Παρασκευή 11 Νοεμβρίου 2016

β1-adrenoceptor autoantibodies increase the susceptibility of ventricular arrhythmias involving abnormal repolarization in guinea pigs

High titers of autoantibodies against the second extracellular loop of β1-adrenergic receptors (β1-AA) can be detected in the sera from patients with ventricular arrhythmias, but a causal relationship between β1-AAs and ventricular arrhythmias has not been established. In this work, electrocardiograms of guinea pigs and isolated guinea pig hearts were recorded. Ventricular tachycardia (VT) and ventricular fibrillation (VF) were evoked by programmed electrical stimulation of the left ventricular epicardium of isolated guinea pig hearts. Monophasic action potential and effective refractory period (ERP) of the left ventricle were recorded in the paced isolated guinea pig hearts. What's more, to increase the specificity, monoclonal autoantibodies against the second extracellular loop of β1-adrenergic receptor (β1-AR mAb) had been used in all experiments. The results showed that β1-AR mAbs induced premature ventricular contractions (PVC) in guinea pigs and isolated guinea pig hearts. In addition, β1-AR mAbs decreased the threshold of VT/VF and prolonged the VT/VF duration. Furthermore, β1-AR mAbs shortened corrected QT interval (QTc) and ERP, and prolonged late-phase repolarization of the monophasic action potential (MAPD90-30). These changes in electrophysiological parameters might be attributed, at least in part, to the arrhythmogenicity of β1-AR mAbs.

This article is protected by copyright. All rights reserved



from Physiology via xlomafota13 on Inoreader http://ift.tt/2fHQxeN
via IFTTT

Δεν υπάρχουν σχόλια:

Δημοσίευση σχολίου

Σημείωση: Μόνο ένα μέλος αυτού του ιστολογίου μπορεί να αναρτήσει σχόλιο.