Reading LabChart Data Exported as .mat.

I have a series of data files from experiments that have been converted via LabChart 8 to .mat files. I use the load function in Matlab to read the data; however, there is inconsistency as to the the number of datastart and dataend columns and the channel references don't always correspond to the extraction done by my program.

Would anyone mind please inspecting my data and code to help interpret the problem and find a solution? The code is below. We could find another means of sharing data.

%User-Defined Input
FileName = '20-341.mat';
Start = 2.94E6; %[(Time in Minutes) x (60 Seconds / Minute) * (1000 Samples / Second)]
Finish = 3.35E6;
SamplingRate = 1000; %Hz
AorticPressure_Channel = 2;
VestPressure_Channel = 3;
RightAtrialPressure_Channel = 5;
%User-Defined Input

Data = load(FileName);
ChannelLength = Data.dataend(AorticPressure_Channel,1) - Data.datastart(AorticPressure_Channel,1);

AorticPressure(ChannelLength+1) = 0;
VestPressure(ChannelLength+1) = 0;
RightAtrialPressure(ChannelLength+1) = 0;

AorticPressure = Data.data(Data.datastart(AorticPressure_Channel,1):Data.dataend(AorticPressure_Channel,1));
VestPressure = Data.data(Data.datastart(VestPressure_Channel,1):Data.dataend(VestPressure_Channel,1));
RightAtrialPressure = Data.data(Data.datastart(RightAtrialPressure_Channel,1):Data.dataend(RightAtrialPressure_Channel,1));