Expert Consensus on the Diagnosis and Management of Digoxin Toxicity.

While there has been a decline in the use of digoxin in patients with heart failure and atrial fibrillation, acute and chronic digoxin toxicity remains a significant clinical problem. Digoxin's narrow therapeutic window and nonspecific signs and symptoms of toxicity create clinical challenges and uncertainty around the diagnostic criteria of toxicity and responsive treatment choices for the bedside clinician. A systematic review of published literature on digoxin toxicity (34,587 publications over 6 decades, with 114 meeting inclusion criteria) was performed to develop 33 consensus statements on diagnostic and therapeutic approaches which were then evaluated through a modified Delphi process involving a panel of experts in cardiology, nursing, emergency medicine, and medical toxicology. The results demonstrate agreement about the need to consider time of ingestion and nature of the exposure (ie, acute, acute-on-chronic, chronic) and the use of digoxin immune Fab for life-threatening exposure to decrease risk of death. While several areas of continued uncertainty were identified, this work offers formalized guidance that may help providers better manage this persistent clinical challenge.

Interdependence of cardiac and endothelial function in patients with symptomatic chronic heart failure of nonischemic etiology.

OBJECTIVE: Endothelial dysfunction has emerged as a therapeutic target in patients with chronic congestive heart failure (CHF). Endothelial dysfunction may impair left ventricular (LV) systolic function by increasing systemic vascular resistance. Conversely, LV impairment may negatively impact endothelial function by reducing shear stress and vascular nitric oxide (NO) bioavailability. This study was undertaken to determine the association between LV and endothelial function in patients with CHF. METHODS: Echocardiographic and vascular ultrasound studies were performed to measure left ventricular ejection fraction (LVEF) and brachial artery flow-mediated vasodilatation (FMD) in 30 subjects with stable New York Heart Association class II-III CHF. All patients received optimal medical therapy. RESULTS: LVEF averaged 25 +/- 9% and brachial artery FMD 1.3 +/- 2.4%. LVEF strongly correlated with FMD among all patients (r = 0.64, P< 0.001) and among those patients with nonischemic (n = 19, r = 0.66, P = 0.002), but not in patients with ischemic etiology (n = 11, r = 0.27, P = 0.42). CONCLUSIONS: LVEF and endothelium-dependent NO vasodilatation are strongly correlated in stable ambulatory patients with systolic CHF of nonischemic etiology. Our study underscores the mutual interaction between central cardiac and peripheral vascular function, thus strengthening a mechanistic rationale for the systemic beneficial effects of interventions targeting either the heart or the vascular endothelium in CHF.