XXXX due to extensive atrial fibrosis: impact on dual chamber pacemaker implantation.

@entity1 @entity1817 @entity13169 @entity955
AIMS: Atrial standstill is characterized by the absence of atrial activity. We report about a series of cases, in which conventional atrial pacemaker lead implantation in @entity1 with symptomatic @entity1817 failed due to lack of excitable right atrial tissue, thus, prompting the diagnosis of @entity13169 . We hypothesized that mapping of the atria with subsequent identification of myocardium still amenable to @entity955 would allow dual chamber pacemaker implantation. METHODS AND RESULTS: In four @entity1 , @entity955 failed. In these @entity1 , spontaneous or fibrillatory electrical activity was absent but the atria could not be captured despite high stimulation voltages at conventional atrial sites. We suspected partial or complete @entity13169 and subsequently confirmed this hypothesis by conventional (n = 1) or electroanatomical mapping (n = 3). Areas of fibrotic tissue were present in all @entity1 as identified by lack of spontaneous electrical activity and inability of local electrical capture via the mapping catheter. Surviving atrial tissue, which could be electrically captured with subsequent conduction of activity to the atrioventricular (AV) node, was present in three @entity1 . Successful targeted @entity955 at these sites was achieved in all these @entity1 . Isolated sinus node activity without conduction to the atria was found in one @entity1 . CONCLUSION: Partial @entity13169 may be present and prevent @entity955 in @entity1 with @entity1817 . In these @entity1 , recognition of partial @entity13169 and identification of surviving muscular islets with connection to the AV node by mapping studies may still allow synchronous AV sequential pacing.
