% this is deltaVplot.m 
% First we must decide when ejection begins.  
% You can get this from animpfplots and find the index where 
% ventricular pressure goes above aortic pressure. 

startindex = 27; %index where Vp goes above Ap.  The beginning of ejection. 
endindex = 66; % index where Af = 0.  The end of ejection. 

deltaVall(1) = 0; %The first value of all deltaV is assigned zero

% Since Time is in Seconds and flow is in ml/min we need to change flow to ml/sec 
% or time to minutes.  The latter is easier so we'll do that

TimeMin = Time/60;

for i = 2:n 
    deltaVall(i) = deltaVall(i-1) +  1/2 * (Af(i) + Af(i-1)) * (TimeMin(i)-TimeMin(i-1));
end

% The above gives us the change in volume througout the entire cycle ... hence "all" 
% We want it to cover only ejection

oppdeltaV(1)=0 %The first value of the opposite of deltaV is zero. 
for i=2:endindex-startindex
    oppdeltaV(i) = deltaVall(startindex+i)-deltaVall(startindex);
end

deltaV = -1 * oppdeltaV
% Now we have the ventricular change in volume during ejection.  
% We want to plot this with the correponding time. 

plot(Time(startindex:endindex-1),deltaV,'r.')
title('Change in Ventricle volume during one ejection')
xlabel('Time in Seconds')
ylabel('deltaV in ml')

%After running this the first time you should generate a plot where the ventricle loses 
%about 25 ml. This makes sense.