Regulation of circulating chromogranin B levels in heart failure.

BACKGROUND: Chromogranin B (CGB) regulates B-type natriuretic peptide (BNP) production. Circulating CGB levels are elevated in heart failure (HF) animal models and HF patients, but also increase in healthy individuals in response to physical activity. Therefore, CGB seems to integrate information from myocardial stress and systemic neuro-endocrine activation. Substantial gaps remain in our understanding of CGB regulation in HF. METHODS AND RESULTS: We conducted a retrospective registry study including 372 patients. CGB and N-terminal pro-BNP (NT-proBNP) plasma levels were assessed in acute HF and chronic valvular HF patients and controls. CGB levels were significantly increased in acute HF and chronic valvular HF, but significantly higher in the latter. Patients in chronic valvular HF with severe mitral regurgitation (cHF-MR) showed significantly higher CGB levels than patients in chronic valvular HF with severe aortic stenosis. CGB levels progressively increased with worsening NYHA functional status and were moderately correlated to NT-proBNP, but independent of left ventricular (LV) ejection fraction (LVEF), LV mass, age and body weight. Finally, cHF-MR patients showed significant reductions of CGB levels after interventional mitral valve repair. CONCLUSION: CGB is a promising emerging biomarker in HF patients with unique potential to integrate information from myocardial stress and neuro-endocrine activation.

Experience With the Wearable Cardioverter-Defibrillator in Patients at High Risk for Sudden Cardiac Death.

BACKGROUND: This study evaluated the wearable cardioverter-defibrillator (WCD) for use and effectiveness in preventing sudden death caused by ventricular tachyarrhythmia or fibrillation. METHODS: From April 2010 through October 2013, 6043 German WCD patients (median age, 57 years; male, 78.5%) were recruited from 404 German centers. Deidentified German patient data were used for a retrospective, nonrandomized analysis. RESULTS: Ninety-four patients (1.6%) were treated by the WCD in response to ventricular tachyarrhythmia/fibrillation. The incidence rate was 8.4 (95% confidence interval, 6.8-10.2) per 100 patient-years. Patients with implantable cardioverter-defibrillator explantation had an incidence rate of 19.3 (95% confidence interval, 12.2-29.0) per 100 patient-years. In contrast, an incidence rate of 8.2 (95% confidence interval, 6.4-10.3) was observed in the remaining cardiac diagnosis groups, including dilated cardiomyopathy, myocarditis, and ischemic and nonischemic cardiomyopathies. Among 120 shocked patients, 112 (93%) survived 24 hours after treatment, whereas asystole was observed in 2 patients (0.03%) with 1 resulting death. CONCLUSIONS: This large cohort represents the first nationwide evaluation of WCD use in patients outside the US healthcare system and confirms the overall value of the WCD in German treatment pathways.

Protected risk stratification with the wearable cardioverter-defibrillator: results from the WEARIT-II-EUROPE registry.

BACKGROUND: The prospective WEARIT-II-EUROPE registry aimed to assess the value of the wearable cardioverter-defibrillator (WCD) prior to potential ICD implantation in patients with heart failure and reduced ejection fraction considered at risk of sudden arrhythmic death. METHODS AND RESULTS: 781 patients (77% men; mean age 59.3 ± 13.4 years) with heart failure and reduced left ventricular ejection fraction (LVEF) were consecutively enrolled. All patients received a WCD. Follow-up time for all patients was 12 months. Mean baseline LVEF was 26.9%. Mean WCD wearing time was 75 ± 47.7 days, mean daily WCD use 20.3 ± 4.6 h. WCD shocks terminated 13 VT/VF events in ten patients (1.3%). Two patients died during WCD prescription of non-arrhythmic cause. Mean LVEF increased from 26.9 to 36.3% at the end of WCD prescription (p < 0.01). After WCD use, ICDs were implanted in only 289 patients (37%). Forty patients (5.1%) died during follow-up. Five patients (1.7%) died with ICDs implanted, 33 patients (7%) had no ICD (no information on ICD in two patients). The majority of patients (75%) with the follow-up of 12 months after WCD prescription died from heart failure (15 patients) and non-cardiac death (15 patients). Only three patients (7%) died suddenly. In seven patients, the cause of death remained unknown. CONCLUSIONS: Mortality after WCD prescription was mainly driven by heart failure and non-cardiovascular death. In patients with HFrEF and a potential risk of sudden arrhythmic death, WCD protected observation of LVEF progression and appraisal of competing risks of potential non-arrhythmic death may enable improved selection for beneficial ICD implantation.

The endothelial nitric oxide synthase cofactor tetrahydrobiopterin shields the remote myocardium from apoptosis after experimental myocardial infarction in vivo.

BACKGROUND: Following myocardial infarction (MI), apoptosis occurs early in the remote myocardium and contributes to the processes of myocardial remodelling. Increased nitrosative stress is a well-known and potent inductor of myocardial apopto¬sis. Excess activation of endothelial nitric oxide synthase (eNOS) increases its uncoupling potential and results in nitrosative stress via formation of peroxynitrite. However, the pathophysiological role of eNOS signalling in the remote myocardium after MI is as yet undefined. AIM: The impact of eNOS activation on pro- and anti-apoptotic signalling in the remote myocardium and the influence of pretreatment with the eNOS cofactor tetrahydrobiopterin (BH4) on eNOS activation, nitrosative stress level, and apoptosis induction and execution were studied in a rat MI model in vivo. RESULTS: Twenty-four hours after anterior MI, eNOS activity in animals treated with left anterior descending coronary artery ligation (LIG) significantly increased in the posterior left ventricular (LV) myocardium as did protein nitrosylation when com¬pared to sham treatment. This was paralleled by induction of apoptosis via the extrinsic and intrinsic pathways. Moreover, anti-apoptotic signalling via protein kinase B/Akt and glycogen synthase-kinase 3 beta was suppressed. Notably, pretreatment with the eNOS cofactor BH4 reduced eNOS activation, prevented excess protein nitrosylation, blunted apoptosis induction, facilitated anti-apoptotic signalling, and eventually prevented apoptosis execution. CONCLUSIONS: Here we showed that 24 h after experimental MI in rats in vivo, apoptosis was induced in the posterior non-in¬farcted LV wall. Evidence is presented that pretreatment with the eNOS cofactor BH4 resulted in less nitrosative stress and weakened apoptotic processes, although the stabilisers contained did participate in this phenomenon. Because apoptosis is a crucial component of myocardial remodelling, influencing eNOS signalling might be an interesting pharmacological target for the development of novel anti-remodelling therapies.