Key result
Syndrome X is linked to a ~58% increase in exertional A/E ratio, showing impaired relaxation.
Why the study?
Left ventricular diastolic properties during isometric exertion in syndrome X were not well characterized.
Does handgrip exertion alter left ventricular diastolic filling dynamics in patients with syndrome X compared to normal subjects and those with coronary artery disease?
Observational (n=55)
Does handgrip exertion alter left ventricular diastolic filling dynamics in patients with syndrome X compared to normal subjects and those with coronary artery disease?
Patients with syndrome X exhibit impaired left ventricular relaxation during isometric exertion similar to patients with multi-vessel coronary artery disease, supporting a generalized left ventricular abnormality.
May support diastolic assessment in syndrome X during exertion; hypothesis-generating for generalized LV abnormality, pending prospective validation.
To study left ventricular diastolic properties in syndrome X, we analyzed transmitral filling dynamics during handgrip exertion. In 14 normal subjects (N), 17 with syndrome X (Syn X), 16 with single-vessel disease (SVD), and 8 with multiple-vessel disease (MVD), transmitral inflow was recorded at baseline and during handgrip (50% of maximal effort for one minute) using pulsed Doppler echocardiography. We measured early diastolic (E) and late atrial (A) inflow velocities, A/E ratio and percent change of A/E from baseline (%A/E). Blood pressure and heart rate increased to the same degree in each group during handgrip. In normal subjects, E did not change with handgrip; A (51 +/- 10 vs 54 +/- 11 cm/sec, P < 0.05) and A/E (1.16 +/- 0.22 vs 1.25 +/- 0.33, P < 0.05) increased minimally. In Syn X subjects, E decreased (51 +/- 10 vs 38 +/- 10 cm/sec, P < 0.0001), A increased (52 +/- 11 vs 60 +/- 14 cm/sec, P < 0.005), and A/E increased markedly (1.07 +/- 0.31 vs 1.68 +/- 0.51, P < 0.0001). The %A/E in Syn X and MVD were significantly larger than that in SVD and N (Syn X: 58 +/- 29%; MVD: 45 +/- 25%; SVD: 22 +/- 21%; N: 8 +/- 13%). Handgrip-induced changes in diastolic filling in syndrome X and are similar to those in MVD and more marked than in SVD. These changes are consistent with impaired ventricular relaxation and support a generalized left ventricular (LV) abnormality in syndrome X.
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Mizushige et al. (1997) conducted an observational in Syndrome X (n=55). Syndrome X vs. Normal subjects was evaluated on Percent change of A/E ratio from baseline (%A/E) during handgrip exertion. Syndrome X was associated with a significantly larger percent increase in the A/E ratio during handgrip exertion (58%) compared to normal subjects (8%), indicating impaired ventricular relaxation.
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