Detecting and Quantifying T-Wave Alternans: The PhysioNet/Computing in Cardiology Challenge 2008 1.0.0

Rcount=Rcount-1;
RR=diff(R)*2;
R = circshift(R.',-1);
MeanRR=mean(RR);
for ii=1:60
    ExCoef(ii)=1-0.15+ii/100;
end;
Tint=double(int32(MeanRR/5)); %T-wave interval length
Tstart=double(int32(MeanRR/17)); %T-wave interval start
ModelT(1:Tint,1)=[1:Tint];
ModelT(1:Tint,2)=0;
for ii=1:NrofLead
    for i=1:Tint
        ModelT(i,2)=ModelT(i,2)+EKG((R(1)+i+Tstart),ii)^2;
    end;
end;
ExCoefG(1)=1;
xt=[1:Tint];

for j=2:Rcount
% for j=2:2
    Tt(1:Tint,1)=[1:Tint];
    Tt(1:Tint,2)=0;
    for ii=1:NrofLead
        for i=1:Tint
            Tt(i,2)=Tt(i,2)+EKG((R(j)+i+Tstart),ii)^2;
        end;
    end;
    for ii=1:60
        Tt1(1:Tint,1)=Tt(1:Tint,1)*ExCoef(ii);
        xt=double([1:Tint]);
        T1(1:Tint,ii)=interp1(Tt1(1:Tint,1),Tt(1:Tint,2),xt,'spline','extrap');
        CC=corrcoef(T1(:,ii),ModelT(:,2));
        MaxC(ii)=CC(2,1);
    end;
    [C,I]=max(MaxC);

    ExCoefG(j)=ExCoef(I);

    ModelT(:,2)=(ModelT(:,2)+T1(:,I))/2;
    Tt1(1:rint,1)=Tt(1:rint,1);
    if ExCoefG(j)<=1
        Tt1(3:rint-2,1)=Tt(3:rint-2,1)*ExCoefG(j);
    else
        Tt1(3:rint,1)=Tt(3:rint,1)*ExCoefG(j);
    end;
    xt=[1:Tint];
    for ii=1:NrofLead
        Tt(1:Tint,2)=EKG((R(j)+Tstart):(R(j)+Tstart)+Tint-1,ii);
        Tder(1:Tint,ii)=interp1(Tt1(1:Tint,1),Tt(1:Tint,2),xt,'spline','extrap');
        TderPr=mean(Tder(1:10,ii));
        TderPb=mean(Tder(Tint-10:Tint,ii));
        for i=1:Tint
            TderCor(i,1)=TderPr+(i-1)*((TderPb-TderPr)/Tint);
        end;
        Tder(:,ii)=Tder(:,ii)-TderCor;
        T((ii-1)*Tint+1:ii*Tint,j)=Tder(:,ii);
        Tcon((j-1)*Tint+1:j*Tint,ii)=Tder(:,ii);
    end;
end;
for ii=1:NrofLead
    Tt(1:Tint,2)=EKG((R(1)+Tstart):(R(1)+Tstart)+Tint-1,ii);
    T((ii-1)*Tint+1:ii*Tint,1)=Tt(:,2);
    Tcon(1:Tint,ii)=Tt(1:Tint,2);
end;