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Preserving normal ventricular activation versus atrioventricular delay optimization during pacing: the role of

I I Iliev1, S Yamachika, K Muta

  • 1Third Department of Internal Medicine, Nagasaki University, Japan. d396027h@stcc.nagasaki-u.ac.jp

Pacing and Clinical Electrophysiology : PACE
|February 10, 2000
PubMed

Insights

Dual chamber (DDD) pacing and single chamber atrial (AAI) pacing effects on cardiac performance were compared in patients with first-degree AV block. Optimal AV delay in DDD pacing improved aortic flow, with AAI pacing being superior only when intrinsic AV conduction was significantly prolonged at lower heart rates.

Area of Science:

  • Cardiology
  • Biomedical Engineering
  • Electrophysiology

Background:

  • Patients with first-degree AV block often have prolonged intrinsic AV conduction.
  • Pacemaker selection (DDD vs. AAI) can influence cardiac performance.
  • Optimizing atrioventricular (AV) delay in DDD pacing is crucial for hemodynamic efficiency.

Purpose of the Study:

  • To compare the effects of DDD pacing with optimized AV delay versus AAI pacing on systolic and diastolic function in patients with first-degree AV block.
  • To evaluate the impact of intrinsic AV conduction time and pacing rate on the relative efficacy of DDD and AAI pacing modes.

Main Methods:

  • Seventeen patients with dual-chamber pacemakers and first-degree AV block were studied.
  • Doppler echocardiography assessed aortic and mitral flow parameters (AFTVI, MFTVI).
  • Comparison of AAI pacing and DDD pacing with individually optimized AV delay at pacing rates of 70/min and 90/min.

Main Results:

  • Optimizing AV delay in DDD pacing increased aortic flow time velocity integral (AFTVI) by 16%.
  • At 70/min, AAI pacing yielded higher AFTVI than DDD when intrinsic AV conduction was significantly prolonged (Stimulus-R interval > 270 ms).
  • At 90/min, DDD pacing demonstrated superior AFTVI compared to AAI pacing; Mitral flow time velocity integral (MFTVI) was generally higher with DDD pacing.

Conclusions:

  • In patients with first-degree AV block, the choice between DDD and AAI pacing impacts systolic performance.
  • The optimal pacing mode depends on the patient's intrinsic AV conduction time and the pacing rate.
  • DDD pacing with optimized AV delay generally offers better hemodynamic performance, particularly at higher pacing rates.

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