Does echocardiographic assessment of IVRT and left atrial dimensions identify early pathologic left ventricular changes in subjects with untreated mild essential hypertension compared to normotensive controls?
Prolonged isovolumic relaxation time and increased left atrial dimension index can help identify early, subtle pathologic left ventricular mass increases in patients with mild essential hypertension.
Left ventricular hypertrophy resulting from hypertension is accompanied by significant morbidity and mortality and in advanced stages may be irreversible. Hence, early detection of cardiac changes in hypertensive patients remains an important diagnostic goal. When the hypertrophy is mild or moderate, parameters of left ventricular diastolic function and measurements of left atrial size may facilitate the distinction between normal variation and pathologic increases in left ventricular mass. We measured left ventricular isovolumic relaxation time (IVRT, the time from aortic valve closure to mitral valve opening) and left atrial dimensions and correlated them to left ventricular mass index measured by M-mode echocardiography and rapid left ventricular filling by radionuclide ventriculography. In 20 subjects with untreated mild essential hypertension, IVRT was prolonged compared to a normotensive age-matched control group (91 +/- 23 vs 65 +/- 13 msec, p less than 0.0001). Left atrial dimension index was increased in patients compared to controls (1.9 +/- 0.4 vs 1.4 +/- 0.5 cm/m2, p less than 0.001), and this increase was related to prolonged IVRT (r = 0.46, p less than 0.001). Abnormal IVRT correlated with both increased left ventricular mass and decreased rapid ventricular filling in the hypertensive subjects. Thus, prolonged IVRT and borderline left atrial dimension may help identify subtle pathologic left ventricular mass increases in hypertensive subjects.
Smith et al. (Sun,) studied this question.