[What is the relevance of an intraventricular ejection pressure gradient induced by exercise?].

Rev Esp Cardiol 2004;57(12):1139-42 1139 Pressure gradients in the left ventricle (LV) during ejection have traditionally been considered a pathological finding. For more than 20 years, however, systolic intraventricular pressure gradients (IVPGs) have been known to exist in physiologic form in normal subjects. Using high-fidelity micromanometers, pressure differences of 3 to 5 mm Hg between the apex and the left ventricular outflow tract (LVOT) have been measured in the normal heart at rest. These pressure differences are the result of an acceleration of blood due to myocardial contraction (initial ventricular impulse)1 and of physiologic disproportion between the chamber diameter and the LVOT (ventriculoannular disproportion).2 These physiologic IVPGs have been empirically shown to be closely related to left ventricular systolic function.2-4 In response to inotropic challenge induced by betaadrenergic drugs or physical exercise, physiologic IVPGs increase noticeably. Nevertheless, there are few data on the potential extent of this physiologic response. In experimental animals with a structurally normal heart, the mean IVPG induced by beta-adrenergic drugs is about 15 mm Hg, although IVPGs above 80 mm Hg have been reported.3 In humans, the extent of systolic IVPGs in asymptomatic subjects at rest versus in stress situations has not been assessed using echocardiography. In 1 study with 6 healthy volunteers who underwent cardiac catheterization, IVPGs above 15 mm Hg were recorded during subED I TO R I A L S