BACKGROUND: Biventricular ( @entity3032 ) pacing has been found to improve systolic function and exercise tolerance in @entity1 with severe @entity712 and @entity5036 . The mechanisms behind this beneficial effect is still not sufficiently clarified. AIM: To evaluate the regional @entity296 ( @entity296 ) during @entity3032 pacing and after acute change of the pacing mode to conventional dual chamber ( @entity3603 ) pacing, and single chamber atrial (AAI) pacing in @entity1 with severe @entity712 and prolonged QRS width treated with chronic @entity3032 pacing. METHODS AND RESULTS: Fourteen @entity1 (age 63+/-7 years, 13 male) were evaluated 13+/-7 months after implantation of a triple-chamber biventricular pacemaker. @entity296 was quantified with @entity36882 -labeled @entity3265 positron emission tomography during @entity3032 pacing, @entity3603 pacing, and AAI pacing. @entity296 was assessed in the anterior, lateral, inferior, and septal regions, and the global mean @entity296 was calculated. Clinical assessment was performed before pacemaker implantation and after at least 3 months of @entity3032 pacing including a 6-min @entity4464 ( @entity4464 ), New York Heart Association (NYHA) class functional score and echocardiography. Global mean @entity296 ( @entity3032 : 0.65+/-0.20 vs. @entity3603 : 0.65+/-0.21 vs. AAI: 0.65+/-0.18 mlg(-1)min(-1)) and @entity296 in each of the four regions did not differ between the three pacing modes. The @entity1 improved clinically during @entity3032 pacing; 6 min @entity4464 increased (338+/-59 vs. 415+/-73 m, P<0.001), NYHA class score improved (class I/II/III/IV: 0/0/11/3 vs. 1/9/2/0, P<0.001), and left ventricular ejection fraction increased (21+/-5 vs. 29+/-8%, P=0.004). CONCLUSION: No differences in regional @entity296 are detectable after chronic @entity3032 pacing when the pacing mode is changed acutely in @entity1 with severe @entity712 and @entity5036 . This finding indicates, that the clinical improvement caused by @entity3032 pacing is not associated with any increase in the @entity296 and thereby @entity26 demand.

Regional @entity296 during chronic biventricular pacing and after acute change of the pacing mode in @entity1 with XXXX and @entity5036 treated with an atrioventricular sequential biventricular pacemaker.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity712 :: ('MESH:D006333', 'Disease') :: ['congestive heart failure'] @entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial perfusion', 'MP'] @entity3265 :: ('MESH:D000641', 'Chemical') :: ['ammonia'] @entity3032 :: ('11657', 'Species') :: ['BiV'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity3603 :: ('MESH:C562924', 'Disease') :: ['DDD'] @entity5036 :: ('OMIM:113900', 'Disease') :: ['bundle branch block'] @entity4464 :: ('MESH:D013009', 'Disease') :: ['walk test', 'WT'] @entity36882 :: ('CHEBI:36935', 'Chemical') :: ['13N']
@entity712 :: (MESH:D006333,Disease) :: ['congestive heart failure']
