In patients with atrial fibrillation and congestive heart failure, a routine strategy of rhythm control does not reduce the rate of death from cardiovascular causes, as compared with a rate-control strategy. (ClinicalTrials.gov number, NCT00597077.)

IntroductionThe extent of ventricular dilation after a myocardial infarction (MI) depends on the magnitude of the initial ischemic damage as well as the tissue healing process (1, 2). This dynamic pathological process includes the expression and activation of the matrix metalloproteinases (MMPs), which may mediate many of the morphological changes that occur after MI in both infarcted and noninfarcted regions (3-5). Members of the MMP family of enzymes degrade specific extracellular matrix components; clinical and experimental studies have shown that MMP expression and activity increase in both MI (5) and dilated cardiomyopathy (6, 7).Because extracellular matrix deposition and organization play a major role in left ventricular (LV) remodeling, MMP inhibition has emerged as a potential therapeutic strategy for patients at risk for the development of congestive heart failure. Administration of a broad-spectrum MMP inhibitor attenuates LV enlargement in pacing-induced congestive heart failure (8) and in the early period after MI occurs (9). Whether this effect depends on the inhibition of many MMPs, or selective inhibition of MMPs can prevent ventricular dilation remains unexplored. Recently, Heymans et al. reported a decreased incidence of rupture at 4 days after MI in MMP-9-deficient animals, suggesting that MMP-9 may have a specific role in early myocardial healing (10). In this study we evaluated the influence of targeted deletion of the MMP-9 gene on LV remodeling after experimental MI in mice. We performed this study with sibling wild-type (WT) controls after at least six backcrosses to minimize genetic variability. All analyses were blinded to genotype; the animals were studied for 15 days. MethodsAnimals and surgery. We used the progeny of heterozygous breeding pairs of mice with targeted disruption of MMP-9, as described by Vu et al. (11). MMP-9-deficient mice have delayed long-bone growth and development due to delayed angiogenesis and ossification; however, by adulthood, these changes result in only a 10% shortening in the long bones. Animals with an FVB background were backcrossed; our studies used the homozygous MMP-9-deficient and sibling WT offspring of generation six or higher. Offspring were eartagged and coded, with tail DNA samples harvested for genotyping using PCR. For MMP-9, we used a sense oligonucleotide primer (5′-GCA TAC TTG TAC CGC TAT GG -3′) and an antisense primer (5′-TAA CCG GAG GTC CAA ACT GG-3′). For the neomycin cassette, we also used a sense oligonucleotide primer (5′-GAA Matrix metalloproteinase-9 (MMP-9) is prominently overexpressed after myocardial infarction (MI). We tested the hypothesis that mice with targeted deletion of MMP9 have less left ventricular (LV) dilation after experimental MI than do sibling wild-type (WT) mice. Animals that survived ligation of the left coronary artery underwent echocardiographic studies after MI; all analyses were performed without knowledge of mouse genotype. By day 8, MMP9 knockout (KO) mice had significantly smaller increases in end-diasto...

Since the inception of the Canadian Cardiovascular Society heart failure (HF) guidelines in 2006, much has changed in the care for patients with HF. Over the past decade, the HF Guidelines Committee has published regular updates. However, because of the major changes that have occurred, the Guidelines Committee believes that a comprehensive reassessment of the HF management recommendations is presently needed, with a view to producing a full and complete set of updated guidelines. The primary and secondary Canadian Cardiovascular Society HF panel members as well as external experts have reviewed clinically relevant literature to provide guidance for the practicing clinician. The 2017 HF guidelines provide updated guidance on the diagnosis and management (self-care, pharmacologic, nonpharmacologic, device, and referral) that should aid in day-to-day decisions for caring for patients with HF. Among specific issues covered are risk scores, the differences in management for HF with preserved vs reduced ejection fraction, exercise and rehabilitation, implantable devices, revascularization, right ventricular dysfunction, anemia, and iron deficiency, cardiorenal syndrome, sleep apnea, cardiomyopathies, HF in pregnancy, cardio-oncology, and myocarditis. We devoted attention to strategies and treatments to prevent HF, to the organization of HF care, comorbidity management, as well as practical issues around the timing of referral and follow-up care. Recognition and treatment of advanced HF is another important aspect of this update, including how to select advanced therapies as well as end of life considerations. Finally, we acknowledge the remaining gaps in evidence that need to be filled by future research.

BACKGROUND It is unknown whether warfarin or aspirin therapy is superior for patients with heart failure who are in sinus rhythm. METHODS We designed this trial to determine whether warfarin (with a target international normalized ratio of 2.0 to 3.5) or aspirin (at a dose of 325 mg per day) is a better treatment for patients in sinus rhythm who have a reduced left ventricular ejection fraction (LVEF). We followed 2305 patients for up to 6 years (mean [±SD], 3.5±1.8). The primary outcome was the time to the first event in a composite end point of ischemic stroke, intracerebral hemorrhage, or death from any cause. RESULTS The rates of the primary outcome were 7.47 events per 100 patient-years in the warfarin group and 7.93 in the aspirin group (hazard ratio with warfarin, 0.93; 95% confidence interval [CI], 0.79 to 1.10; P = 0.40). Thus, there was no significant overall difference between the two treatments. In a time-varying analysis, the hazard ratio changed over time, slightly favoring warfarin over aspirin by the fourth year of follow-up, but this finding was only marginally significant (P = 0.046). Warfarin, as compared with aspirin, was associated with a significant reduction in the rate of ischemic stroke throughout the follow-up period (0.72 events per 100 patient-years vs. 1.36 per 100 patient-years; hazard ratio, 0.52; 95% CI, 0.33 to 0.82; P = 0.005). The rate of major hemorrhage was 1.78 events per 100 patient-years in the warfarin group as compared with 0.87 in the aspirin group (P<0.001). The rates of intracerebral and intracranial hemorrhage did not differ significantly between the two treatment groups (0.27 events per 100 patient-years with warfarin and 0.22 with aspirin, P = 0.82). CONCLUSIONS Among patients with reduced LVEF who were in sinus rhythm, there was no significant overall difference in the primary outcome between treatment with warfarin and treatment with aspirin. A reduced risk of ischemic stroke with warfarin was offset by an increased risk of major hemorrhage. The choice between warfarin and aspirin should be individualized.

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-Administration of an MMP inhibitor attenuates early left ventricular dilation after experimental MI in mice. Further studies in genetically altered mice and other models will improve understanding of the role of MMPs in left ventricular remodeling.

action potential and ionic current remodeling in ventricles of failing canine hearts. Am J Physiol Heart Circ Physiol 283: H1031-H1041, 2002. First published May 30, 2002 10.1152/ ajpheart.00105.2002.-Heart failure (HF) produces important alterations in currents underlying cardiac repolarization, but the transmural distribution of such changes is unknown. We therefore recorded action potentials and ionic currents in cells isolated from the endocardium, midmyocardium, and epicardium of the left ventricle from dogs with and without tachypacing-induced HF. HF greatly increased action potential duration (APD) but attenuated APD heterogeneity in the three regions. Early afterdepolarizations (EADs) were observed in all cell types of failing hearts but not in controls. Inward rectifier K ϩ current (IK1) was homogeneously reduced by ϳ41% (at Ϫ60 mV) in the three cell types. Transient outward K ϩ current (Ito1) was decreased by 43-45% at ϩ30 mV, and the slow component of the delayed rectifier K ϩ current (IKs) was significantly downregulated by 57%, 49%, and 58%, respectively, in epicardial, midmyocardial, and endocardial cells, whereas the rapid component of the delayed rectifier K ϩ current was not altered. The results indicate that HF remodels electrophysiology in all layers of the left ventricle, and the downregulation of IK1, Ito1, and IKs increases APD and favors occurrence of EADs. heterogeneity; early afterdepolarizations; congestive heart failure; arrhythmias

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