Myocardial velocity gradient as a noninvasively determined index of left ventricular diastolic dysfunction in patients with hypertrophic cardiomyopathy.
OBJECTIVE
We 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).


BACKGROUND
Hypertrophic cardiomyopathy is characterized by impaired diastolic function with abnormal stiffness and prolonged relaxation. However, it remains difficult to evaluate these defects noninvasively.


METHODS
Both 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.


RESULTS
The 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).


CONCLUSIONS
A 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.
Kato
Tomoko
T
Cardiovascular Division, Department of Clinical Pathophysiology, Nagoya University, Graduate School of Medicine, Nagoya, Japan.
Noda
Akiko
A
Izawa
Hideo
H
Nishizawa
Takao
T
Somura
Fuji
F
Yamada
Akira
A
Nagata
Kohzo
K
Iwase
Mitsunori
M
Nakao
Akimasa
A
Yokota
Mitsuhiro
M
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D001783:Blood Flow Velocity; D006328:Cardiac Catheterization; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications*; D016022:Case-Control Studies; D003971:Diastole; D015150:Echocardiography, Doppler / Q000379:methods* / Q000592:standards; D004548:Elasticity; D005260:Female; D006439:Hemodynamics; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000145:classification / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000503:physiopathology; D017725:Ventricular Pressure