVEF demonstrated a highly significant correlation of 0.94 (P<0.0001).
These data are obviously preliminary, and the technology in its current iteration may be limited by associated patient characteristics including body size and other cardiac abnormalities. However, the potential to non-invasively “dial up” an LVEF using a smart phone is an exciting possibility.
- Niema M Pahlevan, Derek Rinderknecht, Peyman Tavallali, Marianne Razavi, Thao T Tran, Michael Fong, Robert A Kloner, Marie Csete and Morteza Gharib. A New Noninvasive iPhone Application to Monitor Left Ventricle Ejection Fraction in Heart Failure Patients: Circulation. 2016;134:A17227.