Left ventricular relaxation in patients with left ventricular hypertrophy secondary to aortic valve disease

Calculation of left ventricular diastolic time constant (Tau) in dogs with aortic regurgitation using continuous-wave Doppler spectra

OBJECTIVE

To investigate a new noninvasive method for calculating left ventricular diastolic time constant (Tau) through a continuous-wave aortic regurgitation Doppler spectrum.

METHODS

According to ultrasound guidance, twenty-four animal models (beagles) of aortic regurgitation and acute ischemic left ventricular diastolic dysfunction were created. The left ventricular diastolic function was manipulated with dobutamine or esmolol and fifty-nine hemodynamic stages were achieved. Raw audio signals of the continuous-wave Doppler spectra were collected, and new aortic regurgitation Doppler spectra were built after reprocessing by a personal computer. The updating time of the spectral line was 0.3 ms. The new Doppler spectra contour line was automated using MATLAB (MATrix LABoratory, MathWorks, Natick, MA, USA), and two time intervals, (t2-t1) and (t3-t1) were measured on the ascending branch of the aortic regurgitation Doppler spectrum. Then, the two time intervals were substituted into Bai's equations, and Doppler-derived Tau (Tau-D) was resolved and compared with catheter-derived Tau (Tau-c).

RESULTS

There is no significant difference between Tau-D and Tau-c (45.95 ± 16.90 ms and 46.81 ± 17.31 ms, respectively; P > 0.05). Correlation analysis between Tau-c and Tau-D suggested a strong positive relationship ( r = 0.97, P = 0.000). A Bland-Altman plot of Tau-c and Tau-D revealed fair agreement.

CONCLUSIONS

This new calculation method is simple, convenient, and shows a strong positive relationship and fair agreement with the catheter method.

Technological advances shed light on left ventricular cardiac disturbances in cystic fibrosis

Cystic fibrosis (CF), the most common autosomal recessive lethal disease in Caucasians, causes chronic pulmonary disease and can lead to cor pulmonale with right ventricular dysfunction. The presence of the cystic fibrosis transmembrane conductance regulator (CFTR) in cardiac myocardia has prompted debate regarding possible defective ion channel-induced cardiomyopathy. Clinical heart disease in CF is considered rare and is restricted to case reports. It has been unclear if this is due to the lack of physiological importance of CFTR in the heart, the relatively short lifespan of those with CF, or a technical inability to detect subclinical disease. Extensive echocardiographic investigations have yielded contradictory results, leading to the dogma that left ventricular defects in CF occur secondary to lung disease. In this review, we consider why studies examining heart function in CF have not provided clarity on this topic. We then focus on data from new echocardiographic and magnetic resonance imaging technology, which are providing greater insight into cardiac function in CF and demonstrating that, in addition to secondary effects from pulmonary disease, there may be an intrinsic primary defect in the CF heart. With advancing lifespans and activity levels, understanding the risk of cardiac disease is vital to minimizing morbidity in adults with CF.

Effects of percutaneous transluminal septal myocardial ablation for obstructive hypertrophic cardiomyopathy on systolic and diastolic left ventricular function assessed by pressure-volume loops

The aim of the present study was to determine the long-term effects of percutaneous transluminal septal myocardial ablation (PTSMA) on systolic and diastolic left ventricular (LV) functions in patients with obstructive hypertrophic cardiomyopathy (HC). Ten consecutive patients with symptomatic HC despite optimal medical treatment were referred for PTSMA at our center. LV systolic and diastolic functions were assessed by online LV pressure-volume loops obtained by conductance catheter at baseline and at 6 months after the procedure. At follow-up, the mean gradients at rest and after extrasystole were significantly decreased compared with baseline (88 +/- 29 to 21 +/- 11 mm Hg and 130 +/- 50 to 35 +/- 22 mm Hg, respectively, p <0.01 for the 2 comparisons). End-systolic and end-diastolic pressures significantly decreased (p <0.01), whereas end-systolic and end-diastolic LV volumes significantly increased (p <0.01 for the 2 comparisons). Cardiac output and stroke volume were unchanged, as were ejection fraction (p = 0.25) and maximum dP/dt (p = 0.13). The slope of the end-systolic pressure-volume relation was not decreased, indicating a preserved contractility. The relaxation constant time, end-diastolic stiffness, projected volume of the end-diastolic pressure-volume relation at 30 mm Hg, and diastolic stiffness constant showed a significant improvement of active and passive myocardial diastolic properties. In conclusion, PTSMA is an effective method in the treatment of symptomatic patients with HC. At 6-month follow-up, the LV-aortic gradient was decreased and active and passive LV diastolic properties were increased. Myocardial contractility was not decreased and general hemodynamics was maintained.

Revisiting animal models of aortic stenosis in the early gestation fetus

BACKGROUND

Mechanisms leading to left ventricular hypoplasia and endocardial fibroelastosis in the fetus remain unknown. Prevailing theory is that obstruction to blood flow through the left ventricle leads to elevated end-diastolic pressures, compromised myocardial perfusion, and endocardial ischemia. Fetal interventions are now being performed, based on the presumption that they would prevent such pathogenic mechanisms.

METHODS

Forty first-trimester fetal sheep (mean gestational age, 53 days) were studied. Severe fetal left ventricular outflow obstruction was created by banding the ascending aorta in 25 fetuses; 15 control fetuses underwent "sham" surgery with thoracotomy. Serial fetal echocardiography was used to assess left ventricular growth and fetal hemodynamics. Findings were correlated to morphologic and histopathologic changes, and intracardiac pressure measurements obtained from fetal cardiac catheterization.

RESULTS

Surviving banded fetuses (n = 13) had one of two phenotypes: compensatory left ventricular hypertrophy (n = 7) or noncompensatory left ventricular dilatation (n = 6) with hydrops and severe left ventricular dysfunction. All fetuses had elevated left ventricular end-diastolic pressures (mean, 21 mm Hg; range, 14 to 28 mm Hg), which correlated to the gradient across the ascending aorta (mean, 41 mm Hg; range, 28 to 73 mm Hg). In vivo echocardiography findings were incongruous with those at autopsy, and demonstrated preservation of left ventricular growth indices in all fetuses. Endocardial fibroelastosis and myocardial fibrosis were not observed in any banded fetus.

CONCLUSIONS

While early gestational obstruction to flow can compromise left ventricular function in the fetus, it does not retard normal growth. Similarly, an elevated left ventricular end-diastolic pressure is not sufficient to cause myocardial fibrosis or endocardial fibroelastosis in the fetus.

Left ventricular remodelling index (LVRI) in various pathophysiological conditions: a real-time three-dimensional echocardiographic study

BACKGROUND

Various studies have reported a close correlation between real-time three-dimensional echocardiography (RT3DE) and cine magnetic resonance imaging studies for the assessment of cardiac volumes and mass.

OBJECTIVE

The aim of our study was to evaluate changes in left ventricular volumes and mass in subjects with different pathophysiological conditions. A ratio between left ventricular mass and end-diastolic volume (LVRI), detected by RT3DE, was used to describe various patterns of left ventricular remodelling.

METHODS

RT3DE was performed to calculate left ventricular end-diastolic (LVEDV) and end-systolic volume (LVESV), ejection fraction (LVEF) and mass in 220 selected subjects. Of these, 152 were healthy volunteers, 19 top-level rowers, 23 patients with dilated cardiomyopathy and 26 patients with hypertrophic cardiomyopathy. Off-line analysis was performed by two independent operators by tracing manual endocardial and epicardial borders of the left ventricle through eight cutting planes. Inter- and intra-observer variability were calculated.

RESULTS

Despite the increase in LV volume and mass in the rowers, LVRI remained unchanged compared with control subjects (p = 0.455), while significantly lower values were found patients with dilated cardiomyopathy (p<0.001) and significantly higher values in patients with hypertrophic cardiomyopathy (p<0.001). There was inter- and intra-observer variability.

CONCLUSION

The LVRI may serve as a simple and useful indicator of left ventricular adaptation to physiological and pathological conditions.

Controversies in ventricular remodelling

Ventricular remodelling describes structural changes in the left ventricle in response to chronic alterations in loading conditions, with three major patterns: concentric remodelling, when a pressure load leads to growth in cardiomyocyte thickness; eccentric hypertrophy, when a volume load produces myocyte lengthening; and myocardial infarction, an amalgam of patterns in which stretched and dilated infarcted tissue increases left-ventricular volume with a combined volume and pressure load on non-infarcted areas. Whether left-ventricular hypertrophy is adaptive or maladaptive is controversial, as suggested by patterns of signalling pathways, transgenic models, and clinical findings in aortic stenosis. The transition from apparently compensated hypertrophy to the failing heart indicates a changing balance between metalloproteinases and their inhibitors, effects of reactive oxygen species, and death-promoting and profibrotic neurohumoral responses. These processes are evasive therapeutic targets. Here, we discuss potential novel therapies for these disorders, including: sildenafil, an unexpected option for anti-transition therapy; surgery for increased sphericity caused by chronic volume overload of mitral regurgitation; an antifibrotic peptide to inhibit the fibrogenic effects of transforming growth factor beta; mechanical intervention in advanced heart failure; and stem-cell therapy.

Time Course of Diastolic and Systolic Function Improvement After Pulmonary Valve Replacement in Adult Patients With Tetralogy of Fallot

OBJECTIVES

The aim of this research was to assess right ventricular diastolic and systolic function before and after pulmonary valve replacement (PVR) in adult patients after repair of tetralogy of Fallot.

BACKGROUND

Pulmonary valve replacement (PVR) in adult patients late after repair of tetralogy of Fallot leads to rapid improvement of right ventricular (RV) systolic function.

METHODS

A total of 16 patients and 8 healthy subjects were included. Median age at initial repair was 4.9 (0.9 to 13.1) years, and mean age at PVR was 28.7 (19.5 to 45.6) years. Cardiac magnetic resonance imaging was performed before and 8 and 22 months after PVR. Right ventricular volumes and function as well as RV in- and outflow patterns were assessed.

RESULTS

The volume of the early filling of the RV (Evol) increased from 49.8 +/- 14.7 ml to 53.8 +/- 19.3 ml (not significant) and 62.0 +/- 18.9 ml, respectively (p < 0.05), whereas the volume of the atrial contraction (Avol) remained unchanged. Consequently, the Evol/Avol ratio increased from 1.4 +/- 0.7 before PVR to 1.6 +/- 0.7 at 8 months (not significant) and 2.3 +/- 1.2 at 22 months (p < 0.01). The Evol/Avol ratio was not significantly different from the healthy subjects at 22 months, indicating late recovery of diastolic function. Systolic function improved rapidly after PVR; the indexed RV end-systolic volume decreased from 93.7 +/- 33.0 ml/m2 to 60.9 +/- 18.4 ml/m2 (p < 0.01) and 54.8 +/- 21.0 ml/m2 (p < 0.01).

CONCLUSIONS

In adult patients late after total repair of Fallot, PVR leads to late improvement of diastolic function. We speculate that the rapid volume unloading after PVR increases systolic performance, whereas improvement in diastolic function requires long-term remodeling.

Left ventricular remodeling early after aortic valve replacement: differential effects on diastolic function in aortic valve stenosis and aortic regurgitation

OBJECTIVES

The aim of this study was to evaluate the effect of aortic valve replacement (AVR) on left ventricular (LV) function and LV remodeling, comparing patients with aortic valve stenosis to patients with aortic regurgitation.

BACKGROUND

Aortic valve disease is associated with eccentric or concentric LV hypertrophy and changes in LV function. The relationship between LV geometry and LV function and the effect of LV remodeling after AVR on diastolic filling, in patients with aortic valve stenosis compared with aortic regurgitation, are largely unknown.Nineteen patients with aortic valve disease (12 aortic valve stenosis, 7 aortic regurgitation) were studied using magnetic resonance imaging to assess LV geometry and LV function before and 9 +/- 3 months after AVR. Ten age-matched healthy males served as control subjects.

RESULTS

Before AVR, the ratio between left ventricular mass index (LVMI) and left ventricular end-diastolic volume index (LVEDVI) was only increased in patients with aortic valve stenosis (1.37 +/- 0.16 g/ml) compared with control subjects (0.93 +/- 0.08 g/ml, p < 0.05). After AVR, LVMI/LVEDVI decreased significantly in aortic valve stenosis (to 1.15 +/- 0.14 g/ml, p < 0.0001), but increased significantly in aortic regurgitation (1.02 +/- 0.20 g/ml to 1.44 +/- 0.27 g/ml, p < 0.0001). Before AVR, diastolic filling was impaired in both aortic valve stenosis and aortic regurgitation. Early after AVR, diastolic filling improved in patients with aortic valve stenosis, whereas patients with aortic regurgitation showed a deterioration in diastolic filling.

CONCLUSIONS

Early after AVR, patients with aortic valve stenosis show a decrease in both LVMI and LVMI/LVEDVI and an improvement in diastolic filling, whereas in patients with aortic regurgitation, LVMI decreases less rapidly than LVEDVI, causing concentric remodeling of the LV, most likely explaining the observed deterioration of diastolic filling in these patients.

Doppler echocardiographic assessment of left ventricular filling pressures in elderly patients with moderate/severe aortic stenosis

Doppler-derived mitral inflow indices reflect left ventricular (LV) filling pressures but often vary with age. Diastolic filling is impaired in LV pressure overload states. The objective of this study was to determine the influence of age on the relationship between mitral inflow indices and LV filling pressures in patients with aortic stenosis. The authors studied 57 consecutive patients (age, 77 years; 52% male) with moderate to severe aortic stenosis (aortic valve area < or =1.0 cm(2)) on cardiac catheterization and echocardiographic studies performed within 48 hours of catheterization. Patients with atrial fibrillation, aortic insufficiency, mitral stenosis, and paced rhythm were excluded. Echocardiographic variables obtained from five cardiac cycles were: E/A ratio and deceleration time (DT). Patients were subclassified by age (< and > or =75 years), ejection fraction ([EF] < and > or =50%), and coronary artery disease (CAD). Pulmonary capillary wedge pressure (PCWP) correlated with DT (r=-0.86; p=0.001) and with E/A (r=0.7; p=0.001) more strongly than did LV end-diastolic pressure. Age did not alter the relationship between DT and PCWP (r=-0.92; p=0.001 for < 75 years vs. r=-0.83; p=0.001 for > or =75 years). PCWP was predicted by the equation PCWP=-0.10DT+43, regardless of age. EF also had little influence on the correlation between PCWP and DT (r=-0.80; p=0.001 for EF < 50% vs. r=-0.94; p=0.001 for EF > or =50%). Similarly, there were no significant differences between the regression equations and correlations between the CAD and no-CAD groups: for CAD patients, PCWP=41.8-0.10DT; p < 0.0001; r=-0.84 (p < 0.0001). For no-CAD subjects, PCWP=46.2-0.12DT; p < 0.0001; r=20.92 (p < 0.0001). In patients with significant aortic stenosis, DT correlated strongly with PCWP but not with LV end-diastolic pressure. This relationship was independent of age, CAD, or EF.

Age-related decline in postextrasystolic potentiation in patients with aortic stenosis

In aortic stenosis (AS), postextrasystolic potentiation (PESP), a measure of contractile reserve, has been demonstrated by an increased aortic valve gradient (AVG) after a ventricular extrasystole (VE). We studied age-related changes in PESP in 20 consecutive patients (age, 65-89 years) with significant AS (aortic area <or= 1.0 cm(2)) on cardiac catheterization with VE on AVG pressure recording. Hemodynamics and LV systolic time intervals were averaged from three consecutive beats and from the post-VE beat. Changes (Delta) in AVG, pre-ejection period/LV ejection time ratio (PEP/LVET), aortic diastolic pressures (AoDP), and LV end-diastolic pressures (LVEDP) were calculated. Age was inversely correlated with DeltaAVG (r = -0.84, P = 0.0001), with DeltaPEP/LVET (r = -0.87, P = 0.0001), and with DeltaAoDP (r = -0.89, P = 0.0001), but not with DeltaLVEDP (r = 0.23, P = 0.31). On multivariate analysis, only age was associated with DeltaAVG (r(2) = 0.72, P = 0.0001). There was an age-related decline in PESP in patients with AS, which was accompanied by changes in contractile reserve and afterload reduction, but independent of preload reserve.

Implications of increased left ventricular mass index on in-hospital outcomes in patients undergoing aortic valve surgery

BACKGROUND

Increased left ventricular mass index has been shown to be associated with higher mortality in epidemiologic studies. However, the effect of increased left ventricular mass index on outcomes in patients undergoing aortic valve replacement is unknown.

METHODS

We studied 473 consecutive patients undergoing elective aortic valve replacement to assess the influence of left ventricular mass index on outcomes in patients having this procedure. Echocardiographic left ventricular dimensions were used to calculate left ventricular mass index (considered increased if >134 g/m(2) in male patients and >110 g/m(2) in female patients).

RESULTS

Left ventricular mass index was increased in 24% of patients undergoing aortic valve replacement. Postprocedural complications (respiratory failure, renal insufficiency, congestive heart failure, and atrial and ventricular arrhythmias), length of stay in the intensive care unit, and in-hospital mortality were increased in patients with increased left ventricular mass index. Multivariable analysis identified prior valve surgery (odds ratio, 4.3; 95% confidence interval, 1.2-15.7; P =.030), left ventricular ejection fraction (odds ratio, 1.07; 95% confidence interval, 1.01-1.14; P =.020), history of hypertension (odds ratio, 8.2; 95% confidence interval, 2.2-30.4; P =.002), history of liver disease (odds ratio, 50.4; 95% confidence interval, 4.2-609.0; P =.002), and increased left ventricular mass index (odds ratio, 38; 95% confidence interval, 9.3-154.1; P <.001) as independent predictors of in-hospital mortality. Furthermore, low output syndrome was identified as the most common mode of death (36%) after aortic valve replacement in patients with increased left ventricular mass index.

CONCLUSIONS

Increased left ventricular mass index is associated with increased adverse in-hospital clinical outcomes in patients undergoing aortic valve replacement. Although this finding warrants special modification in perioperative management, further studies are needed to address whether outcomes in asymptomatic patients with aortic valve disease could be improved by earlier aortic valve replacement before a significant increase in left ventricular mass index.

Four year follow up of aortic valve replacement for isolated aortic stenosis: a link between reduction in pressure overload, regression of left ventricular hypertrophy, and diastolic function

OBJECTIVE

To evaluate changes in left ventricular function and the impact of ventricular hypertrophy and pressure gradient early and late after aortic valve replacement in patients with isolated aortic stenosis.

DESIGN

41 patients with isolated aortic stenosis and normal systolic function underwent cross sectional and Doppler echocardiography two months before and two weeks and four years after aortic valve replacement.

RESULTS

Early after the operation, left ventricular mass index (mean (SD)) decreased from 187 (44) g/m(2) to 179 (46) g/m(2), because of a reduction in end diastolic diameter (p < 0.05). Aortic pressure gradients were reduced, as expected. Isovolumic relaxation time was reduced from 93 (20) ms to 78 (12) ms, and deceleration time from 241 (102) ms to 205 (77) ms (p < 0.05). At four years, left ventricular mass index was further reduced to 135 (30) g/m(2) (p < 0.01) as a result of wall thickness reduction in the interventricular septum (from 14 (1.6) mm to 12 (1.4) mm, p < 0.01) and the posterior wall (from 14 (1.6) mm to 12 (1.3) mm, p < 0.01). Diastolic function, expressed by a reduction in isovolumic relaxation time from 93 (20) ms to 81 (15) ms (p < 0.01) and deceleration time from 241 (102) ms to 226 (96) ms (p < 0.05), remained improved. Prolonged isovolumic relaxation time was associated with significant septal and posterior wall hypertrophy (wall thickness > 13 mm) (p < 0.05), whereas prolonged deceleration time was related to high residual gradient (peak gradient > 30 mm Hg ) (p < 0.01).

CONCLUSIONS

Left ventricular diastolic function improves early after surgery for aortic stenosis in parallel with the reduction in the aortic gradient. However, prolongation of Doppler indices of myocardial relaxation and ventricular filling is observed in patients with significant left ventricular hypertrophy and a residual pressure gradient early after surgery. At four years postoperatively, diastolic function remains improved.

Aortic valve replacement in patients with aortic valve stenosis improves myocardial metabolism and diastolic function

PURPOSE

To evaluate whether functional and metabolic changes recover after aortic valve replacement (AVR).

MATERIALS AND METHODS

Eighteen men with aortic valve stenosis (mean pressure gradient +/- SD, 79.9 mm Hg +/- 15.1) underwent magnetic resonance (MR) imaging and phosphorus 31 MR spectroscopy. In nine patients who underwent AVR, MR imaging and spectroscopy were repeated 40 weeks +/- 12 after AVR. Ten age-matched healthy men were control subjects.

RESULTS

Before AVR, the myocardial phosphocreatine (PCr)-to-adenosine triphosphate (ATP) ratio in the 18 patients was 1.24 +/- 0.17 and 1.43 +/- 0.14 in the control group (P <.01). In nine patients who underwent follow-up MR spectroscopy, the ratio increased from 1.28 +/- 0.17 to 1.47 +/- 0.14 (P <.05) following AVR. Before AVR, early acceleration peak corrected for cardiac output was (0.043 +/- 0.008) x 10(-3) sec(-1) in patients and (0.081 +/- 0.033) x 10(-3) sec(-1) in the control group (P <.05). After 40 weeks +/- 12, the mean early acceleration peak corrected for cardiac output in the nine patients increased significantly to (0.055 +/- 0.006) x 10(-3) sec(-1) (P <.05), although it was still significantly lower than that of the control group (P <.05). Before AVR, a significant correlation was found between the myocardial PCr-ATP ratio and left ventricular diastolic function (n = 18; P <.05).

CONCLUSION

Severe aortic valve stenosis leads to a decreased myocardial PCr-ATP ratio and impairment of left ventricular diastolic function; following AVR, the ratio normalizes completely, whereas function improves significantly. There is an association between altered myocardial high-energy phosphate metabolism and impaired left ventricular diastolic function.

Mitral regurgitation and left ventricular diastolic dysfunction similarly affect mitral and pulmonary vein flow Doppler parameters: the advantage of end-diastolic markers

Enhanced early mitral flow and reduced systolic pulmonary vein flow may be caused both by increased left ventricular pressure as the result of diastolic dysfunction and by increased transmitral flow as the result of mitral regurgitation. Nevertheless, Doppler parameters are widely used to predict left ventricular filling pressure. We aimed to analyze the interference of mitral regurgitation with Doppler parameters usually used to estimate left ventricular filling pressure and to identify markers independent of mitral regurgitation, which could reliably estimate increased left ventricular filling pressure. Eighty-four patients (age, 62 +/- 9 years; 82% men) had a complete echocardiographic Doppler examination. Transmitral E- and A-wave velocity, E deceleration time and A duration, pulmonary vein systolic and diastolic velocities, and reversal flow duration and maximal and minimal left atrial volumes were measured. The difference between the duration of pulmonary vein and mitral A waves was calculated (A'-A). Mitral regurgitant volume was quantitatively assessed by echocardiography. Left ventricular end-diastolic pressure was measured invasively. Patients had a wide range of left ventricular ejection fraction (14% to 70%), mitral regurgitant volume (0 to 94 mL), and left ventricular end-diastolic pressure (3 to 37 mm Hg). E velocity, E/A, pulmonary vein systolic and diastolic, and systo-diastolic ratios were significantly and independently correlated with both left ventricular end-diastolic pressure and mitral regurgitant volume. A'-A showed a strong correlation with left ventricular end-diastolic pressure (r = 0.70; P <.0001), but the relation with mitral regurgitant volume was not significant (r = 0.19; P =.08). Mitral regurgitation affects the majority of Doppler parameters widely used to predict filling pressure but does not influence Ad'-Ad, which proved to be the strongest predictor of left ventricular end-diastolic pressure.

Beta-adrenergic receptors and calcium cycling proteins in non-failing, hypertrophied and failing human hearts: transition from hypertrophy to failure

Left ventricular hypertrophy may lead to heart failure. The transition between hypertrophy and heart failure is, however, incompletely understood. On the cellular level, human heart failure is characterized by alterations in Ca(2+)-cycling proteins and beta-adrenergic receptor density, but the hypertrophied human heart remains largely under studied. In this investigation, 21 donor hearts which could not be used for transplantation were studied. Ten of these hearts came from organ donors with documented left ventricular hypertrophy and normal cardiac function. Eleven of the hearts were non-failing, obtained from individuals with no evidence of cardiac disease. Nine failing hearts from transplant recipients were also studied. beta-adrenergic receptor density was determined by radioligand binding. mRNA for atrial natriuretic factor, calsequestrin, sarcoplasmic reticulum Ca(2+)-ATPase, and phospholamban was measured by Northern blot. Actin, calsequestrin, sarcoplasmic reticulum Ca(2+)-ATPase, and phospholamban proteins were quantified by Western blot. In both hypertrophied and failing ventricles, mRNA for atrial natriuretic factor was expressed, as compared to no expression in non-failing hearts. In failing hearts, beta -adrenergic receptor density and both mRNA and protein levels of the Ca(2+)-ATPase were significantly decreased v non-failing hearts. By comparison, hypertrophied hearts showed a reduction in mRNA expression for both the Ca(2+)-ATPase and phospholamban with no change in the corresponding protein levels, and no change in beta-receptors. These data suggest that the previously demonstrated reduction in beta-adrenergic receptors and Ca(2+)-cycling proteins in the failing human heart may be features of the decompensated state, but are not found in human hearts with left ventricular hypertrophy and preserved systolic function.

Evaluation of coronary blood flow reserve by 13N-NH3 positron emission computed tomography (PET) with dipyridamole in the treatment of hypertension with the ACE inhibitor (Cilazapril)

PURPOSE

The purpose of this study was to evaluate the effect of treatment with an angiotensin-converting enzyme (ACE) inhibitor (Cilazapril) for early hypertensive patients in terms of coronary blood flow reserve evaluated by 13NH3-positron emission tomography (PET).

METHODS

Before and after 12 weeks of ACE inhibitor treatment, 13NH3-PET with dipyridamole provocation test was performed, and definite myocardial perfusion and coronary flow reserve (CFR) were calculated.

RESULTS

Compared to our normal subjects previously reported (2.61+/-0.74), average coronary flow reserve was decreased (1.70+/-0.64 in hypertensive patients), and improved after treatment (1.77+/-0.52), but not significantly. Of 12 patients, five (42%) showed improved coronary flow reserve from 1.34 to 1.99 without a significant change in the resting flow. Only one patient (8%) showed deterioration after the ACE inhibitor treatment. The coronary vascular resistance (CVR) after ACE inhibitor treatment of the patients with CFR < 2.0 decreased significantly compared with those with CFR> or = 2.0 (p < 0.03).

CONCLUSIONS

These results indicate that hypertensive patients at the early stage show decreased coronary flow reserve despite having normal resting flow. Treatment with an ACE inhibitor (Cilazapril) for 12 weeks improved coronary flow reserve in 42% of our patients. The CVR of the patients with CFR < 2.0 showed improvement compared to those with CFR> or = 2.0. This result indicates that an ACE inhibitor (e.g., Cilazapril) should be one of the choices for improving CFR if hypertensive patients in early stage show signs of ischemia or diastolic dysfunction, which may be one of the sequels of reserve restriction.

Effect of left ventricular wall mass on Doppler filling patterns in the developing normal human heart

To assess gestational age- and growth-related changes in left ventricular (LV) size, LV wall, and LV transmitral flow velocity patterns, 2-dimensional (2-D) and Doppler echocardiographic studies were performed in 89 normal fetuses aged 16 to 38 weeks. Serial studies were designed in 7 fetuses. Variables measured from 4-chamber views were chamber areas and myocardial wall areas. From these measurements, area shortening fraction and ratio of myocardial wall area to end-diastolic chamber area were calculated. LV end-diastolic chamber area and myocardial wall area increased exponentially with advancing gestational age (r = 0.88 and 0.90, respectively, p < 0.001). Area shortening fraction showed no significant changes with gestational age. Ratio of myocardial wall area to LV end-diastolic chamber area decreased gradually with increasing gestational age (r = -0.77, p < 0.001). With increasing gestational age, mitral peak velocities of early diastole increased (r = 0.82, p < 0.01) with little change in peak velocity during atrial contraction. Multiple regression analysis showed that age-related increases in peak velocity of early diastole were related to advancing gestational age and also to decreases in ratio of myocardial wall area to LV end-diastolic chamber area. Low peak filling velocities during early diastole in younger fetuses may be related partly to relative increase in LV wall mass. The gestational age-related decreases in LV wall mass may be one of the important mechanisms of gestational age-related alterations in diastolic properties, especially relaxation processes.

Reduced myocardial sarcoplasmic reticulum Ca(2+)-ATPase protein expression in compensated primary and secondary human cardiac hypertrophy

Pathological intracellular calcium handling has been proposed to underlie the alterations of contractile behavior in hypertrophied myocardium. However, the myocardial protein expression of intracellular calcium transport proteins in compensated human left ventricular hypertrophy has not yet been studied. We investigated septal myocardial specimens of patients suffering from hypertrophic obstructive cardiomyopathy (n=14) or from acquired aortic valve stenosis (n=11) undergoing myectomy or aortic valve replacement, respectively. For comparison, we studied non-hypertrophied myocardium of six non-failing hearts which could not be transplanted for technical reasons. The myocardial density of the calcium release channel of the sarcoplasmic reticulum (SR) was determined by(3)H-ryanodine binding. Myocardial contents of SR Ca(2+)-ATPase, phospholamban, calsequestrin and Na(+)/Ca(2+)-exchanger were analysed by Western blot analysis. The myocardial SR calcium release channel density was not significantly different in hypertrophied and non-failing human myocardium. In both hypertrophic obstructive cardiomyopathy and in aortic valve stenosis, SR Ca(2+)-ATPase expression was reduced by about 30% compared to non-failing myocardium (P<0.05), whereas the expression of phospholamban, calsequestrin, and the Na(+)/Ca(2+)-exchanger was unchanged. The decrease of SR Ca(2+)-ATPase expression was still observable when related to its regulatory protein phospholamban or to the myosin content of the homogenates (P<0.05). Furthermore, the SR Ca(2+)-ATPase expression was inversely correlated to the septum thickness assessed by echocardiography, but not to age, cardiac index or outflow tract gradient. In primary as well as in secondary hypertrophied human myocardium, the expression of SR Ca(2+)-ATPase is reduced and inversely related to the degree of the hypertrophy. The diminished SR Ca(2+)-ATPase expression might result in reduced Ca(2+)reuptake into the SR and might contribute to altered contractile behavior in hypertrophied human myocardium.

Role of left ventricular mass/volume ratio on transmitral flow velocity patterns from infancy to childhood

Age-related changes in left ventricular diastolic filling have been reported to occur in normal children in studies using Doppler echocardiographic methods. However, little information currently exists on the relationships between transmitral flow velocity patterns and the left ventricular mass. We measured left ventricular end-diastolic volume, left ventricular mass, mass/volume ratio, and transmitral flow velocity patterns by M-mode and Doppler echocardiography in 165 normal children aged 5 days to 195 months. Subjects were divided into 6 age groups: <1; 1 to <3; 3 to <5; 5 to <7; 7 to <9; and > or = 9 years old. The left ventricular end-diastolic volume and mass increased progressively with increasing age. However, the mass/volume ratio in infants <1 year was significantly higher than that in infants 1 to <3 years (1.32+/-0.25 vs. 1.14+/-0.16, p<0.01) without any changes of the ratio thereafter. The peak E wave in infants <1 year was significantly lower than that in 1 to <3 years (71+/-18 vs. 92+/-13 cm/s, p<0.01) without changes thereafter. As the flow velocity time integral of E wave increased and that of A wave remained constant, the flow velocity time integral of E/A wave increased with increasing age. The early diastolic tilling fraction in infants <1 year was lower than that in infants 1 to 3 years. (0.61+/-0.07 vs. 0.70+/-0.06, p<0.01). The atrial filling fraction in infants <1 year was higher than that in infants 1 to <3 years (0.40+/-0.08 vs. 0.30+/-0.06, p<0.01) with a little decrease thereafter. The peak E wave, early diastolic tilling fraction, and the atrial filling fraction correlated with the logarithm of age (p<0.01). Age-related changes in these Doppler echocardiographic findings suggest reduced left ventricular early diastolic filling patterns. The mass/volume ratio correlated linearly with peak E wave, early diastolic filling fraction, and atrial filling fraction (r=-0.38, -0.33, and 0.26, p<0.01). No significant relationships between mass/volume ratio and the other Doppler indices were found. Thus, the age-related reduction in the mass/volume ratio may be one of the mechanisms underlying age-related changes in the early diastolic ventricular filling as assessed by Doppler echocardiography.

Evaluation of left ventricular relaxation using the continuous-wave Doppler velocity profile of aortic regurgitation: noninvasive measurement of left ventricular negative dP/dt and time constant

BACKGROUND

The maximal negative dP/dt [max (-)dP/dt] and time constant (T) are useful indices for evaluating left ventricular (LV) relaxation, but they require invasive procedures.

HYPOTHESIS

The purpose of this study was to obtain max (-)dP/dt and T using the continuous-wave Doppler aortic regurgitation velocity curve (AR-CW) noninvasively. Using the Bernoulli equation, the AR-CW allows accurate determination of the pressure gradients (PG) between the aorta and the left ventricle.

METHODS

In 10 patients with trivial to mild AR, the rising segment of the AR-CW reflecting LV pressure decrease was digitized with the cardiac image analysis system. Transpulmonary contrast-enhanced Doppler echocardiography was used in three patients to obtain intense velocity envelope. The PG curve and the firs derivative curve were reconstructed and the maximal point of the first derivative curve, which is consistent with max(-)dP/dt, was termed as maximal rate of pressure fall (maxRPF). As T (calculated according to the method of Weiss) can be obtained from T=Pm/max(-)dP/dt [Pm: LV pressure at the phase of max(-)dP/dt], we calculated T from Pm/maxRPF (Pm=dicrotic notch pressure-4Vm2) (Vm: AR velocity at the phase of maxRPF).

RESULTS

The Doppler-derived maxRPF and T (TD) approximated the catheter-derived max(-)dP/dt and T (y = 0.85x + 245, r = 0.97, p < 0.001, y = 0.79x + 4, r = 0.87, p < 0.001). In addition, dobutamine echocardiography was performed in nine patients showing increased maxRPF and decreased TD, indicating improvement of LV relaxation.

CONCLUSION

These Doppler-derived new indices are sufficiently useful to evaluate LV relaxation noninvasively.

Early diastolic regional function of the hypertrophied left ventricle

We analyzed cardiac catheterization data from 7 patients with aortic stenosis and 10 patients with nonobstructive hypertrophic cardiomyopathy to compare left ventricular regional diastolic function. Left ventriculogram in the right anterior oblique projection was analyzed by the area method, and regional wall stress and regional area were computed for 4 regions in the mid-portion of the left ventricle. For each region, we assessed the percent area changes (normalized by end-diastolic regional area) and time constant for regional wall stress decrease during the isovolumic relaxation period. Regional non-uniformity during the isovolumic relaxation period was then evaluated by standard deviations for the percent area changes and for regional time constants of the 4 ventricular regions. In patients with hypertrophic cardiomyopathy, both the standard deviations for the percent area changes and the regional time constants were greater (P < 0.05) than those in patients with aortic stenosis, suggesting the presence of pronounced non-uniformity of regional relaxation in hypertrophic cardiomyopathy. The time constant of left ventricular pressure decrease during early relaxation phase was significantly greater (P < 0.01), and the early diastolic peak filling rate of the global left ventricle was significantly smaller (P < 0.05) in patients with hypertrophic cardiomyopathy. Thus, early diastolic left ventricular regional non-uniformity was more pronounced in hypertrophic cardiomyopathy than in aortic stenosis, which was associated with the impairment of relaxation and early filling of the global left ventricle. These findings suggest that different mechanisms are responsible for diastolic dysfunction in primary versus secondary myocardial hypertrophy.

Left ventricular diastolic response to exercise in valvular aortic stenosis

Exercise produces profound alterations in symptoms and hemodynamics in patients with valvular aortic stenosis (AS). Prior studies have demonstrated marked increases in late left ventricular (LV) diastolic filling pressure with exercise. Little information is available on the exercise response of indexes of early LV diastolic performance. Catheter-tip manometer recordings in 11 patients with AS and 5 age-matched controls were obtained at rest and with supine bicycle exercise at the time of cardiac catheterization. Pressure-derived indexes of LV diastolic performance, isovolumic relaxation rate, and diastolic interval data were examined. At rest, early (patients 22 +/- 6 mm Hg, controls 12 +/- 3 mm Hg; p < 0.01), minimal (patients 9 +/- 4 mm Hg, controls 4 +/- 1 mm Hg; p < 0.01), and late (patients 28 +/- 10 mm Hg, controls 13 +/- 3 mm Hg; p < 0.002) LV diastolic pressures were elevated in patients with AS. The time to onset of isovolumic relaxation (patients 422 +/- 31 ms, controls 363 +/- 40 ms; p < 0.01) and minimal LV diastolic pressure (patients 608 +/- 57 ms, controls 448 +/- 52 ms; p < 0.002) at rest were prolonged in patients with AS. With exercise, early (patients 45 +/- 14 mm Hg, controls 15 +/- 3 mm Hg; p < 0.002), minimal (patients 15 +/- 6 mm Hg, controls 2 +/- 1 mm Hg; p < 0.01), and late (patients 38 +/- 10 mm Hg, controls 18 +/- 5 mm Hg; p < 0.002) LV diastolic pressures were elevated, and the time to minimal LV diastolic pressure (patients 528 +/- 26 ms; controls 393 +/- 56 ms) and peak first derivative of LV pressure decline (-LV dP/dt) patients 395 +/- 41 ms, controls 326 +/- 59 ms) were prolonged in AS. Furthermore, patients with AS failed to comparably increase the rate of LV pressure decay and isovolumic relaxation with exercise. The LV diastolic response to exercise in patients with AS is distinguished from the control response by suboptimal and prolonged relaxation and a diminished rate of LV pressure decay. These abnormal responses in early diastolic function coupled with the known abnormal chamber distensibility in AS contribute to significant elevations in early, mid-, and late diastolic pressures with exercise.

Left ventricular function in chronic mitral regurgitation: preoperative and postoperative comparison

OBJECTIVES

The present study was designed to evaluate the effects of surgical procedure on left ventricular systolic and diastolic function in patients with mitral regurgitation.

BACKGROUND

Left ventricular systolic function has been shown to decline after operation in patients with chronic mitral regurgitation.

METHODS

Using simultaneous cineangiography and left ventricular micromanometry, we evaluated left ventricular systolic and diastolic function in 14 patients with chronic mitral regurgitation both preoperatively and at an average of 22 months after operation. Eight patients underwent mitral valve reconstruction, and six had a valve replacement with interruption of the chordae tendineae. We compared these patients with 10 control subjects.

RESULTS

Preoperatively, patients with mitral regurgitation demonstrated normal global and regional left ventricular systolic function. Peak rate of diastolic filling was increased (p < 0.01), and passive chamber stiffness was decreased, compared with that in control subjects (p < 0.01), and there was normal myocardial stiffness. Postoperatively, systolic and diastolic function returned to normal in patients undergoing mitral valve reconstruction. In contrast, global systolic function was depressed in patients after valve replacement (p < 0.05), with regional dysfunction in the area of papillary muscle attachment (p < 0.01). Diastolic function was depressed in this group, with a prolonged time constant of pressure decay (p < 0.01) and a depressed rate of early diastolic filling and strain rate (p < 0.05). Passive elastic stiffness was within the normal range in all postoperative patients.

CONCLUSIONS

The type of operation performed to correct chronic mitral regurgitation has an important effect on postoperative left ventricular function. Systolic and diastolic function are preserved after mitral valve reconstruction. Mitral valve replacement with chordal interruption is associated with global and regional systolic dysfunction and early diastolic filling and relaxation abnormalities.

Regional left ventricular mechanics in hypertrophic cardiomyopathy

BACKGROUND

Nonuniformity is a determinant of diastolic function. In patients with hypertrophic cardiomyopathy, hypertrophy, abnormal calcium handling, and regional ischemia can also play a role. This study was designed to assess regional mechanics, asynchrony, and asynergy in patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

Nine control subjects and 22 patients with hypertrophic cardiomyopathy were studied by biplane left ventriculography and high-fidelity pressure tracings for the assessment of diastolic function by computing the time constant of isovolumic relaxation, peak filling rate, and the constant of passive chamber stiffness. Regional mechanics were evaluated by dividing the left ventricle into six sectors in the right and left anterior oblique projections. Systolic and diastolic asynchrony were assessed from the coefficient of variation of the regional time intervals from end diastole to end systole and to peak filling rate, respectively. Asynergy was evaluated from the coefficient of variation of the regional area reduction. Regional passive elastic properties were estimated by computing the regional constant of chamber stiffness. In patients with hypertrophic cardiomyopathy, isovolumic relaxation was prolonged (time constant of isovolumic relaxation 101 +/- 41 versus 51 +/- 16 milliseconds in control subjects; P < .001) and the constant of chamber stiffness was increased (0.056 +/- 0.038 versus 0.025 +/- 0.010 mL-1; P < .001). Both systolic and diastolic asynchrony as well as asynergy were found. Regional mechanics showed hyperkinesia in the free wall, whereas the septum exhibited normal wall motion and increased constant of chamber stiffness.

CONCLUSIONS

Diastolic function is impaired in hypertrophic cardiomyopathy, and such an impairment is the consequence of nonuniformity and hypertrophy. The regions where the myopathic process is more pronounced show normal wall motion but increased stiffness. The inhomogeneity of regional wall motion with regional hyperkinesia and normokinesia of neighboring regions results in left ventricular asynergy.

Left ventricular diastolic dysfunction late after coarctation repair in childhood: influence of left ventricular hypertrophy

OBJECTIVES

Left ventricular systolic and diastolic function were evaluated late after successful operation for aortic coarctation in childhood.

BACKGROUND

Persistent arterial hypertension and left ventricular hypertrophy after coarctation repair might impair left ventricular function.

METHODS

Biplane angiography and simultaneous high fidelity pressure measurements were performed in 12 patients 3 to 12 years postoperatively (residual pressure gradient 4 mm Hg). Eight patients were normotensive and four had borderline hypertension. Data at rest and after nitroprusside infusion (1.7 micrograms/kg per min) were evaluated and compared with data from 12 control subjects.

RESULTS

Systolic left ventricular function (ejection fraction-end-systolic wall stress relation) was normal in all patients. However, left ventricular muscle mass (113 vs. 86 g/m2), right atrial pressure (5.2 vs. 1.9 mm Hg) and left ventricular end-diastolic pressure (16 vs. 11 mm Hg) were significantly higher in patients than in control subjects. There was a linear relation between muscle mass and left ventricular end-diastolic (r = 0.66, p < 0.001) or right atrial (r = 0.60, p < 0.01) pressure. Left ventricular relaxation and myocardial stiffness were normal. However, there was an upward shift of the diastolic pressure-volume curve when compared with control values, but this shift was reversed by the administration of nitroprusside.

CONCLUSIONS

Systolic function is normal late after coarctation repair. However, diastolic function can be abnormal with an upward shift of the diastolic pressure-volume curve that is reversed by nitroprusside administration and is probably due to residual left ventricular hypertrophy.

Early diastolic left ventricular function as a marker of acute cardiac rejection: a prospective serial echocardiographic study

Changes in left ventricular early diastolic time intervals are sensitive indicators of incipient left ventricular dysfunction. We tested the hypothesis that acute rejection in cardiac transplant recipients is associated with alteration of early diastolic myocardial function, as expressed by the time interval Te, a parameter derived from digitized M-mode echocardiograms. Te is defined as the time interval between maximal posterior wall contraction and the point of peak posterior wall endocardium retraction velocity, as determined by the nadir of the computed first derivative curve. In transplant patients without rejection (group A, n = 48), Te was prolonged compared to healthy individuals (group C, n = 35) (79.0 +/- 12.5 ms vs 64.0 +/- 7.9 ms; p < 0.0001). During acute rejection (group B, n = 18) transplant patients had significantly longer mean Te values compared to transplant patients without rejection (group A) (97.8 +/- 17.9 ms vs 79.0 +/- 12.5 ms; p < 0.0001). Longitudinal studies in individual patients (group D, n = 18) demonstrated that rejection is associated with prolongation of Te (94.5 +/- 16.0 ms during rejection vs 79.0 +/- 10.3 ms before rejection; p < 0.0002) and that Te returns to individual baseline values in response to treatment (79.2 +/- 9.4 ms after therapy vs 79.0 +/- 10.3 ms before rejection; NS). In a prospective study, Te changes in transplant patients (group E, n = 96) were correlated with myocardial biopsy results. Sixty-one biopsies showed acute rejection, and 115 biopsies were negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic and volume correlates of left ventricular diastolic relaxation and filling in patients with aortic stenosis

OBJECTIVE

The aim of the present study was to evaluate the hemodynamic and volume correlates of early diastolic filling and isovolumetric relaxation in patients with aortic stenosis.

BACKGROUND

Left ventricular diastolic relaxation and filling have been found to be heterogeneous in patients with aortic stenosis. Potential mechanisms underlying this heterogeneity include individual differences in the severity of muscle hypertrophy or systolic dysfunction, or both, in the presence and severity of mitral regurgitation and in the level of left atrial pressure.

METHODS

Right (fluid-filled) and left (high fidelity micromanometer) ventricular pressures, left ventricular volumes (contrast angiography) and transmitral inflow dynamics (Doppler echocardiography) were measured in 17 patients with isolated severe aortic stenosis (valve area less than 0.75 cm2). Measurements included left ventricular end-diastolic and end-systolic volumes, left ventricular ejection fraction, peak positive and negative first derivative of left ventricular pressure (dP/dt), the time constant of isovolumetric relaxation (tau), left ventricular end-diastolic pressure, left ventricular mass, left ventricular end-systolic stress, mean capillary wedge pressure and peak early (E) and late (A) transmitral filling velocities. Patients were subclassified according to left ventricular ejection performance at rest and mean capillary wedge pressure.

RESULTS

Patients with normal ejection performance and normal mean capillary wedge pressure had a normal rate of isovolumetric left ventricular pressure decay and an abnormal diastolic filling pattern, with diastolic filling occurring primarily during atrial systole. In contrast, in patients with systolic dysfunction and elevated mean capillary wedge pressure, isovolumetric pressure decay was prolonged and diastolic filling occurred essentially during the rapid filling period, with reduced atrial contribution to left ventricular filling and a short isovolumetric relaxation period. Stepwise multiple linear regression analysis identified two variables as independent predictors of transmitral velocity profile and three variables independently predictive of the rate of left ventricular pressure decay. The single most important predictor of transmitral filling pattern was the pulmonary capillary wedge pressure (p less than 0.0001), followed by the left ventricular peak negative dP/dt (p = 0.002). The single most powerful predictor of the rate of reduction in left ventricular pressure was left ventricular mass index (p less than 0.0001), followed by end-systolic volume index (p = 0.0002) and left ventricular peak negative dP/dt (p = 0.0029).

CONCLUSIONS

In patients with aortic stenosis, left ventricular filling is essentially determined by left atrial pressure, whereas isovolumetric relaxation more closely depends on the severity of muscle hypertrophy and chamber dilation.

Improvement of relaxation velocity parameters by calcium channel blockers in the aging rabbit myocardium

Normal aging in man is known to be associated with a reduction in left-ventricular diastolic function, including the rates of relaxation and filling. Calcium channel blockers have been reported to improve left-ventricular diastolic function in patients with various forms of heart disease. Clinically, the action of calcium channel blockers may be related to either a direct myocardial effect or may be secondary to the peripheral or coronary vasodilation effects. The purpose of this study is to investigate a possible direct effect of calcium channel blockers on modulation of the reported age-related reduction in myocardial relaxation. The direct effects on myocardial relaxation of the dihydropyridine calcium channel blocker, nifedipine, were studied in isolated, perfused interventricular septa and left-ventricular wall from eight young (ages 9 to 18 months) and 14 old (ages 3 to 5 years) rabbits. Septa were perfused with oxygenated Ringer's solution and paced at 48 beats/min. Maximum relaxation velocity per unit of developed tension [-dT/dt]/T, and relaxation time per unit of developed tension tR/T were continuously measured before and after infusion of calcium channel blockers. In absence of drugs, the older rabbits demonstrated a mean [-dT/dt]/T which was 32% lower (p < 0.003) and a mean tR/T which was 45% higher (p < 0.005) than the younger rabbits. When nifedipine was introduced at concentrations > 10(-8) M equivalent to doses above the therapeutic free-plasma concentration in humans, all contraction and relaxation parameters were depressed. However, at lower doses, equivalent to doses in the clinical therapeutic range, [-dT/dt]/T was increased in the older rabbit septa by 18% in the presence of nifedipine. tR/T was shortened in the older rabbit septa by 17% in the presence of nifedipine. Myocardial relaxation in older rabbits after drug infusion approximated these parameters in the younger rabbits prior to drug infusion (P = NS). Calcium channel blockers had similar beneficial effects on the relaxation properties of the myocardium in younger rabbits. All beneficial effects were observed at concentrations of calcium channel blockers which were within and below the clinically therapeutic range of plasma free drug concentration, i.e., 5 x 10(-9) to 4 x 10(-8) M. Potential differences in relaxation effects related to different segments of the myocardium and different mechanical recording vectors were evaluated. Isolated left ventricle preparations from aging rabbits demonstrated improvements in tR/T and [-dT/dt]/T similar to those observed in the septum. Furthermore, improvement in mechanical function along the y-axis and x-axis vectors of the septum was similar.(ABSTRACT TRUNCATED AT 400 WORDS)

Left ventricular flow propagation during early filling is related to wall relaxation: a color M-mode Doppler analysis

OBJECTIVES

This study was designed to evaluate the relation between the velocity of flow propagation and left ventricular relaxation by using color M-mode Doppler echocardiography to analyze flow propagation in the left ventricle.

BACKGROUND

Noninvasive attempts to identify alterations in left ventricular relaxation have been hampered because both the relaxation rate and left atrial filling pressure are the determinants of peak early velocity and filling rate.

METHODS

Color M-mode velocity data were transferred to a microcomputer and compared with conventional pulsed Doppler data to assess the ability of color M-mode echocardiography to analyze velocity field properties. The velocity of flow propagation was measured as the slope of the flow wave front during early filling in normal subjects (n = 29) and in patients with disease that alters relaxation (dilated cardiomyopathy [n = 31], ischemic cardiomyopathy [n = 8], hypertrophic cardiomyopathy [n = 5], systemic hypertension [n = 22] and aortic valve disease [n = 25]). In nine patients with end-stage dilated cardiomyopathy, echocardiographic and left heart catheterization data were obtained at baseline and during intracoronary dobutamine infusion.

RESULTS

Color M-mode and pulsed Doppler echocardiographic data were highly correlated (n = 217, r = 0.94, p less than 0.0001, velocity range 0.2 to 1.5 m/s). The velocity of flow propagation was lower in patients than in normal subjects (0.46 +/- 0.15 vs. 0.84 +/- 0.11 m/s, p less than 0.0001). The decrease was significant in all disease forms with or without left ventricular dilation. The velocity of flow propagation was related to peak early velocity in normal subjects (p less than 0.001) but not in patients. It varied inversely with the isovolumetric relaxation time constant during dobutamine infusion and the two variables were highly correlated (p less than 0.0001).

CONCLUSIONS

The velocity of flow propagation during early filling seems to be highly dependent on the left ventricular relaxation rate and could be an important tool in studying diastolic function.

Recurrence of symptoms after percutaneous aortic balloon valvuloplasty: relationship to Doppler diastolic filling values

Short-term follow-up after percutaneous aortic balloon valvuloplasty shows a high incidence of restenosis. Yet a high percentage of patients with restenosis continue to show symptomatic improvement. Those with decreased left ventricular function originally tend to have a recurrence of symptoms. In this study Doppler-derived diastolic filling values at follow-up were most highly associated with symptom status, suggesting that change in diastolic filling after percutaneous aortic balloon valvuloplasty is one of the factors related to symptoms.

Myocardial oxygen consumption in aortic valve disease with and without left ventricular dysfunction

OBJECTIVE

To assess whether and to what extent myocardial oxygen consumption is modified by hypertrophy and alterations in contractility in patients with aortic valve disease and to evaluate the influence of regression of left ventricular hypertrophy and improvement of contractility on myocardial oxygen consumption after successful aortic valve replacement.

DESIGN

A cohort analytical study to investigate the influence of the "explanatory" variables of myocardial oxygen consumption by multiple regression analysis. A comparison of myocardial oxygen consumption in preoperative patients with that after operation in a group with comparable severity of aortic valve disease before operation (analysis of covariance).

PATIENTS

In six controls and in 43 patients with aortic valve disease and normal coronary arteries standard haemodynamic variables were measured, left ventricular biplane cineangiography performed, and coronary sinus blood flow measured by thermodilution. The patients were divided into three groups: 19 preoperative patients with normal ejection fraction (greater than or equal to 57%) (group 1); nine preoperative patients with reduced ejection fraction (less than 57%) (group 2); 16 postoperative patients (one with preoperative and postoperative measurements (group 3). Postoperative evaluation was performed 12-51 months after surgery.

MAIN OUTCOME MEASUREMENTS

Myocardial oxygen consumption/100 g left ventricular muscle mass and its suspected "explanatory" variables--that is, peak systolic left ventricular circumferential wall stress, heart rate, contractility (assessed by left ventricular ejection fraction), and left ventricular muscle mass index.

RESULTS

Multiple regression analysis showed that the product of peak systolic stress and heart rate (p less than 0.0001) and ejection fraction (p less than 0.03) were positively correlated with myocardial oxygen consumption/100 g and that left ventricular muscle mass index (p less than 0.002) was negatively correlated with myocardial oxygen consumption/100 g (r = 0.72; n = 50 measurements). Myocardial oxygen consumption per 100 g at a given stress-rate product was higher in the controls than in group 1 (hypertrophied ventricles with normal ejection fraction) and was also higher in group 1 than in group 2 (hypertrophied ventricles with reduced ejection fraction). In a subgroup of the postoperative patients with complete regression of hypertrophy and normalisation of contractility, myocardial oxygen consumption per 100 g at a given stress-rate product was indistinguishable from that in controls.

CONCLUSIONS

When the actual stress-rate product was used as an index of overall left ventricular performance the results suggested that mechanical efficiency was increased in hypertrophied ventricles especially when contractility was decreased. These changes in mechanical efficiency seemed to be reversible during the postoperative course when muscle mass and contractility returned to normal.

Regional myocardial blood flow and coronary reserve in hypertensive patients. The effect of therapy

Patients with essential arterial hypertension demonstrate abnormal vasodilator capacity either during increased cardiac metabolic demand or during pharmacological vasodilation. Structural and functional damage to the coronary microcirculation has been proposed as one of the major causes of impaired coronary reserve in this disease. To assess the role of microvascular impairment in regional myocardial blood flow (MBF), 27 patients with essential hypertension were evaluated by dynamic positron emission tomography (PET) at rest, during atrial pacing and after dipyridamole infusion and compared with 13 healthy subjects. All patients had normal coronary arteries, 17 had moderate to severe hypertension and 10 had mild hypertension. Baseline mean MBF of 0.97 +/- 0.25 ml/min/g was significantly increased to 1.60 +/- 0.38 during atrial pacing and 2.35 +/- 0.95 after dipyridamole infusion (p < 0.01); however, mean flow during atrial pacing and after dipyridamole infusion was significantly lower than in healthy subjects (2.15 +/- 0.73 and 3.71 +/- 0.86 ml/min/g, p < 0.05 and p < 0.01, respectively). The MBF response to atrial pacing and dipyridamole infusion was similarly depressed in patients with mild and severe hypertension. The study was repeated after 6 months of antihypertensive treatment with the calcium antagonist verapamil or the angiotensin converting enzyme (ACE) inhibitor enalapril in a subgroup of 20 patients as part of a randomised, single-blind clinical trial. This study is still in progress; the initial 16 patients treated with verapamil or enalapril showed an obvious improvement in MBF values during atrial pacing and after dipyridamole infusion after 6 months of therapy (mean MBF: 2.10 +/- 0.64 and 2.99 +/- 1.63 ml/min/g, respectively, p < 0.05 vs pretreatment values). In conclusion, obvious impairment of MBF during atrial pacing and after dipyridamole infusion was observed in hypertensive patients with normal coronary arteries and this appeared unrelated to the severity of hypertension. Therapy with verapamil or enalapril improved coronary reserve and MBF response to an increase in myocardial oxygen demand.

Left ventricular passive diastolic properties in chronic mitral regurgitation

BACKGROUND

In chronic mitral regurgitation, the myocardium responds to the increased filling volume by geometric alteration and eccentric hypertrophy. This study was designed to evaluate the effects of a pure volume overload on left ventricular diastolic chamber and myocardial properties and to assess the relation of passive diastolic function to systolic ejection performance.

METHODS AND RESULTS

By use of simultaneous cineangiography and left ventricular micromanometry, left ventricular passive diastolic stiffness was evaluated in nine normal controls (group 1), 14 patients with chronic mitral regurgitation and a normal ejection fraction (greater than or equal to 57%, group 2), and 13 patients with mitral regurgitation and a reduced ejection fraction (less than 57%, group 3). Passive diastolic function was evaluated by using a three-constant elastic model. Left ventricular chamber properties were represented by the relation of pressure to volume; myocardial properties were evaluated by relating myocardial midwall stress to midwall strain. The constant of left ventricular chamber stiffness was decreased in group 2 compared with controls (p less than 0.05) but it was normal in group 3. The constant of myocardial stiffness was increased in group 3 compared with groups 1 and 2 (p less than 0.01). Among patients with mitral regurgitation, there was a significant inverse relation between ejection fraction and the constant of myocardial stiffness (r = -0.83).

CONCLUSIONS

The chronic adaptation to volume overload in chronic mitral regurgitation tends to decrease left ventricular chamber stiffness. Patients with mitral regurgitation and a depressed ejection fraction demonstrated diastolic myocardial dysfunction. Compromised diastolic function in patients with chronic mitral regurgitation and reduced systolic performance may contribute to the clinical manifestations of congestive heart failure.

Left ventricular responses to experimental aortic coarctation in growing puppies

The haemodynamic status of 8 coarctated and 7 sham-operated beagle puppies was studied by a catheterization technique at rest and during isoproterenol and volume loading at the ages of 7 (I) and 9 (II) months (5 and 7 months after the experimental coarctation). Proximal aortic systolic and pulse pressures were constantly higher in the coarctation group than in the control group (P less than 0.05), and the systolic pressure gradient across the coarctation was always significantly higher in the coarctation group [I at rest mean 45 +/- 5 (SD) vs 5 +/- 4 mmHg, P less than 0.001, and after I isoproterenol infusion 56 +/- 9 vs 10 +/- 6 mmHg, P less than 0.001, and after I dextran infusion 58 +/- 10 vs 8 +/- 7 mmHg, P less than 0.001]. The time constant of exponential isovolumic left ventricular pressure fall after the isoproterenol tests was longer in the coarctation group (I 28 +/- 8 ms and II, 30 +/- 4 ms) than in the control group (I, 21 +/- 2, P less than 0.05 and II, 19 +/- 3 ms, P less than 0.005), indicating impaired relaxation. The tension time index during the volume loading tests increased in the coarctation dogs (I, 4150 +/- 660 and II, 4080 +/- 810 mmHg s min-1) to higher levels than in the control group (I, 3550 +/- 220, II, 2540 +/- 1140 mmHg s min-1, P less than 0.05 both). Cardiac output, left ventricular end diastolic pressure, inotropic parameters and heart rate were similar in both groups during the infusions.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation between intraventricular pressure and volume in diastole

The pressure-volume curves for 10 patients with various types of heart disease were studied throughout mid to late diastole when both pressure and volume were increasing. The results were used to test a currently held theory that the form of this relation is exponential. It was found that for the patients examined this hypothesis was not valid.

Effects of intravenous verapamil on left ventricular relaxation and filling in stable angina pectoris

Left ventricular (LV) diastolic function is often impaired in coronary artery disease (CAD). To assess whether verapamil could improve LV diastolic properties, 12 patients with CAD undergoing right- and left-sided cardiac catheterization, as well as simultaneous radionuclide angiography, were studied before and during intravenous administration of verapamil (0.1 mg/kg as a bolus followed by 0.007 mg/kg/min). The heart rate was kept constant by atrial pacing in both studies. LV pressure-volume relations were obtained. Verapamil decreased LV systolic pressure (130 +/- 22 to 117 +/- 16 mm Hg, p less than 0.01) and the end-systolic pressure/volume ratio (2.4 +/- 1.3 to 1.6 +/- 0.5 mm Hg/ml, p less than 0.05), and increased LV end-diastolic (13 +/- 4 to 16 +/- 4 mm Hg, p less than 0.02) and pulmonary capillary pressures (10 +/- 5 to 12 +/- 5 mm Hg, p less than 0.005). Despite such negative inotropic effects, cardiac index increased (3.4 +/- 0.7 to 3.9 +/- 0.6 liters/min/m2, p less than 0.02). The time constant of isovolumic relaxation shortened (63 +/- 14 to 47 +/- 9 ms, p less than 0.02); peak filling rate increased (370 +/- 155 to 519 +/- 184 ml/s, p less than 0.001; 2.6 +/- 1.1 to 3.3 +/- 0.9 end-diastolic counts/s, p less than 0.02; and 4.1 +/- 1.6 to 5.5 +/- 1.5 stroke counts/s, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in left ventricular diastolic performance after aortic balloon valvuloplasty: acute and late effects

To evaluate acute and follow-up changes in left ventricular diastolic performance, simultaneous digital left ventriculography and micromanometry were performed in 49 patients undergoing aortic balloon valvuloplasty. All patients improved symptomatically after valvuloplasty, and 26 returned 6.3 +/- 1.5 months later for follow-up catheterization. Immediately after valvuloplasty, aortic valve area increased (before 0.5 +/- 0.2 versus after 0.8 +/- 0.2 cm2, p less than 0.01), cardiac output (before 4.3 +/- 1.2 versus after 4.4 +/- 1.3 liters/min) and ejection fraction (before 51 +/- 18% versus after 52 +/- 17%) did not change and diastolic indexes worsened, signified by a decrease in peak filling rate (before 247 +/- 80 versus after 226 +/- 78 ml/s, p less than 0.01) and increase in the time constant of isovolumetric relaxation (tau) (before 78 +/- 29 versus after 96 +/- 40 ms, p less than 0.01) and the modulus of chamber stiffness (before 0.107 +/- 0.071 versus after 0.141 +/- 0.083, p less than 0.01). At follow-up catheterization, 16 patients continued to have symptomatic improvement (group 1) and 10 had recurrence of symptoms (group 2). Aortic valve area, cardiac output and ejection fraction at follow-up catheterization in both groups were similar and unchanged from values before valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of diastolic function by radionuclide ventriculography

Diastolic filling can be measured by radionuclide ventriculography with use of several techniques including those based on gated and list-mode acquisitions, the first-pass method, and the nuclear probe. Radionuclide ventriculography specifically assesses volumes, rates of volume change, and intervals during ventricular filling. Normal values for diastolic filling measurement vary depending on the individual radionuclide methods used and the age of the patient. Comparative studies of the radionuclide method with contrast angiographic and Doppler echocardiographic techniques for measuring diastole are discussed, and the advantages and disadvantages of the radionuclide techniques are explored. The role of radionuclide assessment of diastolic function in specific clinical examples of hypertrophic cardiomyopathy, hypertension, anthracycline-induced cardiomyopathy, and coronary artery disease is reviewed. Radionuclide ventriculography is an accurate and easily applicable procedure for studying left ventricular volume changes in diastole.

Left ventricular wall stress distribution in chronic pressure and volume overload: effect of normal and depressed contractility on regional stress-velocity relations

Regional stress-velocity relations were determined in a first group of patients (n = 15) with normal (five controls, five patients with aortic stenosis, and five patients with aortic insufficiency) and a second group of patients (n = 10) with depressed contractility (five patients with aortic stenosis and five with aortic insufficiency). LV circumferential wall stress was calculated from high-fidelity pressure and frame-by-frame angiocardiographic data using the Wong thick-wall model. Regional wall stress and shortening velocity were calculated from the endo- to the epicardium, and from the equator to the apex at 35 points. Regional LV wall stress was in all patients lower at the epi- than the endocardium, and lower at the apex than the equator. Regional stress-velocity relations were downward shifted from the endo- to the epicardium and from the equator to the apex (family of curves) in both groups. At corresponding LV regions stress-velocity relations showed significantly smaller slopes and intercepts (downward depression) in group 2 than in group 1. Thus, wall stress distribution is inhomogeneous in the normal, as well as in the pressure and volume overloaded left ventricle. Regional differences in stress-velocity relations within groups (family of curves) are probably related to changes in preload rather than to changes in regional contractility. Downward depression of the regional stress-velocity relations in group 2 is caused by depressed myocardial contractility.

Pulsed Doppler evaluation of right ventricular diastolic filling in children with pulmonary valve stenosis before and after balloon valvuloplasty

To assess right ventricular (RV) diastolic filling in children with pulmonary stenosis (PS), 14 patients (mean age 5.1 years) were examined immediately before and after pulmonary balloon valvuloplasty. Fourteen normal children (mean age 4.8 years) were also studied. From the tricuspid valve inflow Doppler study, the following measurements were made at peak inspiration: peak velocities at rapid filling (peak E) and during atrial contraction (peak A), ratio of peak E to peak A velocities, RV peak filling rate normalized for stroke volume, total area under the Doppler curve, percent of the total Doppler area occurring in the first third of diastole (0.33 area fraction), percent of the total area occurring under the E wave (E area fraction), percent of the total area occurring under the A wave (A area fraction) and the ratio of E area to A area. Before balloon valvuloplasty, the patients with PS had higher peak A velocity (0.64 +/- 0.28 vs 0.39 +/- 0.08 m/s), lower E/A velocity ratio (1.11 +/- 0.52 vs 1.76 +/- 0.45), lower 0.33 area fraction (0.34 +/- 0.14 vs 0.49 +/- 0.08), higher A area fraction (0.45 +/- 0.21 vs 0.27 +/- 0.09) and lower E/A area ratio (1.73 +/- 1.05 vs 2.96 +/- 1.14) than the normal subjects (p less than 0.01). In patients before and after balloon valvuloplasty, there was a significant difference in RV outflow gradient (71 +/- 35 vs 28 +/- 15 mm Hg), but there was no change in any Doppler index. Thus, patients with PS have abnormal diastolic filling with decreased filling in early diastole and increased filling during atrial contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Wide-range load shift of combined aortic valvuloplasty-arterial vasodilation slows isovolumic relaxation of the hypertrophied left ventricle

To assess the effects of left ventricular (LV) load on isovolumic relaxation rate of the hypertrophied LV, wide range LV load shifts were imposed by the sequential use of balloon aortic valvuloplasty (BAV) and arterial vasodilation in 14 patients with severe sclerocalcific aortic stenosis (aortic valve area, 0.45 +/- 0.16 cm2). Micromanometer tip-catheter LV pressure recordings (n = 14) and simultaneous LV angiograms (n = 9) were obtained before BAV, during nitroprusside infusion (NIT) before BAV, 48 hours after BAV, and 48 hours after BAV during NIT. LV peak systolic pressure (LVPSP) decreased from 237 +/- 33 mm Hg before BAV to 200 +/- 33 mm Hg (p less than 0.01) during NIT before BAV, to 201 +/- 27 mm Hg (p less than 0.01) after BAV and to 165 +/- 26 mm Hg (p less than 0.01) during NIT after BAV.LV end-systolic volume (LVESV) decreased from 55 +/- 34 ml before BAV to 25 +/- 23 ml (p less than 0.01) during NIT before BAV, to 30 +/- 32 ml (p less than 0.025) after BAV and to 15 +/- 12 ml (p less than 0.025) during NIT after BAV. LV end-systolic wall stress (LVESs) decreased from 90 +/- 30.10(3) dyne/cm2 before BAV to 41 +/- 13.10(3) dyne/cm2 (p less than 0.01) during NIT before BAV, to 55 +/- 16.10(3) dyne/cm2 (p less than 0.025) after BAV and to 26 +/- 6.10(3) dyne/cm2 (p less than 0.01) during NIT after BAV. Only after sequential BAV-NIT was the time of LV electromechanical systole (LVEST), which marked the onset of the LV isovolumic relaxation period, significantly reduced (from 419 +/- 26 msec before BAV to 363 +/- 28 msec after BAV-NIT [p less than 0.01]). The time constants of LV pressure decay with zero or nonzero asymptote pressure (TO and TPB) remained unchanged after BAV and during NIT before BAV. At the lowest LVPSP, LVESV, and LVESs after sequential BAV-NIT, both TO and TPB significantly prolonged from 35.7 +/- 6.3 to 46.7 +/- 12.6 msec (p less than 0.025) and from 46.6 +/- 12.5 to 73.2 +/- 23.3 msec (p less than 0.01). Phase-plane plots (LV dP/dt vs. LVP) of the LV pressure (P) signal during isovolumic relaxation were constructed for the four different loading states by matching corresponding LVP and LV dP/dt points. For a given LVP value, the corresponding LV dP/dt values on the phase plane plots were comparable before BAV, during NIT before BAV, and after BAV. The corresponding LV dP/dt value was higher during NIT after BAV, impling a slower relaxation rate at the same LVP after sequential BAV-NIT. A shift in the control of isovolumic LV relaxation kinetics from myofilamentary detachment to myoplasmic calcium removal, which proceeds slower in hypertrophied myocardium, could explain the observed slowing of LV isovolumic relaxation after drastic LV unloading of sequential BAV-NIT.

Estimation of left-ventricular systolic performance and its determinants in man from pressures and dimensions of one beat: effects of aortic valve stenosis and replacement

Within a thick heart-chamber wall, there is a midwall element or layer whose displacements best express systolic performance. The volume enclosed by that midwall element (Vm) and the average stress in that element (sigma m) can be calculated accurately by simple formulae. From simultaneous left-side pressure tracings and contrast cine-ventriculograms, Vm and sigma m were calculated at 20-ms intervals for an entire cardiac cycle in five normal subjects and in eight patients before and one year after replacement of stenotic aortic valves. Prior to surgery, the overloaded left ventricles were not hypertrophied enough to restore normal mid- and end-ejection stresses. Four had subnormal cavity ejection fractions, but all had subnormal midwall ejection fractions. All had subnormal fractional midwall ejection rates and prolonged active intervals (from the beginning of activation to the end of deactivation). Judging from pre-ejection pressure-development rates, the pressure-developing ability was not consistently elevated by concentric hypertrophy, because the stress-developing ability (contractility) was usually subnormal. The ability to shorten in the absence of afterload appeared to be subnormal in about half of the cases. The subnormal midwall ejection fractions appeared to be due to various combinations of increased mid- and late-ejection stresses, reduced contractility, and reduced shortening ability. On average and in several cases, reduced shortening ability appeared to be the main cause of the reduced performance. The effect of the slowed fractional midwall ejection rate to reduce the midwall ejection fraction was partially compensated by a prolonged active interval, by prolonged ejection time relative to the active interval, and by a more sustained ejection rate. Valve replacement partially restored all values except contractility towards normal, but the restorations of wall/cavity ratio and active interval were slight.

The dependence of the time constant of left ventricular isovolumic relaxation (tau) on pericardial pressure

The purpose of this study was to investigate the dependence of tau, the time constant of left ventricular (LV) isovolumic relaxation, on pericardial pressure and to compare values of tau as determined by the methods of previous investigators and by a standard exponential curve fit. All of the more recent methods involve an additional parameter--the pressure to which the exponential relaxation finally declines (PB, the pressure intercept in the method of Craig and Murgo and the asymptote in the exponential fits). An additional purpose of the study was to determine the relation of these parameters to pericardial pressure. In eight closed-chest anesthetized dogs, tau was calculated from intracavitary (Plv) and transmural LV pressure (Plv = Plv-Pper) by each method as pericardial (Pper) and LV end-diastolic pressure were changed by pericardial infusion and intravenous volume loading. The time constant determined by the method of Weiss et al was dependent on pericardial pressure; the time constants determined by the other methods were not. PB and the asymptotes were found to be similar and to increase almost equally with pericardial pressure. When pericardial pressure was zero, these values were approximately -20 mm Hg. Thus, both these parameters seem to indicate the same baseline pressure, a pressure that increases pari passu with pericardial pressure. Reported changes in the value of tau calculated from intracavitary LV pressure by the method of Weiss et al may reflect factors other than changes in LV diastolic function.

Influence of glucose and insulin on the exaggerated diastolic and systolic dysfunction of hypertrophied rat hearts during hypoxia

Myocardial hypertrophy can result in increased sensitivity toward the development of mechanical dysfunction during hypoxia. Alterations in glycolytic metabolism may contribute to this. We studied the response to 15 minutes of hypoxia in hypertrophied (deoxycorticosterone-salt hypertension model) and nonhypertrophied rat hearts and examined the influence of a high glucose (27.5 mM) and insulin (100 mU/ml) concentration. In response to hypoxia in the presence of a normal glucose concentration (5.5 mM), left ventricular end-diastolic pressure was higher in hypertrophied than in nonhypertrophied hearts (65 +/- 6 vs. 44 +/- 4 mm Hg; p less than 0.05). Perfusion with high glucose and insulin blunted the rise in left ventricular end-diastolic pressure in both hypertrophied and nonhypertrophied hearts and abolished the difference in diastolic dysfunction between groups during hypoxia (26 +/- 2 vs. 32 +/- 4 mm Hg, respectively; p = NS). At end hypoxia in the presence of a normal glucose concentration, developed pressure was more depressed in hypertrophied than in nonhypertrophied hearts (11 +/- 1 vs. 18 +/- 1% of baseline, respectively; p less than 0.05). Perfusion with high glucose and insulin resulted in improved function in both groups during hypoxia such that a greater impairment of developed pressure was no longer present in the hypertrophied versus nonhypertrophied hearts (21 +/- 1 vs. 24 +/- 2% of baseline, respectively; p = NS). At the end of hypoxic perfusion in the presence of a normal glucose concentration, hypertrophied hearts were producing 38% less lactate than nonhypertrophied hearts. Perfusion with high glucose and insulin increased lactate production in both groups and equalized lactate production between groups. Thus, the greater deterioration in hemodynamic function in hypertrophied hearts compared with nonhypertrophied hearts during hypoxia is associated with lower lactate production. Both the exaggerated hemodynamic dysfunction and deficient lactate production can be ameliorated by perfusion with a high glucose concentration and insulin.