Cardiac MRI for Optimal Heart Failure Outcomes With CRT Upgrades

The scientific premise of this proposal is that left and right ventricular (LV and RV) structural characteristics in patients with existing cardiac implantable electronic devices and heart failure who may benefit from an upgrade to a cardiac resynchronization therapy (CRT) device can be assessed very effectively using cardiac MRI using sequences designed for post-device imaging. Furthermore, a comparative analysis of the differences in LV/RV structural characteristics in patients with existing devices referred for CRT upgrades versus those with de novo CRT implants is expected to be very useful for developing effective strategies for optimal patient selection for CRT upgrades and implementation of CRT upgrades in appropriate patients. Patient selection for CRT upgrades is very important considering that complication rates are higher than in de novo CRT procedures and nonresponse rates are still high. With this in mind, we are performing a study of 100 patients, including 50 prospectively enrolled patients with LVEF less than or equal to 0.35 and New York Heart Association class II-III heart failure, who will be compared with an existing cohort of 50 patients with recent de novo CRT implants, pre-CRT MRIs, and response data. The 50 prospectively enrolled patients having CRT upgrades will undergo a pre-CRT cardiac MRI, pre-CRT/post-CRT echocardiography, and pre-CRT/post-CRT cardiopulmonary exercise testing. In the first aim, we will assess differences in cardiac MRI findings between CRT upgrade patients and de novo CRT patients. In the second aim, we will assess the impact of cardiac MRI findings on LV reverse remodeling and cardiopulmonary capacity in the two groups. In summary, we propose a comprehensive prospective CRT/MRI study in CRT upgrade patients with comparison to a complete MRI dataset of patients with de novo CRT implants in order to identify key differences in MRI findings in these cohorts and the impact of these MRI-based scar and activation findings on clinical outcomes. We expect that our results will have a significant public health impact for patients with heart failure referred for CRT upgrades.