VV timing
The programmable delay between right and left ventricular pacing in CRT devices to optimize cardiac resynchronization.
Full Definition
VV timing represents a critical programming parameter in cardiac resynchronization therapy devices that controls the temporal relationship between right ventricular and left ventricular pacing. This interval can be adjusted to optimize ventricular synchronization and hemodynamic performance, with typical ranges from simultaneous pacing to delays of 80-100 milliseconds in either direction. VV timing optimization often requires echocardiographic guidance or hemodynamic monitoring to determine the setting that provides maximum cardiac output improvement. The optimal VV delay varies among patients based on individual cardiac anatomy, conduction patterns, and underlying cardiomyopathy. Regular reassessment may be necessary as heart failure status changes over time.
Usage
Usage note: Specify direction and magnitude of delay; distinguish from AV timing parameters.
In Context
- "VV timing was optimized to LV-first pacing with 40ms delay for maximum hemodynamic benefit." — CRT optimization report
- "Echocardiographic assessment guided VV timing adjustment from simultaneous to sequential pacing." — Device clinic optimization note