Intramural myocardial shortening in hypertensive left ventricular hypertrophy with normal pump function.

Abstract

BACKGROUND In hypertensive left ventricular hypertrophy (LVH), intrinsic myocardial systolic function may be normal or depressed. Magnetic resonance tagging can depict intramural myocardial shortening in vivo. METHODS AND RESULTS Tagged left ventricular magnetic resonance images were obtained in 30 hypertensive subjects with LVH (mean LV mass index, 142 +/- 41 g/m) and normal ejection fraction (mean, 64 +/- 9%) using spatial modulation of magnetization. In 26 subjects, circumferential myocardial shortening (%S) was compared with results obtained in 10 normal subjects at endocardium, midwall, and epicardium on up to 4 short-axis slices each. Similarly, in 10 subjects, midwall long-axis shortening at basal, midventricular, and apical sites was compared with results obtained in 12 normal volunteers. Circumferential %S was reduced in hypertensive subjects. Mean shortening was 29 +/- 6% at the endocardium in hypertensive subjects versus 44 +/- 6% in normal subjects (P = .0001); 20 +/- 6% at the midwall versus 30 +/- 6% (P = .0001); and 13 +/- 5% at the epicardium versus 21 +/- 5% (P = .0002). However, the transmural gradient in percent shortening from endocardium to epicardium in hypertensive subjects paralleled that in normal subjects. The normal base-to-apex gradient in circumferential %S was absent in LVH. In contrast to normal subjects, circumferential %S showed regional heterogeneity in hypertensive subjects, being maximal in the lateral wall and least in the inferior wall. Longitudinal shortening was also uniformly depressed in hypertensive subjects: 10 +/- 9% at the base versus 21 +/- 6% in normal subjects (P = .0001); 14 +/- 8% at the midventricle versus 18 +/- 3% (P = .03); and 14 +/- 8% at the apex versus 18 +/- 4% (P = .04). CONCLUSIONS In hypertensive LVH with normal pump function, intramural circumferential and longitudinal myocardial shortening are depressed.

Ultrasonic myocardial textural parameters and midwall left ventricular mechanics in essential arterial hypertension

“…Thus a pseudo-normal LV chamber systolic function in the presence of concentric geometry is an expression of depressed myocardial function, suggesting that endocardial shortening is a poor index of real LV function. Furthermore, our ultrasonic data (MFS and CVI) were consistent with the MRI study, 20,21 which showed that intramural myocardial shortening is depressed in hypertensives with LVH and with a 'pseudonormal' left ventricular function. In fact in our study no linear relationship was found between CVI and left ventricular fractional shortening, but we have demonstrated a significant correlation between a depressed MFS and our videodensitometric index of systo-diastolic change in mean gray level, indicating that this variation of echo amplitude could be considered a distinct, 'early' index of an altered myocardial function.…”

“…The relevance of the evaluation of the midwall left ventricular mechanics in the analysis and prognosis of hypertensive patients has been demonstrated in several studies with different methodological approaches (haemodynamic, echo, nuclear magnetic resonance), which take into account the epicardial migration of the midwall during systole. [19][20][21] On the other hand, endocardial fractional shortening overestimates the left ventricular myocardial performance in hypertensive patients and is probably an imperfect index of left ventricular chamber mechanics rather than of myocardial performance. 3 Moreover, in hypertrophic myocardial walls, less intramural percent segment shortening is necessary for the same absolute systolic wall thickening and for the endocardial motion.…”

“…Recently reported developments in nuclear magnetic resonance imaging (tagging) and, almost in part, our videodensitometric method, could potentially provide a method of detecting myocardial fibre movement within the left ventricular wall in the beating human heart. 20 Moreover, ultrasonic videodensitometric methods could present some points of comparison with 'tagging' magnetic resonance imaging (MRI): in fact it is possible with MRI to 'magnetically' tag non-invasively myocardial regions, thus allowing one to follow the real trajectory of the selected myocardial region of interest during the entire cardiac cycle. This method allows us to non-invasively determine the absolute cardiac wall motion in the fixed reference frame.…”

The Athlete’s Heart

“…Studies of myocardial contractile function in the hypertrophied left ventricle resulting from hypertension suggest that intrinsic myocardial performance may be depressed, even when left ventricular ejection fraction remains normal. 82 However, the presumed innocent nature of the athlete's heart does not allow the performance of more invasive studies in athletes. Left ventricular diastolic function is commonly assessed by studying the pattern of ventricular filling through the mitral valve.…”

Left ventricular mass and systolic dysfunction in essential hypertension

“…function is reduced in the presence of LV hypertrophy, and midwall function is able to discriminate subjects with and without LV hypertrophy better than traditional chamber function indexes. 1,[9][10][11] However, the strongest correlate of midwall function is LV geometric pattern, concentric geometry (expressed as relative wall thickness) being a powerful determinant of reduced midwall function. 6,12,13 A marked increase in relative wall thickness was recently reported in 42 hypertensive patients with depressed LV midwall function compared with 117 hypertensive subjects with normal midwall function, even in the absence of differences in LV mass between the groups.…”