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Echocardiographic changes after myocardial infarction in a model of left ventricular diastolic dysfunction.

To determine the early and late effects of myocardial infarction on left ventricular (LV) diastolic function in the rabbit postinfarction model, male New Zealand White rabbits were randomly assigned to ligation of the circumflex artery or sham operation. Serial echocardiographic and Doppler studies were performed on both groups of animals at baseline and 1 h and 3 wk after surgery (n = 10 for each group) after verification of the reproducibility and repeatability of the measurements. At 1 h postinfarction, decreases in early mitral inflow velocity (E wave) and mitral inflow velocity with atrial contraction (A wave) and increases in the mean pulmonary venous systolic-to-diastolic ratio and A wave reversal velocities were observed, without changes in LV geometry. By 3 wk postinfarction, increases in the mitral E-to-A ratio (1.1 +/- 0.3 vs. 2.9 +/- 0.9, P < 0.001) and left atrial area (131 +/- 23 vs. 510 +/- 72 mm2, P < 0.001) and decreases in the pulmonary venous systolic-to-diastolic ratio (0.56 +/- 0.20 vs. 0.79 +/- 0.14, P = 0.008) were consistent with severe diastolic abnormalities (restricted physiology). The findings of this study demonstrate that coronary artery ligation in the rabbit provides a reproducible echocardiographic and Doppler model of LV diastolic dysfunction that is consistent with abnormalities found in humans with previous myocardial infarction, symptoms of heart failure, and preserved LV systolic function.

Animals↗

[Diastolic dysfunction and left ventricular hypertrophy in familial amyloidotic polyneuropathy: a cause-effect relationship?].

UNLABELLED: TTR Met30 Familial Amyloidotic Polyneuropathy of the Portuguese type (FAP) is an incapacitating and lethal hereditary disorder that affects predominantly young adults of both genders. Portuguese type FAP patients have sensory, motor and autonomic polyneuropathy. The generalised systemic amyloid infiltration involves the heart, leading to the characteristic granular bright sparkling echocardiographic pattern. LV wall thickening occurs in the late phases of the disease. LV diastolic dysfunction has been reported in the absence of systolic dysfunction; an abnormal diastolic transmitral flow pattern assessed by pulsed wave Doppler (PW) was described. PW is very much dependent on load conditions. Tissue Doppler imaging (TDI) has been used as a more reliable method to assess long axis diastolic function. OBJECTIVE: 1--To identify the incremental value of TDI in the assessment of diastolic function in FAP. 2--To correlate diastolic pattern abnormalities and left ventricular mass index (LVMI) in FAP patients. METHODS: We performed a prospective evaluation of 24 consecutive FAP patients and selected 14 (sinus rhythm, age < 45 years). Diastolic function was assessed by PW and classified as normal (GI-E/A > 1) or abnormal (GII-E/A < 1). TDI was performed in 4 sites of the mitral annulus (septum, lateral, inferior, anterior). Velocities of the rapid filling wave (E') and atrial contraction wave (A') were measured and E'/A' calculated. In each site we considered the TDI as normal (E'/A' > 1) or abnormal (E'/A' < 1). The LVMI was calculated by Devereux's formula. RESULTS: Age, gender and heart rate were similar in both groups. TDI at the septal mitral annulus was normal in all of the GI patients (E'/A': 1.29 +/- 0.19) and suggestive of abnormal LV relaxation in all of the GII patients (E'/A': 0.82 +/- 0.11, p < 0.0001). TDI revealed abnormal diastolic pattern when a restricted number of sites of the mitral annulus were assessed, even in GI patients and before PW abnormalities occurred. Fractional shortening (FS) and LVMI were similar in GI and GII (FS-GI: 45.5 +/- 5.3, GII 43.5 +/- 8.1%, p: NS; LVMI--GI: 66 +/- 9.3, GII: 67 +/- 3.0 g/m2 p: NS). CONCLUSION: The assessment of mitral annulus motion has introduced new data in the study of diastolic function of FAP patients. An abnormal LV relaxation pattern occurred early in the evolution of the disease in patients with normal LVMI and systolic function.

Adult↗

Effects of venous return reduction in hypertensive patients: is there a Doppler diastolic dysfunction index independent of preload reduction?

The aim of this study was to evaluate the effects of preload reduction on the Doppler transmitral flow pattern in the presence of diastolic dysfunction (hypertensive patients) and normal diastolic function (normal subjects) to identify, if present, one or more indexes of abnormal diastolic ventricular filling independent of variations in preload. For this purpose Doppler echocardiography was performed in 17 patients with hypertension and in 18 normal subjects under basal conditions and after 5 minutes of blood pressure cuff inflation at the root of the four limbs. The two groups showed a similar response to preload reduction: a significant reduction in peak velocity and the time-velocity integral of the E wave and in the ratio of peak velocities of E and A waves. Therefore the differences in left ventricular filling patterns between hypertensive and normal subjects observed under basal conditions were still present after preload reduction. The comparison between normal subjects after preload reduction and hypertensive patients in the basal state showed a higher peak velocity and time-velocity integral of the A wave in the latter (61.2 +/- 16.2 vs 46.2 +/- 9 cm/sec [p less than 0.002] and 5.4 +/- 1.8 vs 3.7 +/- 1 cm [p less than 0.002], respectively) with no differences in the ratios of peak velocities and time-velocity integrals of the E and A waves.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Left ventricular diastolic dysfunction in end-stage dilated cardiomyopathy: simultaneous Doppler echocardiography and hemodynamic evaluation.

Left ventricular diastolic dysfunction is an integral component of end-stage dilated cardiomyopathy. To better characterize this disorder we studied 15 patients undergoing catheterization during cardiac transplant screening evaluation. Pulsed-wave Doppler echocardiographic recordings of mitral inflow were obtained with simultaneous high-fidelity left ventricular and phase-corrected pulmonary capillary wedge pressures. Doppler-derived isovolumic relaxation times were within normal limits, despite a prolonged coefficient of relaxation (tau), and correlated with pulmonary capillary wedge--left ventricular crossover pressure. Peak velocity of early diastolic filling was similar to that reported in normal subjects and did not correlate with crossover pressure or tau. Early diastolic acceleration and deceleration times were shortened compared with reported normal values. Acceleration time correlated with mean negative dP/dt from mitral valve opening to left ventricular minimum pressure and with crossover pressure, and deceleration time correlated with mean dP/dt from left ventricular minimum pressure to the peak of the rapid filling wave. Late diastolic filling at atrial contraction was absent in 12 patients, all of whom had a significant early diastolic rapid filling wave and an elevated end-diastolic pressure. Despite an increase in pulmonary capillary wedge pressure during atrial contraction, the failing ventricles were unable to generate detectable forward transmitral flow. Poor cardiac pump function was shown by low left ventricular stroke volume, which correlated with the diastolic flow velocity integral. Thus, in end-stage cardiomyopathy, the transmitral flow velocity pattern is characterized by normal peak early filling velocity, low normal isovolumic relaxation time, shortened acceleration and deceleration times of early diastolic flow, decreased early flow velocity integral, and absent or decreased filling during atrial contraction. This pattern reflects interaction between elevated transmitral driving pressure and the compromised relaxation and compliance of a left ventricle functioning on an elevated pressure-volume curve.

Adult↗

Hypertensive myocardial fibrosis and diastolic dysfunction: another model of inflammation?

Excessive myocardial fibrosis deteriorates diastolic function in hypertensive hearts. Involvement of macrophages is suggested in fibrotic process in various diseased situations. We sought to examine the role of macrophages in myocardial remodeling and cardiac dysfunction in pressure-overloaded hearts. In Wistar rats with suprarenal aortic constriction, pressure overload induced perivascular macrophage accumulation and fibroblast proliferation with a peak at day 3, decreasing to lower levels by day 28. Myocyte chemoattractant protein (MCP)-1 mRNA was upregulated after day 1, peaking at day 3 and returning to insignificant levels by day 28, whereas transforming growth factor (TGF)-beta induction was observed after day 3, with a peak at day 7, and remained relatively elevated at day 28. After day 7, concentric left ventricular (LV) hypertrophy developed, associated with reactive fibrosis and myocyte hypertrophy. At day 28, echocardiography showed normal LV fractional shortening but decreased ratio of early to late filling wave of transmitral Doppler velocity, and hemodynamic studies revealed elevated LV end-diastolic pressure, suggesting normal systolic but impaired diastolic function. Chronic treatment with an anti-MCP-1 monoclonal neutralizing antibody inhibited not only macrophage accumulation but also fibroblast proliferation and TGF-beta induction. Furthermore, the neutralizing antibody attenuated myocardial fibrosis, but not myocyte hypertrophy, and ameliorated diastolic dysfunction without affecting blood pressure and systolic function. In conclusion, roles of MCP-1-mediated macrophage accumulation are suggested in myocardial fibrosis in pressure-overloaded hearts through TGF-beta-mediated process. Inhibition of inflammation may be a new strategy to prevent myocardial fibrosis and resultant diastolic dysfunction in hypertensive hearts.

Animals↗

Midwall fractional shortening is an independent predictor of left ventricular diastolic dysfunction in asymptomatic patients with systemic hypertension.

Conventional measures of left ventricular (LV) systolic performance suggest that diastolic dysfunction precedes the development of systolic dysfunction in hypertension. Midwall fractional shortening is a new measure of systolic function that identifies hypertensive patients who have evidence of target-organ damage, impaired contractile reserve, and increased mortality. We therefore sought to determine whether depressed midwall fiber shortening is associated with abnormal diastolic function. Echocardiograms were obtained in 102 otherwise healthy hypertensive patients without treatment with normal conventional measures of systolic function. Of these, 15 had depressed midwall shortening based on previously described normative relations. Patients with depressed midwall shortening had slightly higher blood pressure. Abnormal diastolic function, defined as late (A) LV inflow velocity greater than early (E) velocity, was observed in 33% of those with normal midwall shortening but in 60% of those with depressed shortening (p <0.05). Patients with A/E >1 had lower absolute midwall fiber shortening (15 +/- 3% vs 18 +/- 3%, p <0.0001) but similar endocardial shortening. Patients with abnormal midwall shortening had higher A/E and longer isovolumic relaxation times (both p <0.05). In multivariate analysis, midwall fractional shortening, age, and heart rate were independent predictors (p <0.01) of A/E in a model including blood pressure, LV mass, and endocardial shortening. We conclude that subnormal midwall shortening predicts LV diastolic abnormalities in this population of hypertensive patients with otherwise normal measures of LV systolic function. Contrary to our previous understanding, depressed LV systolic performance, when identified with this newer method, occurs coincidentally with impaired diastolic function.

Adult↗

Effects of antihypertensive therapy on diastolic dysfunction in left ventricular hypertrophy.

In systemic hypertension, a certain degree of impairment of left ventricular diastolic function is often detectable, and is the consequence of two factors: elevated afterload and left ventricular hypertrophy. The goal of improving diastolic dysfunction can thus be achieved by lowering blood pressure and by inducing a regression in left ventricular hypertrophy. A reduction in blood pressure by intravenous administration of verapamil has proved capable of enhancing left ventricular filling properties in patients with hypertension. This finding has not been corroborated, however, in midterm protocols using an array of drugs (beta-blockers, dihydropyridines, diltiazem, and diuretics). Reduction in left ventricular mass can be achieved by several categories of drugs, and it has been shown that a decrease in mass is accompanied by an improvement in the early diastolic filling pattern. The kind of drug used to accomplish mass reduction seems to be irrelevant as far as the improvement in diastolic function is concerned. The pattern of left ventricular hypertrophy, however, might play a role in influencing the outcome on diastolic mechanics of left ventricular mass decrease.

Adrenergic beta-Antagonists↗

Role of left ventricular regional diastolic abnormalities for global diastolic dysfunction in patients with hypertrophic cardiomyopathy.

BACKGROUND: The usefulness of Doppler strain rate imaging for assessment of left ventricular regional diastolic function has not been fully determined. OBJECTIVE: We aimed to clarify the relationships between diastolic strain rates and global diastolic function and find a useful index for regional diastolic function in patients with hypertrophic cardiomyopathy (HCM). METHODS: Strain rate curves were obtained using an apical approach at 12 different sites of the left ventricular myocardium in 25 patients with HCM and 20 control subjects, and peak early diastolic strain rate (ESR), peak late diastolic strain rate, and the time from QRS to ESR were measured. The flow propagation velocity was measured using color M-mode Doppler echocardiography as a global diastolic index. RESULTS: Each of the spatially averaged values of ESR and ESR/peak late diastolic strain rate and the coefficients of variation of time from QRS to ESR was significantly correlated with flow propagation velocity, but the best correlation was observed in ESR. Although both ESR and peak late diastolic strain rate of each myocardial segment of patients with HCM tended to decrease as the wall thickness increased, only ESR significantly decreased even in the segments without apparent hypertrophy. CONCLUSIONS: In patients with HCM, the reduction of ESR was more closely associated with global diastolic dysfunction than asynchrony, and ESR may be a useful and sensitive index for regional diastolic function.

Cardiomyopathy, Hypertrophic↗

Prognostic value of the atrial pulsed Doppler recordings of transmitral flow in the assessment of left ventricular diastolic dysfunction.

Volume sample location is the most important factor influencing pulsed Doppler recordings of left ventricular (LV) diastolic filling. Transmitral diastolic flow velocities measured at the tips of mitral valve leaflets are usually higher than those obtained from atrial location. Nevertheless, independently of volume sample location, differences between early to late velocities ratio (E/A) are nonsignificant, so E/A became the most useful index of ventricular diastolic performance. In some patients, however, with E/A > 1 measured between the tips of mitral leaflets, the pattern of delayed LV relaxation, with diminished E and predominant A wave (E/A < 1), is often obtained from left atrial volume sample location. The aim of our study was to compare LV dimensions and wall thickness between patients with E/A > 1 recorded both at the tips of mitral valve leaflets and in the left atrium and patients with E/A > 1 at the tips of mitral valve leaflets and E/A < 1 in the left atrium. The study population consisted of 51 patients with E/A > 1 recorded between the tips of mitral valve (E/Avent) and excluded pseudonormalized filling pattern. The study population was divided into two groups based on Doppler profile recorded in the left atrium: group A--26 patients with E/A < 1 (E/Aatr) and group B--25 patients with E/Aatr > 1. Patients from group A were significantly older (55.6 +/- 12.8 vs 43.5 +/- 10.5 yrs, p < 0.001) and had increased body mass index (28.8 +/- 4.4 vs 25 +/- 4.1 kg/m2, p < 0.01) compared to subjects from group B. The average thickness of intraventricular septum was 13.5 +/- 2.8 mm in group A and 9.7 +/- 1.6 mm in group B, the average thickness of LV posterior wall was 11.6 +/- 1.7 and 9.2 +/- 1.8 mm, respectively. The results of this study suggest that abnormal atrial recordings of diastolic flows may reflect the earliest stage of left ventricular diastolic dysfunction in asymptomatic patients with echocardiographic signs of mild cardiac damage.

Adult↗

Echocardiographic indices of left ventricular diastolic dysfunction in 647 individuals with preserved left ventricular systolic function.

BACKGROUND: Knowledge about the occurrence of isolated diastolic dysfunction (DD) in the general population is limited. AIMS: This population study was performed to assess the frequency and distribution pattern of echocardiographic indices of left ventricular (LV) DD in an elderly population aged 50-89 years in which LV systolic function is preserved. METHODS AND RESULTS: The study population (n=764) recruited from the background population answered a heart failure questionnaire and underwent echocardiography. Excluding subjects with a LV ejection fraction <50% or atrial fibrillation, diastolic function was evaluated in 647 subjects. The frequency of impaired relaxation according to earlier guidelines was 0.5%, vs. 2.5% using age- and gender-specific normal values of 'E/A-ratio' and 'deceleration time'. In a subpopulation of 167 participants, 6.6% had 'pseudonormalisation'. No difference was found in the frequency of dyspnea in subjects with impaired relaxation or 'pseudonormalisation' compared to subjects with normal filling pattern. CONCLUSION: The prevalence of LV impaired relaxation was highly dependent on the choice of normal (cut-off) values for Doppler indices. Furthermore, our findings suggest that either isolated DD is often asymptomatic, or that Doppler flow derived parameters as a diagnostic method for assessing DD have a low specificity when used as a screening tool in the general population.

Age Factors↗

Diastolic dysfunction and left atrial volume: a population-based study.

OBJECTIVES: We examined the association between diastolic function and left atrial volume indexed to body surface area (LAVi) in a population-based study. BACKGROUND: Atrial enlargement has been suggested as a marker of the severity and duration of diastolic dysfunction (DD). However, the association between DD and atrial enlargement and their individual prognostic implications in the population is poorly defined. METHODS: A cross-sectional sample of Olmsted County, Minnesota, residents > or =45 years of age (n=2,042) underwent comprehensive Doppler echocardiography and medical record review. RESULTS: The LAVi increased with worsening DD: 23 +/- 6 ml/m2 (normal), 25 +/- 8 ml/m2 (grade I DD), 31 +/- 8 ml/m2 (grade II DD), 48 +/- 12 ml/m2 (grades III to IV DD). In bivariate analyses, age, left ventricular mass index, and DD grade were positively associated, whereas female gender and ejection fraction (EF) were inversely associated with LAVi (p <0.001 for all). When controlling for age, gender, cardiovascular (CV) disease, EF, and left ventricular mass, grade II DD was associated with a 24%, and grade III to IV DD was associated with a 62% larger LA volume (p <0.0001 for both). The area under the receiver-operator characteristic curve for LAVi to detect grade I, grade II, or grade III to IV DD was 0.57, 0.81, and 0.98, respectively. Both DD and LAVi were predictive of all-cause mortality, but when controlling for DD, LAVi was not an independent predictor of mortality. CONCLUSIONS: These data suggest that DD contributes to LA remodeling. Indeed, DD is a stronger predictor of mortality; presumably it better reflects the impact of CV disease within the general population.

Aged↗

Prevalence of suspected diastolic dysfunction in patients with a clinical diagnosis of congestive heart failure.

INTRODUCTION: The prevalence of diastolic left ventricular (LV) dysfunction in a population presenting with a suspected diagnosis of congestive heart failure (CHF) is questionable and widely variable in the current literature. To minimize the disparity, we evaluated a large echocardiographic database to investigate the prevalence of systolic and suspected diastolic LV dysfunction in those with a suspected clinical diagnosis of CHF. METHODS: We retrospectively reviewed echocardiograms performed at our institution and evaluated the prevalence of abnormal LV systolic and diastolic function in those with a suspected clinical diagnosis of CHF. Diastolic dysfunction was defined as the presence of left atrial enlargement, left ventricular hypertrophy and reverse trans-mitral inflow ratio (E/A reversal). RESULTS: Of the 636 echocardiograms with CHF as the primary diagnosis, 461 had measured LV function. Normal LV systolic function were found in 238 of the patients (48%). Isolated diastolic LV dysfunction was found in 166 patients (36%). Twelve percent of the patients with a suspected clinical diagnosis of CHF had normal LV systolic and diastolic function. CONCLUSION: Normal LV systolic function was seen in nearly one-half of the echocardiograms with a suspected clinical diagnosis of CHF. Suspected LV diastolic dysfunction was observed in one-third of the echocardiograms with a suspected clinical diagnosis of CHF.

Diastole↗

Diastolic stress echocardiography: a novel noninvasive diagnostic test for diastolic dysfunction using supine bicycle exercise Doppler echocardiography.

Left ventricular filling pressures can be estimated reliably by combining mitral inflow early diastolic velocity (E) and annulus velocity (E'). An increased E/E' ratio reflects elevated filling pressures and may be useful in assessing an abnormal increase in filling pressures for patients with diastolic dysfunction. The purpose of this study was to evaluate the feasibility of supine bicycle exercise Doppler echocardiography for assessing left ventricular diastolic pressure during exercise. Mitral inflow and septal mitral annulus velocities were measured at rest and during supine bicycle exercise (25-W 3-minute increments) in 45 patients (19 men; mean age, 59 years) referred for evaluation of exertional dyspnea. None had echocardiographic or electrocardiographic evidence of myocardial ischemia with exercise. Patients were classified according to E/E' ratio at rest: 26 had E/E' < or = 10 at rest (group 1) and 19 had E/E' > 10 (group 2). For group 1, 17 had no increase in E/E' during exercise (group 1A) and 9 did (group 1B). For group 2, E/E' did not increase during exercise. Despite different responses of E/E', there was no significant difference in changes of mitral inflow indices (E, A, E/A, deceleration time) between groups. Although the percentage of dyspnea as a primary reason for stopping exercise was similar for the groups, exercise duration was significantly shorter for groups 1B (7.2 +/- 2.5 minutes) and 2 (7.1 +/- 3.3 minutes) than in group 1A (10.4 +/- 3.7 minutes, P = .0129). Diastolic stress echocardiography using a supine bicycle is technically feasible for demonstrating changes in E/E' (filling pressure) with exercise. Our preliminary results suggest the hemodynamic consequences of exercise-induced increase in diastolic filling pressure can be demonstrated noninvasively with exercise Doppler echocardiography.

Adult↗

[Diastolic dysfunction and its relation to myocardial fibrosis in essential hypertension].

This study elucidated diastolic left ventricular dysfunction and whether myocardial interstitial fibrosis correlates with diastolic dysfunction in mild to moderate systemic hypertension (HT). Six normotensive subjects, 18 hypertensive patients without left ventricular hypertrophy (LVH) and 10 hypertensive patients with significant LVH were evaluated. M-mode echocardiography was used to determine fractional shortening (FS), isovolumic relaxation time (IRT), and left ventricular filling volume during rapid and slow filling periods and the atrial contraction period (RFV, SFV, ACV). The quotients of the left ventricular filling volume and the end-diastolic volume and stroke volume were also calculated. Simultaneous biventriculography was used to determine the end-diastolic thickness of the interventricular septum and posterior wall. Right ventricular endomyocardial biopsies were performed to calculate the percentages of fibrosis. The FS was normal in all groups. The percentages of fibrosis in the two HT groups were significantly greater than those in the normals. The IRT of the HT groups was significantly greater, and the RFV, RFV/EDV and RFV/SV were significantly less than those of the normals. Multiple regression analysis showed that the wall thickness and the percentages of fibrosis correlated significantly with IRT, RFV, RFV/EDV and RFV/SV. The standard coefficients of correlation of wall thickness and the percentages of fibrosis were 0.333 and 0.239 in respect to IRT, and -0.304 and -0.473 in respect to RFV. There were significant correlations between the percentages of fibrosis and RFV (r = -0.675), RFV/EDV (r = -0.664) and RFV/SV (r = -0.602) in the normals and in cases of HT without LVH.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗

[Diagnosis of left-ventricular diastolic dysfunction in patients with predialysis chronic renal failure].

AIM: To specify effectiveness of different methods for assessment of diastolic function in patients with pre-dialysis chronic renal failure (CRF). MATERIAL AND METHODS: Forty non-diabetic pre-dialysis CRF patients (20 males and 20 females, mean age 51 +/- 11 years) were studied. Serum creatinine was 209.3 +/- 117.4 mcmol/l. 19 patients had chronic heart failure (CHF) of NYHA class I-III. M-mode echocardiography and Doppler echocardiography were performed. Transmitral and pulmonary venous flows were assessed by Doppler echocardiography and the flow propagation velocity (Vp) was estimated by color M-mode Doppler echocardiography. The ratio of peak E-wave velocity of transmitral flow to Vp (E/Vp) was calculated. All the patients had preserved systolic function (ejection fraction > 45%). RESULTS: Interpretation of transmitral flow was difficult in 16 (40.0%) patients. During Valsalva's manoeuvre the E-wave peak velocities, the A-wave velocities and the ratio E/A were decreasing. However, we did not reveal any correlation between E/A and NYHA class of heart failure (r = 0.18; p = 0.32). Interpretation of pulmonary venous flow was possible only in 24 (60.0%) patients. Vp estimation by color M-mode Doppler echocardiography improved evaluation of diastolic function in 15 of 16 patients with problems of transmitral flow assessment. A negative correlation was revealed between NYHA class and Vp (r = -0.39; p = 0.013) and a positive correlation was between NYHA class and E/Vp (r = 0.45; p = 0.004). CONCLUSION: Vp assessed by color M-mode Doppler echocardiography improves the diagnosis of diastolic dysfunction in patients with chronic renal insufficiency. This method has an advantage over pulmonary venous flow investigation. The Valsalva's manoeuvre is low-effective for differential diagnosis of transmitral flow types.

Blood Flow Velocity↗

Structural abnormalities and not diastolic dysfunction are the earliest left ventricular changes in hypertension. HARVEST Study Group.

It has been claimed that diastolic dysfunction is the earliest cardiac abnormality in hypertension, preceding the development of left ventricular (LV) structural abnormalities. To detect early signs of hypertensive cardiac involvement 722 subjects (533 men and 189 women), 18-45 years old, with stage I hypertension, were studied by M-mode and Doppler echocardiography. Blood pressure was measured by 24-h ambulatory monitoring. Ninety-five normotensive individuals of similar age and gender distributions were studied as controls. Significant, though modest, changes of LV mass and geometry were found in the participants in comparison with the normotensive controls. The increment was +10.4 g/m2 for LV mass index, +1.8 mm for LV wall thickness, and +0.032 for relative wall thickness. A slight increase in atrial filling peak velocity was found in the hypertensive subjects at Doppler analysis of transmitral flow, but the ratio of early to atrial velocity of LV diastolic filling did not differ between the two groups. In multiple regression analyses, which included age, body mass index, heart rate, smoking, and physical activity, 24-h mean blood pressure emerged as a significant predictor of LV mass index (men, P = .003; women, P = .04) and wall thickness (men, P = .03; women, P = .004) in the hypertensive subjects, whereas no index of diastolic filling was significantly associated with ambulatory blood pressure in either gender. The present data indicate that changes in LV anatomy are the earliest signs of hypertensive cardiac involvement. Left ventricular filling is affected only marginally in the initial phase of hypertension.

Adolescent↗

Cellular and molecular mechanisms of systolic and diastolic dysfunction in an avian model of dilated cardiomyopathy.

We investigated the cellular and molecular mechanisms of systolic and diastolic dysfunction in a furazolidone (Fz)-induced model of dilated cardiomyopathy (DCM) in turkey poults. Serial echocardiograms disclosed marked systolic dysfunction in the Fz-treated poults, and ventricular weight and left ventricular (LV)/body weight ratio were significantly increased. Isolated heart experiments were performed to determine LV pressure-volume (P-V) relationships. In addition, LV sarcomere lengths (SLs) were measured after hearts had been fixed, and wall stress (sigma)-SL relationships were determined. When compared to control hearts, LV chamber volume in DCM hearts was approximately 3-fold increased, the active or developed LV P-V relationship was markedly depressed, the passive or diastolic P-V relationship was steeper, and SLs were significantly shorter. However, the developed sigma-SL relationships of DCM and control hearts were not different indicating that intrinsic myocardial capacity to generate active force is unaffected in this model of DCM. In contrast, passive sigma, and passive tension in trabecular muscle preparations increased much more steeply with SL in DCM than normal hearts. Trabecular muscle experiments disclosed that the increase in passive myocardial stiffness was primarily collagen based. Titin, the giant sarcomeric molecule, which is an important determinant of passive myocyte properties in normal myocardium, did not contribute significantly to increased passive myocardial stiffness in DCM. We conclude that increased collagen-based passive myocardial stiffness is the major cause of the steeper passive or diastolic P-V relationship in DCM. Further, altered passive myocardial properties and ventricular geometry in DCM play a critical role to reduce ventricular systolic function by limiting SL extension during diastole, thereby limiting the use of the myocardial length-tension relationship.

Animals↗

[Effects of verapamil on left ventricular diastolic dysfunction].

To assess the effects of verapamil on left ventricular relaxation and filling dynamics in patients with left ventricular diastolic dysfunction (LVDD), Doppler echocardiography (DE) and cardiac catheterization (Cath) were simultaneously performed in 30 cases with LVDD. The left ventricular filling and relaxation indices were measured with DE and Cath respectively, before and after intravenous injection of verapamil. The result showed that after verapamil injection all left ventricular filling measured with DE were significantly improved in all cases, while left ventricular relaxation indices showed significant improvement only in patients with hypertrophic cardiomyopathy and hypertensive heart disease but no changes in patients with old myocardial infarction. There were no significant correlations between left ventricular filling and relaxation indices. It is concluded that the major mechanism of left ventricular filling improvement induced by verapamil is the reduction of left ventricular afterload and verapamil has different therapeutic effects on LVDD with different etiology.

Adolescent↗