IQ.SPECT technology performs Myocardial Perfusion Imaging (MPI) in less than five minutes compared to conventional 20-25 minute scans. The aim of this study was to optimise the IQ.SPECT reconstruction and compare with conventional MPI scanning and Echocardiography using perfusion and ECG-gated imaging. 18 patients were imaged using IQ.SPECT in addition to conventional SPECT and the IQ.SPECT reconstruction parameters were optimised to produce comparable findings with conventional SPECT. Images were analysed quantitatively using QPS and QGS software and qualitatively by clinician scoring. IQ.SPECT LVEF values were compared to those obtained using conventional MPI and Echocardiography. Optimum reconstruction parameters for perfusion images were found to be: 6 subsets, 6 iterations, with a Gaussian filter cut-off of 8, and for gated images: 3 subsets, 15 iterations with a Gaussian filter cut-off of 10. No significant difference was found between perfusion images from IQ.SPECT and those from conventional SPECT. IQ.SPECT LVEF values differed, on average, by 15% from those using conventional SPECT and by 25% from those using Echocardiography. The disagreement between LVEF values suggests that caution is needed for borderline LVEF.