Effect of Cardiac Resynchronization Therapy on Left Ventricular Size and Function in Chronic Heart Failure

Abstract

for the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) Study GroupBackground-Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate to severe systolic heart failure and ventricular dyssynchrony. The purpose of the present study was to determine whether improvements in left ventricular (LV) size and function were associated with CRT. Methods and Results-Doppler echocardiograms were obtained at baseline and at 3 and 6 months after therapy in 323 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Of these, 172 patients were randomized to CRT on and 151 patients to CRT off. Measurements were made of LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E-wave) and late (A-wave) diastolic filling, and the myocardial performance index. At 6 months, CRT was associated with reduced end-diastolic and end-systolic volumes (both PϽ0.001), reduced LV mass (PϽ0.01), increased ejection fraction (PϽ0.001), reduced MR (PϽ0.001), and improved myocardial performance index (PϽ0.001) compared with control. ␤-Blocker treatment status did not influence the effect of CRT. Improvements with CRT were greater in patients with a nonischemic versus ischemic cause of heart failure. Conclusions-CRT in patients with moderate-to-severe heart failure who were treated with optimal medical therapy is associated with reverse LV remodeling, improved systolic and diastolic function, and decreased MR. LV remodeling likely contributes to the symptomatic benefits of CRT and may herald improved longer-term survival. (Circulation.

Tissue doppler imaging is superior to strain rate imaging and postsystolic shortening in the prediction of reverse remodeling in both ischemic and nonischemic heart failure after cardiac resynchronization therapy

“…It is probably a combination of improvement in intraventricular synchronicity, 4 hemodynamics, 20,21 atrioventricular synchronicity, 22 interventricular synchronicity, 4,6 and mitral regurgitation. 4,6 Reverse remodeling response was consistently observed, 5,6,9,20 which was thought to contribute to the beneficial effect on symptoms and may herald the improvement of long-term survival. 6 -8 Clinical and volumetric nonresponders to CRT are consistently observed in approximately one third of patients.…”

Cardiac Resynchronization Therapy in CKD Stage 4 Patients

“…Treatment of HF with CRT has been associated with improved renal function potentially through several mechanisms (6)(7)(8)(9). CRT often results in a significant improvement in LV systolic function, which therefore improves systemic hemodynamic status and prerenal circulation (6,(22)(23)(24)(25)(26)(27)(28)(29). In addition, CRT decreases central venous pressure, which is described to play an important role in the progression of renal failure (3,29,30).…”

Current approach to treatment of ischemic mitral regurgitation

“…В настоящее время уже доказано, что сердечная ре-синхронизирующая терапия (СРТ) значимо уменьшает степень митральной регургитации при наличии механи-ческой диссинхронии миокарда ЛЖ [6,7]. В исследова-нии InSync показано уменьшение степени митральной регургитации у 67% пациентов [8].…”