Left ventricular compliance: mechanisms and clinical implications

Effects of milrinone on left ventricular remodeling after acute myocardial infarction

BACKGROUND

Left ventricular remodeling after an acute myocardial infarction may result in progressive left ventricular dilation that may be associated with increased mortality. We studied the effects of the phosphodiesterase inhibitor milrinone on left ventricular remodeling after acute myocardial infarction.

METHODS AND RESULTS

Rats (n = 90) were randomized to undergo either left coronary artery ligation or sham operation. Three weeks after surgery, rats received either no treatment or milrinone, which was continued until 2 days before the rats were killed. Ninety days after the initial surgery, hemodynamic measurements were made before and after volume loading. The rats were killed, the hearts were removed, and passive pressure-volume curves were obtained. The hearts were fixed at a constant pressure and analyzed morphometrically. Compared with untreated infarcted rats, milrinone-treated infarcted rats had a lower left ventricular end-diastolic pressure (1.7 +/- 0.4 versus 4.3 +/- 1.4 mm Hg, p less than 0.05), a lower left ventricular volume (1.25 +/- 0.20 versus 2.37 +/- 0.30 ml/kg, p less than 0.001) and a lower left ventricular wall stress index (1.3 +/- 0.2 versus 1.7 +/- 0.1, p less than 0.05). Left ventricular chamber stiffness was higher in milrinone-treated infarcted rats than in untreated infarcted rats. Milrinone had no cardiac effect on uninfarcted animals.

CONCLUSION

Chronic milrinone therapy after acute myocardial infarction improves cardiac hemodynamic indexes and attenuates progressive left ventricular dilation.

Changes in left ventricular diastolic filling during the development of left ventricular hypertrophy: observations using Doppler echocardiography in a unique canine model

To examine changes in diastolic left ventricular filling during the development of left ventricular hypertrophy, serial pulsed Doppler echocardiographic studies were performed in a canine model of left ventricular hypertrophy induced by neurogenic pressor episodes. This model is unique since left ventricular hypertrophy develops without sustained hypertension. The neurogenic pressor episodes produced progressive increases in left ventricular mass of 17% by 3 weeks (p less than 0.03) and 23% by 9 weeks (p less than 0.001). During the course of hypertrophy development, there were no changes in resting heart rate, blood pressure, left ventricular volumes or ejection fraction, or end-systolic wall stress. However, peak early filling (peak E) velocity decreased from 65 +/- 5 cm/sec to 53 +/- 4 cm/sec by 3 weeks (p less than 0.05) and remained depressed at 9 weeks. In addition, peak E/A (the ratio of early to late peak filling) decreased by 3 weeks (p less than 0.01) and the contribution of atrial filling to total left ventricular diastolic filling increased by 9 weeks (p less than 0.005). There were significant correlations between the changes in left ventricular mass and the change in peak E velocity at 3 weeks (r = -0.92, p less than 0.001) but not at 9 weeks. These data indicate that left ventricular filling abnormalities occur early in the course of the development of left ventricular hypertrophy, are not a result of loading alterations related to sustained hypertension, and do not change significantly following increasing stages of hypertrophy.

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.

Regional myocardial blood flow and left ventricular diastolic properties in pacing-induced ischemia

The relation between left ventricular diastolic abnormalities and myocardial blood flow during ischemia was studied in eight open chest dogs with critical stenoses of the proximal left anterior descending and circumflex coronary arteries. The heart was paced at 1.7 times the heart rate at rest for 3 min. In dogs with coronary stenoses, left ventricular end-diastolic pressure increased from 8 +/- 1 to 14 +/- 2 mm Hg during pacing tachycardia (p less than 0.01) and 16 +/- 3 mm Hg (p less than 0.01) after pacing, with increased end-diastolic and end-systolic segment lengths in the ischemic regions. Left ventricular diastolic pressure-segment length relations for ischemic regions shifted upward during and after pacing tachycardia in dogs with coronary stenoses, indicating decreased regional diastolic distensibility. In dogs without coronary stenoses, the left ventricular diastolic pressure-segment length relation was unaltered. Pacing tachycardia without coronary stenoses induced an increase in anterograde coronary blood flow (assessed by flow meter) in both the left anterior descending and circumflex coronary arteries, and a decrease in regional vascular resistance. In dogs with coronary stenoses, regional vascular resistance before pacing was decreased by 18%; myocardial blood flow (assessed by microspheres) was unchanged in both the left anterior descending and circumflex coronary artery territories. During pacing tachycardia with coronary stenoses, regional coronary vascular resistance did not decrease further; subendocardial myocardial blood flow distal to the left anterior descending coronary artery stenosis decreased (from 1.03 +/- 0.07 to 0.67 +/- 0.12 ml/min per g, p less than 0.01), as did subendocardial to subepicardial blood flow ratio (from 1.04 +/- 0.09 to 0.42 +/- 0.08, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Pericardial influences on right and left ventricular filling dynamics

The influence of the pericardium on right and left ventricular filling was studied using two-dimensional and Doppler echocardiography in 14 open-chest dogs. Doppler echo parameters of filling included early (E) and late (A) velocities and their ratio (E/A) for the mitral and tricuspid valves. Right and left ventricular volumes were calculated from orthogonal two-dimensional echocardiographic images. Data were compared at three levels of left ventricular end-diastolic pressure (6 +/- 2, 13 +/- 3, and 21 +/- 4 mm Hg) at matched heart rates before and after pericardiectomy. The instantaneous diastolic pressure gradient was measured in 12 of the dogs. Pericardiectomy resulted in an increase in early mitral velocity, peak early diastolic pressure gradient, and E/A but not early mitral velocity normalized for end-diastolic volume. In contrast, for the tricuspid valve flow, pericardiectomy did not change E but caused a marked increase in A and a decrease in E/A. Right ventricular end-diastolic volumes at matched left ventricular end-diastolic volumes were similar before and after the pericardium was removed. However, removal of the pericardium caused a significant decrease of the slope for the right (86.0 +/- 27.0 x 10(-4) versus 50.0 +/- 19.5 x 10(-4) mm Hg/ml, p less than 0.01), but not left, ventricular ln end-diastolic pressure-volume relation (21.2 +/- 9.2 x 10(-3) versus 21.4 +/- 5.3 x 10(-3) mm Hg/ml, p = NS), and a decrease of the pressure intercept for the left (3.0 +/- 2.0 versus 1.6 +/- 0.9 mm Hg, p less than 0.05), but not right, ventricular ln end-diastolic pressure-volume relation (2.8 +/- 1.4 versus 1.4 +/- 0.8 mm Hg, p = NS). In conclusion, filling of the two ventricles is affected by the pericardium over a wide range of physiological ventricular volumes and pressures. At matched left ventricular end-diastolic volume, pericardiectomy causes a fundamental alteration in right, but not left, ventricular filling.

Left ventricular mass regression after aortic valve replacement measured by ultrafast computed tomography

Left ventricular mass and function were measured using ultrafast computed tomography, and were correlated with clinical status in 17 patients with aortic stenosis and/or insufficiency undergoing aortic valve replacement or balloon valvuloplasty. Wall mass was 159 +/- 38 gm/m2 initially, decreased 25% to 116 +/- 29 gm/m2 at 4 month (p less than 0.001), and decreased a total of 34% to 105 +/- 33 gm/m2 at 8 months after valve repair. By 8 months not only was the mean wall mass within the normal range, but only three patients retained abnormal hypertrophy. Ejection fraction increased 8% (p = 0.06). Clinical function improved in all patients, with only three patients remaining outside of New York Heart Association functional class 1 at 8 months. Regression of ventricular mass into the normal range correlated with attainment of class 1 functional status (p less than 0.02), despite a lack of increase of ejection fraction. The single patient followed for 8 months after valvuloplasty had minor wall mass regression and minor clinical improvement.

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)

Right ventricular diastolic function during exercise: effect of ischemia

The effects of exercise on right ventricular diastolic function were evaluated in 14 patients who underwent supine rest and exercise right ventricular angiography. On the basis of coronary anatomy and exercise left ventricular regional wall motion analysis, these patients were classified into two groups: Group 1 (n = 7) had no or only mild coronary artery disease and Group 2 (n = 7) had significant coronary disease and exercise-induced left ventricular wall motion abnormalities suggesting ischemia. Chamber stiffness at rest was higher in Group 2 (48 x 10(-3) ml-1/m2) than in Group 1 (18 x 10(-3) ml-1/m2, p = 0.006). During exercise, right ventricular filling rate in the second half of diastole was significantly lower in Group 2 (126 versus 276 ml/m2 per s, p less than 0.03). The time constant of right ventricular pressure decay decreased significantly in both groups with exercise; however, both groups displayed a parallel upward shift of the pressure-volume curve with exercise. Because ischemia could not be demonstrated in Group 1, it is an unlikely explanation for this shift. Septal shifting was not a significant factor with exercise. Because of an increase in left ventricular end-diastolic volume with exercise and a close correlation between right and left ventricular end-diastolic pressures (r = 0.96 for Group 1 and r = 0.76 for Group 2), pericardial constraint is the most likely cause for this upward shift of the pressure-volume curve. Therefore, an increase in right ventricular end-diastolic pressure may not be a reliable indicator of ischemia during exercise because this pressure is coupled to changes in left ventricular volume and pericardial constraint.

Early regression of left ventricular diastolic abnormalities in hypertensive patients treated with nifedipine

The effects of nifedipine on blood pressure (BP), left ventricular hypertrophy, and diastolic function were evaluated in 14 patients with essential hypertension (EH). All males with a mean age of 44 +/- 6 years (range 35-58 years), and in ten normotensive subjects (control group) aged 32-42 years (mean age 36 +/- 4). A complete echocardiogram (ECHO) was performed in basal conditions after 1 and 6 months of therapy with nifedipine (20-40 mg/day). Left ventricular echocardiograms (LV ECHO, M-mode, two-dimensional guided) were plotted with a simultaneous ECG tracing by means of a computerized system that allows evaluation of the following parameters: LV end-diastolic and systolic diameters (EDD, ESD); variations in LV diameter and volume during the entire cardiac cycle, and the velocities of such variations; end-diastolic thicknesses of the interventricular septum and posterior wall (ST, PWT); LV mass, mass/volume (M/V) index, end-diastolic diameter/thickness (D/Th) index, and LV ejection fraction (EF). Left ventricular volume curves were obtained and the contributions of rapid filling (RF) and atrial systole (AS) to EDV were evaluated. Filling velocities during RF (vRF) and AS (vAS) were estimated, as well as the isovolumic relaxation period (IR). No significant changes were observed in the heart rate. After 1 month of therapy, systolic and diastolic BP were significantly decreased (p less than 0.05). ST and PWT were reduced, with a simultaneous increase in EDD and EDV (p less than 0.01). LV mass was slightly reduced, as was the M/V index. The D/Th index was increased (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Correlates of diastolic filling abnormalities in hypertension: a Doppler echocardiographic study

Hypertension and aging are both associated with changes of left ventricular (LV) diastolic filling and increased LV mass. To determine whether diastolic filling abnormalities are present in hypertension independent of aging and significant hypertrophy, we studied 19 hypertensive patients following a period of 4 weeks when they were not receiving therapy and 18 normotensive subjects matched for sex, age, and LV mass. All subjects had normal systolic function and ejection fraction as assessed by radionuclide angiography. We measured peak velocity of early filling (E), late filling (A), and their ratio (E/A) by Doppler echocardiography. Filling indices were abnormal in hypertensive patients, but none of the filling indices were significantly correlated with LV mass. E was inversely related to age (r = -0.62; p less than 0.01) and diastolic blood pressure (r = 0.45; p less than 0.05) in normotensive individuals, but these correlations were not significant in hypertensive patients. E was not significantly correlated to LV mass or wall thickness. In contrast, A was influenced by septal wall thickness and blood pressure in both groups. E/A correlated inversely with age in both normal individuals (r = -0.74) and hypertensive patients (r = -0.51). These findings indicate that diastolic filling abnormalities in hypertension are not solely caused by either LV hypertrophy or by aging and therefore must be in part related to the hemodynamic load or altered myocardial or chamber properties.

Altered systolic and diastolic function in children after "successful" repair of coarctation of the aorta

We investigated whether left ventricular (LV) structural or functional abnormalities persist in children on long-term follow-up after successful correction of coarctation of the aorta. Two-dimensional directed M-mode and Doppler echocardiographic examinations were performed in 11 such subjects and 22 age-matched control subjects. Digitized tracings were made from M-mode recordings of the LV and Doppler mitral valve inflow recordings to measure septal, posterior wall, and LV dimensions, LV mass, shortening fraction, peak shortening and lengthening velocities, diastolic filling time, peak E velocity, peak A velocity, and velocity time integrals. Despite group similarities in age, body size, and systolic blood pressure, greater fractional shortening (p = 0.0001), indexed peak shortening velocity (p less than 0.001), and greater LV mass index (p less than 0.05) were seen in the coarctation group in the face of lower LV wall stress (p = 0.0001). LV mass index correlated with the resting arm-leg gradient, which ranged from -4 to +10 mm Hg. The coarctation group had decreased early filling (p less than 0.006) with compensatory increased late diastolic filling (p less than 0.05). Diastolic filling abnormalities were prominent in the older coarctation subjects and were related to both systolic blood pressure (p less than 0.001) and LV mass index (p less than 0.01). Despite apparently successful repair of coarctation of the aorta, persistent alterations in both systolic and diastolic LV function and LV mass are present in children at long-term follow-up, which are related to the resting arm-leg gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular diastolic function in systemic hypertension

Right (RV) and left ventricular (LV) diastolic function was evaluated in 50 patients with mild, uncomplicated essential hypertension using pulsed-wave Doppler echocardiography. Patients with pulmonary, valvular or coronary artery disease were excluded and antihypertensive drugs were discontinued for the 2 weeks preceding the study. Ten normotensive patients without heart disease acted as control subjects. In the hypertensive patients, RV peak velocity of atrial filling was higher (42 +/- 10 vs 31 +/- 7 cm/s, p less than 0.01) and deceleration half-time was prolonged (96 +/- 20 vs 83 +/- 10 ms, difference not significant); ratio of early/atrial filling velocity (1.1 +/- 0.3 vs 1.7 +/- 0.4, p less than 0.001) and peak filling rate corrected to stroke volume (3.6 +/- 0.7 vs 5.3 +/- 0.9 SV/s, p less than 0.001) were lower. LV filling parameters showed similar changes. RV filling parameters did not correlate with age, LV mass or septal thickness but correlated weakly with LV radius/thickness ratio. There was good correlation between RV and the following corresponding LV filling parameters: peak filling rate, r = 0.68, p less than 0.001; ratio of early/atrial filling, r = 0.88, p less than 0.0001; and deceleration half-time, r = 0.62, p less than 0.001. Data indicate that RV diastolic function is abnormal in essential hypertension and these abnormalities are closely related to those of LV diastolic function.

Relation of pulmonary vein to mitral flow velocities by transesophageal Doppler echocardiography. Effect of different loading conditions

It has previously been demonstrated that predictable changes occur in mitral flow velocities under different loading conditions. The purpose of this study was to relate changes in pulmonary venous and mitral flow velocities during different loading conditions as assessed by transesophageal echocardiography in the operating room. Nineteen patients had measurements of hemodynamics, that is, mitral and pulmonary vein flow velocities during the control situation, a decrease in preload by administration of nitroglycerin, an increase in preload by administration of fluids, and an increase in afterload by infusion of phenylephrine. There was a direct correlation between the changes in the mitral E velocity and the early peak diastolic velocity in the pulmonary vein curves (r = 0.61) as well as a direct correlation between the deceleration time of the mitral and pulmonary venous flow velocities in early diastole (r = 0.84). This indicates that diastolic flow velocity in the pulmonary vein is determined by the same factors that influence the mitral flow velocity curves. A decrease in preload caused a significant reduction in the initial E velocity and prolongation of deceleration time, and an increase in preload caused an increase in E velocity and shortening of deceleration time. An increase in afterload produced a variable effect on the initial E velocity and deceleration time and was dependent on the left ventricular filling pressure. The change in systolic forward flow velocity in the pulmonary vein was directly proportional to the change in cardiac output (r = 0.60). The pulmonary capillary wedge pressure correlated best with the flow velocity reversal in the pulmonary vein at atrial contraction (r = 0.81). Use of pulmonary vein velocities in conjunction with mitral flow velocities can help in understanding left ventricular filling.

Prognostic significance of radionuclide-assessed diastolic function in hypertrophic cardiomyopathy

To evaluate the prognostic significance of diastolic function in hypertrophic cardiomyopathy (HC), technetium-99m gated equilibrium radionuclide angiography, acquired in list mode, was performed in 161 patients. Five diastolic indexes were calculated. During 3.0 +/- 1.9 years, 13 patients had disease-related deaths. With univariate analysis, these patients were younger (29 +/- 20 vs 42 +/- 16 years; p less than 0.05), had a higher incidence of syncope (p less than 0.025), dyspnea (p less than 0.001), reduced peak filling rate (2.9 +/- 0.9 vs 3.4 +/- 1.0 end-diastolic volume/s; p = 0.09) with increased relative filling volume during the rapid filling period (80 +/- 7 vs 75 +/- 12%; p = 0.06) and decreased atrial contribution (17 +/- 7 vs 22 +/- 11%; p = 0.07). Stepwise discriminant analysis revealed that young age at diagnosis, syncope at diagnosis, reduced peak ejection rate, positive family history, reduced peak filling rate, increased relative filling volume by peak filling rate and concentric left ventricular hypertrophy were the most statistically significant (p = 0.0001) predictors of disease-related death (sensitivity 92%, specificity 76%, accuracy 77%, positive predictive value 25%). Discriminant analysis excluding the diastolic indexes, however, showed similar predictability (sensitivity 92%, specificity 76%, accuracy 78%, positive predictive value 26%). To obtain more homogeneous groups for analysis, patients were classified as survivors (116) or electrically unstable (40), including sudden death, out-of-hospital ventricular fibrillation and nonsustained ventricular tachycardia during 48-hour ambulatory electrocardiography, and heart failure death or cardiac transplant (5).(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular diastolic function in normotensive adolescents with different genetic risk of hypertension

Abnormalities of the diastolic function of the left ventricle are the first sign of cardiac involvement in arterial hypertension. We have studied the diastolic function in a group of normotensive adolescents with confirmed family history of hypertension. M-mode echocardiography was performed in 86 normotensive males aged 14-19 years: 41 sons of at least one hypertensive parent (SHT) and 45 sons of normotensive parents (SNT). Cross-sectional area of the left ventricle and left ventricular (LV) mass index were significantly greater in the SHT than in the SNT group (10.05 +/- 1.84 vs. 8.9 +/- 1.56 cm/m2, p less than 0.01 and 129.3 +/- 296.3 vs. 109.23 +/- 25.7 g/m2, p less than 0.002, respectively). No significant difference between the two groups was observed in the indices of left ventricular diastolic function, except for mitral valve opening rate (463.51 +/- 90.45 in SHT vs. 416.71 +/- 78.84 mm/s in SNT; p less than 0.02). From the analysis of the subgroup of adolescents having left ventricular mass greater than the upper normal value, we observed that they showed mean time of rapid filling significantly longer than SNT: this could represent an early marker of the pathological character of such hypertrophy. Our results suggest that the higher LV mass observed in the SHT is not associated with chamber and myocardial stiffness abnormalities.

Significance of Doppler indices of diastolic filling of the left ventricle: comparison with invasive hemodynamics in a canine model

Doppler measurements of mitral flow velocity curves have been proposed as a method for characterizing diastolic filling of the left ventricle. Different velocity curves have been empirically described in different disease states and under differing loading conditions in humans, but relating these various Doppler parameters to hemodynamic measurements of ventricular diastolic properties has not been fully elucidated. The effect of differing loading conditions (preload reduction, preload increase, afterload increase) on the Doppler mitral flow velocity and high-fidelity left atrial-left ventricular pressures was examined in seven closed-chest, anesthetized dogs. Preload reduction by balloon inflation in the inferior vena cava resulted in significant decreases in E velocity (early diastolic velocity) from 0.39 +/- 0.09 m/sec to 0.29 +/- 0.10 m/sec (p less than 0.01) and prolongation of deceleration time from 131 +/- 18 msec to 165 +/- 60 msec (p less than 0.05). Preload increase by infusion of fluids resulted in a significant increase in E velocity from 0.39 +/- 0.09 m/sec to 0.49 +/- 0.10 m/sec (p less than 0.001) and shortening of the deceleration time from 131 +/- 18 msec to 95 +/- 15 msec (p less than 0.001). The effect of afterload increase was variable and was dependent upon the left atrial pressure. Significant but weak positive correlations were noted between E velocity and maximal left atrial-left ventricular pressure gradient (r = 0.47, p less than 0.001) and total change in left ventricular pressure (r = 0.68, p less than 0.001), with inverse relationships between the deceleration time and these parameters. There was no overall relationship between the time constant tau and the E velocity, but an inverse relationship emerged when the data were examined according to different filling pressures. These results indicate that none of the mitral velocity measurements should be directly equated with other measurements of diastolic function. However, distinct velocity curves emerged under differing loading conditions that help in interpreting the meaning of these curves.

Effects of atenolol on left ventricular hypertrophy and early left ventricular function in essential hypertension

Echocardiographic studies of left ventricular (LV) hypertrophy indicate clinical benefits of antihypertensive therapy. Therefore, M-mode and Doppler techniques were used to assess changes in LV hypertrophy after 10, 30 and 50 weeks of atenolol therapy (50 or 100 mg once daily) in 19 patients with essential hypertension. After 50 weeks of atenolol treatment, the most notable changes were: for M-mode parameters, increases (p less than 0.05) in diastolic LV internal dimension, radius to thickness ratio and stroke volume, and decreases (p less than 0.01) in total wall thickness and heart rate; for Doppler parameters, increases (p less than 0.01) in slope and peripheral resistance, and decreases (p less than 0.01) in heart rate, stroke volume and cardiac output. The decreased total wall thickness and increased radius to thickness ratio suggest a trend toward regression of LV hypertrophy. These findings, along with improvements in blood pressure, pulse and exercise stress tests, indicate potential benefits of atenolol in managing patients with essential hypertension and LV hypertrophy.

Absence of left ventricular volume loading in infants with coarctation of the aorta and a large ventricular septal defect

Clinical characteristics and angiographic ventricular volume data were obtained in 25 infants aged 1 to 66 days who presented with coarctation of the aorta, ventricular septal defect and congestive heart failure to determine if left ventricular volume loading was present and if there were hemodynamic or volumetric variables that were predictive of operative mortality in this group. Pulmonary to systemic flow ratio averaged 2.8 +/- 0.8 and right ventricular/left ventricular peak pressure ratio was 0.96 +/- 0.12. Left ventricular end-diastolic volume averaged 116 +/- 49% of normal and was less than the investigators' lower limit of normal in 5 (20%) of 25 patients. In contrast, right ventricular end-diastolic volume, measured in eight patients, averaged 173 +/- 47% of normal and was greater than the investigators' upper limit of normal in seven (88%) of eight. Left ventricular ejection fraction averaged 0.47 +/- 0.17 and was below normal (less than 0.55) in 14 (58%) of 24 patients. Preoperative volume and ejection fraction data did not differ in infants with coarctation plus ventricular septal defect and a similar group of 19 infants with isolated coarctation. Abnormal left ventricular operative volume distensibility was inferred by normal or decreased left ventricular end-diastolic volume and increased left ventricular end-diastolic pressure (greater than 12 mm Hg) in 12 (55%) of 24 patients. Early plus late mortality was related to left ventricular size: 3 of 5 patients with a small left ventricular end-diastolic volume died, compared with only 4 of 20 with a normal or increased volume (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive measurement of left ventricular filling pressures by means of transmitral pulsed Doppler ultrasound

In 54 consecutive patients, ages 59 +/- 11 years, the transmitral diastolic flow velocity profile was derived by means of pulsed Doppler echocardiography simultaneously with right-sided heart catheterization. In 30 of them, ages 57 +/- 10 years, left-sided heart catheterization was performed at the same time. The sample volume was positioned exactly in the mitral anulus plane, bisecting the anulus. The ratio of the time-velocity integrals of the A wave (atrial contraction) and E wave (early filling) was calculated (A/E ratio of integrals). Linear regression analysis showed a highly significant linear correlation of the A/E ratio of integrals with regard to left ventricular (LV) end-diastolic pressure (r = 0.98, p less than 0.001) and pulmonary capillary wedge pressure (r = 0.98, p less than 0.001). The A/E ratio of integrals also correlated with other hemodynamic parameters, such as cardiac output (r = -0.73, p less than 0.001), cardiac index (r = -0.74, p less than 0.001) and stroke volume index (r = -0.65, p less than 0.001). For 19 additional patients, ages 55 +/- 8 years, the values of LV end-diastolic pressure and pulmonary capillary wedge pressure were calculated by means of the corresponding formulas from the first data set. The correlation between the calculated and invasively measured LV filling pressures expressed in terms of intraclass correlation coefficients shows highly significant correlations for both LV end-diastolic pressure (intraclass correlation coefficient = 0.99, p less than 0.001) and pulmonary capillary wedge pressure (intraclass correlation coefficient = 0.99, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparability of echocardiography and chest X-ray following myocardial infarction

In a group of 23 patients with first-time myocardial infarction (MI) we compared the results of echocardiography and chest X-ray as measured 1 week, 2 months, and 6 months following acute MI. Left ventricular end-diastolic dimension (LVEDd) and left atrial (LA) dimension were measured from the echocardiogram, and the cardiac volume in ml/m2 body surface area (BSA) was calculated from the chest X-ray. A progressive increase in LA dimension was noticed during the 6-month period: a significant increase after 2 months (P less than 0.001) with a further increase at 6 months compared with after 2 months (P less than 0.001). The changes in LA dimension were more pronounced in anterior and Q-wave infarction (P less than 0.001) than in inferior and non-Q-wave infarction (P less than 0.01). On the other hand, LVEDd showed a less conspicuous change: a moderate increase (P less than 0.05) at 2 and 6 months, also with a more pronounced change in anterior wall and Q-wave infarction (P less than 0.01). There was no significant concurrent change in the calculated heart volume in ml/m2 BSA, as measured from the chest X-ray. It is suggested that the observed changes in LA dimension reflect reduced left ventricular compliance after MI.

Functional and structural abnormalities in patients with dilated cardiomyopathy

Passive diastolic properties of the left ventricle were determined in 10 control subjects and 12 patients with dilated cardiomyopathy. Simultaneous left ventricular angiography and high fidelity pressure measurements were performed in all patients. Left ventricular chamber stiffness was calculated from left ventricular pressure-volume and myocardial stiffness from left ventricular stress-strain relations with use of a viscoelastic model. Patients with dilated cardiomyopathy were classified into two groups according to the diastolic constant of myocardial stiffness (beta). Group 1 consisted of seven patients with a normal constant of myocardial stiffness less than or equal to 9.6 (normal range 2.2 to 9.6) and group 2 of 5 patients with a beta greater than 9.6. Structural abnormalities (percent interstitial fibrosis, fibrous content) in patients with dilated cardiomyopathy were assessed by morphometry from right ventricular endomyocardial biopsies. Heart rate was similar in the three groups. Left ventricular end-diastolic pressure was significantly greater in patients with cardiomyopathy (18 mm Hg in group 1 and 22 mm Hg in group 2) than in the control patients (10 mm Hg). Left ventricular ejection fraction was significantly lower in groups 1 (37%) and 2 (36%) than in the control patients (66%). Left ventricular muscle mass index was significantly increased in both groups with cardiomyopathy. The constant of chamber stiffness (beta*) was slightly although not significantly greater in groups 1 and 2 (0.58 and 0.58, respectively) than in the control group (0.35). The constant of myocardial stiffness beta was normal in group 1 (7.0; control group 6.9, p = NS) but was significantly increased in group 2 (23.5). Interstitial fibrosis was 19% in group 1 and 43% (p less than 0.001) in group 2 (normal less than or equal to 10%). There was an exponential relation between both diastolic constant of myocardial stiffness (beta) and interstitial fibrosis (IF) (r = 0.95; p less than 0.001) and beta and fibrous content divided by end-diastolic volume index (r = 0.93; p less than 0.001). It is concluded that myocardial stiffness can be normal in patients with dilated cardiomyopathy despite severely depressed systolic function. Structural alterations of the myocardium with increased amounts of fibrous tissues are probably responsible for the observed changes in passive elastic properties of the myocardium in patients with dilated cardiomyopathy. The constant of myocardial stiffness (beta) helps to identify patients with severe structural alterations (group 2), representing possibly a more advanced stage of the disease.

Plasma atrial natriuretic factor in essential hypertension: relation to cardiac size, function and systemic hemodynamics

To evaluate determinants of elevated plasma atrial natriuretic factor levels in patients with hypertension, immunoreactive plasma atrial natriuretic factor in 54 normal subjects and 40 untreated hypertensive patients was compared with echocardiographic measurements of cardiac size, function and systemic hemodynamics. In normal subjects, plasma atrial natriuretic factor was related to age, systolic blood pressure and left atrial and ventricular chamber sizes, but only age and ventricular size were independent predictors. In untreated hypertensive patients, atrial natriuretic factor was directly related to age, atrial size, systolic pressure, peripheral resistance and ventricular systolic performance; age, atrial size and peripheral resistance were independent predictors. Eight patients with elevated atrial natriuretic factor values (greater than 25 fmol/ml) were significantly (p less than 0.01) older and had greater atrial and ventricular size and higher systolic pressure and function than normal subjects or patients with normal natriuretic factor levels. Plasma atrial natriuretic factor was inversely related to peak diastolic filling rate in normal subjects (r = -0.59; p less than 0.001), whereas it was positively related to the proportional contribution of atrial systole to left ventricular filling in hypertensive patients (r = 0.77; p less than 0.001). These findings suggest that in normal subjects, impairment of ventricular relaxation with age may contribute to atrial natriuretic factor secretion by increasing left atrial afterload; the correlation with left ventricular size may reflect physiologic fluctuations in plasma volume. In patients with uncomplicated hypertension, left atrial enlargement and consequent stronger atrial contraction contributed to increased atrial natriuretic factor release, whereas no independent relation existed with left ventricular hypertrophy or systolic function. Because ventricular relaxation was normal and ventricular size and systolic performance were increased in hypertensive patients with high atrial natriuretic factor levels, the observed increase in left atrial size and atrial contribution to ventricular filling might reflect a primary increase in venous return in this subset of hypertensive patients.

Hemodynamic abnormalities following cardiac transplantation: relationship to hypertension and survival

The prevalence and long-term implications of hemodynamic abnormalities seen at 1 year following orthotopic heart transplantation and their relationship to post-transplant hypertension were prospectively evaluated in 82 consecutive asymptomatic recipients taking cyclosporine and prednisone who underwent annual catheterization. Abnormal left ventricular end-diastolic pressure (LVEDP), ejection fraction (EF), and left ventricular end-diastolic pressure-volume ratio (R) were the most prevalent hemodynamic abnormalities (27%, 14%, and 23%, respectively, at 1 year). Patients with abnormal LVEDP or R had higher (p less than 0.05) mean systemic arterial pressure (MAP). During follow-up, hemodynamic abnormalities disappeared in some patients while they developed in some others. Transplant patients with abnormal LVEDP, EF, or R at 1 year who normalized at 2 years had a significant (p less than 0.05) decrease in MAP. Likewise, patients with normal LVEDP, EF, or R at 1 year who subsequently developed abnormalities had a significant (p less than 0.05) increase in MAP. The presence of hemodynamic abnormalities at 1 year was not associated with a poorer survival (mean follow-up 2.6 +/- 1.1 years). In summary, hemodynamic abnormalities in asymptomatic transplant recipients taking cyclosporine and prednisone appear to be related to the level of post-transplant hypertension and do not signify an adverse prognosis over the first 3 years.

Effect of nitroglycerin-induced reduction of left ventricular filling pressure on diastolic filling in acute dilated heart failure

Recent information has suggested that early diastolic filling may be influenced by the left ventricular filling pressure, especially in the failing left ventricle. Acute severe left ventricular dysfunction was induced in 14 dogs by severe left ventricular global ischemia produced by left main coronary artery microsphere embolization until the left ventricular end-diastolic pressure was greater than or equal to 20 mm Hg. To assess the importance of left ventricular filling pressure on left ventricular diastolic filling, nitroglycerin was infused and titrated to reduce left ventricular end-diastolic pressure to less than 15 mm Hg in seven dogs, whereas the remaining seven dogs were observed for 1 h after acute severe left ventricular dysfunction. In both groups of dogs, severe left ventricular dysfunction resulted in left ventricular dilation and elevation of end-diastolic pressure, reduction in area ejection fraction (echocardiographically determined) and an early redistribution of diastolic filling (increased filling fractions at one-third and one-half diastole) despite prolongation of the time constant of left ventricular pressure decline. Pressure-area plots shifted upward and rightward with severe left ventricular dysfunction and were unchanged at 1 h as were all other variables. Nitroglycerin infusion reduced left ventricular size and filling pressure, redistributed diastolic filling to later in diastole as characterized by reduced filling fraction at one-third diastole (left ventricular dysfunction 48.8 +/- 9.7%, nitroglycerin 17.9 +/- 7.9%, p less than 0.001) and shifted downward left ventricular pressure-area plots. Nitroglycerin also improved the time constant of relaxation (left ventricular dysfunction 83 +/- 15 ms, nitroglycerin 52 +/- 15 ms, p less than 0.001) and lengthened the diastolic filling period.(ABSTRACT TRUNCATED AT 250 WORDS)

Doppler left ventricular diastolic filling abnormalities in aortic stenosis and their relation to hemodynamic parameters

Doppler mitral flow indexes and their relation to invasively measured hemodynamic diastolic indexes were assessed in 13 patients with isolated aortic stenosis (AS), and compared to Doppler indexes in 10 normal subjects matched for age, heart rate, left ventricular (LV) ejection fraction and LV load. Patients with AS showed no difference in Doppler early filling (E) indexes, but demonstrated greater Doppler atrial filling (A) indexes in comparison to normal subjects: atrial velocity (89 +/- 31 vs 56 +/- 7 cm/s), atrial integral (11.4 +/- 4.8 vs 5.7 +/- 1.6 cm), A/E velocity (1.69 +/- 0.89 vs 1.06 +/- 0.26) and A/E integral (3.53 +/- 6.64 vs 0.81 +/- 0.27) (all p less than 0.05). Doppler indexes in patients with AS did not correlate with hemodynamic indexes of LV relaxation or chamber stiffness. Significant correlations were observed between Doppler and angiographic peak filling rates (r = 0.70) and between Doppler atrial filling velocity and LV end-diastolic volume (r = -0.66), LV end-diastolic pressure (r = -0.48) and LV ejection fraction (r = 0.53) (all p less than 0.05). These data indicate that, compared to matched normal subjects, most patients with AS have an increased atrial contribution to LV filling. However, in patients with decreased LV function, atrial function may also be depressed, as indicated by a decreased atrial contribution to LV filling, resulting in "normalization" of the Doppler mitral flow pattern.

Influence of alteration in preload on the pattern of left ventricular diastolic filling as assessed by Doppler echocardiography in humans

We examined the influence of alterations in preload on pulsed Doppler indexes of left ventricular diastolic function in 50 patients including 12 without cardiovascular disease, 29 with coronary artery disease, and nine with critical aortic stenosis. Micromanometer left ventricular pressure was recorded simultaneously with pulsed Doppler echocardiography of left ventricular inflow and M-mode echocardiography of left ventricular diameter. Chamber stiffness constants, kd and kv, were obtained from the diastolic pressure-diameter and pressure-volume relations, respectively. Relaxation was measured by the isovolumic relaxation time constants, TL and TD, derived from the exponential left ventricular pressure decay and maximum negative dP/dt. In 41 patients after nitroglycerin treatment, left ventricular end-diastolic pressure decreased from 18 +/- 5 to 13 +/- 4 mm Hg (p less than 0.001). The ratio of peak early to peak atrial filling velocities and time-velocity integral ratios decreased from 1.08 +/- 0.57 to 0.90 +/- 0.42 (p less than 0.001) and from 1.77 +/- 0.95 to 1.41 +/- 0.71 (p less than 0.001), respectively. The peak early filling velocity and time-velocity integral decreased from 56.1 +/- 15.7 to 49.9 +/- 14.5 cm/sec (p less than 0.001) and from 7.9 +/- 2.7 to 6.8 +/- 2.8 cm (p less than 0.001), respectively. Relaxation (TL, TD, and maximum negative dP/dt) and chamber stiffness (kd and kv) were not impaired after nitroglycerin administration. In 48 patients after ventriculography, left ventricular end-diastolic pressure increased from 18 +/- 6 to 22 +/- 8 mm Hg (p less than 0.001). The peak early and peak atrial filling velocities increased from 57.4 +/- 15.2 to 68.3 +/- 19.7 cm/sec (p less than 0.001) and from 61.0 +/- 22.7 to 69.4 +/- 23.2 cm/sec (p less than 0.01), respectively. As a result, the ratio of peak early to peak atrial filling velocity was unchanged. However, in the aortic stenosis group, the ratio of peak early to peak atrial filling velocity increased from 0.95 +/- 0.64 to 1.10 +/- 0.72 (p less than 0.02). Relaxation and chamber stiffness were unchanged. Thus, a reduction or increase in preload may induce a diastolic filling pattern that mimics or masks diastolic dysfunction, respectively. Preload conditions need to be accounted for when the status of diastolic function is extrapolated from the pulsed Doppler mitral inflow velocity profile.

The significance of increased left ventricular outflow tract velocities in the elderly measured by continuous wave Doppler

Forty-four elderly patients (mean age 80 +/- 7 years) with elevated left ventricular outflow tract velocities and corresponding outflow tract gradients documented by continuous wave Doppler are reported (mean peak gradient 50 +/- 28). They had severe left ventricular hypertrophy, small left ventricular end-diastolic dimensions, and supernormal ejection fractions. Thirty-nine percent had a history of hypertension. They were predominantly female, had uniform concentric left ventricular hypertrophy, and had a high incidence of congestive heart failure. Diastolic function was found to be reduced in the elderly group compared to young patients with hypertrophic cardiomyopathy and to age- and sex-matched normal controls. It is concluded that most elderly patients with increased left ventricular outflow tract velocities are etiologically distinct from young patients with hypertrophic cardiomyopathy.

Transmitral flow changes during dipyridamole-induced ischemia. A Doppler-echocardiographic study

Myocardial ischemia results in altered left ventricular (LV) diastolic compliance, reflected by an abnormal mitral inflow pattern on Doppler echocardiography. To investigate the relationship of Doppler echocardiography and regional myocardial systolic function during dipyridamole infusion, we evaluated transmitral flow changes detected by pulsed Doppler technique during a high-dose dipyridamole echocardiography test (DET, two-dimensional echo monitoring with dipyridamole infusion, up to 0.84 mg/kg over 10 min). The DET response produced two groups: group 1 (34 patients) with negative DET, and group 2 (35 patients) with positive DET, defined as the development of a newly onset LV regional asynergy. The E/A values overlapped at baseline (1.07 +/- .32 vs .92 +/- .22; p = NS) but differed at peak changes (.92 +/- .26 vs. 75 +/- .25; p less than .01). Heart rate changes could not account for the observed Doppler changes, since the values of R-R interval were similar in the groups, both basally (.927 +/- .226 vs .867 +/- .143 s; p = NS) and at peak dipyridamole (.754 +/- .100 vs. 681 +/- .112; p = NS). Transient myocardial ischemia induced by dipyridamole administration is accompanied by changes in transmitral flow, which consist of an increase in the relative atrial contribution to LV filling, possibly owing to an acute impairment in LV relaxation.

Effects of ischemia, bypass surgery and past infarction on myocardial contraction, relaxation and compliance during exercise

Abnormalities of left ventricular function during ischemia have been described in animal models and in humans. Exercise, while a physiologic means of inducing ischemia, has a complex effect on left ventricular function by itself. In addition, patients with coronary artery disease have a diversity of chronic changes in myocardial structure and function. Therefore, with use of micromanometer left ventricular pressure measurements and ventricular volumes, calculated from biplane cineangiograms, left ventricular function at rest and during exercise was studied in 57 patients. Exercise-induced ischemia produced a decrease in ejection fraction, an increase in end-systolic volume, dramatic increases in diastolic pressures and an upward shift in the diastolic pressure-volume relation. Central to these changes was abnormal myocardial contraction and relaxation, with reduced regional shortening and impaired left ventricular pressure decay. However, nonischemic areas were capable of augmented shortening, and global pressure decay did accelerate slightly. These findings demonstrate that exercise-induced adjustments in contraction and relaxation are intertwined with ischemia-related abnormalities. Exercise studies in patients after bypass surgery and in patients with scars from distant myocardial infarction were useful in clarifying confounding factors. For example, asynchrony of contraction and relaxation, and chronic changes in passive chamber properties, also compromise systolic and diastolic function during exercise. In patients with coronary artery disease without ischemia during exercise, left ventricular end-diastolic pressure, but not early diastolic pressure, increased during exercise. The increase in pressure was appropriate for a slight increase in end-diastolic volume in a ventricle with a steep pressure-volume relation. Furthermore, end-systolic volume, while maintained during exercise, was not reduced, as occurs normally.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and hemodynamic results after mitral valve replacement in patients with obstructive hypertrophic cardiomyopathy

Mitral valve replacement has been performed in patients with obstructive hypertrophic cardiomyopathy if: (1) the interventricular septum is smaller than 18 mm in the region of usual resection; (2) atypical septal morphology is encountered; (3) a previous left ventricular myomectomy has been performed but residual major obstruction and symptoms persist; or (4) intrinsic mitral valve disease exists. Since 1983, mitral valve replacement has been performed in 58 patients with obstructive HCM only. Thirty-three female patients (mean age, 47.9 years) and 25 men (mean age, 45.7 years) met criteria 1 through 3 for mitral valve replacement. Patients with intrinsic mitral valve disease (criterion 4) were omitted from this study. All patients were in New York Heart Association functional class III or IV and had failed optimal medical therapy. Low-profile mechanical prostheses and bioprostheses were implanted, and the early mortality (less than 30 days or in the hospital) was 8.6% (5/58). Six patients (11.3%) died late, 3 suddenly of probably arrhythmia, 2 of respiratory failure, and 1 of an anticoagulant-related complication. After mitral valve replacement, 40 (83%) of 48 patients surviving operation and returning for evaluation were in functional class I or II, whereas 8 patients were in functional class III. Hemodynamic data obtained 6 months postoperatively showed that pulmonary artery wedge pressure was normal (13.7 +/- 4 mm Hg [+/- standard deviation]), left ventricular end-diastolic pressure had decreased (10.9 +/- 3.4 mm Hg), cardiac index was maintained (2.6 +/- 0.6 L/min/m2), and resting and provoked gradients were unremarkable. Mean follow-up was 24.2 months, actuarial survival was 86% at 3 years, and survival free from thromboembolism, anticoagulant-related complication, reoperation, and congestive heart failure for the same interval was 68%. Complications such as ventricular septal defect and complete heart block are avoided in patients undergoing mitral valve replacement, but device-related and cardiac-related complications can add to the morbidity and mortality in these patients in the long term.

Left ventricular diastolic function: comparison of pulsed Doppler echocardiographic and hemodynamic indexes in subjects with and without coronary artery disease

To evaluate the influence of left ventricular chamber stiffness and relaxation on Doppler echocardiographic indexes of diastolic function, 35 patients (mean age 60 +/- 12 years) were examined; 24 had coronary artery disease and 11 (Group I) had no cardiovascular disease. Micromanometer left ventricular pressure was recorded simultaneously with Doppler echocardiograms of mitral valve inflow and M-mode echocardiograms of left ventricular diameter. The chamber stiffness constant (k) was derived from the pressure-diameter relation. Relaxation was assessed by the isovolumic relaxation time constant (tau) derived from the exponential left ventricular pressure decay. The patients with coronary artery disease were classified into two groups on the basis of complete (Group II; n = 10) and incomplete (Group III; n = 14) relaxation. In Group I (no coronary disease), significant correlations were demonstrated between the chamber stiffness constant and the peak early filling velocity (r = 0.73; p less than 0.02), peak early to atrial filling velocity ratio (r = 0.82; p less than 0.005), atrial time-velocity integral (r = -0.73; p less than 0.02), early to atrial time-velocity integral ratio (r = 0.70; p less than 0.05), percent atrial contribution to filling (r = -0.64; p less than 0.05) and one-half filling fraction (r = 0.73; p less than 0.02). In Group II (coronary disease with complete relaxation), the chamber stiffness constant correlated with peak early filling velocity (r = 0.68; p less than 0.05), early filling time-velocity integral (r = 0.65; p less than 0.05) and early to atrial time-velocity integral ratio (r = 0.74; p less than 0.02). No correlations between k and Doppler indexes were found in Group III (coronary disease with incomplete relaxation). However, Group III demonstrated significant correlations between tau and the peak early filling velocity (r = -0.71; p less than 0.005), percent atrial contribution to filling (r = 0.56; p less than 0.05) and mean acceleration rate of early filling (r = -0.79; p less than 0.002). Thus, in subjects with normal relaxation, increasing chamber stiffness was associated with an enhanced peak early filling velocity and volume and decreased filling during atrial systole. This finding differs strikingly from the proposed influence of chamber stiffness on diastolic filling postulated by several researchers.(ABSTRACT TRUNCATED AT 400 WORDS)

Beta-adrenergic stimulation with isoproterenol enhances left ventricular diastolic performance in hypertrophic cardiomyopathy despite potentiation of myocardial ischemia. Comparison to rapid atrial pacing

Impaired left ventricular relaxation and filling is an important pathophysiologic mechanism in hypertrophic cardiomyopathy. To determine whether isoproterenol, known to improve relaxation in isolated cardiac muscle, could favorably modify this effect, we assessed simultaneous left ventricular volume and regional systolic asynchrony (by radionuclide angiography), left ventricular pressure (by micromanometer catheters), and lactate metabolism in 12 patients with hypertrophic cardiomyopathy. Pressure-volume relations were studied during atrial pacing stress to induce myocardial ischemia and during isoproterenol infusion to similar heart rates. Angina occurred in 10 patients with pacing and in 11 patients during isoproterenol infusion; lactate consumption was reduced in nine patients during isoproterenol compared with pacing, including five patients who produced lactate with isoproterenol. During isoproterenol compared with pacing, peak left ventricular pressure was higher (205 +/- 33 vs. 142 +/- 21 mm Hg, p less than 0.001), ejection fraction was higher (77 +/- 10% vs. 71 +/- 12%, p less than 0.02), and regional systolic nonuniformity was diminished. Despite ischemia, these changes in load and nonuniformity during isoproterenol were associated with enhanced diastolic function compared with pacing tachycardia: isoproterenol reduced T 1/2, the half-time of pressure decline after peak negative dP/dt (from 46 +/- 10 to 33 +/- 6 msec, p less than 0.001), shifted the diastolic pressure-volume curve downward and rightward in 10 of 12 patients, and increased end-diastolic volume (from 77 +/- 18% to 100 +/- 11% of control values, p less than 0.001) with no change in end-diastolic pressure (19 +/- 7 to 19 +/- 5 mm Hg, p = NS). Thus, despite ischemia, isoproterenol improved left ventricular relaxation and filling compared with tachycardia in the absence of beta-adrenergic stimulation. Although isoproterenol is detrimental in hypertrophic cardiomyopathy by provoking ischemia, these data suggest that the adverse effects of ischemia on ventricular relaxation and distensibility may be alleviated by beta-adrenergic stimulation, possibly as a result of enhanced inactivation and restored load sensitivity.

Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part I. Physiologic and pathophysiologic features

In the past, evaluation of the myocardium has been limited to examining systolic function of the heart. Recently, however, investigators have demonstrated that abnormalities of diastolic function of the heart provide important contributions to the signs and symptoms experienced by patients with heart disease. In addition, abnormalities of diastolic function may precede abnormalities of systolic function in the early stages of disease. Diastolic filling of the heart, however, is a complex sequence of interrelated events. In order to understand diastolic function, each of these factors contributing to filling of the heart must be examined. They include relaxation, passive compliance, atrial contraction, erectile effect of the coronary arteries, viscoelastic properties, ventricular interaction, and pericardial restraint--all of which are interrelated. In addition, diastolic factors are affected by changes in loading conditions and contractility, and they demonstrate nonuniformity in time and space. This report provides an overview of these various factors from the clinical perspective, based on studies involving the isolated papillary muscle and the isolated heart as well as basic clinical studies.

Radionuclide angiographic assessment of left ventricular diastolic filling in amyloid heart disease: a study of patients with familial amyloid polyneuropathy

To assess left ventricular diastolic filling in amyloid heart disease, 17 patients with familial amyloid polyneuropathy and 20 normal subjects were examined by radionuclide angiography. None of the patients showed clinical evidence of restrictive cardiomyopathy. All but two patients had normal left ventricular ejection fraction. Peak filling rate was significantly lower and time to peak filling rate was significantly greater in patients than in normal subjects (2.60 +/- 0.52 versus 3.10 +/- 0.44 EDV/s, p less than 0.001, and 215 +/- 53 versus 147 +/- 18 ms, p less than 0.001, respectively). The mean left ventricular filling volume during rapid diastolic filling and atrial systole in patients was 54.5 +/- 19.5% and 44.2 +/- 21.6% of the stroke volume, respectively, compared with 83.8 +/- 6.6% (p less than 0.001) and 20.0 +/- 6.0% (p less than 0.001), respectively, in normal subjects. Although 10 of the 14 patients without clinical evidence of overt heart disease had normal ventricular wall thickness as well as normal ejection fraction, 8 of the 10 showed abnormal diastolic filling. In patients with familial amyloid polyneuropathy, indexes of diastolic filling were significantly related to ventricular wall thickness alone. The incidence and magnitude of abnormalities in time to peak filling rate and contribution of rapid filling as well as atrial systole to ventricular filling increased with age and duration of illness. Thus, abnormal diastolic filling can be seen even in the early stage of familial amyloid polyneuropathy and may be related to myocardial amyloid deposition as well as to fibrosis. Careful consideration should be given to age and duration of illness when diastolic filling is assessed in this disorder.

Diastolic filling in acute left ventricular dysfunction: role of the pericardium

Patients with congestive heart failure and elevated left ventricular filling pressures demonstrate an abnormal pattern of diastolic filling that is characterized by a redistribution of diastolic filling to early diastole with reduced reliance on late diastolic filling. The diastolic filling pattern superficially resembles that which is seen with constrictive pericarditis. To examine potential mechanisms for these clinical findings, a model of ischemic left ventricular dysfunction was produced in seven dogs by repeated coronary microsphere embolization, producing a dilated left ventricle with reduced systolic function. Measurements of left ventricular systolic and end-diastolic pressures, rate of rise of left ventricular pressure (dP/dt) and echocardiographic end-diastolic and end-systolic areas were obtained at baseline, during intermediate embolization (moderate left ventricular systolic dysfunction, dilation and mild increases in left ventricular end-diastolic pressure), postembolization (further embolization resulting in severe left ventricular systolic dysfunction, dilation and marked increases in left ventricular end-diastolic pressure), after thoracotomy and after pericardiectomy. The filling fraction at 1/3 and 1/2 of diastole and the time constant of left ventricular pressure decline were also determined. Repetitive coronary microembolization caused progressive left ventricular dilation and decreasing systolic function, which did not change after opening the chest or pericardium. The filling fraction at 1/3 and 1/2 of diastole declined with intermediate embolization (12.0 +/- 5.6% and 23.1 +/- 10.8%, respectively) as compared with baseline values (29.0 +/- 11.9%, 42.9 +/- 15.6%, p less than 0.05). After embolization, there was an increase in the 1/3 and the 1/2 filling fraction (47.5 +/- 8.9%, 72.0 +/- 6.0%, respectively, p less than 0.01) as compared with baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of anesthetic induction on myocardial function and metabolism: a comparison of fentanyl, sufentanil and alfentanil

Anaesthetic induction may induce myocardial ischaemia. A prospective randomized trial was instituted to compare the effect on ventricular function and myocardial metabolism of induction with fentanyl (FEN) or its analogues sufentanil (SUF) or alfentanil (ALF) in 96 patients undergoing elective coronary artery bypass grafting (CABG). Haemodynamic, metabolic (coronary sinus oxygen and lactate extraction) and gated ventriculographic measurements were made awake pre-induction (PRE), after induction (IND) and after intubation (INT). Induction was performed with FEN 75 micrograms.kg-1, SUF 15 micrograms.kg-1 or ALF 125 micrograms.kg-1 and metocurine. Fentanyl induction was associated with the greatest stability of mean arterial pressure (MAP), cardiac performance, and systolic function without associated myocardial lactate production. SUF produced the greatest depression of systolic function (p less than 0.05) but without haemodynamic instability or myocardial lactate production in all but one patient. Induction with ALF produced the greatest reduction in MAP (p less than 0.05) associated with the greatest decrease in diastolic compliance (p less than 0.05) and 50 per cent incidence of myocardial lactate production (p less than 0.05) with no significant change in coronary blood flow or myocardial oxygen consumption.