Estudo inteligente na Hipertrofia Assimétrica.

Standing and Exercise Doppler Echocardiography in Obstructive Hypertrophic Cardiomyopathy: The Range of Gradients with Upright Activity
.Journal of the American Society of Echocardiography

Issue: Volume 24(1), January 2011, p 75–82

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AB Background: The ideal provocative maneuver in patients with hypertrophic cardiomyopathy (HCM) is a subject of ongoing investigation. Standing is a fundamental activity of daily life. This study examined acquisition of standing, Valsalva, and post-exercise left ventricular outflow tract gradients in HCM. Methods: Rest supine, standing, and post-Valsalva gradients were measured in 98 consecutive patients with HCM who were referred for outpatient echocardiography. In 53 (54%) of the 98 patients, symptom-limited treadmill exercise was also performed, with gradients measured immediately after in the supine position. Results: Fifty-six (57%) of the 98 patients had resting gradient < 30 mm Hg and would thus be characterized as nonobstructive at rest. In the 98 patients, median gradients were 25 mm Hg at rest (range 0-205 mm Hg), increasing to 44 mm Hg after standing (range 0-309 mm Hg), an increase of 76%, and were again higher after Valsalva, 64 mm Hg (range 0-256 mm Hg) (P < .001). In the 53 patients who had gradient assessed after exercise, they were higher still, 100 mm Hg (range 0-256 mm Hg) (P < .001). In 29 patients (30%), standing provoked a higher gradient than Valsalva. 
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Estudo interessante que avalia o efeito de ficar em pé sobre o gradiente na via de saída.
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The patient was then asked to stand, and after 2 minutes of equilibration Doppler gradient was acquired over the next minute. To facilitate imaging while standing, the sonographer positioned the patient's left arm on the patient's head. This opened rib spaces and improved imaging.
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Standing gradients were not difficult to acquire; acceptable traces were obtained in 98% of patients attempted by an experienced sonographer.
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 Conclusion: Although standing increased gradients by 76%, it is not as potent a provocative maneuver as Valsalva or treadmill exercise. Nevertheless, standing is recommended as a physiologic provocative maneuver. In some patients standing may guide therapy; in others, the standing and exercise gradient provide a correct appreciation of the range of physiologically experienced gradients during daily upright activity.
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