• Tomoko Kato, Akiko Noda, Hideo Izawa, Takao Nishizawa, Fuji Somura, Akira Yamada, Kohzo Nagata, Mitsunori Iwase, Akimasa Nakao, and Mitsuhiro Yokota.
• Cardiovascular Division, Department of Clinical Pathophysiology, Nagoya University, Graduate School of Medicine, Nagoya, Japan.
• J. Am. Coll. Cardiol. 2003 Jul 16; 42 (2): 278-85.

ObjectivesWe investigated the utility of the peak negative myocardial velocity gradient (MVG) derived from tissue Doppler imaging (TDI) for evaluation of diastolic dysfunction in patients with hypertrophic cardiomyopathy (HCM).BackgroundHypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively.MethodsBoth TDI and conventional echocardiography were performed in 36 patients with HCM and in 47 control subjects. Left ventricular (LV) pressure was measured simultaneously in all HCM patients and in 26 controls.ResultsThe peak negative MVG occurred soon after the isovolumic relaxation period during the initial phase of rapid filling (auxotonic relaxation). It was significantly smaller in HCM patients than in control subjects (2.32 +/- 0.52/s vs. 4.82 +/- 1.15/s, p < 0.0001); the cutoff value for differentiation between all HCM patients and 47 normal individuals was determined as 3.2/s. Both the left ventricular end-diastolic pressure (LVEDP) (19.6 +/- 6.1 mm Hg vs. 6.5 +/- 1.7 mm Hg, p < 0.0001) and the time constant of LV pressure decay during isovolumic diastole (tau) (44.0 +/- 6.7 ms vs. 32.1 +/- 5.5 ms, p < 0.0001) were increased in HCM patients compared with controls. The peak negative MVG was negatively correlated with both LVEDP (r = -0.75, p < 0.0001) and tau (r = -0.58, p < 0.0001).ConclusionsA reduced peak negative MVG reflects both prolonged relaxation and elevated LVEDP. The peak negative MVG might thus provide a noninvasive index of diastolic function, yielding unique information about auxotonic relaxation in patients with HCM.

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