PPI
Also written as: PPI — Post-Pacing Interval
Post-pacing interval; the time from a paced ventricular beat to the next intrinsic atrial activity during tachycardia.
Full Definition
Post-pacing interval (PPI) is an electrophysiological measurement used during ventricular tachycardia (VT) studies to determine if a tachycardia originates from a specific ventricular location. The measurement involves pacing from a particular site during ongoing VT and measuring the interval from the last paced ventricular stimulus to the return of the original VT morphology. When the PPI closely matches the VT cycle length (typically within 20-30 ms), it suggests that the pacing site is within or very close to the VT circuit, making it a valuable target for ablation therapy. This technique is particularly important in substrate-based VT ablation procedures and helps guide catheter positioning during electrophysiology studies.
Usage
Usage note: Not to be confused with proton pump inhibitor; context usually clarifies meaning in cardiology.
In Context
- "The PPI at this location was 345 ms, matching the VT cycle length of 340 ms, indicating proximity to the critical isthmus." — Electrophysiology study report
- "Concealed entrainment with a PPI equal to the tachycardia cycle length confirmed the ablation target site." — Cardiac ablation procedure note