Background: Cardiac pacing witnessed many advances in the last years, with favorable outcome of saving more lives in different heart diseases associated with conduction abnormalities. Devices usually programmed by manufacturers. However, it did not provide optimal pacing and manual programming was advised.

Aim of the work: This study aimed to assess the value of manual optimization of atrioventricular delay (AVD) in dual chamber pacemaker (DDD) patients in comparison of default AVD, using three-dimensional Echocardiography.

Patients and Methods: Fourty patients with DDD were included. They received pacemaker due to high grade of atrioventricular (AV) block. All were submitted full history taking, general and cardiac clinical examination in a systematic pattern. All were subjected to resting 12-leads electrocardiography, and the pacemaker position was confirmed by chest X ray. Dual-chamber pacemakers were interrogated and programmed using St. Jude Medical, Inc. programmer. All patients were checked after 6 weeks and outcome was compared to original values.

Results: Patient's age ranged between 29 and 66 years, and 27 (67.5%) were males. Complete heart block was the principal indication for initial pacing (87.5%) followed by Mobitz type II heart block (12.5%). Three-dimensional echocardiography revealed that, manual pacing was associated with significant increase of end-systolic volume, end-diastolic volume, ejection fraction and velocity time integral (224.0 ±87, 93.0±34.8, 63.9±3.84 and 63.9±3.84 vs. 187.0±80.6, 75.8±19.4, 60.1±3.09 and 29.2 + 12.7, respectively). Symptom's improvement revealed that, 21 (77.7%) patients who presented with dyspnea, 15 (83.3%) in dizziness and 20 (90.5%) in the palpitation.

Conclusion: It is recommended to use AVD optimization for all patients of DDD pacemakers. This may be associated with long-term benefit mainly for the systolic functions. Echocardiography is the gold standard of timing optimization through mitral flow Doppler as its waves could mark for atrial contraction which is used for AV timing optimization.