Fang, James C.

BACKGROUND: With evolving therapy for heart failure with reduced ejection fraction, the benefits of adding a defibrillator in patients undergoing cardiac resynchronization therapy (CRT) remain unclear, particularly for nonischemic cardiomyopathy (NICM). This study evaluates long-term survival among patients with NICM treated with CRT defibrillator (CRT-D) versus CRT pacemaker (CRT-P). METHODS: DECIDE-CRT (Cardiac Resynchronization With or Without Defibrillator in Non-Ischemic Cardiomyopathy) is a multicenter cohort study across 170 US Veterans Affairs hospitals. We identified patients with NICM receiving primary-prevention CRT-P or CRT-D between January 1, 2006, and December 31, 2020. Using a propensity score approach, we applied inverse probability of treatment weighting to balance baseline characteristics between the CRT-P and CRT-D groups. An inverse probability of treatment weighting–weighted Cox model estimated hazards for all-cause mortality. Secondary outcomes included generator replacement, device-related infections, hospitalization for heart failure, and ventricular arrhythmias. RESULTS: Of 16 609 CRT recipients, 3965 met NICM primary-prevention criteria (CRT-D=3158; CRT- P =807). At baseline, patients with NICM receiving CRT-P were much older, with more cardiovascular and noncardiovascular comorbidities compared with the CRT-D group. During the median follow-up of 5.2 years, the mortality rate for CRT-P versus CRT-D was 9.46 versus 9.21 per 100 person-years (RR, 0.97 [95% CI, 0.71–1.13]; P =0.66). The adjusted hazard ratio for all-cause mortality using the inverse probability of treatment weighting-Cox model was 0.90 (95% CI, 0.71–1.13; P =0.34). There was no difference in adjusted hazard for heart failure hospitalization (hazard ratio, 1.27 [95% CI, 0.86–1.87]), while the CRT-D group had higher rates of generator replacement and device-related infections. CONCLUSIONS: This nationwide observational study from the Veterans Affairs Health system did not demonstrate a clear survival advantage with the addition of a defibrillator among patients with NICM receiving CRT although residual confounding cannot be excluded. Given the uncertainty surrounding the incremental benefit of the defibrillator in this setting, a randomized trial is needed to test the incremental value of CRT-D over CRT-P in NICM.

Background Right ventricular (RV) maladaptation to elevated pulmonary afterload is the primary determinant of outcomes in pulmonary artery (PA) hypertension; however, the pathobiological mechanisms underlying RV decompensation remain poorly understood. Methods We performed global untargeted metabolomics on plasma from 55 patients who underwent gold‐standard RV‐PA coupling measurements using multibeat pressure volume loop assessment in a single‐center cohort and from 1027 patients with coupling surrogate measurements in a larger multicenter cohort, the PVDOMICS (Pulmonary Vascular Disease Phenomics) study. Age and sex‐adjusted linear regression was performed to identify associations between metabolites and coupling metrics. Additionally, we performed a metabolic flux analysis using gene expression data from RV tissue in an independent cohort of 32 patients. Partial least squares–discriminant analysis was used to identify metabolites and reactions characteristic of the decompensated RV. Results RV‐PA coupling was negatively associated with tricarboxylic acid (TCA) cycle intermediate levels. Specifically, plasma α‐ketoglutarate and fumarate were significantly associated with all coupling metrics in both cohorts. Metabolic flux analysis indicated that decompensated RVs exhibited aberrant TCA cycle activity, including reduced acetyl coenzyme A entry and increased lactate elimination, suggesting a shift from the TCA cycle toward glycolysis at the RV tissue level. Conclusions We identify an association between circulating TCA cycle intermediate levels and RV‐PA uncoupling in 2 independent cohorts, and dysregulated TCA cycle metabolism in decompensated PA hypertension RVs, suggesting that aberrant TCA cycle metabolism could represent a hallmark of RV maladaptation in PA hypertension. Further study of this pathway is warranted to develop novel biomarkers of RV function or RV‐targeted therapies.

Background The utility of longitudinal, circumferential, and radial strain and strain rate in determining prognosis in chronic heart failure is not well established. Methods and Results In 416 patients with chronic systolic heart failure, we performed speckle‐tracking analyses of left ventricular longitudinal, circumferential, and radial strain and strain rate on archived echocardiography images (30 frames per second). Cox regression models were used to determine the associations between strain and strain rate and risk of all‐cause mortality, cardiac transplantation, and ventricular‐assist device placement. The area under the time‐dependent ROC curve ( AUC ) was also calculated at 1 year and 5 years. Over a maximum follow‐up of 8.9 years, there were 138 events (33.2%). In unadjusted models, all strain and strain rate parameters were associated with adverse outcomes ( P <0.001). In multivariable models, all parameters with the exception of radial strain rate ( P =0.11) remained independently associated, with patients in the lowest tertile of strain or strain rate parameter having a ≈2‐fold increased risk of adverse outcomes compared with the reference group ( P <0.05). Addition of strain to ejection fraction ( EF ) led to a significantly improved AUC at 1 year (0.697 versus 0.633, P =0.032) and 5 years (0.700 versus 0.638, P =0.001). In contrast, strain rate did not provide incremental prognostic value to EF alone. Conclusions Longitudinal and circumferential strain and strain rate, and radial strain are associated with chronic heart failure prognosis. Strain provides incremental value to EF in the prediction of adverse outcomes, and with additional study may be a clinically relevant prognostic tool.