title: [Effect of dynamic exercise on left ventricular hemodynamics in obstructive cardiomyopathy].
abstract: The behavior of left ventricular (LV) outflow tract obstruction in hypertrophic obstructive cardiomyopathy (HOCM) during dynamic exercise was studied in 9 patients during cardiac catheterization. Pressure measurements were carried out with high fidelity tip manometers and cardiac output was measured by the thermodilution method. Resting intraventricular pressure gradients varied from 5 to 75 mm Hg (mean 41 +/- 30 mm Hg) and all patients had postextrasystolic gradients of more than 100 mm Hg. Under supine bicycle exercise (mean work load 80 watts) heart rate increased from 74 +/- 9 to 97 +/- 10 min-1, cardiac output rose from 4.32 +/- 0.7 to 8.36 +/- 2.0 l/min, and LV intraventricular pressure gradient dropped significantly to 16 +/- 4 mm Hg. This improvement of LV outflow tract obstruction was associated with an increase in LV enddiastolic pressure from 14 +/- 5 mm Hg to 25 +/- 2 mm Hg, an augmentation of dP/dt max from 1225 +/- 300 to 1748 +/- 200 mm Hg/sec and a deterioration of systolic to diastolic pressure-time index ratio. These preliminary results indicate partial normalization of the LV outflow tract obstruction in HOCM during supine bicycle exercise; this favorable effect is probably due to an increased enddiastolic LV volume.
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D006328:Cardiac Catheterization; D002302:Cardiac Output; D002312:Cardiomyopathy, Hypertrophic / Q000503:physiopathology*; D003971:Diastole; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006334:Heart Function Tests; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D013815:Thermodilution
vernacular_title: Effet d'un effort dynamique sur l'hémodynamique du ventricule gauche lors d'une cardiomyopathie obstructive.