Assessment of regional atrial function in patients with hypertrophic cardiomyopathies using tissue Doppler imaging.

BACKGROUND

This study applied tissue Doppler imaging and color tissue Doppler imaging to study atrial function changes in patients with hypertrophic cardiomyopathy (HCM). The profile of the segmental atrial velocities and the strain rate were determined and compared with those of normal matched control subjects.

METHODS

This study investigated 20 patients with HCM and 20 age-matched healthy control subjects. In a four-chamber apical view, tissue Doppler imaging was used to measure the lateral left and right atrial (LA and RA) and interatrial septal (IAS) wall systolic, early, and late diastolic velocities. Similarly, the atrial strain rate during ventricular systole (SR(S)) and the early (SR(E)) and late (SR(A)) diastolic phases in patients and control subjects were measured. The interventricular septal tissue Doppler-derived isovolumic relaxation time was calculated.

RESULTS

Only the IAS annular and middle segments showed a significant reduction in the early diastolic velocity (mean, 4.01 +/- 2.2 vs 8.7 +/- 1.1, p = 0.001; 3.23 +/- 2 vs 6.01 +/- 1.9, p = 0.001, respectively) for the patients with HCM in comparison with the control subjects. Generally, the atrial strain rate was clearly reduced. The systolic strain rate (SR(S)) was significantly reduced in the LA wall in the annular (p = 0.007) and middle (p = 0.001) segments and in the IAS middle segment (p = 0.007). Similarly, there was a reduction of the early diastolic strain rate (SR(E)) in the LA annular (p = 0.001) and middle (p = 0.01) segments and in the IAS annular (p = 0.05) and middle (p = 0.001) segments, as well as in the RA annular segment (p = 0.02). The RA middle segments showed insignificant changes.

CONCLUSION

Atrial function may be affected by HCM due to impairment of myocardial diastolic function. Strain rate imaging is reproducible, yields readily obtained parameters that provide unique data about global and longitudinal segmental atrial contraction, and can quantify the atrial dysfunction in patients with HCM.