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Background: The aim of the study was to assess the effect of hemodialysis (HD) on left ventricular outflow tract gradient (LVOTG) measured both in supine and upright position (provocative maneuver to unload LV cavity by rapid preload reduction). Supine/standing echocardiography was performed immediately before and immediately after HD. For additional verification of the hypothesis about preload-dependence of LVOTG, the echocardiograms after long (2-day delay HD due to weekend) versus short (usual 1-day) pause between HDs were compared. Methods: Forty-one patients on chronic HD (mean age 44 ± 11 years) were examined using a portable hand-carried echocardiograph. In accordance with the prestudy assumption the ultrafiltration volume was significantly greater during HD after a long pause in comparison to HD after a short pause (3707 ± 2826 mL vs. 2665 ± 1152 mL P < 0.05). Results: After a long pause, the mean value of LVOTG at the pre-HD was mildly increased in the supine position and remained at a similar level in the upright position (13.1 ± 6.1 vs. 13.6 ± 9.1 mmHg). Mean LVOTG at the post-HD in the supine position was similar to pre-HD, however the orthostatic stress test induced a significant increase of LVOTG (13.9 ± 15.2 vs. 18.2 ± 19.9 mmHg P < 0.05). After a short pause at the pre-HD the LVOTG in the supine position and after the orthostatic provocation was very similar to measurements after long pause (13.3 ± 9.1 vs. 13.3 ± 10.8 mmHg). At the post-HD the mean value of LVOTG increased during upright posture but the differences were of borderline significance (13.2 ± 6.6 vs. 17.9 ± 18.6 mmHg P = 0.052). Conclusions: HD predisposed to standing-provoked LVOTG especially when a long pause (2 days) between HDs induced a greater weight gain and subsequently a larger volume of ultrafiltration was needed to reduce hypervolemia. (Echocardiography 2010;27:603-607) [ABSTRACT FROM AUTHOR]

Objectives: The aim of the study was to assess inducibility of left ventricular outflow tract (LVOT) gradient by change of position from supine to upright and by treadmill exercise in treated patients with hypertrophic cardiomyopathy (HCM) without obstruction at rest. Methods: We studied 37 treated HCM patients (21 men and 16 women, mean age 44 ± 12 years) with LVOT gradient <30 mmHg at rest in supine position. The patients were then placed in upright position and the gradient was reexamined. The patients who developed LVOT gradient ≥30 mmHg during this maneuver were not exercised, whereas the remaining patients (nonobstructive in orthostatic position) performed moderate-intensity exercise on a treadmill, with continuous monitoring of the LVOT gradient. For comparison with resting measurements, gradients at peak exercise (in upright position) and at recovery (in supine position) were used. The resting minimal distance between the mitral valve and ventricular septum at systole was used to assess the degree of narrowing of LVOT. Results: The orthostatic position provoked LVOT gradient ≥30 mmHg in 8 of 37 patients. At peak exercise, 10 of the remaining 29 patients developed significant LVOT gradient. At recovery in supine position, this significant gradient disappeared in 6 of 10 patients, despite only a short delay in measurement. Of resting echocardiographic parameters, only systolic mitral–septal distance differentiated between the provocable and nonprovocable subgroups. Patients with provocable gradient (either by changing position or by exercise) presented with lower values of this parameter than the nonprovacable subgroup. Conclusions: In nonobstructive HCM patients under treatment, the LVOT gradient was inducible by upright position in 21.6% and by upright moderate exercise in 34.5%. The minimal septal–mitral distance may be useful to identify patients with provocable obstruction. [ABSTRACT FROM AUTHOR]