Why, how and when do we need to optimize the setting of cardiac resynchronization therapy?

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Cardiac resynchronization therapy (CRT) utilizes adjustable atrioventricular (AV) and interventricular (VV) timings to enhance left ventricular (LV) function.
• Current CRT device optimization strategies lack universal consensus, with varying methodologies proposed.
• Physiological states like rest and exercise significantly alter LV loading, potentially requiring dynamic adjustments to optimal AV and VV intervals.

Purpose of the Study:

• To review existing methodologies for optimizing AV and VV intervals in CRT devices.
• To discuss the rationale, timing, and practical application of AV and VV interval optimization based on current evidence.
• To provide an overview of findings from multicenter trials focused on AV and VV interval optimization.

Main Methods:

• Literature review of current echocardiographic and non-echocardiographic methods for AV and VV interval optimization.
• Analysis of evidence supporting different optimization techniques.
• Synthesis of data from multicenter clinical trials on CRT timing optimization.

Main Results:

• Multiple methods exist for AV and VV interval optimization, but no single approach is universally adopted.
• LV loading conditions vary between rest and exercise, impacting optimal timing settings.
• Multicenter trials provide valuable insights into the efficacy of various AV and VV optimization strategies.

Conclusions:

• Standardized protocols for AV and VV interval optimization in CRT are needed.
• Optimization strategies should consider patient-specific physiology and varying conditions like exercise.
• Further research and consensus are required to refine CRT programming for improved patient outcomes.