Background: In patients with heart failure, the presence of left ventricular contractile reserve (LVCR) during stress echo (SE) may result in a good response to cardiac resynchronization therapy (CRT). Aim: Toassess the feasibility and accuracy of LVCR by Peak Rest (Systolic Blood Pressure End Systolic Volume) (SPBESV). One can calculate the left ventricular contractile reserve by dobutamine stress echocardiography and assess the correlation of this method to EF related LVCR. Patients and methods: On 71 patients, this cross-sectional investigation was carried out. They were recommended to perform dobutamine echocardiography either to assess ischemia in those with intermediate pretest probability or to assess viability in those with a kinetic wall motion and with those with low ejection fraction. Every patient underwent a thorough history review, general examination, and local examination. ECG, resting and stress transthoracic echocardiography. Results: CR Simpson showed a moderate positive significant correlation with the peak-rest EF Simpson in the viability group and moderate positive significant correlation in the ischemic group. While CR m-mode and peak-rest EF m-mode had a significant correlation in the ischemic group and a non-significant one in the viability. Conclusion: With the two techniques for obtaining the raw ESV values required to calculate Force, LVCR can be estimated with accuracy. While the Simpson approach is more accurate in calculating absolute ESV values, m-mode may also accurately analyse relative (rest-stress) changes. There was no discernible difference between the viable and non-viable groups in terms of LVCR by peak-to-rest ratio in the ischemic and non-ischemic people.