Early postoperative changes in left ventricular chamber size, architecture, and function in aortic stenosis and aortic regurgitation and their relation to intraoperative changes in afterload: a prospective two-dimensional echocardiographic study

We prospectively studied 16 patients with isolated aortic stenosis and eight with isolated aortic regurgitation undergoing aortic valve replacement, using two-dimensional echocardiography preoperatively, intraoperatively, and 41 +/- 7 days postoperatively to calculate the intraoperative change in afterload, quantify the postoperative changes in left ventricular chamber size, architecture, load and function, determine whether the postoperative left ventricular remodeling correlated with the intraoperative change in afterload in aortic stenosis and aortic regurgitation, and assess whether preoperative afterload excess precluded postoperative improvement in left ventricular function. Preoperative left ventricular mass, end-systolic meridional and circumferential wall stresses, ejection fraction, and stress-shortening relations in patients with aortic stenosis and aortic regurgitation were similar. However, our patients with aortic regurgitation had severe systolic dysfunction, with ejection fraction less than 55% in all but one patient, compared with only 10 of 16 patients with aortic stenosis. Left ventricular end-diastolic volume, mass/volume ratio, and chamber shape were significantly different in patients with aortic stenosis and aortic regurgitation (174 +/- 64 vs 294 +/- 140 ml, p less than .01; 1.81 +/- 0.63 vs 1.14 +/- 0.18, p less than .01; and 0.59 +/- 0.09 vs 0.69 +/- 0.09, p less than .05, respectively). Intraoperative end-systolic meridional and circumferential stresses fell significantly in patients with aortic stenosis but remained unchanged in those with aortic regurgitation. The changes in left ventricular volume and ejection fraction during early postoperative remodeling (6 weeks) correlated with the intraoperative change in afterload in patients with aortic stenosis. In contrast, there was no intraoperative change in afterload in patients with aortic regurgitation and no significant changes in left ventricular volume, architecture, or function at 6 weeks or at 6 months. The differences in left ventricular remodeling and changes in function between patients with aortic stenosis and aortic regurgitation in the early postoperative period most probably relates to the major difference in intraoperative reduction in afterload, although a contributory role may have been played by the preoperative left ventricular dysfunction in those with aortic regurgitation that was underestimated by measurement of ejection fraction.     

Age-related variations of left ventricular endocardial and midwall function in healthy infants, children, and adolescents.

BACKGROUND: In pediatric age echocardiographic evaluation of left ventricular systolic function is usually based on indexes obtained by measurements at the endocardial level. In the presence of ventricular hypertrophy this may lead to an overestimation of systolic function. The aim of this study was to assess the developmental changes of left ventricular systolic mechanics measured at the endocardial and midwall levels. METHODS: In 239 normal subjects divided into six age groups we measured left ventricular end-diastolic volume, mass and mass/volume ratio, fractional shortening, and rate-corrected mean velocity of circumferential shortening at the endocardial and midwall levels. Endocardial meridional end-systolic stress and midwall circumferential end-systolic stress were considered as indexes of afterload. Relations of extent and velocity of fiber shortening to afterload at the endocardial and midwall levels were used to assess left ventricular contractility. RESULTS: Blood pressure, left ventricular afterload, volume and mass increased, whereas the mass/volume ratio remained stable during growth. Fractional shortening and mean velocity of circumferential shortening at the endocardial level decreased and showed an inverse relation to afterload. Midwall fractional shortening and rate-corrected mean velocity of circumferential shortening were lower during the first months and did not change during the first year of life. CONCLUSIONS: Left ventricular volume and mass increase with age, mass/volume ratio remains almost constant while afterload increases. Endocardial systolic function indexes are higher in the first period of life, due to low afterload and increased mass/volume ratio. In the first months of life the left ventricular myocardium shows a greater sensitivity to changes in afterload and a reduced contractility measured at the midwall level.     

Normal values for noninvasive estimation of left ventricular contractile state and afterload in children

The outcome and suitability for therapeutic interventions in children with congenital heart disease depend frequently on left ventricular function. Congenital heart disease is characterized by changes in loading conditions, making it difficult to assess ventricular contractility using conventional load-dependent indexes. Two-dimensional and M-mode echocardiography and arterial blood pressure were used to study left ventricular morphometrics and contractility in 44 normal children, aged 2 to 12 years. Left ventricular end-systolic and end-diastolic length, diameter, wall thickness, volume and mass all showed linear increases with body surface area (p less than 0.001 in all). Shortening and ejection fractions, velocity of circumferential fiber shortening, morphometric ratios and endocardial meridional and circumferential stress (mean 46 and 115 g/cm2, respectively) all remained constant. A load-independent measure of the normal resting left ventricular contractile state was determined by relating the rate-corrected velocity of circumferential fiber shortening to end-systolic endocardial meridional and circumferential stress; there was an inverse linear correlation (r = -0.641 and -0.557 respectively, p less than 0.001). These data provide a quantitative basis for assessment of myocardial hypertrophy, afterload and contractile state in childhood.     

Impaired left ventricular functional reserve in hypertensive patients with left ventricular hypertrophy

To determine whether patients with hypertension and especially those with left ventricular hypertrophy have subtle changes in cardiac function, we measured the increase in left ventricular ejection fraction and in systolic blood pressure to end-systolic volume index ratio with exercise in 40 hypertensive patients and 16 age-matched normotensive volunteers. Twenty-two hypertensive patients without hypertrophy had normal end-systolic wall stress at rest and exercise responses. In contrast, the 18 patients with echocardiographic criteria for left ventricular hypertrophy demonstrated a significant increase in end-systolic wall stress at rest compared with normal subjects (69 +/- 16 vs. 55 +/- 15 10(3) x dyne/cm2, p less than 0.05) despite having normal resting left ventricular size and ejection fraction. In patients with left ventricular hypertrophy, the increase in ejection fraction with exercise was less than in the normotensive control subjects (7 +/- 7 vs. 12 +/- 8 units, p less than 0.05), and delta systolic blood pressure to end-systolic volume with exercise was reduced (3.3 +/- 3.8 vs. 8.3 +/- 7.7 mm Hg/ml/m2, p less than 0.05). The hypertensive patients with hypertrophy displayed a shift downward and to the right in the relation between systolic blood pressure to end-systolic volume ratio and end-systolic wall stress compared with control subjects and hypertensive patients without left ventricular hypertrophy. Thus, hypertensive patients with left ventricular hypertrophy by echocardiography and normal resting ejection fraction exhibit abnormal ventricular functional responses to exercise. This finding may have implications in identifying patients at higher risk for developing heart failure.     

Left ventricular mechanics in dilated cardiomyopathy

The influence of altered chamber shape on the evaluation of left ventricular (LV) mechanics in idiopathic dilated cardiomyopathy (IDC) is unknown. Nine patients with IDC and 7 subjects with normal LV function were studied with simultaneous LV pressure and M-mode echographic recordings in order to derive LV meridional wall stress. The major axis of the left ventricle, determined from the left ventriculogram at rest, allowed for derivation of circumferential wall stress. The IDC group was characterized by larger end-diastolic and end-systolic LV volumes, increased LV mass, depressed angiographic ejection fraction and more spherical LV chamber shape. Both end-systolic meridional (114 +/- 30 kdyne/cm2) and circumferential (251 +/- 73 kdyne/cm2) wall stresses were elevated in patients with IDC, although the ratio of these stresses was less than normal (2.2 +/- 0.1 vs 2.7 +/- 0.2, respectively). LV load alteration with phenylephrine or nitroglycerin allowed for construction of end-systolic stress-minor-axis dimension and end-systolic stress-minor-axis shortening relations. Similar mean slopes of the meridional end-systolic stress-dimension relation were noted in IDC and normal subjects, although the line was displaced to the right in IDC. The slope of the circumferential end-systolic stress-dimension relation was, however, decreased in patients with IDC. Moreover, the end-systolic stress-fractional minor-axis shortening relation in patients with IDC was displaced downward from the normal relation supporting depressed contractile function in these IDC patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Quantitative evaluation of left ventricular systolic function using bidimensional echocardiography: comparison with cineangiography

The aim of the study was to compare the evaluation of the left ventricular systolic function performed both by angiography and 2D-echocardiography on 80 subjects (31 with coronary artery disease, 18 with left ventricular volume overload, 10 with left ventricular pressure overload, 14 with mitral valve disease and 7 normal controls). The 2D-echocardiograms of the left ventricle with simultaneous measurement of the right arm systolic blood pressure was performed within 24 hours of the angiographic examination. The following parameters were obtained using the two methods: end-diastolic volume index, end-systolic volume index, ejection fraction, left ventricular mass index, mass/volume ratio, end-systolic circumferential stress, contractility expressed as end-systolic circumferential stress/end-systolic volume ratio; the end-systolic circumferential stress/ejection fraction ratio was calculated only by 2D-echocardiography. The afterload and contractility were not calculated in subjects with coronary artery disease and left ventricular outflow gradient. No statistically significant differences were shown between the two methods, except a slight under-estimation by echocardiography of the angiographic end-diastolic volume index (93.1 +/- 38.9 ml/m2 vs 115 +/- 39.9 ml/m2; p less than 0.01) and over-estimation of the mass/volume ratio (1.38 +/- 0.33 g/ml vs 1.2 +/- 0.44 g/ml; p less than 0.01) was shown between the two methods for all parameters. A depressed contractile state was also demonstrated by the end-systolic circumferential stress/ejection fraction ratio. The inter and intraobserver variability was 6.6 +/- 4.4% (range 0.16%) and 4.2 +/- 3% (range 1.11%) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular contractility and contractile reserve in humans after cardiac transplantation

Limited data are available concerning left ventricular contractility and contractile reserve in the chronically denervated, transplanted human heart. This is primarily because of the inability of traditional tests of left ventricular performance to distinguish changes in contractility from alterations in ventricular loading conditions. In this study, load-independent end-systolic indexes of left ventricular contractility were measured by echocardiography and calibrated carotid pulse tracings in 10 patients who had undergone orthotopic cardiac transplant (age 48 +/- 4 years; interval from operation to study 1.2 +/- 0.8 years) and in 10 normal control subjects (age 25 +/- 4 years) matched for donor heart age (25 +/- 6 years). None of the transplant patients had evidence of rejection as determined by endomyocardial biopsy. Baseline left ventricular contractility was assessed over a wide range of afterload generated by infusion of methoxamine. Contractile reserve was measured as the response to an infusion of dobutamine plus methoxamine. Before afterload challenge, baseline left ventricular percent fractional shortening was higher for the transplant patients than for the control subjects (36.5 +/- 5.7% vs 32.1 +/- 2.1%; p less than .05). These differences occurred at a time that end-systolic wall stress (a measure of afterload) was significantly lower for the transplant patients (38 +/- 16 vs 50 +/- 9 g/cm2; p less than .05). When the left ventricular end-systolic pressure-dimension and stress-shortening relationships were determined for the transplant and control subjects, no differences in contractility or contractile reserve were noted. Thus the chronically denervated, transplanted, nonrejecting human left ventricle demonstrates normal contractile characteristics and reserve.     

Early detection of cardiac dysfunction in patients with anorexia nervosa by tissue Doppler imaging

BACKGROUND: Cardiac damage is a major complication of chronic starvation. The aim of this study was to evaluate the changes of left ventricular function in patients with anorexia nervosa by means of pulsed tissue Doppler imaging. METHODS: A total of 20 females (age 22.4+/-4.3 years) with overt anorexia nervosa, 20 matched healthy thin females with body mass index < 19 kg/m2 and 20 matched healthy normal-weight females underwent both standard echocardiography and tissue Doppler imaging. Myocardial systolic wave (Sm) and early (Em) and atrial (Am) diastolic waves were measured on the basal lateral segment and the basal interventricular septum from the apical four-chamber view. RESULTS: When compared with control groups, the anorexia nervosa group showed lower left ventricular mass (p < 0.0001), lower Sm peak of both lateral wall (6.5+/-0.9 vs. 9.4+/-2.1 and vs. 9.5+/-1.9 cm/sec, p < 0.001) and septum (5.6+/-1.5 vs. 8.6+/-1.6 and vs. 8.8+/-1.5 cm/sec, p < 0.001), and comparable Em, Am and Em/Am ratio. The ratio between transmitral peak E and Em was significantly greater in anorexic patients than in controls (lateral wall: 8.1+/-0.1 vs. 6.8+/-0.2 and vs. 6.9+/-0.2, p < 0.001; septum: 10.8+/-0.4 vs. 8.8+/-0.5 and vs. 8.8+/-0.3, p < 0.001). No differences were observed between thin and normal-weight females. In the anorexia nervosa group, S(m) peak was significantly related to left ventricular mass indexed, at both septum (r = 0.55, p < 0.02) and lateral wall (r = 0.49, p < 0.03) levels. CONCLUSIONS: These results show that anorexia nervosa is associated with left ventricular systolic dysfunction, which is related with the reduction of cardiac mass. Tissue Doppler imaging can give useful information in the identification of regional left ventricular dysfunction, in addition to traditional parameters.     

Left ventricular performance in patients with coexistent mitral stenosis and aortic insufficiency

Isolated mitral stenosis and isolated aortic insufficiency impose unique and opposite loading conditions on the left ventricle. To assess these combined effects, hemodynamic and angiographic factors were compared among normal subjects and patients with isolated mitral stenosis, isolated aortic insufficiency or combined mitral stenosis and aortic insufficiency. Left ventricular end-diastolic volume index was lower in patients with combined lesions and severe or moderate aortic insufficiency than in patients with isolated severe or moderate aortic insufficiency (138 +/- 19 versus 206 +/- 20 cc/m2 and 87 +/- 5 versus 145 +/- 22 cc/m2, respectively) (p less than 0.05 for both). Left ventricular end-diastolic and end-systolic volume indexes were normal in two-thirds of patients with combined lesions and moderate or severe aortic insufficiency, whereas these indexes were high in all but one patient with isolated moderate or severe aortic insufficiency. Among patients with moderate or severe aortic insufficiency, 8 of 14 with isolated insufficiency had a reduced ejection fraction or circumferential fiber shortening rate compared with 5 of the 9 patients with combined lesions. Among patients with isolated aortic insufficiency, left ventricular end-systolic wall stress and end-diastolic and end-systolic volume indexes were higher (p less than 0.05) in those with reduced ejection performance than in those with normal ejection performance. These variables did not differ between patients with reduced or normal ejection performance in the group with combined lesions. The contractile index (ratio of end-systolic wall stress to end-systolic volume index) was significantly depressed in patients with severe aortic insufficiency in the groups with isolated aortic insufficiency or combined lesions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship of contractile state to ejection performance in patients with chronic aortic valve disease

To assess the relative contributions of afterload mismatch and impaired contractility to pump dysfunction in patients with chronic aortic valve disease, simultaneous left ventricular cineangiography and micromanometry were performed in 56 patients: 21 with severe aortic stenosis, 16 with severe aortic regurgitation, and 19 normal control subjects. Left ventricular mass was increased in patients with aortic stenosis and aortic regurgitation (172 +/- 52 and 224 +/- 63 g/m2, respectively, vs 89 +/- 16 for control subjects; p less than .05) as were end-diastolic volume (101 +/- 39 and 167 +/- 44 vs 77 +/- 16 ml/m2; p less than .05) and end-systolic volume (50 +/- 40 and 84 +/- 43 vs 24 +/- 7 ml/m2; p less than .05). Although ejection fraction was depressed in both abnormal groups (0.56 +/- 0.18 for patients with aortic stenosis and 0.53 +/- 0.13 for those with aortic regurgitation vs 0.69 +/- 0.05 for control subjects; p less than .05), the decrease in ejection fraction was disproportionate to the mild degree of afterload mismatch (end ejection stress 129 +/- 17 in patients with aortic stenosis and 154 +/- 58 in those with aortic regurgitation vs 117 +/- 46 kdyn/cm2 in control subjects; p = NS) with 10 of 21 patients with aortic stenosis and 12 of 16 patients with aortic regurgitation falling below the 95% prediction limit of the linear inverse relationship between ejection fraction and end-systolic stress for controls (EF = 0.78 - 0.00074 X ESS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Determinants of left ventricular function in isolated rheumatic mitral stenosis

Left ventricular end-diastolic volume (preload), peak systolic wall stress (afterload), instant Emax (contractility index = peak systolic left ventricular pressure/end-systolic volume), left ventricular mass, left ventricular ejection fraction (LVEF) alone and normalised for mass index, were studied in 30 patients with isolated rheumatic mitral stenosis (group 1) and compared with 24 normal individuals (group II) who served as control. Preload was not different in the two groups (p = NS), afterload was increased in group I (p = 0.01), while LVEF, Emax, left ventricular mass and mass normalised LVEF were reduced in mitral stenosis as compared to normal control (p less than 0.01- less than 0.001). Comparison of patients with reduced ejection performance (LVEF less than 50%, n = 9, group IA) with those having normal LVEF (n = 21 group IB) revealed increased left ventricular end-diastolic volume and reduced left ventricular mass, mass normalised ejection fraction and Emax (in IA p less than 0.05). Peak systolic wall stress was comparable in these two subgroups. This study shows that the major determinant of left ventricular dysfunction in isolated rheumatic mitral stenosis is impaired contractility and not the loading factors.     

Direct quantitation of right and left ventricular volumes with nuclear magnetic resonance imaging in patients with primary pulmonary hypertension.

To test the utility of electrocardiographically gated spin echo nuclear magnetic resonance (NMR) imaging in quantitating right and left ventricular volumes and function in patients with primary pulmonary hypertension, right and left ventricular end-diastolic and end-systolic volumes, stroke volumes and ejection fractions were determined in 11 patients with primary pulmonary hypertension and in 10 subjects with normal echocardiographic findings. Ventricular chamber volumes were computed by summing the ventricular chamber volumes of each NMR slice at end-diastole and end-systole. This technique was verified by comparison of results obtained by this method and with the water displacement volumes of eight water-filled latex balloons and ventricular casts of eight excised bovine hearts. In the patients with primary pulmonary hypertension, right ventricular volume indexes were 121 +/- 45 ml/m2 at end-diastole and 70.1 +/- 41.6 ml/m2 at end-systole; both values were significantly greater than values in the normal subjects (67.9 +/- 13.4 and 27.9 +/- 7.5 ml/m2, respectively). Left ventricular end-diastolic volume index was significantly less in the patients (44.9 +/- 9.7 ml/m2) than in the normal subjects (68.9 +/- 13.1 ml/m2). There was no significant difference in left ventricular end-systolic volume between the two groups (24.4 +/- 8.6 and 27.1 +/- 7.8 ml/m2, respectively). Right and left ventricular ejection fractions in the patients with primary pulmonary hypertension (0.43 +/- 0.21 and 0.46 +/- 0.15, respectively) were significantly less than values in normal subjects (0.59 +/- 0.09 and 0.6 +/- 0.11, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Systolic stress in mitral stenosis

Left ventricular systolic stress was studied in nineteen patients with mitral stenosis, twelve in sinus rhythm and seven in atrial fibrillation. Left ventricular dimensions and volumes and septal and posterior wall thickness were measured by means of M and two bidimensional echocardiography at rest and during isometric exercise. Expulsive indices: fractional shortening, ejection fraction and mean circumferential shortening rate were calculated. Ventricular mass, meridional stress and several end-systolic stress or pressure/volume relationships were estimated. Patients with atrial fibrillation were older and had systolic dysfunction: greater end-systolic volumes and depression of both expulsive fractions and some of the end-systolic indices. Preload and wall thickness were normal. Patients with atrial fibrillation showed higher ventricular stress as a consequence of greater ventricular dimensions. Ejection fraction correlates directly with mitral valve area and inversely with inotropic state and heart rate. It is concluded that systolic dysfunction in mitral stenosis is multifactorial. The most important determinants of the abnormality are heart rate and inotropic state. The study did not show any primary abnormality of afterload or hypotrophy of the left ventricle.     

Changes in left ventricular size, wall thickness, and function in anemic patients treated with recombinant human erythropoietin.

Left ventricular size and function were evaluated in 15 anemic chronic hemodialysis patients before and after the administration of recombinant human erythropoietin (rHuEPO). All patients were studied with two-dimensional and M-mode echocardiographic examinations before the initiation of rHuEPO (T1) and at 28 +/- 7 weeks of rHuEPO therapy (T2). The two-dimensional targeted M-mode echocardiographic measurements obtained were: end-diastolic dimension (EDD); end-systolic dimension (ESD); stroke dimension (SD); dimensional shortening (SD/EDD); systolic posterior wall thickness (PWs); diastolic posterior and interventricular septal thickness; end-systolic wall stress (ESWS); and left ventricular mass. Mean hematocrit in these patients increased almost 50%. The EDD decreased from a mean value (+/- SEM) of 6.41 +/- 0.33 to 4.93 +/- 0.21 cm (p less than 0.05). ESD decreased from a mean value of 4.16 +/- 1.2 to 2.77 +/- 0.06 cm (p less than 0.05). The calculated mean SD decreased slightly but not significantly from 2.21 +/- 0.69 to 2.19 +/- 0.60 cm. The calculated SD/EDD increased from a mean 0.35 +/- 0.09 to 0.44 +/- 0.07 (p less than 0.05). ESWS fell from 59.2 +/- 12.2 to 37.6 +/- 9.3 gm/cm2 (p less than 0.01), and left ventricular mass fell (p less than 0.05) from 347 +/- 15.2 to 227 +/- 59 gm. There was no significant difference in resting heart rate or systolic blood pressure between T1 and T2. The increase in dimension shortening reflects afterload reduction, as indicated by the fall in end-systolic wall stress.(ABSTRACT TRUNCATED AT 250 WORDS)     

Load dependency of end-systolic pressure-volume relations in isolated, ejecting canine hearts

If characteristic muscle properties such as myocardial viscosity and/or shortening deactivation influence left ventricular ejection in the whole heart, the slope of the left ventricular end-systolic pressure-volume relation should be a function of both the contractile state and the loading mode. Thus, the load dependence of the end-systolic pressure-volume relation was examined using isolated, perfused canine hearts ejecting saline into a hydraulic loading system. The instantaneous left ventricular volume was measured with a plethysmograph. Under constant coronary flow and heart rate, two regression lines for end-systolic pressure-volume relations in two sets of loading modes were obtained: (1) Preload (left ventricular end-diastolic pressure; 4-15 mmHg) changes under fixed afterload impedance (preload changes); (2) Afterload impedance (peripheral resistance; 1.9-9.6 x 10(3) dyn sec cm-5) changes under fixed left ventricular end-diastolic volume (afterload changes). The slope of the end-systolic pressure-volume relation with afterload changes was steeper than that with preload changes (6.3 +/- 0.7 vs 4.8 +/- 0.6 mmHg/ml, p less than 0.05). Accordingly, under constant coronary flow, the slope of the end-systolic pressure-volume relation depended on loading conditions within the physiological range of afterload impedance and preload. This finding supports our hypothesis and implies that the slope change is of limited value as a contractile index in the ejecting heart.     

Noninvasive evaluation of global left ventricular function with use of cine nuclear magnetic resonance

Previous reports have validated the accuracy of nuclear magnetic resonance (NMR) imaging for quantitating ventricular volumes and myocardial mass. In this study, a new rapid NMR imaging method, cine NMR imaging, was used to compare left ventricular volumes determined from the transverse plane and short-axis plane in healthy volunteers and patients with dilated cardiomyopathy. With use of the short-axis plane, left ventricular mass at end-systole and end-diastole were determined and left ventricular systolic wall thickening at three different levels was assessed. For validation in the current study, cine NMR imaging and two-dimensional echocardiographic measurements of left ventricular volumes were correlated. Left ventricular volumes of the normal volunteers (end-systolic volume = 34 +/- 3.8 ml, end-diastolic volume = 90.4 +/- 7.2 ml) and patients with cardiomyopathy (end-systolic volume = 173 +/- 28.3 ml, end-diastolic volume = 219.5 +/- 29.6 ml) obtained in the transverse plane were nearly identical to those obtained in the short-axis plane (normal volunteers, end-systolic volume = 30.3 +/- 3.5 ml, end-diastolic volume = 84.7 +/- 7.0 ml and patients with cardiomyopathy, end-systolic volume = 179.1 +/- 27.8 ml, end-diastolic volume = 227 +/- 30.9 ml) and correlated highly (r = 0.91) with volumes obtained by two-dimensional echocardiography. Assessment of left ventricular mass over a broad range using cine NMR imaging in a short-axis plane was identical at end-systole (normal volunteers, 117 +/- 10 g; patients with cardiomyopathy, 202 +/- 20 g) and end-diastole (normal volunteers, 115 +/- 10 g; patients with cardiomyopathy, 194 +/- 21 g).(ABSTRACT TRUNCATED AT 250 WORDS)     

Preservation of left ventricular performance with reduced ischemic dysfunction by intravenous nisoldipine

The effect of intravenous nisoldipine on cardiac performance was examined during pacing-induced ischemia in 14 patients with coronary artery disease. The relative contributions of afterload reduction or prevention of myocardial ischemia were assessed using load-independent global (peak-systolic pressure/end-systolic volume) and regional (peak-systolic pressure/end-systolic radial length) "contractile" indexes. Nisoldipine decreased aortic pressure (predrug, 109 +/- 14 vs postdrug, 88 +/- 13 mm Hg, p less than 0.01) and prevented elevation of left ventricular end-diastolic pressure during rapid atrial pacing (predrug, 7.9 +/- 5.7 vs postdrug, -0.5 +/- 4.9 mm Hg, p less than 0.001). Resting cardiac index (predrug, 3.3 +/- 0.6 vs postdrug, 4.2 +/- 0.7 liters/min/m2, p less than 0.05), and left ventricular ejection fraction (predrug, 68.1 +/- 9.0 vs postdrug, 74.2 +/- 9.4%, p less than 0.05) increased after nisoldipine, which also prevented the deterioration in left ventricular ejection fraction (predrug, -8.1 +/- 7.9 vs postdrug, -1.0 +/- 3.7%, p less than 0.05) and fractional radial shortening (predrug, -8.7 +/- 13.1 vs postdrug, 3.7 +/- 16.4%, p less than 0.01) during rapid atrial pacing. Under these conditions, nisoldipine preserved myocardial function, as determined by global peak-systolic pressure/end-systolic volume (predrug, -0.82 +/- 0.39 vs postdrug, 0.17 +/- 1.54 mm Hg/ml, p less than 0.05) and regional (peak-systolic pressure/end-systolic radial length, predrug, -23.8 +/- 36.1 vs postdrug, 12.7 +/- 36.3 mm Hg/cm, p less than 0.01) "contractile" indexes. Intravenous nisoldipine maintains ventricular performance during rapid atrial pacing via a combination of systemic vasodilation and amelioration of ischemic myocardial dysfunction.     

Association between the exercise ejection fraction response and systolic wall stress in patients with chronic aortic insufficiency

We studied the exercise ejection fraction response in 56 patients with chronic aortic insufficiency. All had left ventricular dilatation but preserved resting ejection fraction and minimal or no symptoms. The exercise ejection fraction increased by 0.05 units or greater in 18 (32%) patients (group I), remained within 0.05 units of the resting value in 18 (32%) patients (group II), and fell by 0.05 units or greater in 20 (36%) patients (group III). There were no significant differences among the groups in left ventricular end-diastolic dimension, end-systolic dimension, or fractional shortening by echocardiography or in resting left ventricular volumes and ejection fraction by radionuclide angiography. Left ventricular end-systolic wall stress was significantly higher in group III than in either group I or group II (89 +/- 20 vs 70 +/- 18 and 69 +/- 17 X 10(3) dyne/cm2; p less than .005). At peak exercise there were no differences among groups in systolic blood pressure. However, end-systolic volume increased from 65 +/- 28 to 77 +/- 36 ml/m2 in group III and fell from 50 +/- 21 to 28 +/- 18 ml/m2 in group I during exercise. Thus, at peak exercise end-systolic volume was nearly three times greater in group III than in group I. Although stress could not be determined directly during exercise, the directional changes in its determinants suggest that it also would have been higher in group III patients. A highly significant inverse correlation was present between the ejection fraction response and the change in end-systolic volume (r = -.87, p less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Left ventricular mass in diabetes-hypertension.

BACKGROUND--This study was undertaken to identify whether diabetes mellitus (DM) accelerates the development of left ventricular hypertrophy (LVH) in hypertensive patients. METHODS--Cardiac structure, systolic function, and hemodynamics were evaluated by two-dimensional M-mode echocardiography in diabetic and nondiabetic patients with essential hypertension. RESULTS--Patients with hypertension with and without DM had the same end-systolic and end-diastolic dimensions, cardiac output, total peripheral resistance, and ejection fraction. Diabetic hypertensive patients had greater interventricular septum (1.32 +/- 0.20 vs 1.07 +/- 0.20 cm) and posterior wall (1.20 +/- 0.20 vs 1.00 +/- 0.10 cm) thickness than did nondiabetic hypertensive patients. Consequently, left ventricular mass index was greater in patients with hypertension and DM than in those without DM (158 +/- 45 vs 113 +/- 20 g/m2). With the use of Devereux criteria for recognition of LVH (left ventricular mass index above 134 g/m2 in men and above 110 g/m2 in women), 72% of the diabetic patients had LVH, whereas only 32% of the nondiabetic patients had LVH. Left ventricular contractility, as reflected by the ratio of end-systolic wall stress to end-systolic volume index, was decreased in diabetic compared with nondiabetic hypertensive patients. CONCLUSIONS--The data suggest that DM accelerates the development of LVH in patients with essential hypertension independent of arterial pressure and, therefore, may contribute to the increased cardiovascular morbidity and mortality in patients with hypertension.     

Left ventricular end-systolic wall stress--dimension relationship in unanesthetized dogs with perinephritic hypertension

To study myocardial contractility in hypertensive hearts with normal wall motion, we examined left ventricular end-systolic wall stress-dimension relationships (ESWDR) during a baseline period (CS: control stage) and in the eighth week after induction of systemic hypertension by Page's method (HS: hypertensive stage) in unanesthetized dogs. The mean aortic blood pressure increased from 94 +/- 11 to 142 +/- 26 mmHg (p less than 0.01). The end-diastolic left ventricular posterior wall thickness increased significantly during the HS (9.4 +/- 1.3 vs 7.3 +/- 1.3 mm; HS vs CS), and its dimension was significantly (p less than 0.05) smaller than it was during the CS (37.0 +/- 4.2 vs 39.9 +/- 4.6 mm; HS vs CS). There were no significant differences between the 2 stages in left ventricular fractional shortening (31.9 +/- 5.0 vs 32.6 +/- 2.8; HS vs CS), in end-systolic meridional left ventricular wall stress (75.3 +/- 10.8 vs 68.3 +/- 15.6 10(3) dynes/cm2; HS vs CS), or in the ESWDR slopes (98.6 +/- 17.7 vs 94.0 +/- 19.7; HS vs CS). The ESWDR dimension intercepts significantly decreased from 2.0 +/- 0.3 to 1.8 +/- 0.3 cm during the HS; that is, the relationship shifted to the left with no significant change in the slope. At autopsy, the ratio of left ventricular weight to body weight of the hypertensive dogs was significantly (p less than 0.01) greater than that of sham-operated control dogs (6.0 +/- 0.9 vs 4.3 +/- 0.5 g/kg).(ABSTRACT TRUNCATED AT 250 WORDS)