Background and purpose: The presence of left ventricular (LV) diastolic suction constitutes old knowledge. However, even though frequently discussed, it has only rarely been elucidated with modern ultrasonic technique. Hypovolemia is thought to reveal evidence of suction (1). The high sampling rate/temporal resolution of both blood pooland tissue pulsed Doppler enables LV blood-to-tissue timing. With the stipulation that a preceding early diastolic LV tissue lengthening to the mitral inflow might indicate LV suction, we sought to investigate this at rest and during a preload reduction in normal individuals. Methods: Twelve healthy subjects (aged 28±4 years, 9 women) were examined with a Vivid 7, GE Medical Systems, including pulsed blood pooland tissue Doppler. The end-expiratory LV mean ‘E-e’ time interval (i.e. between the onsets of the mitral inflow (E) and the early diastolic LV lengthening (e), calculated with the R-wave of the ECG as a reference), the right ventricular (RV) early diastolic maximal velocity (e max), the mean LV e max, as well as the global isovolumic relaxation time (IVRT) were assessed at: horizontal rest, tilting to standing up (45‘) and lying back down. Results: With a presumed preload reduction (standing up), the LV IVRT increased (from 52±13 to 81±17 ms, p=0.006). The ‘E-e’ interval was slightly positive at rest (7±7 ms), but no change in E-e with a preload reduction became significant for all 12. However, two kinds of reactions might be distinguished. The onset of LV tissue lengthening was further antedated in relation to that of the mitral inflow in 9/12 individuals (from 8±8 to 25±11 ms, p=0.008). The remaining 3, who failed to exhibit this, displayed a greater fall in RV E max (-8.5±2.2 vs -3.0±2.7 cm/s, p=0.012), as well as in LV mean E max (-6.5±1.6 vs -3.5±1.5 cm/s, p=0.026) at standing up suggesting that a more pronounced preload reduction might have been induced. These 3 did not differ in height (174±4 vs 174±9 cm, p=NS), but had a lower BMI (18.9±1.0 vs 23.6±3, p=0.021) and also reported of a habitual orthostatic tendency. Conclusion: Our results even though not unambiguous may support evidence of LV suction in the normal heart, detectable through Doppler bloodto tissue timing. The different responses to a presumed preload reduction raises the question whether, still, an optimal volume level might be required for suction to be seen. 1. ‘Mitral annulus velocity at onset of filling a marker of diastolic suction’ Opdahl A, Remme EW, Helle-valle T, Edvardsen T, Vartdal T, Pettersen E, Ihlen H, Smiseth OA (e-poster at the ESC, 2006).