CGMP LEVELS FOLLOWING ANP CHALLENGE ARE MARKERS OF SUBSEQUENT SUCCESSFUL REVERSION OF LONE ATRIAL-FIBRILLATION TO SINUS RHYTHM

The? aim of the present study, was to assess whether cGMP release to A NP stimulation can be a biochemical marker of subsequent successful el ectrical cardioversion of lone atrial fibrillation to sinus rhythm. Fo r this purpose, we studied 13 patients with chronic, lone atrial fibri llation of less than one year's duration who presented to our laborato ry for electrical therapy of their arrhythmia. Prior to electrical car dioversion, peripheral venous cGMP levels were assessed at baseline an d following an intravenous challenge of 50 Ug human ANP. Venous blood samples for cGMP assessment were taken a) at baseline, b) 5 and IO min s after the end of ANP infusion. ANOVA of repeated measures was used f or statistical analysis Eight of the study patients were successfully cardioverted to sinus rhythm, while the remaining 5 were not. Although no difference was noted between the two groups regarding the mean tim e of arrhythmia duration as well as left atrial and ventricular dimens ions, ANP stimulation provoked significantly greater cGMP release inpa tients whose arrhythmia reverted to sinus rhythm, when compared with t hat of patients whose arrhythmia persisted (p<0.001). Therefore, cGMP levels following ANP challenge might discriminate between patients wit h chronic AF who are going to be successfully cardioverted and those w ho are not. These findings imply that the underlying atrial disease mi ght be different ill extent/nature between Patients with lone AF respo nsive to cardioversion and those with resistant arrhythmia.