Study of Coronary Blood Flow in Adults with Heart Failure, Left Bundle Branch Block, and Cardiac Resynchronization Therapy

What this Trial Is About

Researchers are investigating the effects of cardiac resynchronization therapy CRT in patients with symptomatic heart failure who have a low left ventricular ejection fraction LVEF of 35% or less and left bundle branch block LBBB. About one-third of patients receiving CRT do not show improvement, and this study aims to understand how CRT affects coronary blood flow in the left anterior descending artery LAD in patients with non-ischemic dilated cardiomyopathy and LBBB. The study hypothesizes that CRT improves heart function not only by resynchronizing the hearts contractions but also by enhancing blood flow in coronary arteries. The study will enroll 60 patients with heart failure caused by non-ischemic dilated cardiomyopathy and LBBB, some with CRT devices and some without. Researchers will measure absolute coronary flow and resistance in the LAD using invasive procedures, including fractional flow reserve FFR, with CRT devices turned on and off to compare effects. These measurements will help evaluate how CRT influences blood flow and heart muscle work. Participants will undergo invasive flow measurements during the study procedure to assess coronary blood flow and heart function. Researchers will closely monitor absolute coronary flow during the procedure to understand the impact of CRT. The study is conducted at an outpatient cardiology clinic and involves assessing heart rhythm, medical therapy stability, and other heart health factors. The total duration and follow-up details are not specified, but the focus is on real-time measurements during the procedure.

Absolute Coronary Flow in Patients With Heart Failure With Reduced Ejection Fraction and Left Bundle Branch Block With Cardiac Resynchronization Therapy