[Left ventricular inflow behavior in dual chamber stimulation with differential atrioventricular conduction: an...

The influence of the AV interval on early passive (E) and late active diastolic filling (A) during transmitral flow was analyzed in patients with AV sequential pacing. In 16 patients with dual-chamber pacemakers at the age of 25 to 76 years CW- and color Doppler echocardiography was used to determine inflow time (t), flow velocity (Vmax), the E/A ratio, the time-velocity integral (TVI), and the inflow jet at constant AV sequential pacing (80 bpm) with various AV interval settings (50-100-150-200-250 ms). The inflow pattern was compared to findings in 16 normals (age 26 +/- 7 years). The prolongation of the AV interval from 50 to 250 ms resulted in the following changes: 1) Decrease of tE: 220 +/- 30 ms to 170 +/- 40 ms (p less than 0.05), of VmaxE: 78 +/- 12 to 68 +/- 14 cm/s) (ns) and of TVI-E: 8.5 +/- 2.1 to 5.6 +/- 1.7 cm (p less than 0.001); 2) Increase of tA: 140 +/- 30 to 270 +/- 60 ms (p less than 0.001), of VmaxA: 48 +/- 18 to 73 +/- 24 cm/s (p less than 0.001) and of TVI-A: 2.4 +/- 1.1 to 6.1 +/- 2.9 cm (p less than 0.001); 3) Decrease of the E/A ratio from 1.6 +/- 05 to 0.85 +/- 02. Longer AV intervals shortened the total diastolic filling period and produced more diastolic aliasing without change of the relative diastolic inflow jet. The AV interval of 150 ms was associated with an abnormal high atrial component of transmitral inflow, as found with abnormal diastolic LV function.(ABSTRACT TRUNCATED AT 250 WORDS)