USE only (Matlab)

This assignment is about heart rate variability.

PART1:

You will calculate some time domain variables to see if there are differences in terms of HRV between the conditions of the recorded ECGs. Sampling frequency of the recorded signals is 1000Hz.

Data contains 3 variables:

1. ecgREST: ECG recorded at rest,

2. ecgDURINGWATER: ECG recorded during drinking water,

3. ecgAFTERWATER: ECG recorded after drinking water.

Steps:

1) Load ECGdata.mat

2) Find the peaks (R)

3) Calculate time difference (RR or NN interval) between successive R peaks.

4) Plot the ECG signals (for the 3 ECG signals in the dataset) and show that you have correctly detected the R peaks.(Screen capture different time intervals: 5 or 6 intervals will be enough.)

5) Plot RR intervals (calculated from the 3 ECG signals in the dataset)

6) Copy these Matlab figures and paste them into Word document for submission.

7) Calculate NN50 and pNN50. Comment on the values.

Note: Dont forget to add a screen capture of the workspace. Variables and the sizes of the variables are important.

PART2:

In this part, RR intervals that you have calculated in Part1 for ECGs recorded at REST and AFTER DRINKING WATER will be used.

Steps:

1. Plot histograms of RR intervals. (2 histograms)

2. Find the number of elements inside the bins and the position of the bin centers.

3. Plot these bins with respect to the position of the bin centers.

4. Fit a linear polynomial to the increasing part of the plot in Step 3.

5. Calculate the values of this polynomial (y) for a range of t values (for example for t=700 to 1200)

6. Plot these values as a line on the plot of Step3.

7. Repeat Steps 4, 5, and 6 for the decreasing part of the plot in Step 3.

8. Find the points where these two linear polynomials (lines that fit the increasing and decreasing part of the plot in Step 3) cross the x-axis (or time axis). These points are N and M, respectively. Calculate M-N.

9. Remove the bins that contain number of elements less than 10% of the bin that contains the maximum number of elements.

10. Repeat Steps 3 to 9.