The influence of left ventricular stroke volume on aortic root motion: an echocardiographic study.

Abstract

Aortic root motion was studied in 24 normal volunteers at rest and during the Valsalva maneuver, isometric exercise, and amyl nitrite inhalation. In addition root motion was correlated with the stroke volumes determined at cardiac catheterization in 24 patients. The root has distinct systolic movement, the amplitude and duration of which were easily measured both at rest and during the interventions. At rest,the mean (+/-1 SE) systolic amplitude of the anterior aortic wall was 11.2 +/- 0.5 mm and that of the posterior wall 9.5 +/- 0.3 mm. During the strain phase of the Valsalva maneuver anterior wall amplitude fell to 8.2 +/- 0.4 mm and the posterior wall to 7.3 +/- 0.5 mm (P less than 0.001). With release, anterior wall amplitude rebounded to 12.5 +/- 0.8 mm and the posterior wall to 10.8 +/- o.5 mm, values greater than control (P less than 0.01). With isometric exercise there was no change in amplitude compared to rest; however, amyl nitrite caused an increase in the anterior wall to 13.5 +/-0.8 mm and posterior wall to 11.9 +/-0.6 mm (P less than 0.01). In the patient group the amplitude of posterior wall motion correlated weakly with cardiac index (r = 0.63) and stronger with stroke index (r = 0.78). This study quantifies the echocardiographic pattern of normal aortic root motion. The findings indicate that the aortic root motion is an index of stroke volume; they further suggest that root motion is acutely sensitive to variations in stroke volume since its amplitude changed in accord with the documented effects of the employed maneuvers on stroke volume.