Patients with heart failure treated with metoprolol do not demonstrate an improvement in systolic performance until after 1 month of therapy and may have a mild reduction in function initially. Long-term therapy with metoprolol results in a reversal of maladaptive remodeling with reduction in left ventricular volumes, regression of left ventricular mass and improved ventricular geometry by 18 months.
Myocardial failure has been considered to be an irreversible and progressive process characterized by ventricular enlargement, chamber geometric alterations, and diminished pump performance. However, more recent evidence has suggested that certain types of medical therapy may lead to retardation and even reversal of the cardiomyopathic process. In the failing heart, long-term neurohormonal/autocrine-paracrine activation results in abnormalities in myocyte growth, energy production and utilization, calcium flux, and receptor regulation that produce a progressively dysfunctional, mechanically inefficient heart. Interventions such as ACE inhibition and beta-blockade result in a reduction in the harmful long-term consequences of neurohormonal/autocrine-paracrine effects and retard the progression of left ventricular dysfunction or ventricular remodeling. Furthermore, in subjects with idiopathic dilated or ischemic cardiomyopathy, antiadrenergic therapy with beta-blocking agents appears to be able to partially reverse systolic dysfunction and ventricular remodeling. Although the precise mechanisms underlying this latter effect have not yet been elucidated, the general mechanism appears to be via improvement in the biological function of the cardiac myocyte. Such an improvement in the intrinsic defect(s) responsible for myocardial failure will likely translate into important clinical benefits.
These data demonstrate that in patients with cardiomyopathy, metoprolol treatment improves myocardial performance and energetics, and favorably alters substrate utilization. Beta-adrenergic blocking agents, such as metoprolol, are hemodynamically and energetically beneficial in the treatment of myocardial failure.
After 200 years of use, digitalis still appears to have a place in our armamentarium for heart failure and atrial fibrillation despite the proven survival benefits with ACE inhibitors and beta-blockers. Digoxin therapy is inexpensive and well tolerated and may result in considerable savings. Digoxin is the only oral inotrope that does not increase mortality in heart failure patients, particularly if low doses are being used. Digoxin therapy should be used in patients with systolic heart failure who continue to have signs and symptoms despite therapeutic doses of ACE inhibitors or diuretics or in patients with atrial fibrillation with or without heart failure for rate control.
Background
Allogeneic mesenchymal precursor cells (MPC) injected during left ventricular assist device (LVAD) implantation may contribute to myocardial recovery. This trial explores the safety and efficacy of this strategy.
Methods and Results
In this multi-center, double-blind, sham-procedure controlled trial, 30 patients were randomized (2:1) to intramyocardial injection of 25M MPCs or medium during LVAD implantation. The primary safety endpoint was incidence of infectious myocarditis, myocardial rupture, neoplasm, hypersensitivity reaction, and immune sensitization (90 days post-randomization). Key efficacy endpoints were functional status and ventricular function, while temporarily weaned from LVAD support (90 days post-randomization). Patients were followed until transplant or 12 months post-randomization, whichever came first. Mean age was 57.4 (±13.6) years, mean LVEF 18.1%, and 66.7% were destination therapy LVADs. No safety events were observed. Successful temporary LVAD weaning was achieved in 50% of MPC and 20% of control patients at 90 days (p=0.24); the posterior probability that MPCs increased the likelihood of successful weaning is 93%. At 90 days, 3 deaths occurred in control and none in MPC patients. Mean LVEF following successful wean was 24.0% (MPC=10) and 22.5% (Control=2) (p=0.56). At 12 months, 30% of MPC and 40% of control patients were successfully temporarily weaned from LVAD support (p=0.69) and 6 deaths occurred in MPC patients. Donor-specific HLA sensitization developed in 2 MPC and 3 control patients and resolved by 12 months.
Conclusions
In this preliminary trial, administration of MPCs appeared to be safe and there was a potential signal of efficacy. Future studies will evaluate the potential for higher or additional doses to enhance the ability to wean LVAD recipients off support.
Clinical Trial Registration Information
ClinicalTrials.gov. Identifier: NCT01442129.
Surveys of prescribing patterns in both hospitals and primary care have usually shown delays in translating the evidence from clinical trials of pharmacological agents into clinical practice, thereby denying patients with heart failure (HF) the benefits of drug treatments proven to improve well-being and prolong life. This may be due to unfamiliarity with the evidence-base for these therapies, the clinical guidelines recommending the use of these treatments or both, as well as concerns regarding adverse events. ACE inhibitors have long been the cornerstone of therapy for systolic HF irrespective of aetiology. Recent trials have now shown that treatment with beta-blockers, aldosterone antagonists and angiotensin receptor blockers also leads to substantial improvements in outcome. In order to accelerate the safe uptake of these treatments and to ensure that all eligible patients receive the most appropriate medications, a clear and concise set of clinical recommendations has been prepared by a group of clinicians with practical expertise in the management of HF. The objective of these recommendations is to provide practical guidance for non-specialists, in order to increase the use of evidenced based therapy for HF. These practical recommendations are meant to serve as a supplement to, rather than replacement of, existing HF guidelines.
This study demonstrates that ventricular arrhythmias do not specifically predict sudden death in patients with moderate-to-severe heart failure. Thus, the finding of asymptomatic NSVT on ambulatory ECG does not identify specific candidates for antiarrhythmic or device therapy.
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