Search

Hyponatremia (HN) occurs commonly in patients with acute heart failure and confers a worse prognosis. Current HN treatment varies widely, with no consensus. This study recorded treatment practices currently used for patients hospitalized with acute heart failure and HN. Data were collected prospectively from 146 US sites on patients hospitalized with acute heart failure and HN (serum sodium concentration [Na+] ≤130 mEq/L) present at admission or developing in the hospital. Baseline variables, HN treatment, and laboratory values were recorded. Of 762 patients, median [Na+] was 126 mEq/L (interquartile range, 7) at baseline and increased to 130 mEq/L at discharge. Fluid restriction was the most commonly prescribed therapy (44%), followed by no specific HN treatment beyond therapy for congestion (23%), isotonic saline (5%), tolvaptan (4%), and hypertonic saline (2%). Median rate of change in [Na+] varied by treatment (0.5 [interquartile range, 1.0] to 2.3 [8.0] mEq/L/d) and median treatment duration ranged from 1 (interquartile range, 1) to 6 (5) days. Fluid restriction and no specific HN treatment resulted in similar changes in [Na+], and were least effective in correcting HN. Few patients (19%) had [Na+] ≥135 mEq/L at discharge. The most commonly used treatment approaches for HN (fluid restriction and no specific treatment) in acute heart failure increased [Na+] minimally, and most patients remained hyponatremic at discharge.

ObjectivesThis study sought to examine the relationships between in-hospital and post-discharge body weight changes and outcomes among patients hospitalized for acute heart failure (AHF).BackgroundBody weight changes during and after hospitalization for AHF and the relationships with outcomes have not been well characterized.MethodsA post hoc analysis was performed of the ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide and Decompensated Heart Failure) trial, which enrolled patients admitted for AHF regardless of ejection fraction. In-hospital body weight change was defined as the difference between baseline and discharge/day 10, whereas post-discharge body weight change was defined as the difference between discharge/day 10 and day 30. Spearman rank correlations of weight change, urine output (UOP), and dyspnea relief as assessed by a 7-point Likert scale are described. Logistic and Cox proportional hazards regression was used to evaluate the relationship between weight change and outcomes.ResultsStudy participants with complete body weight data (n = 4,172) had a mean age of 65 ± 14 years, and 66% were male. Ischemic heart disease was reported in 60% of patients and the average ejection fraction was 30 ± 13%. The median change in body weight was -1.0 kg (interquartile range: -2.1 to 0.0 kg) at 24 h and -2.3 kg (interquartile range: -5.0 to -0.7 kg) by discharge/day 10. At hour 24, there was a weak correlation between change in body weight and UOP (r = -0.381), and minimal correlation between body weight change and dyspnea relief (r = -0.096). After risk adjustment, increasing body weight during hospitalization was associated with a 16% increase per kg in the likelihood of 30-day mortality or HF readmission for patients showing weight loss ≤1 kg or weight gain during hospitalization (odds ratio per kg increase 1.16, 95% confidence interval [CI]: 1.09 to 1.27; p < 0.001). Among the subset of patients experiencing >1-kg increase in body weight post-discharge, increasing body weight was associated with higher risk of 180-day mortality (hazard ratio per kg increase 1.16; 95% CI: 1.09 to 1.23; p < 0.001).ConclusionsA substantial number of patients experienced minimal weight loss or frank weight gain in the context of an AHF trial, and increasing body weight in this subset of patients was independently associated with a worse post-discharge prognosis.

Prevention of diminished parasympathetic control of the heart in experimental heart failure. Am J Physiol Heart Circ Physiol 287: H1780-H1785, 2004. First published June 10, 2004; 10.1152/ajpheart.00430.2004.--Decreased synaptic transmission in parasympathetic ganglia contributes to abnormal parasympathetic function in heart failure (HF). Because nicotinic ACh receptors (nAChR) mediate synaptic transmission at the ganglion and upregulate in response to chronic exposure to agonist in vitro, we tested the hypothesis that repeated exposures of ganglionic neurons to a nAChR agonist can prevent a loss of parasympathetic control in HF. Two sets of experiments were performed. In set 1, unpaced control dogs and dogs undergoing pacing-induced HF were treated with a repeated intravenous nicotinic agonist during the development of HF. Under conditions of sympathetic blockade, R-R responses to a bolus injection of 200 [micro]g 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP: nicotinic agonist) were found to be increased five times over the untreated group after 6 wk. In experimental set 2, dogs treated with weekly DMPP injections and in HF were anesthetized and underwent electrical stimulation of the right vagus nerve, which showed sinus cycle length responses > 10 times that of controls (P < 0.05). Complete ganglionic blockade with hexamethonium abolished all responses, confirming that synaptic transmission was mediated entirely by nAChRs in both controls and HF. Despite decreased ganglionic function leading to reduced parasympathetic control of the heart in HF, repeated exposure with a nicotinic agonist during the development of HF results in not only preserved but also supranormal effects of parasympathetic stimulation on the sinus node. ganglion: nicotinic acetylcholine receptor: vagal; synapse

Parasympathetic control of the heart is attenuated in heart failure (HF). We investigated possible mechanisms and sites of altered vagal control in dogs with HF induced by rapid pacing. Muscarinic blockade reduced the R-R interval by 308 ms in controls but only by 32 ms in HF, indicating low levels of resting vagal tone. Vagomimetic doses of atropine sulfate prolonged the R-R interval by 109 ms in controls and increased standard deviation of the R-R interval by 66 ms but only by 46 and 16 ms, respectively, in HF. Bradycardia elicited by electrical stimulation of the vagus nerve was also attenuated in the HF group. Conversely, muscarinic receptor activation by bethanechol, and indirectly by neostigmine, elicited exaggerated R-R interval responses in HF. To investigate possible mechanisms, we measured muscarinic receptor density ([B.sub.max]) and acetylcholinesterase activity in different areas of the heart. In sinoatrial nodes, [B.sub.max] was increased (230 [+ or -] 75% of control) and acetylcholinesterase decreased (80 [+ or -] 6% of control) in HF. We conclude that muscarinic receptors are upregulated and acetylcholinesterase is reduced in the sinus node in HF. Therefore, reduced vagal control in HF is most likely due to changes of presynaptic function (ganglionic), because postsynaptic mechanisms augment vagal control in HF. cholinergic; parasympathetic; autonomic

Analysis of changes in autonomic control of heart rate in conscious dogs with left ventricular (LV) dysfunction and heart failure (HF) due to rapid pacing shows that heart rate is minimally affected by vagal and sympathetic control in these dogs. The contribution of vagal control of heart rate and control vagal outflow is minimal during the early developmental stage of LV dysfunction. Low levels of atropine vagomimetically affects heart rate in HF and the effects are observed after beta-blockade.f

Activation of the baroreceptors in anaesthetized rats without and with LVD through phenylephrine-induced arterial pressure increase helps study the impairment of baroreflexes during left ventricular dysfunction (LVD) arising from chronic myocardial infarction without congestive heart failure and the role of abnormal central neural mechanisms in causing the impairment. The baroreflex regulation of ventilatory, sympathetic and heart rate responses in rats with moderate LVD is defective, and an inverse relationship exists between baroreflex gains and infarct size. The reduced baroreflexes may arise from abnormal afferent pathways despite the contribution of central mechanisms to the defective barosympathetic reflex.

A study examined the assumption that reflex sympathoexcitation results when intracoronary adenosine stimulates cardiac sympathetic afferent fibers 2 mg of adenosine was administered into the left anterior descending artery over 2 minutes, in dogs having sinoaortic denervation and vagotomy. Intracoronary adenosine caused no variation in blood pressure or renal sympathetic nerve activity, prior to dipyridamole infusion. The sympathoexcitatory response induced by the stimulation of adenosine receptors is caused by the stimulation of the adenosine cardiac sympathetic afferent fibers.