Analysis of direct and indirect heartbeat data variations

1. A method for measuring variability between direct heartbeat data and indirect heartbeat data, the method comprising:

receiving first heartbeat data from an electrocardiogram over a period of time;

receiving second heartbeat data from an indirect measure of heartbeat data over at least a portion of the period of time;

calculating, by a computing device, a difference between the first heartbeat data and the second heartbeat data;

comparing, by the computing device, the difference to determine a variation;

estimating, by the computing device, an elasticity of arteries of an individual by analyzing the difference between the first heartbeat data and the second heartbeat data over time;

selecting, by the computing device, subsets of the first heartbeat data and subsets of the second heartbeat data;

performing, by the computing device, a spectral analysis of the selected subsets of the first heartbeat data and subsets of the second heartbeat data; and

presenting, by a display device, the spectral analysis, wherein the spectral analysis includes detection of features of the selected subsets of the first heartbeat data and subsets of the second heartbeat data.

2. The method of claim 1 , further comprising:

plotting graphical representations of beat-to-beat differences;

performing measurements at different conditions; and

determining more or less variance based upon the different conditions.

3. The method of claim 1 , further comprising using a pulse oximeter oxygen saturation sensor to provide the indirect measure.

4. The method of claim 1 , further comprising using a pressure sensor to provide the indirect measure.

5. The method of claim 1 , wherein the spectral analysis is presented in near real-time.

6. The method of claim 1 , wherein the selecting subsets includes selecting a desired signal from between the first heartbeat data and the second heartbeat data.