Background The aim of this work was to evaluate the effect of high-intensity interval exercise (i.e., 30 s at 100% of max workload, followed by 30 s at rest, 45 min 3 days/week working-out schedule for 12 weeks) on left ventricular function and aortic elastic properties among chronic heart failure (CHF) patients. Methods This study is a phase III clinical trial. Of the 100 consecutive CHF patients (NYHA classes II-IV, ejection fraction < 50%) that were randomly allocated, 72 completed the study (exercise training group, n = 33, 63 ± 9 years, 88% men, and control group, n = 39, 56 ± 11 years, 82% men). All patients underwent cardiopulmonary stress test, non-invasive high-fidelity tonometry of the radial artery, pulse wave velocity measurement using a SphygmoCor device and echocardiography before and after the completion of the training program. Results Both groups reported similar medical characteristics and physical activity status. General mixed effects models revealed that the intervention group reduced pulse wave velocity by 9% (p = 0.05); Emv/Vp by 14% (p = 0.06); E to A ratio by 24% (p = 0.004), E to Emv ratio by 8% (p = 0.05), MLHFQ score by 66% (p = 0.003) and the depression score by 19% (p = 0.5); increased augmentation index by 29%; VTI by 4% (p = 0.05), 6-minute-walk distance up to 13% (p = 0.05), peak oxygen uptake by 28% (p = 0.001) and peak power by 25% (p = 0.005). There were no significant changes in the control group. Conclusion Interval high-intensity aerobic training, combined with strength exercise, seems to benefit aortic dilatation capacity and augmented systolic pressure in parallel with improvement in left ventricular diastolic function and quality of life.