Peter Moritz Becher

Heart Failure (HF) is a multi-faceted and life-threatening syndrome characterized by significant morbidity and mortality, poor functional capacity and quality of life, and high costs. HF affects more than 64 million people worldwide. Therefore, attempts to decrease its social and economic burden have become a major global public health priority. While the incidence of HF has stabilized and seems to be declining in industrialized countries, the prevalence is increasing due to the ageing of the population, improved treatment of and survival with ischaemic heart disease, and the availability of effective evidence-based therapies prolonging life in patients with HF. There are geographical variations in HF epidemiology. There is substantial lack of data from developing countries, where HF exhibits different features compared with that observed in the Western world. In this review, we provide a contemporary overview on the global burden of HF, providing updated estimates on prevalence, incidence, outcomes, and costs worldwide.

BACKGROUND: Obesity and diabetes mellitus are important metabolic risk factors and frequent comorbidities in heart failure with preserved ejection fraction. They contribute to myocardial diastolic dysfunction (DD) through collagen deposition or titin modification. The relative importance for myocardial DD of collagen deposition and titin modification was investigated in obese, diabetic ZSF1 rats after heart failure with preserved ejection fraction development at 20 weeks. METHODS AND RESULTS: Four groups of rats (Wistar-Kyoto, n=11; lean ZSF1, n=11; obese ZSF1, n=11, and obese ZSF1 with high-fat diet, n=11) were followed up for 20 weeks with repeat metabolic, renal, and echocardiographic evaluations and hemodynamically assessed at euthanization. Myocardial collagen, collagen cross-linking, titin isoforms, and phosphorylation were also determined. Resting tension (Fpassive)-sarcomere length relations were obtained in small muscle strips before and after KCl-KI treatment, which unanchors titin and allows contributions of titin and extracellular matrix to Fpassive to be discerned. At 20 weeks, the lean ZSF1 group was hypertensive, whereas both obese ZSF1 groups were hypertensive and diabetic. Only the obese ZSF1 groups had developed heart failure with preserved ejection fraction, which was evident from increased lung weight, preserved left ventricular ejection fraction, and left ventricular DD. The underlying myocardial DD was obvious from high muscle strip stiffness, which was largely (±80%) attributable to titin hypophosphorylation. The latter occurred specifically at the S3991 site of the elastic N2Bus segment and at the S12884 site of the PEVK segment. CONCLUSIONS: Obese ZSF1 rats developed heart failure with preserved ejection fraction during a 20-week time span. Titin hypophosphorylation importantly contributed to the underlying myocardial DD.

TRIF is a member of the innate immune system known to be involved in viral recognition and type I IFN activation. Because IFNs are thought to play an important role in viral myocarditis, we investigated the role of TRIF in induced myocarditis in mice. Whereas C57BL/6 (wild-type) mice showed only mild myocarditis, including normal survival postinfection with coxsackievirus group B serotype 3 (CVB3), infection of TRIF(-/-) mice led to the induction of cardiac remodeling, severe heart failure, and 100% mortality (p < 0.0001). These mice showed markedly reduced virus control in cardiac tissues and cardiomyocytes. This was accompained with dynamic cardiac cytokine activation in the heart, including a suppression of the antiviral cytokine IFN-β in the early viremic phase. TRIF(-/-) myocytes displayed a TLR4-dependent suppression of IFN-β, and pharmacological treatment of CVB3-infected TRIF(-/-) mice with murine IFN-β led to improved virus control and reduced cardiac inflammation. Additionally, this treatment within the viremic phase of myocarditis showed a significant long-term outcome indexed by reduced mortality (20 versus 100%; p < 0.001). TRIF is essential toward a cardioprotection against CVB3 infection.

To investigate whether heart rate reduction via I(f)-channel blockade and β-receptor blockade prevents left ventricular (LV) dysfunction, we studied ivabradine and metoprolol in angiotensin II-induced heart failure. Cardiac dysfunction in C57BL/6J mice was induced by implantation of osmotic pumps for continuous subcutaneous dosing of angiotensin II (1.8 mg/kg per day SC) over a period of 3 weeks. Ivabradine (10 mg/kg per day) and metoprolol (90 mg/kg per day), which resulted in similar heart rate reduction, or placebo treatments were simultaneously started with infusion of angiotensin II. After 3 weeks, LV function was estimated by conductance catheter technique, cardiac remodeling assessed by estimation of cardiac hypertrophy, fibrosis, and inflammatory stress response by immunohistochemistry or PCR, respectively. Compared with controls, angiotensin II infusion resulted in hypertension in impaired systolic (LV contractility, stroke volume, end systolic elastance, afterload, index of arterial-ventricular coupling, and cardiac output; P<0.05) and diastolic (LV relaxation, LV end diastolic pressure, τ, and stiffness constant β; P<0.05) LV function. This was associated with a significant increase in cardiac hypertrophy and fibrosis. Increased cardiac stress was also indicated by an increase in cardiac inflammation and apoptosis. Both ivabradine and metoprolol led to a similar reduction in heart rate. Metoprolol also reduced systolic blood pressure. Ivabradine led to a significant improvement in systolic and diastolic LV function (P<0.05). This was associated with less cardiac hypertrophy, fibrosis, inflammation, and cardiac apoptosis (P<0.05). Metoprolol treatment did not prevent the reduction in cardiac function and adverse remodeling, despite a reduction of the inflammatory stress response. Behind heart rate reduction, additional beneficial cardiac effects contribute to heart failure prevention with I(f)-channel inhibition.

BACKGROUND: The therapeutic efficacy of the cardiac glycoside digitoxin in patients with heart failure and reduced ejection fraction is not established. METHODS: In this international, double-blind, placebo-controlled trial, we randomly assigned patients with chronic heart failure who had a left ventricular ejection fraction of 40% or less and a New York Heart Association (NYHA) functional class of III or IV or a left ventricular ejection fraction of 30% or less and an NYHA functional class of II in a 1:1 ratio to receive digitoxin (at a starting dose of 0.07 mg once daily) or matching placebo in addition to guideline-directed medical therapy. The primary outcome was a composite of death from any cause or hospital admission for worsening heart failure, whichever occurred first. RESULTS: Among 1240 patients who underwent randomization, 1212 fulfilled the criteria for inclusion in the modified intention-to-treat population: 613 patients in the digitoxin group and 599 in the placebo group. Over a median follow-up of 36 months, a primary-outcome event occurred in 242 patients (39.5%) in the digitoxin group and 264 (44.1%) in the placebo group (hazard ratio for death or first hospital admission for worsening heart failure, 0.82; 95% confidence interval [CI], 0.69 to 0.98; P = 0.03). Death from any cause occurred in 167 patients (27.2%) in the digitoxin group and 177 (29.5%) in the placebo group (hazard ratio, 0.86; 95% CI, 0.69 to 1.07). A first hospital admission for worsening heart failure occurred in 172 patients (28.1%) in the digitoxin group and 182 (30.4%) in the placebo group (hazard ratio, 0.85; 95% CI, 0.69 to 1.05). At least one serious adverse event occurred in 29 patients (4.7%) in the digitoxin group and 17 (2.8%) in the placebo group. CONCLUSIONS: Treatment with digitoxin led to a lower combined risk of death from any cause or hospital admission for worsening heart failure than placebo among patients with heart failure and reduced ejection fraction who received guideline-directed medical therapy. (Funded by the German Federal Ministry of Research, Technology, and Space and others; DIGIT-HF EudraCT number, 2013-005326-38.).