Cardiac resynchronization therapy improves renal function in human heart failure with reduced glomerular filtration rate.

BACKGROUND: Renal dysfunction is an important independent prognostic factor in heart failure (HF). Cardiac resynchronization therapy (CRT) improves functional status and left ventricular (LV) function in HF patients with ventricular dyssynchrony, but the impact of CRT on renal function is less defined. We hypothesized that CRT would improve glomerular filtration rate as estimated by the abbreviated Modification of Diet in Renal Disease equation (eGFR). METHODS AND RESULTS: The Multicenter InSync Randomized Clinical Evaluation (MIRACLE) study evaluated CRT in HF patients with NYHA Class III-IV, ejection fraction or=130 ms. Patients were evaluated before and 6 months after randomization to control (n = 225) or CRT (n = 228). Patients were categorized according to their baseline eGFR: >or=90 (category A), 60

Left ventricular mechanical load and contractile function in patients with chronic mitral regurgitation.

BACKGROUND AND AIM OF THE STUDY: Left ventricular adaptation to chronic volume overload results in dramatic changes in ventricular geometry and hemodynamics. These changes are reflected in alterations in mechanical load and, eventually, contractile function. METHODS: The study included 17 patients undergoing clinically driven invasive evaluation for mitral regurgitation (MR). Simultaneous catheter-tip manometry and M-mode echocardiography allowed for derivation of meridional and circumferential wall stress at end-diastole, end-systole, peak systole, and the average over the systolic ejection period. Assessment of contractile function was performed by analysis of: the overall group relationship between baseline end-systolic stress (ESS) and end-systolic dimension (ESD); subject-specific analysis of the relationship between ESS and ESD derived from pharmacologic load alteration; and subject- specific analysis of the relationship between left ventricular minor axis shortening and ESS. The acquired data were compared to data from 10 control subjects who were undergoing invasive evaluation and were free from cardiovascular disease. RESULTS: Compared to controls, patients with chronic MR (mean regurgitant fraction 57%) were characterized by significantly increased angiographic end-diastolic and end-systolic volumes, lower cardiac indices, and similar left ventricular ejection fractions. Patients with chronic MR were also characterized by increased preload (end-diastolic stress) and afterload (mean systolic stress). ESS was not consistently increased in these patients, despite the increased chamber size. The severity of clinical symptoms was associated with the magnitude of alteration in afterload (mean systolic stress). Using different methodologies, a substantial prevalence of depressed contractile function was identified in those patients with preserved ejection fraction. CONCLUSION: When compared to an age- and gender-matched controls, symptomatic patients with MR have similar left ventricular ejection performance in the setting of increased pre-load and after-load. Symptom severity was associated with increased afterload. The prevalence of contractile dysfunction in this setting was substantial.

Sustained reverse left ventricular structural remodeling with cardiac resynchronization at one year is a function of etiology: quantitative Doppler echocardiographic evidence from the Multicenter InSync Randomized Clinical Evaluation (MIRACLE).

BACKGROUND: Cardiac resynchronization therapy (CRT) is an effective therapy for patients with moderate to severe heart failure and prolonged QRS duration. The purpose of this study was to determine whether reverse left ventricular (LV) remodeling and symptomatic benefit from CRT were sustained at 12 months, and if so, in what proportion of patients this occurred. METHODS AND RESULTS: Serial Doppler echocardiograms were obtained at baseline and 6 and 12 months after CRT in 228 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Measurements were made of LV end-diastolic (EDV) and end-systolic (ESV) volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E wave) and late (A wave) diastolic filling, and myocardial performance index. At both 6 and 12 months, respectively, CRT was associated with reduced LV EDV (P<0.0001 and P=0.007) and LV ESV (P<0.0001 and P<0.0001), improved ejection fraction (P<0.0001 and P<0.0001), regression of LV mass (P=0.012 and P<0.0001), and reduced MR (P<0.0001 and P<0.0001). LV filling time, transmitral E/A ratio, and myocardial performance index all improved at 12 months compared with baseline (P<0.001, P=0.031, and P<0.0001). Reverse LV remodeling with CRT occurred in more patients at 6 than at 12 months (74% versus 60%, respectively; P<0.05) and was greater in patients with a nonischemic than an ischemic etiology. CONCLUSIONS: Reverse LV remodeling and symptom benefit with CRT are sustained at 12 months in patients with New York Heart Association class III/IV heart failure but occur to a lesser degree in patients with an ischemic versus a nonischemic etiology, most likely owing to the inexorable progression of ischemic disease.

Racial differences in the prevalence of cardiac sources of embolism in subjects with unexplained stroke or transient ischemic attack evaluated by transesophageal echocardiography.

Little is known about the distribution of cardiac sources of embolism among African-Americans with cryptogenic cerebrovascular events. We compared the prevalence of potential cardiac sources of embolism between black and white patients referred to our laboratory for transesophageal echocardiographic (TEE) evaluation of unexplained stroke or transient ischemic attack. Records were reviewed to exclude subjects with high-risk cardiac or vascular disorders likely to explain the index event. Of 297 patients satisfying the inclusion criteria, 196 were white and 87 black. Potential cardioembolic sources were significantly less common in blacks than in whites (adjusted odds ratio [OR], 0.44; 95% confidence interval [CI] 0.26 to 0.75), and related largely to the difference in prevalence of interatrial communication (OR 0.40; 95% CI 0.21 to 0.74). In contrast, African-Americans had a higher prevalence of left ventricular (LV) hypertrophy (OR 3.50; 95% CI 1.97 to 6.22), and particularly, moderate or severe hypertrophy (OR 4.03; 95% CI 1.88 to 9.65) compared with whites. In conclusion, in African-Americans with unexplained cerebrovascular events, the yield of TEE for potential cardioembolic sources, and especially interatrial communication, is lower than in their white counterparts. African-Americans exhibit a substantially higher prevalence of LV hypertrophy, which may be a marker for a higher burden of subclinical cerebrovascular disease involved in the pathogenesis of cryptogenic cerebral ischemia in this population.