Background-A respiratory cycle for nitric oxide (NO) would involve the formation of vasoactive metabolites between NO and hemoglobin during pulmonary oxygenation. We investigated the role of these metabolites in hypoxic tissue in vitro and in vivo in healthy subjects and patients with congestive heart failure (CHF compared with relaxations induced at 95% (PϽ0.05), consistent with an allosteric mechanism of hypoxic vasodilation. We also measured transpulmonary gradients of NO metabolites in healthy control subjects and in patients with CHF. In CHF patients but not control subjects, levels of SNO-Hb increase from 0.00293Ϯ0.00089 to 0.00585Ϯ0.00137 mol NO/mol hemoglobin tetramer (Pϭ0.005), whereas HbFeNO decreases from 0.00361Ϯ0.00109 to 0.00081Ϯ0.00040 mol NO/mol hemoglobin tetramer (Pϭ0.03) as hemoglobin is oxygenated in the pulmonary circulation. These metabolite gradients correlated with the hemoglobin O 2 saturation gradient (PϽ0.05) and inversely with cardiac index (PϽ0.05) for both CHF patients and control subjects. Conclusions-We confirm that RBC-bound NO mediates hypoxic vasodilation in vitro. Transpulmonary gradients of hemoglobin-bound NO are evident in CHF patients and are inversely dependent on cardiac index. Hemoglobin may transport and release NO bioactivity to areas of tissue hypoxia or during increased peripheral oxygen extraction via an allosteric mechanism.

Our preliminary data suggested LAA closure with ACP is safe, feasible with encouraging 1-yr clinical outcomes. Further large-scaled trials are needed to confirm the efficacy of this device.

In conclusion, this document reflects a consensus approach by expert implanters on the steps of LAAO technique and best practices for implantation of the AMPLATZER Amulet device, along with some practical tips to minimise the complication rate.

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Objective-To review the eYcacy of intraaortic balloon counterpulsation (IABCP) in medically refractory ventricular arrhythmia. Design-Retrospective analysis of the outcome of patients with ventricular arrhythmia treated with IABCP after transfer between 1992 and 1997. Setting-Tertiary cardiac referral centre. Patients-21 patients (mean age 58 years) who underwent IABCP for control of ventricular arrhythmia. All had significant left ventricular impairment (mean ejection fraction 28.6%); 18 had coronary artery disease. Results-Before IABCP, 10 patients had incessant monomorphic ventricular tachycardia and 11 had paroxysmal ventricular tachycardia and/or ventricular fibrillation (VT/VF). IABCP resulted in suppression of ventricular arrhythmia in 18 patients, of whom 13 were weaned from IABCP. After stabilisation of ventricular arrhythmia, 10 patients were maintained on medical treatment alone and one underwent endocardial resection. IABCP was maintained until cardiac transplantation in five patients. One patient had a fatal arrest before discharge and one died from progressive heart failure. IABCP failed to control ventricular arrhythmia in three patients and was subsequently discontinued. A cardiac assist device was employed in one of these until cardiac transplantation; the other two were eventually stabilised on medical treatment. Nineteen patients were discharged from hospital. Overall survival was 95% at mean follow up of 25.7 months. Conclusions-IABCP can be an eVective means of controlling refractory ventricular arrhythmia, allowing time for the institution of more definitive treatment. (Heart 1999;82:96-100)