Impaired left ventricular filling in borderline hypertensive patients without cardiac structural changes

Myocardial performance index in hypertensive disorders of pregnancy: The relationship between blood pressures and angiogenic factors

OBJECTIVE

To study the association between cardiac function measured by myocardial performance index (MPI), blood pressures and angiogenic factors measured at the time of echocardiography in patients with and without hypertensive disorders of pregnancy (HDP).

METHODS

We prospectively studied 189 pregnant women and evaluated whether changes in cardiac function observed on echocardiography were correlated with higher blood pressures and whether higher blood pressures were associated with antiangiogenic proteins (soluble fms-like tyrosine kinase, sFlt1; soluble endoglin, sEng). Comprehensive echocardiograms, including measurement of MPI, were performed on all patients. sFlt1 and sEng levels were measured using enzyme-linked immunosorbent assay.

RESULTS

Overall, 189 patients were divided into tertiles based on mean arterial pressure (MAP). The MPI was worst in tertile 3 (0.50 ± 0.15) compared to tertile 1 (0.42 ± 0.10), p = 0.0004. sFlt1 (pg/ml) and sEng (ng/ml) were highest in tertile 3 compared to tertile 1: 15055.37 vs. 1623.01 and 33.06 vs. 8.15, respectively, with p-value <0.001. In crude multivariate regression analysis, MAP was positively correlated with MPI (r = 0.32, p < 0.001), GLS (r = 0.54, p < 0.001), sFlt1 (r = 0.60, p < 0.001) and sEng (r = 0.61, p < 0.001). After adjustment for confounders, these relationships persisted between MAP and MPI (r = 0.31, p = 0.0003), GLS (r = 0.46, p < 0.001), sFlt1 (r = 0.56, p < 0.001) and sEng (r = 0.58, p < 0.001).

CONCLUSION

Mean arterial pressure correlates with worsening cardiac function as measured by MPI and serum levels of angiogenic factors. Further studies are needed to evaluate whether a reduction in blood pressure will reverse changes in MPI or reduce levels of angiogenic proteins seen among women with HDP.

Losartan Reduces Left Ventricular Hypertrophy Proportionally to Blood Pressure Reduction in Hypertensives, but Does Not Affect Diastolic Cardiac Function

In contrast to the well-recognized salutary effects of angiotensin-converting enzyme inhibition, the value of angiotensin II type I (ATl)-receptor blockade on left ventricular hypertrophy (LVH) is controversial. In addition, the data on the influence of this therapy on cardiac diastolic function are scarce. Thirty-nine patients with moderate primary hypertension, LVH, and normal systolic function received losartan, 50 to 100 mg daily. Transthoracic echocardiography was performed at baseline and after 6 months of treatment. Thirty-one patients completed and were included in the study (16 males, 61.1 ±1.0 years). The patients were divided into responders if mean blood pressure (BP) decreased >5 mm Hg at the end of the study (20 patients) and non-responders (mean BP decrease ≤5 mm Hg, 11 patients). The BP and the LVH were significantly reduced (systolic BP by 10.0%, diastolic BP 6.5%, mean BP 8.2%, left ventricular mass index [LVMI] 6.2%, interventricular septum 5.8%, posterior wall 3.0%) (p≤0.02), attributed to the reduction of BP and LVH in responders; the LVH in non-responders did not alter with treatment. A significant correlation was noted between changes in BP and LVMI ( r =0.60, p<0.001). The systolic cardiac function remained normal. The Doppler parameters usually used to assess the diastolic function of the LV (early diastolic filling velocity [E wave], late diastolic filling velocity [A wave], ratio of E/A waves, isovolumic relaxation time), which were abnormal at baseline, did not change with treatment. The size of the left atrium increased (p<0.05) at the end of the study. In conclusion, a 6-month course with losartan decreased BP and LVH. However, the LVH regression was rather associated with the reduction of the hemodynamic stimulus per se, than any trophic effect of the drug in the myocardium. The diastolic cardiac function remained abnormal with treatment.

The Degree of Albuminuria Is Related to Left Ventricular Hypertrophy in Hypertensive Diabetics and Is Associated with Abnormal Left Ventricular Filling: A Pilot Study

The association of albuminuria and left ventricular (LV) hypertrophy (LVH) in diabetics aggra vates the prognosis. The authors studied the relation between LVH and the degree of albu minuria in diabetics and investigated the relationship of albuminuria to LV filling. A comparison was made between 30 hypertensive diabetics, 10 of whom had microalbuminuria (MIC) and 20 had macroalbuminuria (MAC), and 18 diabetics who were normotensive and normalbuminuric (NOR). LV mass index (LVMI) and LV ejection fraction (LVEF) were measured during echocar diography. LV filling pattern at rest and at peak standardized isometric exercise (IME) using handgrip was assessed by measuring E/A (peak velocity of the early/atrial filling waves) of the transmitral flow during Doppler and echocardiography. Each patient underwent a stress ECG test. LVMI was higher in MAC (132.3 ±55.4) than in MIC (115.6 ±32.5) or NOR (90.0 ±31.8) (p<0.01). There were more patients in MAC with LVH (n = 13) and abnormal filling (n = 9 at rest and 16 with IME) than in MIC (LVH = 5, abnormal filling = 1 at rest and 10 during IME) or NOR (LVH = 3, abnormal filling = 1 at rest and 9 during IME) (p < 0.02). LVMI was not related to LVEF. Although blood pressure was not different between MAC and MIC groups, it was signif icantly higher than in the NOR group. This study suggests that a high degree of albuminuria in hypertensive diabetics is associated with greater value for LVMI and an increased incidence of LVH independent of blood pressure level or systolic LV function. LVH is associated with abnormal LV filling. The degree of albuminuria may predict LVMI and LVH, which are associated with abnormal LV filling. This association of abnormal LV filling with albuminuria in hypertensive diabetic patients may account for their high risk of cardiovascular events.

Possible Mechanisms Underlying Aging-Related Changes in Early Diastolic Filling and Long Axis Motion-Left Ventricular Length and Blood Pressure

Background

The transmitral E wave and the peak velocity of early diastolic mitral annular motion (e`) both decrease with age, but the mechanisms underlying these age-related changes are incompletely understood. This study investigated the possible contributions of blood pressure (BP) and left ventricular end-diastolic length (LVEDL) to age-related reductions in E and e`.

Methods

The study group were 82 healthy adult subjects <55 years of age who were not obese or hypertensive. Transmitral flow and mitral annular motion were recorded using pulsed-wave Doppler. LVEDL was measured from the mitral annular plane to the apical endocardium.

Results

Age was positively correlated with diastolic BP and septal wall thickness (SWT), inversely correlated with LVEDL (β = -0.25) after adjustment for sex and body surface area, but was not related to left ventricular end-diastolic diameter (LVEDD). Age was also inversely correlated with E (r = -0.36), septal e`(r = -0.53) and lateral e`(r = -0.53). On multivariable analysis, E was inversely correlated with diastolic BP and LVEDD, septal e`was inversely correlated with diastolic BP and positively correlated with SWT and LVEDL, after adjusting for body mass index, whilst lateral e`was inversely correlated with diastolic BP and positively correlated with LVEDL.

Conclusion

The above findings are consistent with higher BP being a contributor to age-related reductions in both E and e`and shortening of LVEDL with age being a contributor to the age-related reduction in e`. An implication of these findings is that slowing of myocyte relaxation is unlikely to be the sole, and may not be the main, mechanism underlying age-related decreases in E and e`.

Brain natriuretic hormone predicts stress-induced alterations in diastolic function

BACKGROUND

Mental stress (MS) reduces diastolic function (DF) and may lead to congestive heart failure with preserved systolic function. Whether brain natriuretic hormone (brain natriuretic peptide [BNP]) mediates the relationship of MS with DF is unknown.

METHODS

One hundred sixty individuals aged 30 to 50 years underwent 2-hour protocol of 40-minute rest, videogame stressor and recovery. Hemodynamics, pro-BNP samples and DF indices were obtained throughout the protocol. Separate regression analyses were conducted using rest and stress E/A, E' and E/E' as dependent variables. Predictor variables were entered into the stepwise regression models in a hierarchical fashion. At the first level, age, sex, race, height, body mass index, pro-BNP and left ventricular mass (LVM) were permitted to enter the models. The second level consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The final level contained cross-product terms of race by SBP, DBP and HR.

RESULTS

E/A ratio was lower during stress compared to rest and recovery (P < 0.01). Resting E/A ratio was predicted by a regression model of age (-0.31), pro-BNP (0.16), HR (-0.40) and DBP (-0.23) with an R² = 0.33. Stress E/A ratio was predicted by age (-0.24), pro-BNP (0.08), HR (-0.38) and SBP (-0.21) with total R² = 0.22. Resting E' model consisted of age (-0.22), pro-BNP (0.26), DBP (-0.27) and LVM (-0.15) with an R² = 0.29. Stress E' was predicted by age (-0.18), pro-BNP (0.35) and LVM (-0.18) with an R² = 0.18. Resting E/E' was predicted by race (0.17, B > W) and DBP (0.24) with an R² = 0.10. Stress E/E' consisted of pro-BNP (-0.36), height (-0.26) and HR (-0.21) with an R² = 0.15.

CONCLUSIONS

pro-BNP predicts both resting and stress DF, suggesting that lower BNP during MS may be a marker of diastolic dysfunction in apparently healthy individuals.

Does the relationship between natriuretic hormones and diastolic function differ by race?

INTRODUCTION

Heart failure develops earlier and is more prevalent in blacks than whites because of their higher incidence of hypertension and diabetes and likely subsequent diastolic dysfunction. Natriuretic peptides (NP) prevent cardiac malfunction through pressure, natriuresis action. However, whether race affects the relationships of NP action with cardiac function is unknown.

METHODS

To assess this, 55 (21 whites and 27 males) normotensive adults underwent a 2-hour protocol of 40 minutes rest, video game stressor and recovery. Mitral inflow and myocardial velocities (tissue Doppler) were recorded every 20 minutes. Blood pressure and heart rate were obtained at 10-minute intervals. Blood samples for pro-atrial NP and pro-brain NP (pro-BNP) were collected every 40 minutes.

RESULTS

There were differences in the association between (1) the changes from rest to stress for E/A ratio and double product (whites, r = -0.42; blacks, r = 0. 10; P = 0.034 for difference between correlations); (2) stress E(m) and pro-atrial NP (whites, r = 0.59; blacks, r = -0.25; P = 0.025); (3) rest E(m) and BNP (whites, r = 0.83; blacks r = -0.17; P = 000); (4) rest E(m)/A(m) and pro-BNP (whites, r = 0.70; blacks, r = -0.42; P = 0.003); (5) rest E/E(m) and pro-BNP (whites, r = -0.61; blacks, r = 0.31; P = 0.015) and (6) stress E and pro-BNP (whites, r = 0.56; blacks, r = -0.18; P = 0.043).

CONCLUSION

The higher correlations between levels of NP and diastolic function indices both at rest and stress suggest that NP protective action is more pronounced in whites than in blacks.

Stress reduces diastolic function in youth

OBJECTIVE

Research regarding the influence of mental stress (MS) on heart function focused primarily on heart contractility. We hypothesized that MS results in attenuated diastolic function (DF) as early as in adolescence and this effect may differ by race and sex.

METHODS

161 normotensive adolescents (81 blacks and 80 females) performed resting (control) and MS (experimental) conditions on separate visits. Visits lasted for 3 hours (1-hour rest, video game challenge and recovery for experimental visit. Mitral inflow early (E) to late (A) filling velocities (E/A) ratio; mitral valve annular early velocity (E') and E/E' ratio were recorded every 30 minutes to evaluate DF.

RESULTS

BP and HR increased during experimental visit (all p values < .01). E/A ratio progressively increased during control visit (mean [SE], from 1.93 ± 0.42 to 2.01 ± 0.47) but decreased during the stress phase of experimental visit (from 1.91 ± 0.44 to 1.87 ± 0.50, p interaction < .001). In white males, E' increased from rest to stress phase (from 10.3 ± 2.55 to 10.7 ± 2.28 cm/s), whereas E' decreased in white females (from 11.0 ± 2.62 to 10.6 ± 2.53 cm/s), black males (from 10.5 ± 2.31 to 9.9 ± 2.19 cm/s), and black females (from 10.6 ± 2.22 to 10.3 ± 1.86 cm/s, p interaction < .04). During stress, higher A was associated with higher E/E' ratio.

CONCLUSIONS

Recurrent episodes of mental stress may increase the risk of poor DF, and these adverse effects may be stronger in females and black males.

Mineralocorticoid receptor blockade improves diastolic function independent of blood pressure reduction in a transgenic model of RAAS overexpression

There is emerging evidence that aldosterone can promote diastolic dysfunction and cardiac fibrosis independent of blood pressure effects, perhaps through increased oxidative stress and inflammation. Accordingly, this investigation was designed to ascertain if mineralocorticoid receptor blockade improves diastolic dysfunction independently of changes in blood pressure through actions on myocardial oxidative stress and fibrosis. We used young transgenic (mRen2)27 [TG(mRen2)27] rats with increases in both tissue ANG II and circulating aldosterone, which manifests age-related increases in hypertension and cardiac dysfunction. Male TG(mRen2)27 and age-matched Sprague-Dawley rats were treated with either a low dose (∼1 mg·kg(-1)·day(-1)) or a vasodilatory, conventional dose (∼30 mg·kg(-1)·day(-1)) of spironolactone or placebo for 3 wk. TG(mRen2)27 rats displayed increases in systolic blood pressure and plasma aldosterone levels as well as impairments in left ventricular diastolic relaxation without changes in systolic function on cine MRI. TG(mRen2)27 hearts also displayed hypertrophy (left ventricular weight, cardiomyoctye hypertrophy, and septal wall thickness) as well as fibrosis (interstitial and perivascular). There were increases in oxidative stress in TG(mRen2)27 hearts, as evidenced by increases in NADPH oxidase activity and subunits as well as ROS formation. Low-dose spironolactone had no effect on systolic blood pressure but improved diastolic dysfunction comparable to a conventional dose. Both doses of spironolactone caused comparable reductions in ROS/3-nitrotryosine immunostaining and perivascular and interstitial fibrosis. These data support the notion mineralocorticoid receptor blockade improves diastolic dysfunction through improvements in oxidative stress and fibrosis independent of changes in systolic blood pressure.

Differential effects of antihypertensive treatment on left ventricular diastolic function: an ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) substudy

OBJECTIVES

We hypothesized that an amlodipine-based regimen would have more favorable effects on left ventricular (LV) diastolic function.

BACKGROUND

Different antihypertensive therapies may vary in their effect on LV diastolic function.

METHODS

The HACVD (Hypertension Associated Cardiovascular Disease) substudy of ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) collected detailed cardiovascular phenotypic data on a subset of 1,006 participants recruited from 2 centers (St. Mary's Hospital, London, and Beaumont Hospital, Dublin). Conventional and tissue Doppler echocardiography and measurement of plasma B-type natriuretic peptide (BNP) were performed approximately 1 year after randomization to atenolol-based or amlodipine-based antihypertensive treatment to assess LV diastolic function.

RESULTS

On-treatment blood pressure (BP) (mean +/- SD) was similar in both groups: atenolol-based regimen, systolic BP of 137 +/- 17 mm Hg, diastolic BP of 82 +/- 9 mm Hg; amlodipine-based regimen, systolic BP of 136 +/- 15 mm Hg, diastolic BP of 80 +/- 9 mm Hg. Ejection fraction did not differ between groups, but early diastolic mitral annular velocity (E'), a measure of diastolic relaxation, was lower in patients on the atenolol-based regimen: atenolol-based regimen, 7.9 +/- 1.8; amlodipine-based regimen, 8.8 +/- 2.0. A measure of left ventricular filling pressure, E/E', and BNP were significantly higher in patients on the atenolol-based regimen. Differences in E', E/E', and BNP remained significant after adjustment for age and sex. Further adjustment for systolic BP, LV mass index, and heart rate had no impact on differences in mean E' or BNP. The difference in E/E' was attenuated.

CONCLUSIONS

Patients receiving treatment with an amlodipine-based regimen had better diastolic function than patients treated with the atenolol-based regimen. Treatment-related differences in diastolic function were independent of BP reduction and other factors that are known to affect diastolic function.

Are Gestational and Essential Hypertension Similar? Left Ventricular Geometry and Diastolic Function

OBJECTIVE

To evaluate the differences and similarities in diastolic function and left ventricular geometry in gestational and essential hypertension.

METHODS

Thirty-nine consecutive gestational hypertensive pregnant women in the third trimester of gestation (GH), 40 nonpregnant essential hypertensive women (EH), and 38 normotensive nonpregnant women (N) matched for age were enrolled into the study and underwent echocardiographic and Doppler evaluations. The GH and EH patients were evaluated prior to the administration of any drug treatment.

RESULTS

Left atrial function was similar in GH and N subjects and lower than that in EH patients. Both GH and EH patients had early left ventricular diastolic filling pattern significantly different as compared to N subjects (longer isovolumetric relaxation time, deceleration time of the E wave, and lower E wave velocity in GH and EH vs. N), whereas the late filling properties were similar in GH and N subjects with a lower A velocity, and velocity-time integral vs. EH (p < 0.05). Systolic fraction of the pulmonary vein flow was similar in GH and EH patients and lower in N subjects. Altered left ventricular geometry was more common in GH than in EH, whereas normotensive subjects did not show any alteration of the geometric pattern.

CONCLUSIONS

Gestational and essential hypertension induce similar early altered diastolic filling of the left ventricle. Essential hypertension is characterized by a compensatory late filling mechanism due to an enhancement of left atrial function. Gestational hypertension is characterized by altered left ventricular geometry, which is far less common during essential hypertension.

The effect of nondipping blood pressure patterns on cardiac structural changes and left ventricular diastolic functions in normotensives

BACKGROUND

Cardiac structural changes have been reported to be more prominent in nondipper normotensives than the dipper ones. But the influence of nondipping status on cardiac diastolic functions of normotensives has not been studied yet. In this study, we investigated the effect of nondipping status on both cardiac structural changes and left ventricular (LV) diastolic functions in normotensives.

METHODS

We performed ambulatory blood pressure (BP) monitoring (ABPM) and echocardiography in 62 normotensive subjects with the following criteria: (1) office BP < 140/90 mmHg; (2) average 24-hour ambulatory BP < 130/80 mmHg.

RESULTS

In the evaluation by tissue Doppler imaging (TDI), the early diastolic myocardial peak velocity (Em) and Em/late diastolic myocardial peak velocity (Am) ratio (Em/Am ratio) were lower in nondippers than those in dippers (P = 0.009 and P < 0.001, respectively). Isovolumic relaxation time (IRT) and myocardial performance index (MPI) were higher in nondippers than those in dippers (P = 0.036 and P = 0.026, respectively). Nondipping status, independent of other factors, was observed to cause both a decrease in the Em and Em/Am ratio and an increase in IRT. However, its effect on IRT was not statistically significant (coefficient =-0.27, P = 0.027; coefficient =-0.37, P = 0.002; coefficient = 0.20, P = 0.082, respectively).

CONCLUSIONS

Nondipping of nocturnal BP seems to be a determinant of cardiac remodeling and LV diastolic dysfunction (LVDD) and may result in a cardiovascular (CV) risk independent of the increase in LV mass (LVM) in normotensives.

Gender differences in diastolic function among youth

BACKGROUND

Youth were studied to determine the influence of gender on diastolic function, which has been shown to express abnormalities early in the course of congestive heart failure.

METHODS

The study participants were 121 normotensive individuals (53 girls, 68 boys) ages 14 to 18 years. Demographics, hemodynamics, and Doppler-derived indices of diastolic function were collected. Dependent measures of diastolic function were the ratio of early (E) to late (A) peak filling velocities and the isovolumetric relaxation time (IVRT).

RESULTS

The girls had a higher relative wall thickness (RWT) (36.58% +/- 4.59% vs 34.60% +/- 4.01%; p < 0.02), higher A (48.40 +/- 8.47 cm/s vs 42.36 +/- 10.43 cm/s; p < 0.001), a lower E/A ratio (1.96 +/- 0.40 vs 2.38 +/- 0.68; p < 0.01), and a shorter IVRT (51.80 +/- 11.14 ms vs 59.00 +/- 14.36 ms; p < 0.01) than the boys. The differences in deceleration time were not significant (181.30 +/- 81.33 ms vs 170.30 +/- 31.06 ms). Hierarchical stepwise regression analysis predicting E/A ratio found gender (male > female) to be the best predictor (R (2 )= 0.09) followed by heart rate (R (2) increase = 0.07; total R (2 )= 0.15; p < 0.01) and by RWT (R (2) increase = 0.05; total R (2 )= 0.21; p < 0.015). For IVRT prediction, gender (male > female) was the best predictor (R (2 )= 0.11), followed by total peripheral resistance (R (2) increase = 0.06; total R (2 )= 0.17; p < 0.017).

CONCLUSION

The study data indicate that gender differences in diastolic function exist already in youth. Girls show a higher RWT, a lower E/A ratio, and a shorter IVRT. The implications of these differences for cardiovascular morbidity and mortality of the two genders require attention.

Hypertensive heart disease: effects of lifestyle modifications and antihypertensive drug treatment

Target-organ protection in hypertensive patients has become increasingly important. This review will focus on hypertensive heart disease that is mainly characterized by myocardial hypertrophy and increased interstitial fibrosis. Cardiac remodeling develops as an adaptive response but actually represents a powerful independent risk factor for cardiovascular morbidity and mortality. The review will begin with a brief discussion on the complex pathophysiology of hypertensive cardiac remodeling and its clinical consequences. The effects of nonpharmacologic and pharmacologic antihypertensive treatments on the development and progression of hypertensive heart disease are presented. Finally, the impact of the regression of myocardial hypertrophy and fibrosis on cardiac function and cardiovascular risk are discussed.

Diastolic filling abnormalities in children with essential hypertension

OBJECTIVE

To evaluate whether essential hypertension impacts diastolic function in children.

STUDY DESIGN

In this cross-sectional study, patients with essential hypertension (n = 50) were compared with a normotensive group (n = 53). Echocardiographic assessment of diastolic function included measures derived from transmitral, color M-mode, and tissue Doppler interrogation. Cardiac dimensions, wall thickness, geometry, and systolic function were also assessed. Multiple linear regression analysis was performed to identify predictors of altered diastolic function.

RESULTS

Diastolic filling abnormalities were found in 36% of the children with blood pressure elevation. Those subjects with concentric hypertrophy were more significantly affected. Abnormalities in indices reflective of left ventricular (LV) relaxation occurred more commonly (39%) than those of LV compliance (33%). Elevated indexed LV mass was found to be the most significant independent predictor of diastolic filling abnormalities.

CONCLUSIONS

LV diastolic filling abnormalities were found in one-third of the pediatric subjects with essential hypertension. Whether these changes represent an adaptive or maladaptive response requires further study.

Subclinical Atherosclerosis and Incipient Regional Myocardial Dysfunction in Asymptomatic Individuals

OBJECTIVES

This study sought to determine whether increased carotid intima-media thickness (IMT) is related to reduced regional myocardial function in participants of the Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND

Carotid artery IMT is an established index of subclinical atherosclerosis, and tagged magnetic resonance imaging (MRI) can detect incipient alterations of segmental function that precede overt myocardial failure.

METHODS

The MESA study is a prospective observational study including four ethnic groups free from clinical cardiovascular disease. Peak midwall systolic circumferential strain (ECC) and regional strain rates were calculated by harmonic phase from tagged MRI data of 500 participants. Systolic ECC and diastolic strain rate were regressed on IMT of the common carotid artery defined by ultrasound, with adjustments for body mass index, blood pressure, cholesterol, diabetes, smoking, left ventricular hypertrophy, C-reactive protein, age, and gender.

RESULTS

The mean participant age was 66 +/- 10 years (mean +/- SD). Among the 58 participants, 4% were male and the interquartile (25th to 75th percentile) range for IMT was 0.25 mm. Multiple linear regression analyses showed that increased IMT was related to reduced systolic regional function (less shortening ECC) in all myocardial regions (p < 0.05), except in the inferior wall. The analyses also showed that greater IMT was associated with a lower diastolic strain rate (diastolic reduced function) in all regions (p < 0.01), except in the anterior wall.

CONCLUSIONS

Greater carotid IMT is associated with alterations of myocardial strain parameters reflecting reduced systolic and diastolic myocardial function. These observations indicate a relationship between subclinical atherosclerosis and incipient myocardial dysfunction in a population free of clinical heart disease.

Impaired left ventricular diastolic function during isometric exercise in asymptomatic patients with hyperlipidaemia

BACKGROUND

Left ventricular (LV) diastolic dysfunction is an early sign, and may be more sensitive indicator, of ischaemic heart disease (IHD) than systolic dysfunction.

METHODS

LV diastolic function was assessed during isometric exercise (IME) in 37 consecutive normotensive hyperlipidaemics (LIP), without cardiac history or symptoms. Each patient underwent a stress ECG test and 2-D echo and Doppler cardiography. During the latter, transmitral flow at rest and at peak standardised IME using handgrip was studied. From the tracings, the E/A (peak velocity of the early/atrial components), the contribution of atrial systole to LV filling (ACF), the deceleration time (DT) of the E wave and the isovolumic relaxation time (IVRT) were calculated. Results were compared to 37 age-matched normal healthy volunteers (NOR).

RESULTS

Resting E/A was not different between NOR and the LIP. A significant reduction in E/A with IME was observed in LIP but not in NOR. Impaired LV filling (shown by E/A<1) was demonstrated in five patients (13%) at rest and in 20 patients (54%) at peak IME. All NOR had E/A>1 suggesting normal LV filling. Fifteen of the 30 patients with negative stress ECG test demonstrated LV diastolic dysfunction. ACF was higher in LIP than NOR and increased significantly (P<0.005) by 23% during IME. DT and IVRT in LIP were not different from NOR. In neither NOR nor LIP, were the LV diastolic functional parameters related to gender, smoking habit or levels of total cholesterol, LDL- or HDL-cholesterol or triglycerides.

CONCLUSION

The prevalence of LV diastolic dysfunction in asymptomatic patients with hyperlipidaemia despite a negative stress ECG test may be evidence of early underlying pre-clinical myocardial ischaemia.

Relation of impaired left ventricular filling to systolic midwall mechanics in hypertensive patients with normal left ventricular systolic chamber function: the Losartan Intervention for Endpoint Reduction in Hypertension (LIFE) study

BACKGROUND

Patients with hypertensive left ventricular (LV) hypertrophy commonly have diastolic dysfunction with preserved LV ejection fraction. LV systolic midwall shortening (MWS) may be impaired in hypertensive patients with normal LV ejection fraction. However, it is unclear whether impaired LV filling is related to depressed systolic midwall mechanics.

METHODS

Echocardiographic measures of LV diastolic filling and systolic performance were compared in 632 unmedicated patients with stage II or III hypertension and LV hypertrophy determined by electrocardiogram, with LV ejection fraction >55% and <2+ mitral regurgitation.

RESULTS

Stress-corrected LV MWS, an index of myocardial contractility, was lower in patients with abnormal as opposed to normal LV filling patterns (98% +/- 12% vs 102% +/- 10%, P <.001) and in patients with prolonged as opposed to normal isovolumic relaxation time (IVRT) (98% +/- 13% vs 101% +/- 12%, P =.014). Stress-corrected MWS was <85% of predicted levels in more patients with abnormal LV filling patterns (11.8% vs 6.3%) or with long IVRT (> or =105 msec) (34% vs 21%, both P <.05). In regression analyses, lower stress-corrected MWS and higher LV mass were independent correlates of longer IVRT, while lower stress-corrected MWS was the only independent correlate of prolonged mitral valve deceleration time (P =.017). Higher LV mass had strong, statistically independent relationships to longer IVRT (by 0.3 g/msec) and decreased stress-corrected MWS (by 0.5 g/%; both P <.0001), independent of body size and age.

CONCLUSION

In patients with moderate hypertension and target organ damage who have normal LV ejection fraction, impaired early diastolic LV relaxation (abnormal E/A ratio, prolonged IVRT and deceleration time) is associated with impaired LV systolic midwall mechanics independent of higher LV mass.

Early carotid atherosclerosis and cardiac diastolic abnormalities in hypertensive subjects

Despite the fact that it is known that hypertension may be associated to early atherosclerosis manifestations, few data are to date available on the relationship between early carotid abnormalities and left ventricular diastolic dysfunction. To address this issue, 142 hypertensive patients (64 females and 78 males) younger than 55 years, at the first diagnosis of mild-to-moderate essential hypertension (WHO/ISH criteria), were selected from a database consisting of 3541 subjects referred to ultrasound cardiovascular laboratory in the last 5 years. Carotid intima-media thickness (IMT) was detected by high-resolution vascular ultrasound and left ventricular structure and function by the use of Doppler echocardiography. According to carotid IMT values, all patients were subgrouped into two groups consisting of 89 (62.6%) pts with IMT > or = 1 mm (A) and 53 (37.4%) pts with IMT < 1 mm (B). Our results show that isovolumic relaxation time (IVRT), deceleration time of E velocity (EDT) and left ventricular relative wall thickness (LV-RWT) were significantly (P < 0.05) higher in group A (IVRT 112 +/- 8.9 ms; EDT 288 +/- 21.8 ms; LV-RWT 0.40 +/- 0.08) than in group B (IVRT 92.3 +/- 4.6 ms; EDT 203.3 +/- 27.01 ms; LV- RWT 0.37 +/- 0.06). Moreover, the prevalence of left ventricular hypertrophy (LVH) was significantly (P < 0.01) higher in group A (30/89; 33.7%) than in group B (8/53; 15%). A positive correlation (P < 0.001) between IMT, EDT and IVRT was found only in hypertensives without LVH. These results are consistent with the indication that IMT evaluation has to be recommended both in hypertensive patients with LVH and in those without LVH, but with left ventricular diastolic dysfunction. This approach might improve the prognostic stratification of hypertensive subjects and it might be suitable to recognize the subset of patients at a higher risk of cardiovascular disease or events early.

Aldosterone antagonist improves diastolic function in essential hypertension

Experimental studies demonstrated that mineralocorticoid antagonists prevent or reverse myocardial fibrosis. Therefore, we tested the hypothesis that the aldosterone antagonist canrenone can improve left ventricular diastolic function in essential hypertension. Using digitized M-mode echocardiography and 24-hour blood pressure monitoring (ABPM), we realized a prospective, randomized, controlled study on 34 never-treated essential hypertensives with left ventricular diastolic dysfunction. Echocardiogram and ABPM were repeated after 6 months of effective antihypertensive treatment with ACE inhibitors and calcium antagonists (second evaluation) and then after a 6-month period with 17 patients randomly assigned to add canrenone 50 mg/d to the previous treatment (third evaluation). At the basal evaluation 32 patients had left ventricular concentric hypertrophy, and 2 patients had left ventricular concentric remodeling. All the patients had normal left ventricular systolic function. At the second evaluation blood pressure was reduced (P<0.0001), left ventricular mass index decreased (P<0.0001), and diastolic function improved (P<0.0001). After randomization, the canrenone and control groups had similar 24-hour blood pressure and left ventricular morpho-functional characteristics. At the third evaluation, despite unchanged blood pressure and similar decrease of left ventricular mass index, the canrenone group, compared with control group, showed a significantly greater increase in left ventricular diastolic indices. In essential hypertension, a low dose of aldosterone antagonist added to antihypertensive treatment significantly improved left ventricular diastolic function. This improvement, not accounted for by changes in blood pressure and left ventricular mass, can be therefore ascribed to a direct action of the drug on the myocardium.

Impact of diastolic Doppler indices on exercise capacity in hypertensive patients with electrocardiographic left ventricular hypertrophy (a LIFE substudy)

OBJECTIVE

To assess whether Doppler evidence of impaired early diastolic relaxation during exercise is associated with lesser exercise capacity in hypertensive patients.

DESIGN

Single center addition to the echocardiographic substudy in the Losartan Intervention For Endpoint (LIFE) reduction in hypertension study.

SETTING

University hospital out-patient clinic.

METHODS

A total of 60 patients (29 women and 31 men) with essential hypertension and electrocardiographic LV hypertrophy.

INTERVENTIONS

Assessment of Doppler echocardiography and ergospirometry during semi-upright bicycling.

MAIN OUTCOME MEASURE

Exercise capacity and its relation to diastolic Doppler indices at rest and during exercise.

RESULTS

Average resting blood pressure was 181/97 +/- 18/9 mmHg, LV mass/body surface area 127 +/- 26 g/m2, midwall shortening 16 +/- 2%, and isovolumic relaxation time (IVRT) and transmitral early to atrial filling velocity (E/A) ratio 121 ms and 0.80, respectively. Exercise capacity, assessed as peak oxygen uptake and exercise load at exhaustion in all patients, were 20 and 25% higher, respectively, in men than women (both P < 0.01). In multivariate analysis, higher peak exercise load was related to male gender, higher E/A ratio at rest, greater reduction in IVRT during exercise and higher peak exercise heart rate (multiple R2 = 0.59, P < 0.01). Younger age, greater reduction in IVRT during exercise, higher midwall shortening and peak exercise heart rate were associated with higher peak oxygen uptake (multiple R2 = 0.47, P < 0.01).

CONCLUSION

Diastolic LV performance significantly influences exercise capacity in hypertensive patients with LV hypertrophy. Impaired exercise capacity is more strongly associated with blunted reduction in IVRT during exercise than with lower E/A ratio at rest.

Left ventricular mass and global function in essential hypertension after antihypertensive therapy

This study compares left ventricular global function in 55 patients (25 with hypertrophy and 30 without hypertrophy) with essential hypertension, whose blood pressure had been stable for longer than 1 year, with that in 35 healthy subjects. Left ventricular global function was calculated using the echocardiographic Doppler index as described by Tei et al. (Tei index). No significant differences were observed in echocardiographic left ventricular systolic function between the three groups. Left ventricular global function differed significantly between the three groups, however, suggesting impaired left ventricular global function even in the absence of left ventricular hypertrophy. Similar changes were observed in the ratio of peak velocity of atrial systole to peak velocity of early diastole during left ventricular inflow waveform (A/E), indicating that this disorder mainly reflects impaired left ventricular diastolic function. Unlike A/E, the Tei index is not affected by increasing age, and, therefore, is appropriate for evaluating left ventricular global function in hypertensive patients, most of whom are middle-aged or older. This index may be useful for determining treatment strategy and evaluating treatment effects.

Effect of the Valsalva manoeuver on diastolic filling indices in patients with essential hypertension

In some hypertensive patients, echocardiographic examination does not reveal any pathologic finding in spite of a documented blood pressure elevation. In our study, we investigated the effect of preload reduction with Valsalva manoeuver on transmitral flow velocities in hypertensive patients with normal mitral flow pattern and compared the results with a healthy control group. Sixty-eight patients without evidence of coronary artery disease or heart failure (28 female, 40 male, age 50 +/- 7) were divided in two groups according to their E/A ratio as those with diastolic dysfunction (n = 36) and without diastolic dysfunction (DD(-): n = 32). DD(-) patients and the control group (n = 20) performed Valsalva manoeuver and their pulsed-Doppler mitral flow measurements were repeated at the strain phase. During Valsalva manoeuver, E wave velocity decreased in all subjects. In the controls, peak A velocity showed a similar decline and E/A ratio remained over 1.0. However, in 72% of DD(-) patients A velocity did not change or increased and their E/A ratio fell below 1.0. In 47% of the patients with an E/A ratio reversal after Valsalva manoeuver, myocardial perfusion scintigraphy revealed reversible defects whereas none of the patients whose E/A ratio remained over 1.0 had perfusion defects. It is concluded that: (1) in hypertensive patients with normal E/A ratio Valsalva manoeuver should be performed in order to unmask a probable false normal finding, (2) an important percent of hypertensive individuals have left ventricular relaxation abnormalities, and (3) diastolic dysfunction develops together with a decrease in coronary reserve.

The impact of diabetes on left ventricular filling pattern in normotensive and hypertensive adults: the Strong Heart Study

OBJECTIVES

We sought to determine the effect of diabetes mellitus (DM) on left ventricular (LV) filling pattern in normotensive (NT) and hypertensive (HTN) individuals.

BACKGROUND

Diastolic abnormalities have been extensively described in HTN but are less well characterized in DM, which frequently coexists with HTN.

METHODS

We analyzed the transmitral inflow velocity profile at the mitral annulus in four groups from the Strong Heart Study: NT-non-DM (n = 730), HTN-non-DM (n = 394), NT-DM (n = 616) and HTN-DM (n = 671). The DM subjects were further divided into those with normal filling pattern (n = 107) and those with abnormal relaxation (AbnREL) (n = 447).

RESULTS

The peak E velocity was lowest in HTN-DM, intermediate in NT-DM and HT-non-DM and highest in the NT-non-DM group (p < 0.001), with a reverse trend seen for peak A velocity (p < 0.001). In multivariate analysis, E/A ratio was lowest in HTN-DM and highest in NT-non-DM, with no difference between NT-DM and HTN-non DM (p < 0.001). Likewise, mean atrial filling fraction and deceleration time were highest in HTN-DM, followed by HTN-non-DM or NT-DM and lowest in NT-non-DM (both p < 0.05). Among DM subjects, those with AbnREL had higher fasting glucose (p = 0.03) and hemoglobin A1C (p = 0.04).

CONCLUSIONS

Diabetes mellitus, especially with worse glycemic control, is independently associated with abnormal LV relaxation. The severity of abnormal LV relaxation is similar to the well-known impaired relaxation associated with HTN. The combination of DM and HTN has more severe abnormal LV relaxation than groups with either condition alone. In addition, AbnREL in DM is associated with worse glycemic control.

Exercise intolerance in rats with hypertensive heart disease is associated with impaired diastolic relaxation

A decrease in functional capacity is one of the most important clinical manifestations of hypertensive heart disease, but its cause is poorly understood. Our purpose was to evaluate potential causes of hypertension-induced exercise intolerance, focusing on identifying the type(s) of cardiac dysfunction associated with the first signs of exercise intolerance during the course of hypertensive heart disease. Exercise capacity was measured weekly in Dahl salt-sensitive rats as they developed hypertension as well as in Dahl salt-resistant control rats. Exercise capacity was unchanged from baseline during the first 8 weeks of hypertension, suggesting that hypertension itself did not cause exercise intolerance. After 9 to 12 weeks of hypertension, exercise capacity decreased in salt-sensitive rats but not in control rats. After 10 weeks of hypertension, indices of diastolic function (early truncation of the E wave), as assessed by echocardiography at rest, were decreased in the salt-sensitive rats. When exercise capacity had decreased by approximately 25% in a rat, the heart was isolated, and left ventricular (LV) compliance and systolic function were measured. At that time point, LV hypertrophy was modest (an approximately 20% increase in LV mass), and systolic function was normal or supernormal, indicating that exercise intolerance began during "compensated" LV hypertrophy. Passive LV compliance remained normal in salt-sensitive rats. Thus, in this model of hypertensive heart disease, exercise intolerance develops during the compensated stage of LV hypertrophy and appears to be due to changes in diastolic rather than systolic function. However, studies in which LV function is assessed during exercise are needed to conclusively define the roles of systolic and diastolic dysfunction in causing exercise intolerance.

Noninvasive indexes of left atrial diastolic function in hypertrophic cardiomyopathy

OBJECTIVES

Our goal was to noninvasively assess left atrial diastolic function and its relation to the impaired left ventricular filling in patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

We studied 34 patients with hypertrophic cardiomyopathy, 26 patients with secondary forms of left ventricular hypertrophy (aortic stenosis, fixed subaortic stenosis, hypertension), and 21 control subjects. Left atrial diastolic function was assessed by measuring acceleration time (SAT), deceleration time (SDT), and the EF (mean deceleration rate) slope of the pulmonary venous flow systolic wave (SW). Left ventricular diastolic function assessed by transmitral Doppler included peak early left ventricular and peak atrial filling velocities, the ratio of early-to-late peak velocities, isovolumic relaxation time, deceleration time, and EF slope. In patients with hypertrophic cardiomyopathy, acceleration time was significantly reduced (P<.05), deceleration time was significantly prolonged (P<.0001), and EF slope was significantly reduced (P<.01). These indexes were similar among the other two groups. No statistically significant difference existed between the subgroups of hypertrophic cardiomyopathy in the above indexes. Patients with hypertrophic cardiomyopathy and secondary forms of left ventricular hypertrophy had evidence of left ventricular diastolic dysfunction. In patients with hypertrophic cardiomyopathy, no correlation existed between left atrial and left ventricular diastolic function indexes (r = -0.26 to 0.33).

CONCLUSIONS

Echocardiographic indexes of left atrial relaxation and filling are abnormal in patients with hypertrophic cardiomyopathy but not in secondary forms of left ventricular hypertrophy. These indexes are abnormal in all forms of hypertrophic cardiomyopathy irrespective of left ventricular outflow tract obstruction and distribution of hypertrophy; they are not solely attributable to left ventricular diastolic dysfunction. The above may imply that hypertrophic cardiomyopathy is a cardiac myopathic disease that involves the heart muscle as a whole, irrespective of distribution of hypertrophy and obstruction.

Left ventricular filling patterns in patients with systemic hypertension and left ventricular hypertrophy (the LIFE study). Losartan Intervention For Endpoint

Abnormal left ventricular (LV) filling may exist in early stages of hypertension. Whether this finding is related to LV hypertrophy is currently controversial. This study was undertaken to assess relations between abnormal diastolic LV filling and LV geometry in a large series of hypertensive patients with electrocardiographic LV hypertrophy. M-mode, 2-dimensional, and pulsed Doppler echocardiographic recordings of mitral inflow velocity and isovolumetric relaxation time (IVRT) were obtained in 750 patients with stage I to III hypertension and LV hypertrophy determined by electrocardiography (sex-adjusted Cornell voltage duration criteria or Sokolow-Lyon voltage criteria) after 14 days of placebo treatment. The patients' mean age was 67+/-7 years and 44% were women. One hundred forty patients (19%) had normal LV geometric pattern, 79 (11%) had concentric remodeling, 342 (45%) had eccentric LV hypertrophy, and 189 (25%) had concentric LV hypertrophy. A normal LV filling pattern was found in 116 patients (16%), abnormal relaxation in 519 (69%), "pseudonormal" filling was found in 83 (11%), and a restrictive filling pattern in 32 (4%). Prolonged IVRT was associated with LV hypertrophy (p<0.01) as well as elevated relative wall thickness (p<0.05). A stronger difference (p<0.01) in IVRT was found between groups with and without LV hypertrophy. Multiple regression analysis revealed that increased LV mass correlated with prolonged IVRT, whereas LV mass and geometry were not associated with peak early LV filling velocity (E), peak atrial filling velocity (A) ratio or mitral valve E-peak deceleration time, although IVRT was found to be an independent correlate of E/A ratio and deceleration time. Thus, abnormal IVRT was highly prevalent in all LV geometric subgroups among hypertensive patients with electrocardiographic LV hypertrophy, even in those with normal LV geometry determined by echocardiography. We found that IVRT differed significantly among patient groups with different LV geometric patterns, primarily because of the association of IVRT to LV mass.

Effects of valsartan on left ventricular diastolic function in patients with mild or moderate essential hypertension: comparison with enalapril

OBJECTIVE

This study compares the effects of an AT1 angiotensin II receptor antagonist (valsartan) with those of an ACE inhibitor (enalapril) on left ventricular (LV) diastolic function in patients with mild or moderate essential hypertension and no evidence of LV hypertrophy at echocardiography.

METHODS

A total of 24 patients (16 men, mean age 47 +/- 8 years) underwent radionuclide ambulatory monitoring (Vest) of LV function at rest and during upright bicycle exercise testing before and after two 4-week treatment periods with valsartan (80-160 mg/day orally) and enalapril (20-40 mg/day orally) according to a double-blind, crossover randomization scheme.

RESULTS

In the overall population no differences between the two treatments were found in LV peak filling rate (PFR) either at rest or at peak exercise. In a subgroup analysis it was found that baseline PFR was normal (= 2.5 EDV/sec) in 12 patients (subgroup A) and impaired (< 2.5 EDV/sec) in the remaining 12 (subgroup B). In both subgroups, valsartan and enalapril induced a significant and comparable reduction of systolic and diastolic blood pressure. In subgroup A, valsartan and enalapril did not induce significant changes in PFR. In subgroup B, valsartan increased PFR both at rest (from 2.0 +/- 0.3 to 2.4 +/- 0.3 EDV/sec, P < 0.01) and at peak exercise (from 4.1 +/- 1.1 to 4.4 +/- 1.0 EDV/s, P < 0.05), whereas enalapril did not change PFR either at rest (2.0 +/- 0.4 EDV/s, P < 0.01 versus valsartan) or at peak exercise (3.7 +/- 1.1 EDV/sec, P < 0.05 versus valsartan).

CONCLUSIONS

Valsartan-induced renin-angiotensin system blockade is able to improve LV filling in patients with mild or moderate essential hypertension and impaired diastolic function. These findings support the hypothesis of a contribution of the renin-angiotensin system in the control of LV diastolic function in these patients.

Brain natriuretic peptide as a marker of cardiac involvement in hypertension

Hypertensive patients with heart abnormalities have increased risk of cardiovascular events. Brain natriuretic peptide is a natriuretic peptide mainly of ventricular origin produced in response to pressure and stretch. We hypothesise that brain natriuretic peptide could be a useful marker of cardiac remodelling in hypertensive patients. We studied 36 consecutive community mild-to-moderate hypertensive patients and 11 well-matched normotensive controls with respect to clinical characteristics, brain natriuretic peptide, creatinine and echocardiography parameters (M-mode, 2-D arid transmitral pulsed Doppler). Brain natriuretic peptide levels were significantly higher in hypertensive patients than in controls [36.54 (IQR: 38.61) vs. 10.30 (IQR: 13.20) pg ml(-1), p<0.0001] and it was correlated with left ventricular mass index. Hypertensive patients with impairment of diastolic filling had significantly higher brain natriuretic peptide concentrations than patients with no abnormalities on echocardiography [61.16 (45.38) vs. 31.27 (18.10) pg ml(-1), p=0.001]. Multivariate analysis showed that only diastolic dysfunction and left ventricular mass index were significantly and independently related with brain natriuretic peptide concentrations in this population. In conclusion, impairment of diastolic function and left ventricular mass index are related to brain natriuretic peptide levels, thus giving the insight that this peptide can be a marker of ventricular remodelling in hypertensive patients.

The pathogenesis of familial hypertrophic cardiomyopathy: early and evolving effects from an alpha-cardiac myosin heavy chain missense mutation

Familial hypertrophic cardiomyopathy (FHC) is a genetic disorder resulting from mutations in genes encoding sarcomeric proteins. This typically induces hyperdynamic ejection, impaired relaxation, delayed early filling, myocyte disarray and fibrosis, and increased chamber end-systolic stiffness. To better understand the disease pathogenesis, early (primary) abnormalities must be distinguished from evolving responses to the genetic defect. We did in vivo analysis using a mouse model of FHC with an Arg403Gln alpha-cardiac myosin heavy chain missense mutation, and used newly developed methods for assessing in situ pressure-volume relations. Hearts of young mutant mice (6 weeks old), which show no chamber morphologic or gross histologic abnormalities, had altered contraction kinetics, with considerably delayed pressure relaxation and chamber filling, yet accelerated systolic pressure rise. Older mutant mice (20 weeks old), which develop fiber disarray and fibrosis, had diastolic and systolic kinetic changes similar to if not slightly less than those of younger mice. However, the hearts of older mutant mice also showed hyperdynamic contraction, with increased end-systolic chamber stiffness, outflow tract pressure gradients and a lower cardiac index due to reduced chamber filling; all 'hallmarks' of human disease. These data provide new insights into the temporal evolution of FHC. Such data may help direct new therapeutic strategies to diminish disease progression.

Diastolic function and insulin resistance in essential hypertension

We studied the relationship of insulin metabolism to diastolic function in 41 hypertensive patients and 24 healthy subjects. They underwent a 75-g oral glucose tolerance test. Integrated response of insulin to the glucose load was calculated as the area under the curve of insulin (AUC-I) and glucose (AUC-G). The ratio AUC-I/AUC-G was taken as an index of insulin resistance. Echocardiographic examination was performed to measure left ventricular mass. We used pulsed Doppler technique to assess the ratio of early to late transmitral peak velocity (E/A). The hypertensives had higher fasting insulin concentrations, insulin levels at 60 min and at 120 min after oral glucose load. They had higher AUC-I and higher index of insulin resistance compared to normotensives. Patients with hypertension had a lower E/A ratio in comparison to normotensive volunteers. In all subjects, the E/A ratio was negatively correlated with fasting insulin and insulin concentrations at 30, at 60 and at 120 min, AUC-I and insulin resistance index. Multiple regression analysis was performed to evaluate the above relationships, when the effects of confounding factors such as age, heart rate and systolic blood pressure were taken into account. We found that E/A ratio is negatively correlated to insulin concentrations at 120 min and to AUC-I in hyperinsulinemic subgroup of subjects (fasting insulin> 10). We conclude, that insulin metabolism and E/A ratio, which reflects diastolic function of the left ventricle, are related in hypertension.

Effects of changes in atrioventricular gradient and contractility on left ventricular filling in human diastolic cardiac dysfunction

The factors responsible for abnormalities in diastolic filling indexes as assessed by noninvasive testing in human beings have been extensively studied but are not completely understood. We therefore investigated left ventricular diastolic filling indexes by radionuclide angiography during right atrial pacing simultaneously with assessment of a directly measured left atrioventricular gradient and a time constant of isovolumic relaxation in 11 patients with hypertension and diastolic dysfunction. Loading conditions were altered with nitroprusside and phenylephrine, and contractility was improved by dobutamine infusion. The maximum left atrioventricular gradient at constant heart rates was determined by loading conditions and was not significantly affected by increases in contractility or an improvement in isovolumic relaxation rate. The peak filling rate according to radionuclide angiography was highly dependent on the atrioventricular gradient and was not affected by enhancement of the isovolumic relaxation rate.

Parental hypertension and cardiac alterations in normotensive children and adolescents

The objective of this investigation was the examination of the relation of left ventricular mass (LVM) and function with cardiovascular response to exercise in normotensive adolescents at risk for hypertension. Carried out was a prospective, cross-sectional study of 47 subjects (age, 10 to 18 years), who underwent dynamic and isometric exercise, 24-hour Holter monitoring, and echocardiography. Twenty-nine had normotensive parents (group 2, "at risk"). Both groups were similar for age, race, sex, body mass index, blood pressures, and resting heart rates. Group 2 had a higher E/A ratio (2.3 +/- 0.5 vs 2.0 +/- 0.5; p = 0.039) and higher heart rates during stage IV of dynamic exercise (188 +/- 20 beats/min vs 176 +/- 18 beats/min; p = 0.046). The LVM, 24-hour heart rates, and exercise systolic blood pressures (SBP) were similar in both groups. Only in group 2, SBP at peak dynamic and isometric exercise correlated best with LVM (r = 0.74, p < 0.002; r = 0.82, p < 0.001). It is concluded that altered hemodynamic regulatory mechanisms may exist before the establishment of hypertension in normotensive subjects with parental hypertension.

Mechanisms, diagnosis, and treatment of diastolic heart failure

Diastolic heart failure, in the absence of LV systolic dysfunction, is a common clinical condition that can be demonstrated in as many as one third of patients with congestive heart failure. Diastolic dysfunction caused by abnormalities in LV filling can be a result of many pathologic conditions, including hypertrophy, infiltrative cardiomyopathies, or myocardial ischemia. The major physiologic determinants of LV filling can be divided into cellular mechanisms, hemodynamic characteristics, and hormonal influences. Cellular mechanisms for impaired LV inactivation are determined by the handling of calcium within the myocyte during excitation-contraction-relaxation coupling. The hemodynamic characteristics of LV diastolic filling are determined by loading conditions, the time constant of isovolumic relaxation, heart rate, ventricular nonuniformity, pericardial restraint, myocardial elasticity, chamber compliance, and coronary blood flow. The sympathetic nervous system and the renin-angiotensin system are important modulators of diastolic filling, directly or indirectly. The diagnosis of heart failure is confirmed by a combination of clinical tests including invasive and noninvasive techniques, each of which has advantages and disadvantages. Treatment of medical conditions in which diastolic heart failure is a prominent component include pharmacotherapy with calcium channel antagonists, beta-adrenergic blocking agents, diuretic agents, and angiotensin-converting-enzyme inhibitors. Certain conditions associated with diastolic filling abnormalities such as pericardial disease or severe ischemic heart disease may be best managed by surgical or percutaneous intervention. Future research will include further delineation of the cellular mechanisms of active myocardial relaxation and clinical investigation into treatment directed at improving outcome.

The Bergen Blood Pressure Study: prehypertensive changes in cardiac structure and function in offspring of hypertensive families

Cardiac morphology and function were determined by echocardiography in normotensive offspring of 23 hypertensive and 22 normotensive families. The family histories of hypertension or normotension were based on 27 years' observation of parental blood pressure. Pulsed Doppler and M-mode echocardiography were performed in standard views. Out of the total 109 offspring, 94 participated in the present study (age (mean +/- SD) 36 +/- 7 years). Left ventricular posterior wall thickness was higher in offspring of hypertensive than normotensive families (10.1 +/- 1.7 vs. 9.3 +/- 1.5 mm; p < 0.05). Offspring of hypertensive families had lower transmitral early/late peak flow velocities (p < 0.001) and higher transmitral late peak flow velocities (p < 0.001) than offspring of normotensive families, but the differences between groups became inconsistent after adjustment for confounding variables (including left ventricular structural parameters). On the other hand, the family history of hypertension was consistently associated with increased transmitral early peak flow velocity and increased transmitral acceleration and deceleration slopes p < 0.05), a pattern suggesting increased left ventricular stiffness. Increased posterior wall thickness and diastolic functional changes may indicate cardiac hypertrophy and decreased left ventricular compliance and precede the development of hypertension in offspring of hypertensive families.