Treatment of heart failure with normal ejection fraction

The Effect of Renin-Angiotensin System Inhibitors on the Recurrence of Atrial Fibrillation After Catheter Ablation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Renin-angiotensin system (RAS) inhibitors were reported to modify the arrhythmia substrate and reverse atrial remodeling. However, the role of RAS inhibitors on AF recurrence after catheter ablation remains much more controversial. In this study, a meta-analysis was performed to explore the effect of RAS inhibitors on AF recurrence after catheter ablation.We searched PubMed, Cochrane Library, EMBASE, and Web of Science for all articles published up to July 2019 on the effect of RAS inhibitors on AF recurrence rate after ablation. We used the random-effects model to estimate the odds ratios (ORs) and confidence intervals (CI). The I2 statistic was used to evaluate statistical heterogeneity. A two-tailed P value of <0.05 was considered statistically significant. Results were further analyzed by subgroup according to the type of study design.We included 13 studies, including 3661 patients with AF, in this analysis, of which 4 were randomized controlled trials (RCTs) and the others were cohort studies. Overall, treatment with RAS inhibitors showed a significant reduction of AF recurrence after catheter ablation (OR, 0.61; 95% CI, 0.45-0.82). Additionally, both the RCT (OR, 0.35; 95% CI, 0.24-0.49) and non-RCT (OR, 0.76; 95% CI, 0.57-1.00) groups demonstrated that RAS inhibitors could reduce the AF recurrence rate after catheter ablation in the subgroup analysis.Our meta-analysis suggests that RAS inhibitors had significant benefit in reducing the recurrence rate of AF after catheter ablation.

Exercise Training Improved Longitudinal Intrinsic Left Ventricle Function in Heart Failure with Preserved Ejection Fraction

Exercise improves morbidity, fatality rate, and quality of life in heart failure with low ejection fraction, but fewer data available in heart failure with preserved ejection fraction (HFPEF). The purpose of this study is to test the hypothesis that exercise training might improve the longitudinal intrinsic left ventricular (LV) function in HFPEF patients. This quasi-experimental study had recruited 30 patients with HFPEF. Exercise training program had been performed for a month with a total of 20 times exercise sessions and evaluated every 2 weeks. Echocardiography was performed before sessions, second week and fourth week of exercise training. Six-minute walk tests (6MWTs) and quality-of-life variables using Minnesota living with HF scoring and the 5-item World Health Organization Well-Being Index scoring were measured before and after exercise as well. Left ventricular filling pressure, represented by the ratio of early diastolic mitral flow velocity/early diastolic annular velocity and left atrial volume index, improved during exercise. The longitudinal intrinsic LV function, represented by four-chamber longitudinal strain, augmented during exercise ( p  < 0.001). Aerobic capacity, measured by 6MWT, increased significantly ( p  = 0.001). Quality of life improved significantly during exercise ( p  < 0.001). Exercise training was suggested to improve the longitudinal intrinsic LV function and quality of life in HFPEF. Clinical Trial Registration: ACTRN12614001042639.

Digitoxin improves cardiovascular autonomic control in rats with heart failure

The effects of chronic treatment with digitoxin on arterial baroreceptor sensitivity for heart rate (HR) and renal sympathetic nerve activity (rSNA) control, cardiopulmonary reflex, and autonomic HR control in an animal model of heart failure (HF) were evaluated. Wistar rats were treated with digitoxin, which was administered in their daily feed (1 mg/kg per day) for 60 days. The following 3 experimental groups were evaluated: sham, HF, and HF treated with digitoxin (HF + DIG). We observed an increase in rSNA in the HF group (190 ± 29 pps, n = 5) compared with the sham group (98 ± 14 pps, n = 5). Digitoxin treatment prevented an increase in rSNA (98 ± 14 pps, n = 7). Therefore, arterial baroreceptor sensitivity was decreased in the HF group (−1.24 ± 0.07 bpm/mm Hg, n = 8) compared with the sham group (−2.27 ± 0.23 bpm/mm Hg, n = 6). Digitoxin did not alter arterial baroreceptor sensitivity in the HF + DIG group. Finally, the HF group showed an increased low frequency band (LFb: 23 ± 5 ms2, n = 8) and a decreased high frequency band (HFb: 77 ± 5 ms2, n = 8) compared with the sham group (LFb: 14 ± 3 ms2; HFb: 86 ± 3 ms2, n = 9); the HF+DIG group exhibited normalized parameters (LFb: 15 ± 3 ms2; HFb: 85 ± 3 ms2, n = 9). In conclusion, the benefits of decreasing rSNA are not directly related to improvements in peripheral cardiovascular reflexes; such occurrences are due in part to changes in the central nuclei of the brain responsible for autonomic cardiovascular control.

A change of heart: oxidative stress in governing muscle function?

Redox/cysteine modification of proteins that regulate calcium cycling can affect contraction in striated muscles. Understanding the nature of these modifications would present the possibility of enhancing cardiac function through reversible cysteine modification of proteins, with potential therapeutic value in heart failure with diastolic dysfunction. Both heart failure and muscular dystrophy are characterized by abnormal redox balance and nitrosative stress. Recent evidence supports the synergistic role of oxidative stress and inflammation in the progression of heart failure with preserved ejection fraction, in concert with endothelial dysfunction and impaired nitric oxide-cyclic guanosine monophosphate-protein kinase G signalling via modification of the giant protein titin. Although antioxidant therapeutics in heart failure with diastolic dysfunction have no marked beneficial effects on the outcome of patients, it, however, remains critical to the understanding of the complex interactions of oxidative/nitrosative stress with pro-inflammatory mechanisms, metabolic dysfunction, and the redox modification of proteins characteristic of heart failure. These may highlight novel approaches to therapeutic strategies for heart failure with diastolic dysfunction. In this review, we provide an overview of oxidative stress and its effects on pathophysiological pathways. We describe the molecular mechanisms driving oxidative modification of proteins and subsequent effects on contractile function, and, finally, we discuss potential therapeutic opportunities for heart failure with diastolic dysfunction.

Pressure overload

This review discusses cardiac consequences of pressure overload. In response to elevated pressure, the ventricular hypertrophy compensates for the increased wall stress. However, the ventricular hypertrophy involves numerous structural adaptations that may lead to ventricular dysfunction and, eventually, heart failure. Particular emphasis is placed on molecular mechanisms that govern the development of hypertrophy and that may lead to maladaptive structural changes resulting in adverse cardiac events.

Cardiac displacement-induced hemodynamic instability during off-pump coronary artery bypass surgery and its predictors

BACKGROUND

Emergent conversion to an on-pump procedure during an off-pump coronary artery bypass surgery (OPCAB) due to hemodynamic instability is associated with increased morbidity and mortality. The aim of this study was to evaluate the predictors of hemodynamic instability associated with mechanical heart displacement during OPCAB and the fate of these patients.

METHODS

Data of 494 patients who underwent elective, isolated OPCAB between December 2006 and April 2010 were reviewed. Hemodynamic instability was defined as mixed venous oxygen saturation (SvO(2) ) <60% during grafting. Pre-operative variables including the presence of diastolic dysfunction and mitral regurgitation (MR) were evaluated for their predictive value for hemodynamic instability by logistic regression analysis. Outcome variables were also compared between patients who developed hemodynamic instability and those who did not.

RESULTS

In univariate analysis, body mass index, diabetes mellitus, chronic obstructive pulmonary disease (COPD), left ventricular ejection fraction, diastolic dysfunction, MR ≥ grade 1, higher creatinine and the use of diuretics were identified as risk factors. In multivariate analysis of these variables, COPD and creatinine remained as independent risk factors for hemodynamic instability. These patients also had significantly lower cardiac output and SvO(2) after sternum closure and a higher incidence of composite morbidity end points.

CONCLUSION

COPD and pre-operative creatinine level were identified as independent risk factors of mechanical heart displacement-induced hemodynamic instability during OPCAB. As these patients were associated with significantly lower SvO(2) even at the end of surgery and with adverse outcome, consideration may be given to initiate preemptive measures to increase SvO(2) before or during grafting.

Cardiorenal syndrome caused by heart failure with preserved ejection fraction

Since cardiorenal dysfunction is usually secondary to multiple factors acting in concert (and not only reduced cardiac output) in the present paper we are going to focus on the interrelationship between heart failure with normal ejection fraction and the development of cardiorenal syndrome. The coexistence of renal impairment in heart failure with preserved ejection fraction (CRS type 2 and 4) is common especially in older females with hypertension and/or diabetes. It can be hypothesized that the incidence of this disease association is growing, while clinical trials enrolling these patients are still lacking. The main mechanisms thought to be involved in the pathophysiology of this condition are represented by the increase of intra-abdominal and central venous pressure and the activation of the renin-angiotensin system. Differently from CRS in heart failure with reduced ejection fraction, the involvement of the kidney may be under-diagnosed in patients with heart failure and preserved ejection fraction and the optimal therapeutic strategy in this condition, though challenging, is far to be completely elucidated. Further studies are needed to assess the best therapeutic regimen in patients with renal dysfunction (and worsening) and heart failure and preserved ejection fraction.