Matlab code to plot ECG signal

From the simulation plot for one cycle or wave above, we can find the following information:

1.       The shape of a P-wave is smooth and rounded. The initial recording of the P wave lasts for approximately 21ms (65 -44) and the amplitude is not greater than 0.0437mv.

2.       The QRS complex lasts for approximately 17 ms (271 -254) and has an amplitude of 1.68mV, which is measured from the top of the R wave to the bottom of the S wave.

3.       The voltage of a T wave is 0.326 mV

4.       BPM or heart rate is 84 beat/min

5.       PP interval is 171ms (224-53).

  ECG mini homework

close all;

clear all;

clc;

%

%S=load('I:\BIOM_Signal_processing\Hw5\ECGsignal_1.mat')

y1=xlsread('J:\BIOM_Signal_processing\Hw5\ECGsignal_1.xls');

fs = 250 % find the sampling rate or frequency

T = 1/fs;% sampling rate or frequency

% find the length of the data per second

N = length(y1);

ls = size(y1);

t = (0 : N-1)/fs;% sampling period

figure; %subplot(1,2,1);

%subplot(1,2,1);

plot(t,y1);

title ('plot of the orignal ECG signal');

xlabel ('time (sec)');

ylabel ('ECG Amplitute (mv)');

grid on;

figure;

%%% Create a period

y1new = y1(10:350);

ax = axis; axis([ax(1:2) -3.2 3.2])

t2 = (0 : length (y1new)-1)/fs;% sampling period

%subplot(1,2,2);

plot (y1new);

title ('plot one typical period of the signal amplitude spectrume of the  ECG signal');

xlabel ('time (msec)');

ylabel ('ECG Amplitute  (mv)');

figure;

%%% Create a period

y1new1 = y1(40:200);

ax = axis; axis([ax(1:2) -3.2 3.2])

t2 = (0 : length (y1new)-1)/fs;% sampling period

%subplot(1,2,2);

plot (y1new1);

title ('plot PQRST cycle of the ECG signal');

xlabel ('time (msec)');

ylabel ('ECG Amplitute  (mv)');

%% heart rate analysis

% count the dominat peak

beat_count =0;

for k = 2 : length(y1)-1

    %the peak has to be greater than 1 and greater than the value before it and greater then the value after it.

    if(y1(k)> y1(k-1) && y1(k) > y1(k+1) && y1(k)> 1)

         beat_count = beat_count +1;

    end       

end

display (k);

disp('dominant peaks');

%% divide the peak count by the duration in minute

duration_in_sec = N/fs;

duration_in_minute = duration_in_sec/60;

BPM = beat_count/duration_in_minute;