LEFT ATRIAL APPENDAGE FUNCTION DURING DDD AND VVI PACING

Objective-To examine, using transoesophageal echocardiography, the pos sible disturbances of left atrial appendage function during VVI and DD D pacing in patients with a normal atrium paced with a dual chamber sy stem. Design-Randomised controlled trial. Setting-Tertiary care centre . Patients-22 patients (mean age 68 (SD 6) years) who had been paced w ith dual chamber pacemakers for at least six months. Exclusion criteri a were valvar disease, cardiomyopathy, hypertension, and diabetes mell itus. Interventions-All patients underwent a transoesophageal echocard iographic evaluation of left atrial appendage function under DDD and W I modes in random order. Measurements were made after at least two mon ths' pacing in each mode. Main outcome measures-Echocardiographic indi ces of left atrial appendage flow under both pacing modes. Results-All 22 patients had higher emptying and filling flow velocities under DDD than under WI mode. The filling and emptying flow velocity integrals were also significantly higher under DDD mode (P < 0.001, P = 0.019). Conclusions-Left atrial appendage function, as reflected in indices of emptying and filling assessed by transoesophageal echocardiography, i s significantly different with DDD than with WI pacing. This may expla in the higher incidence of thromboembolic episodes in patients paced u nder WI mode.