Showing papers by "Gan-Xin Yan published in 2001"
TL;DR: This study provides the first direct evidence from intracellular action potential recordings that phase 2 EAD can be generated from intact ventricular wall and produce a trigger to initiate the onset of TdP under QT prolongation.
Abstract: Background—This study examined the role of phase 2 early afterdepolarization (EAD) in producing a trigger to initiate torsade de pointes (TdP) with QT prolongation induced by dl-sotalol and azimilide. The contribution of transmural dispersion of repolarization (TDR) to transmural propagation of EAD and the maintenance of TdP was also evaluated. Methods and Results—Transmembrane action potentials from epicardium, midmyocardium, and endocardium were recorded simultaneously, together with a transmural ECG, in arterially perfused canine and rabbit left ventricular preparations. dl-Sotalol preferentially prolonged action potential duration (APD) in M cells dose-dependently (1 to 100 μmol/L), leading to QT prolongation and an increase in TDR. Azimilide, however, significantly prolonged APD and QT interval at concentrations from 0.1 to 10 μmol/L but shortened them at 30 μmol/L. Unlike dl-sotalol, azimilide (>3 μmol/L) increased epicardial APD markedly, causing a diminished TDR. Although both dl-sotalol and azimi...
265 citations
TL;DR: This study provides the first direct evidence from intracellular recordings that phase 2 EAD could be generated from rabbit intact hypertrophied LV wall in the absence of APD prolonging agents, resulting in R on T extrasystoles capable of initiating polymorphic VT under enhanced TDR.
Abstract: The effects of left ventricular hypertrophy (LVH) on the generation of phase 2 early afterdepolarization (EAD) and transmural dispersion of repolarization (TDR) were assessed using arterially perfu...
155 citations