Ejection Phase Indices Research Articles

Right ventricular performance and contractile reserve in patients with severe heart failure. Assessment by pressure-area relations and association with outcome.

Right ventricular (RV) performance appears to be important in patients with severe heart failure. Although clinical assessments of RV function previously have been limited to load-dependent ejection phase indices, a new method has been developed using the relatively load-insensitive concepts of pressure-volume relations with automated echocardiographic measures of RV cross-sectional area as a surrogate for volume. Sixteen patients with New York Heart Association functional class IV heart failure and group mean left ventricular ejection fraction of 20 +/- 5% were studied. RV pressure-area loops were recorded on-line from echocardiographic measures of RV area and high-fidelity pressure during transient inferior, vena caval balloon occlusions. RV contractile reserve was assessed as its functional response to an increase in dobutamine from 5.7 +/- 4.1 to 13.1 +/- 4.7 micrograms/kg per minute. Complete data sets were available in 13 patients. Group mean RV end-systolic elastance (E'es) and maximal elastance (E'max) increased with augmented dobutamine infusion (2.9 +/- 1.5 to 5.5 +/- 3.3 mm Hg/cm2 and 3.3 +/- 1.6 to 6.4 +/- 3.9 mm Hg/cm2, respectively; P < .01 versus baseline), although individual responses were variable. During a 30-day follow-up, 9 patients remained unstable, requiring continuous intravenous inotropic therapy; 6 of these had profound deterioration requiring mechanical circulatory support. The remaining 4 patients had a comparatively good short-term outcome with clinical stability. A 100% increase in RV E'es or E'max was associated with a good short-term outcome (P < .05). RV performance can be assessed by pressure-area relations in patients with heart failure. RV contractile reserve in response to increases in dobutamine was associated with a good short-term outcome and may be of prognostic value in patients with severe heart failure.

Endocardial versus midwall measurement of left ventricular function in mild hypertension

To compare endocardial and midwall measurement of left ventricular fractional shortening in assessing cardiac systolic function in hypertension. Seventeen hypertension clinics in northeast Italy. Left ventricular endocardial fractional shorteningcircumferential stress relationship versus midwall shortening-stress relationship in the subjects divided according to relative wall thickness (RWT) and left ventricular mass indexed by body surface area. Borderline-to-mild hypertensives [n = 635, aged 33 +/- 0.3 years (mean +/- SEM), office blood pressure 146 +/- 0.4/94 +/- 0.2 mmHg (means +/- SEM)] in the Harvest Study and 50 normotensive controls with similar age and sex distributions. Blood pressure was measured by 24 h ambulatory monitoring. Left ventricular dimensional and functional indices were assessed by M-mode echocardiography. In the subjects divided into quintiles of RWT, the left ventricular shortening-stress relationship was increased in a parallel fashion when calculated by endocardial and by midwall measurements for RWT < or = 0.35. Instead, for greater RWT values (> or = 0.37) endocardial measurement constantly gave large values than did midwall measurement. Both the endocardial and the midwall shortening-stress relationships progressively decreased with increasing RWT. However, the endocardial shortening-stress relationship remained greater than normal at any RWT, whereas the midwall shortening-stress relationship was decreased for RWT > or = 0.37. In a multiple-regression analysis RWT was the most potent predictor of the endocardialmidwall shortening difference, left ventricular mass and 24 h systolic blood pressure being the second and third most potent predictors. We found a parallel increase in indices of cavity emptying and of myocardial contractility in mild hypertensive subjects with normal left ventricular geometry. When the RWT is increased, ejection phase indices may be normal in the presence of decreased myocardial contractility.

RIGHT VENTRICULAR PERFORMANCE AND LEFT VENTRICULAR ASSIST DEVICE FILLING

Mandarino, W A; Winowich, S; Gorcsan, J III; Gasior, T A; Pham, S; Griffith, B P; Kormos, R L Author Information

Salutary effect of Terminalia Arjuna in patients with severe refractory heart failure

Twelve patients with refractory chronic congestive heart failure (Class IV NYHA), related to idiopathic dilated cardiomyopathy (10 patients); previous myocardial infarction (one patient) and peripartum cardiomyopathy (one patient), received Terminalia Arjuna, an Indian medicinal plant, as bark extract (500 mg 8-hourly) or matching placebo for 2 weeks each, separated by 2 weeks washout period, in a double blind cross over design as an adjuvent to maximally tolerable conventional therapy (Phase I). The clinical, laboratory and echocardiographic evaluation was carried out at baseline and at the end of Terminalia Arjuna and placebo therapy and results were compared. Terminalia Arjuna, compared to placebo, was associated with improvement in symptoms and signs of heart failure, improvement in NYHA Class (Class III vs. Class IV), decrease in echo-left ventricular enddiastolic (125.28 ± 27.91 vs. 134.56 ± 29.71 ml/m 2; P < 0.005) and endsystolic volume (81.06 ± 24.60 vs. 94.10 ± 26.42 ml/m 2; P < 0.005) indices, increase in left ventricular stroke volume index (44.21 ± 11.92 vs. 40.45 ± 11.56 ml/m 2; P < 0.05) and increase in left ventricular ejection fractions (35.33 ± 7.85 vs. 30.24 ± 7.13%; P < 0.005). On long term evaluation in an open design (Phase II), wherein Phase I participants continued Terminalia Arjuna in fixed dosage (500 mg 8-hourly) in addition to flexible diuretic, vasodilator and digitalis dosage for 20–28 months (mean 24 months) on outpatient basis, patients showed continued improvement in symptoms, signs, effort tolerance and NYHA Class, with improvement in quality of life. One patient died of cerebrovascular accident while another had sudden cardiac death, 16 months and 14 months after entry into Phase II, respectively. No significant clinical untoward effect occurred during Terminalia Arjuna or placebo therapy. The mechanism of beneficial effects of Terminalia Arjuna needs evaluation but it could be related to one or more of the constituents which have cardiotonic (glycosides) or free radicle scavenger (tannins, flavones) properties. In conclusion, adjuvent Terminalia Arjuna therapy in our patients with refractory congestive heart failure, mostly related to idiopathic dilated cardiomyopathy, appeared safe and caused long lasting improvement in symptoms and signs of heart failure along with improvement in left ventricular ejection phase indices with definite improvement in quality of life. We believe that these preliminary observations open a new vista for future research in therapy of myocardial failure.

952-30 Left Ventricular Ejection Performance Improves Late After Aortic Valve Replacement in Patients with Aortic Stenosis and Reduced Ejection Fraction

To assess the time course and magnitude of change in left ventricular (LV) wall stress and ejection performance indices, 24 patients undergoing aortic valve replacement (AVR) for aortic stenosis were prospectively evaluated. Each patient underwent resting radionuclide angiography (RNA), echocardiography, and cardiac catheterization (high fidelity pressure) before AVR, then RNA and echocardiogram at one week and six months after AVR. Patients were stratified by preoperative ejection fraction (EF) into reduced EF (&lt;50%) and normal EF (≥50%) groups. Pre-operatively, peak positive dp/dt was lower in the reduced EF group (1300 vs 1700 mmHg/sec, p = 0.035), and wall stress was elevated similarly in both groups (p = NS). Temporal Relationships of EF and Wall Stress Pre-op 1 Week 6 Mos Normal EF (n = 14) Mean Ejection Fraction (%) 66 64 68 Mean Wall Stress (dyne/cm 2 × 10 3 ) 62 34 44 Reduced EF (n = 10) Mean Ejection Fraction (%) 38 37 57 Mean Wall Stress (dyne/cm 2 × 10 3 ) 78 52 61 Wall stress was reduced at one week post-operatively (p &lt; 0.005) in both groups. Ejection fraction remained depressed in the reduced EF group. By six months, however, EF had dramatically improved in the reduced EF group (p = 0.002). In patients with LV dysfunction, EF remains low one week after AVR despite rectification of afterload mismatch. At six months, however, ejection performance improves. Therefore, when measured by ejection phase indices, the surgical benefit from AVR is not evident until late post-operatively.

Quantitated left ventricular systolic mechanics in children with septic shock utilizing noninvasive wall-stress analysis

Objective: To quantitate ventricular systolic mechanics in septic children. Design: Prospective wall-stress analysis was compared to standard ejection phase indices. Setting: University-based pediatric intensive care unit. Patients: Fifteen children with sepsis (hemodynamically stable, n = 5; in shock, n = 10). Measurements and Main Results: Left ventricular ejection phase indices: shortening fraction (shortening) and corrected mean velocity of circumferential shortening (velocity) were adjusted for end-systolic wall stress (stress). Ejection phase, performance (stress-shortening relation), contractility (stress-velocity relation), and afterload (stress) were indexed to age-corrected normal means, with variance of ≥2 sd regarded as significant. Preload index represented variance between performance and contractility indices. All hemodynamically stable septic patients had normal performance, contractility, and preload. Afterload was increased in three of five patients. Of the patients with septic shock, six often had decreased performance (decreased contractility and increased afterload, n = 4; decreased afterload, n = 1; and severe preload deficit, n = 1). Despite aggressive volume resuscitation, six of ten children in septic shock had evidence of diminished preload. Follow-up studies in the septic shock patients demonstrated reversal of depressed ventricular contractility within 3 to 6 days in all four patients initially affected (p < .05). One patient developed late decreased performance and contractility in association with multiple organ failure. Ventricular loading abnormalities persisted in a follow-up study of these patients including a preload deficit in five of ten patients in shock. Conclusions: The frequency rate (40%) of reversible impaired ventricular contractility in children with septic shock is significant. Afterload is normal or increased in the majority of septic subjects, possibly due to acute ventricular dilation. Decreased preload contributes to altered ventricular performance in the majority of children with septic shock, persisting days after the initiation of therapy. Wall-stress analysis provided detailed information regarding ventricular mechanics that was not otherwise obtainable by standard ejection phase indices. (Crit Care Med 1994; 22:1647–1658)

Quantitated left ventricular systolic mechanics in children with septic shock utilizing noninvasive wall-stress analysis

To quantitate ventricular systolic mechanics in septic children. Prospective wall-stress analysis was compared to standard ejection phase indices. University-based pediatric intensive care unit. Fifteen children with sepsis (hemodynamically stable, n = 5; in shock, n = 10). Left ventricular ejection phase indices: shortening fraction (shortening) and corrected mean velocity of circumferential shortening (velocity) were adjusted for end-systolic wall stress (stress). Ejection phase, performance (stress-shortening relation), contractility (stress-velocity relation), and afterload (stress) were indexed to age-corrected normal means, with variance of > or = 2 SD regarded as significant. Preload index represented variance between performance and contractility indices. All hemodynamically stable septic patients had normal performance, contractility, and preload. Afterload was increased in three of five patients. Of the patients with septic shock, six of ten had decreased performance (decreased contractility and increased afterload, n = 4; decreased afterload, n = 1; and severe preload deficit, n = 1). Despite aggressive volume resuscitation, six of ten children in septic shock had evidence of diminished preload. Follow-up studies in the septic shock patients demonstrated reversal of depressed ventricular contractility within 3 to 6 days in all four patients initially affected (p < .05). One patient developed late decreased performance and contractility in association with multiple organ failure. Ventricular loading abnormalities persisted in a follow-up study of these patients including a preload deficit in five of ten patients in shock. The frequency rate (40%) of reversible impaired ventricular contractility in children with septic shock is significant. Afterload is normal or increased in the majority of septic subjects, possibly due to acute ventricular dilation. Decreased preload contributes to altered ventricular performance in the majority of children with septic shock, persisting days after the initiation of therapy. Wall-stress analysis provided detailed information regarding ventricular mechanics that was not otherwise obtainable by standard ejection phase indices.

Norepinephrine-induced left ventricular dysfunction in anesthetized and conscious, sedated dogs

These studies were conducted to evaluate effects of high dose norepinephrine infusion on left ventricular function in anesthetized and conscious dogs. Separate groups of pentobarbital anesthetized closed-chest dogs received norepinephrine infusion for 90 min followed by 1 h of recovery. Arterial pressure, electrocardiogram, two-dimensional echocardiogram and an equilibrium radionuclide angiogram were monitored. One hour following infusion of norepinephrine, left ventricular ejection fraction was reduced in a dose-dependent fashion. Fractional shortening was similarly reduced, with increased left ventricular systolic and diastolic dimensions also observed. Left ventricular end-systolic wall stress was increased at 60 min following infusion of norepinephrine but not saline: saline, 68 ± 8, norepinephrine, 4 μg/kg/min, 113 ± 8 g/cm 2. The left ventricular end-systolic wall stress/fractional shortening relationship showed reduction of contractility. In 10 conscious dogs pretreated with morphine, norepinephrine at 5 μg/kg/min × 90 min produced similar changes to those seen in anesthetized animals. Ejection fraction was reduced from 0.69 ± 0.3 to 0.36 ± 0.04 at 60 min post infusion. Fractional shortening was also reduced. Left ventricular end-diastolic dimension was increased. However, when animals were followed for 1 week, complete recovery occurred within 48 h. Histology showed mild contraction band necrosis in acute experiments and mild perivascular fibrosis in chronic experiments. Therefore, norepinephrine cardiotoxicity produced significant left ventricular dilation and reduction of ejection phase indices of left ventricular function associated with reduced contractility. In chronic dogs, histologic changes were mild, and left ventricular dysfunction was reversible.

Cardiac structural and functional abnormalities in adult patients with growth hormone deficiency.

Little information is available on cardiac involvement in GH-deficient adults. Thus, we evaluated cardiac structure and function by means of one- and two-dimensional echocardiography in 11 adult patients [3 women and 8 men; mean age, 27.2 +/- 3.8 (+/- SD) yr] affected with GH deficiency. Twelve age- and sex-matched normal subjects served as the control group. All patients had been treated with extractive GH over 9 yr, and therapy withdrawal had been performed at least 3 yr before entering the study. GH-deficient patients had significantly lower values of interventricular septum (7.1 +/- 1 vs. 9 +/- 0.4 mm; P < 0.01) and left ventricular posterior wall thickness (6.1 +/- 1 vs. 9 +/- 0.4 mm; P < 0.01), which resulted in a significantly smaller left ventricular mass index (54 +/- 11 vs. 85 +/- 15 g/m2; P < 0.001). The left ventricular end-diastolic and end-systolic diameters did not differ significantly after correction for body area surface, whereas ejection phase indices showed lower values, with a fractional shortening of 34 +/- 4% vs. 38 +/- 5% (P < 0.05) and an ejection fraction of 59 +/- 9% vs. 69 +/- 10% (P < 0.05). In conclusion, the results of this study demonstrate the involvement of cardiac muscle in patients affected with GH deficiency.

Evidence for biventricular involvement in acromegaly: a Doppler echocardiographic study

To investigate left and right ventricular involvement in acromegaly, 20 patients were studied by Doppler echocardiography. Nine of them had systemic hypertension. Right ventricular free wall thickness was significantly increased in acromegalic patients (8 +/- 2 vs 4 +/- 1 mm; P < 0.001). Left ventricular mass index was augmented both in the whole group and in the subgroup of normotensive acromegalics, as compared with normals (134 +/- 33 and 115 +/- 20 vs 80 +/- 18 g.m-2; P < 0.01). Ejection phase indices were normal in the patient group, while impaired left and right ventricular diastolic filling was found. In fact isovolumic relaxation time was prolonged (118 +/- 21 vs 78 +/- 12 ms; P < 0.001), ratio of early to late mitral (0.9 +/- 0.3 vs 1.8 +/- 0.5; P < 0.001) and tricuspid (1.0 +/- 0.2 vs 1.4 +/- 0.3; P < 0.001) flow velocities were significantly decreased as compared with controls. Superior vena cava flowmetry was also abnormal showing a marked decrease of diastolic filling wave and, consequently, of the ratio between peak diastolic and peak systolic flow velocity. No significant differences were observed between normotensive and hypertensive acromegalics, except for left ventricular mass index (115 +/- 20 vs 156 +/- 31 g.m-2; P < 0.01). These findings indicate that abnormal diastolic filling patterns of transmitral, transtricuspid, and superior vena cava flowmetry suggesting 'impaired relaxation' associated with increased left and right ventricular mass, frequently occur in acromegaly.

Analysis of fractional area change at various levels in the normal left ventricle

Percent change in left ventricular cross-sectional area between diastole and systole (fractional area change) is an ejection phase index of contractile function. 1 Normal values for fractional area change have been determined at the level of the papillary muscles in the echocardiographic parasternal short-axis view, 2 and fractional area change has been found to correlate well with ejection fraction in both normal and abnormal subjects. 3 We studied 8 subjects with normal left ventricular function to assess whether fractional area change varies significantly at different cross-sectional levels of the left ventricular cavity.

Effects of simultaneous alterations in preload and afterload on measurements of left ventricular contractility in patients with dilated cardiomyopathy: Comparisons of ejection phase, isovolumetric and end-systolic force-velocity indexes

Objectives. The study was designed to critically evaluate the clinical utility of ejection phase and nonejection phase indexes of contractile state in patients with severe left ventricular dysfunction.Background. Ejection phase indexe of left ventricular systolic performance are unable to differentiate contractility changes from alterations in loading conditions. Isevolumetric and end-systolic force-velocity indexes have been proposed as alternative measurements of contractile state that are load independent.Methods. Seventeen patients with nonischemic dilated cardiomyopathy were studied during cardiac catheterization. High fidelity central aortic and left ventricular pressure measurements were made with simultaneous echocardiographic recordings of chamber minor- and long-axis dimensions and wall thickness. Data were acquired under control conditions, during nitropusisside infusion and with dopamine (6μg/kg per min).Results. Patients were classified into those without (group 1, n = 10) and those with (group 2, n = 7) a decrease in end-diastolic circumferential wail stress in response to dopamine. There were no baseline differences between the groups in functional class, left ventricular chamber geometry or cardiovascular hemodynamics. Ejection phase indexes were variably altered by changes in preload, afterload and heart rate, thereby complicating physiologic interpretation of data. Dopamine increased the commonly used isovolumetric index, maximal rate of rise in left ventricular pressure (dP/dtmax, by 64% for group 1 but by only 16% for group 2 (p < 0.001), resulting in an underestimation of contractile state change in 41% of patients. In contrast, the left ventricular end-systoic circumferential wall stress-rate-corrected velocity of fiber shortening relation, which incorporates afterload, ventricular wall mass and heart rate in its analysis, was a sensitive contractility measurement that was preload independent and equally augmented by dopamine for both groups.Conclusions. Of the left ventricular contractility indexes evaluated, the end-systolic circumferential wall stress-rate corrected velocity of fiber shortening relation was the most physiologically appropriate for assessing pharmacologically induced changes in inotropic state that were accompanied by complex alterations in loading conditions in patients with dilated cardiomyopathy.

Left ventricular performance in neonates on extracorporeal membrane oxygenation.

The evaluation of left ventricular systolic performance in infants undergoing extracorporeal membrane oxygenation (ECMO) using traditional ejection-phase indices is hampered by significant alterations in preload and afterload. Therefore, a load-independent index, which relates heart-rate-corrected mean velocity of circumferential fiber shortening (VCFc) to afterload, measured as end-systolic wall stress (ESS), was used to assess left ventricular function in 18 term neonates undergoing ECMO. The mean age at the onset of ECMO was 75.5 h and the duration of therapy was 171 +/- 106 h. Left ventricular performance was highest before the onset of ECMO (VCFc = 1.65 +/- 0.49 circ/s) and decreased toward normal during (1.38 +/- 0.33 circ/s) and following ECMO (1.29 +/- 0.16 circ/s). Initially, nine of 17 (53%) patients had enhanced performance for the degree of afterload but in only 16 of 48 (33%) studies during ECMO and none following ECMO was VCFc elevated beyond the normal range predicted for ESS. These changes in left ventricular performance may be the result of variations in exogenous, as well as endogenous, catecholamines rather than intrinsic alterations in myocardial contractility. It is concluded that the VCFc/ESS relation permits a meaningful assessment of ventricular performance in critically ill neonates undergoing ECMO.

Surgical treatment of ventricular tachycardia by balloon electric shock ablation

We have previously described a new surgical technique for control of arrhythmogenic foci in patients with recurrent ventricular tachycardia that we call balloon electric shock ablation. With this method sequential shocks are delivered to a grid of electrodes on a balloon that can be introduced across the mitral valve into the intact ventricle. A series of experiments was undertaken to investigate possible deleterious effects of balloon electric shock ablation when shocks are delivered directly to the mitral valve apparatus. In six animals shocks totaling 1200 joules were given through a closely spaced electrode grid applied to the area of the mitral valve. Nine to 12 weeks later, left ventricular and mitral valve function were assessed. Balloon electric shock ablation in the basilar portion of the ventricle was associated with decreased myocardial performance, as evidenced by ejection phase indices. In five of six animals balloon ablation led to minor thickening of the valve leaflets and chordal attachments plus necrosis of adjacent myocardium, including papillary muscles. In these animals there was no significant dysfunction of the valve observed. In the remaining animal, however, ablation was centered on the posterior papillary muscle and resulted not only in necrosis of the base of the papillary muscle but also in full-thickness scarring and thinning of the adjacent left ventricular wall. In this dog, mitral regurgitation was seen on long-term follow-up. We conclude that when balloon electric shock ablation is used to destroy a localized area of myocardium in the basilar portion of the intact ventricle, the procedure results in decreased myocardial performance. When shocks were directly applied to the mitral valve apparatus in five of six animals, ablation did not result in significant negative effects on the structure and function of the valve. In the sixth dog, however, shock delivery resulted in transmural necrosis and thinning at the site of papillary muscle insertion and was associated with severe mitral regurgitation with volume loading. Therefore caution should be used when considering clinical application of this technique if the area to be ablated is in the basal portion of the heart.

Noninvasive estimation of left ventricular contractile state and afterload in normal newborn infants

Cardiac performance is altered by loading conditions and by heart rate, especially in newborn infants. Ejection phase indexes such as ejection fraction and fractional shortening might be useful in evaluating their cardiac function. The clinical use of these indexes is limited by the inability to distinguish between the effects of altered loading conditions and of abnormalities in left ventricular contractility. The relation between end-systolic endocardial meridional stress and the rate-corrected velocity of circumferential fiber shortening is a sensitive echocardiographic method for evaluating left ventricular contractility, which is relatively independent of loading. 1–5 There have been no reports on the relation between endocardial meridional stress and rate-corrected velocity of circumferential fiber shortening in newborns. We studied the relation between endocardial meridional stress and the rate-corrected velocity of circumferential fiber shortening in normal newborn infants to determine the normal values and to estimate the contractile state.

Alterations in myocardial contractility in conscious dogs with dilated cardiomyopathy

We investigated the changes in left ventricular (LV) geometry and myocardial contractility in eight conscious chronically instrumented dogs studied before and after the development of dilated cardiomyopathy induced by rapid ventricular pacing. Significant increases (P less than 0.01) were observed in cardiac dimensions in both the LV long and short axes and in end-diastolic volume (control: 53 +/- 1 ml; cardiomyopathy: 76 +/- 2 ml) and end-systolic volume (control: 27 +/- 2 ml; cardiomyopathy: 56 +/- 7 ml). This was associated with the left ventricle assuming a more spherical shape with LV long-to-short axis ratio falling from 1.59 +/- 0.05 to 1.47 +/- 0.04 (P less than 0.05). Both isovolumic (LV dP/dt) and ejection phase indexes (LV mean velocity of circumferential fiber shortening, corrected LV short-axis diameter at point of maximum shortening, and LV ejection fraction) were depressed by 50%. The end-systolic elastance was also depressed significantly (control: 16.6 +/- 0.7 g.cm-2.ml-1; cardiomyopathy: 10.1 +/- 1.7 g.cm-2.ml-1, P less than 0.02). However, cardiac output was maintained at 3 wk due to a compensatory tachycardia (+31 +/- 3 beats/min), plasma volume expansion (+295 +/- 68 ml, P less than 0.05), and greater reliance on the Frank-Starling mechanism. However, in an additional four dogs studied at 4-5 wk, cardiac output fell significantly (P less than 0.05). Thus rapid ventricular pacing results in dilated congestive cardiomyopathy in conscious dogs characterized by globally depressed myocardial systolic function and changes in LV shape.

Left ventricular mechanics in preeclampsia

Increased systemic vascular resistance and contracted blood volume are characteristic findings in preeclampsia. These alterations in cardiovascular hemodynamics can adversely affect ejection phase indices of left ventricular performance making it difficult to separate abnormalities resulting from changes in load from those caused by depressed myocardial contractility. To address this issue the contractility-sensitive, load-independent relationship between left ventricular end-systolic wall stress and rate-corrected velocity of fiber shortening was assessed in 10 nulliparous patients with preeclampsia. Comparisons were made with data obtained from 10 age-matched normotensive women with uncomplicated pregnancies (control subjects). Studies were performed by means of two-dimensionally targeted M-mode echocardiography and calibrated carotid pulse tracings during early labor, 1 day after delivery, and 4 weeks after delivery. During early labor and 1 day after delivery, patients with preeclampsia had elevated blood pressure and increased total systemic resistance. These parameters returned to normal by 4 weeks after delivery. Before delivery and 24 hours after delivery, the patients with preeclampsia had lower overall left ventricular performance (as measured by cardiac output and rate-corrected velocity of fiber shortening) and higher left ventricular afterload (as measured by left ventricular end-systolic wall stress) when compared with control subjects. These differences were no longer present 4 weeks after delivery. Despite the time-related intergroup differences in hemodynamics, left ventricular contractility was similar between normotensive and preeclampsic subjects at all stages of the study. Thus when load is eliminated as a confounding variable, the decrements in overall left ventricular performance measured in patients with preeclampsia reflect a mechanically appropriate response to increased afterload rather than an abnormality in the ventricular contractile state.

Changes in cardiac function during extracorporeal membrane oxygenation for persistent pulmonary hypertension in the newborn infant

The effects of extracorporeal membrane oxygenation (ECMO) on cardiac function and its determinants (preload, afterload, contractility, and heart rate) are largely unknown, although some evidence exists that function may decrease. To determine whether cardiac function decreases and what changes in the determinants take place during and after ECMO, we observed 26 newborn infants with persistent pulmonary hypertension. Serial echocardiograms were performed before ECMO, during maximum cardiopulmonary bypass, and after ECMO. Cardiac function was assessed by using standard echographic ejection phase indices (shortening fraction and cardiac output). Heart rate, preload (left ventricular end-diastolic dimension and area), afterload (left ventricular end-systolic wall stress), and contractility (relationship between velocity of circumferential fiber shortening and wall stress) were also measured. Ejection phase indices significantly decreased during ECMO (shortening fraction 33% to 25%, cardiac output 205 to 113 ml/kg/min; p less than 0.05) and returned to normal after ECMO (shortening fraction 26% to 34%, cardiac output 107 to 240 ml/kg/per minute; p less than 0.05). Heart rate also significantly decreased during ECMO (158 to 118 beats/min; p less than 0.05). Preload significantly increased after ECMO (left ventricular end-diastolic dimension 1.4 to 1.6 cm, left ventricular end-diastolic area 1.9 to 2.2 cm2; p less than 0.05). There were no significant changes in contractility and afterload during any study period. We conclude that, although left ventricular ejection phase indices and heart rate decreased during ECMO, these changes were transient and resolved when bypass was terminated. Contractility and afterload did not appear affected by bypass.

Echocardiographic evaluation of cardiac structure and function in elderly subjects with isolated systolic hypertension

One hundred four participants in the Systolic Hypertension in the Elderly Program (SHEP) trial (mean age 71 +/- 6 years) were examined by Doppler echocardiography to gain information on the cardiac structural and functional alterations in isolated systolic hypertension. Participants had a systolic blood pressure greater than 160 mm Hg with diastolic blood pressure less than 90 mm Hg and were compared with 55 age-matched normotensive control subjects. Left ventricular mass index was significantly higher in the participants than in the normotensive subjects (103 +/- 28 versus 87 +/- 23 g/m2, p = 0.0014) and 26% of the participants met echocardiographic criteria for left ventricular hypertrophy compared with 10% of normotensive subjects. Left atrial index was also greater in participants than in normotensive subjects (2.26 +/- 0.32 versus 2.11 +/- 0.24 cm/m2, p = 0.005) and 51% of participants had left atrial enlargement. Doppler measures of diastolic filling were significantly different between the two groups, with peak atrial velocity higher (76 +/- 17 versus 69 +/- 17 cm/s, p = 0.02) and ratio of peak early to atrial velocity lower (0.76 +/- 0.23 versus 0.86 +/- 0.22, p = 0.0124) in participants. There was no correlation between left ventricular mass index and Doppler measures of diastolic function, but relative wall thickness correlated significantly with peak atrial velocity (r = 0.22, p = 0.016) and peak early to peak atrial velocity ratio (r = 0.24, p = 0.007). There was no difference in M-mode ejection phase indexes of systolic performance (shortening fraction and peak velocity of circumferential fiber shortening) between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Timing of operation for aortic regulation: Relation to postoperative contractile state

With angiography and pressure measurement, we determined left ventricular volume, wall stress, and systolic performance in 30 patients with aortic regurgitation before and after successful aortic valve replacement. End-systolic wall stress was greatly elevated preoperatively and decreased to normal postoperatively. Systolic pump performance assessed as ejection phase indexes was severely depressed preoperatively and improved to normal or near-normal postoperatively in most patients. The ratio of end-systolic wall stress to end-systolic volume index (ESS/ESVI), an index of myocardial contractility, was greatly decreased before operation. Postoperatively, the ratio increased in all patients, becoming normal in 12 of the 13 patients who had a preoperative ESS/ESVI of 2.9 or greater. However, 15 of 17 patients in whom the ESS/ESVI ratio was less than 2.9 still had subnormal ratios, which indicates the presence of irreversible contractile dysfunction. Stepwise multivariate analysis showed that preoperative ESS/ESVI was the only independent discriminator of postoperative normalization of the contractile function as assessed by ESS/ ESVI. After aortic valve replacement, myocardial contractile state does not return to normal in a considerable number of patients. It is important to offer aortic valve replacement for aortic regurgitation before the chance for a good functional result is lost. The ESS/ESVI ratio may be a useful index in determining the timing of operation in patients with aortic regurgitation.