OK, here's my (ugly) solution (withou using findpeaks). I've re-named your data set, and did some pre-processig.
load ecg
y = ecgSamplePreProc;
Ts = 1/150; % sampling freq = 150 Hz;
t = Ts*[0:length(y)-1]';
%% Do some preliminary cleaning
idx = [1:600];
t(idx) = []; y(idx) = []; % drop start-u transients
y = y - mean(y); % remove any bias
plot(t,y,'.-')
Now we are ready to identify the peaks. (I'm not sure if that's the same as your R-wave, but it's a start.)
n = length(y);
thresh = 0.7;
pauseOn = false;
irange = [-5:5];
pk = [1];
pauseOn = true;
for i=10:n-10
if y(i) > thresh
yr = y(i+irange);
if y(i) >= max(yr) && pauseOn && (i > pk(end)+50)
pk = [pk;i];
pauseOn = true;
end
if y(i) < -thresh
pauseOn = false;
end % if
end
end
plot(t,y, ...
t(pk), y(pk), 'ro')
yline(thresh,'--','color',0.5*[1,1,1])
The results look like:
and a zoomed version is:
Of course you could try findpeaks as well.
