The AVI was classified as normal, too long or too short.

To demonstrate the three categories of transmitral inflow pattern, one patient was analyzed with an optimal, a too short and a too long AV-sense interval. A) A normal AVI (135 ms) presents with separated E- and A waves, the A wave maximized in size and length and no diastolic mitral regurgitation. B) When the AVI is programmed too short (70 ms) an A wave truncation occurs (short, small and abruptly terminating A wave). C) A too long AVI (250 ms) presents with a complete E/A fusion. Such E/A fusion occurred in 19.4% (CI 12.6–26.2%) of the analyzed patients in sinus rhythm.