Effect of type 2 diabetes mellitus on left ventricular geometry and systolic function in hypertensive subjects: Hypertension Genetic Epidemiology Network (HyperGEN) study. (49/927)

BACKGROUND: Type 2 diabetes is a cardiovascular risk factor. It remains to be elucidated in a large, population-based sample whether diabetes is associated with changes in left ventricular (LV) structure and systolic function independent of obesity and systolic blood pressure (BP). METHODS AND RESULTS: Among 1950 hypertensive participants in the HyperGEN Study without overt coronary heart disease or significant valve disease, 20% (n=386) had diabetes. Diabetics were more likely to be women, black, older, and have higher BMI and waist/hip ratio than were nondiabetics. After adjustment for age and sex, diabetics had higher systolic BP, pulse pressure, and heart rate; lower diastolic BP; and longer duration of hypertension than nondiabetics. LV mass and relative wall thickness were higher in diabetic than nondiabetic subjects independent of covariates. Compared with nondiabetic hypertensives, diabetics had lower stress-corrected midwall shortening, independent of covariates, without difference in LV EF. Insulin levels and insulin resistance were higher in non-insulin-treated diabetics (n=195) than nondiabetic (n=1439) subjects (both P:<0.01). Insulin resistance positively but weakly related to LV mass and relative wall thickness. CONCLUSIONS: In a relatively healthy, population-based sample of hypertensive adults, type 2 diabetes was associated with higher LV mass, more concentric LV geometry, and lower myocardial function, independent of age, sex, body size, and arterial BP. structural and functional abnormalities in addition to, and independent of, atherosclerosis.(13) (14) In the Framingham cohort, diabetes was associated with higher LV mass in women but not men.(15) High blood pressure (BP), obesity, and abnormal lipid profile, which often coexist with diabetes, tend to be associated with preclinical cardiovascular abnormalities(16) and may contribute to the association of diabetes with cardiovascular events. Cardiac features of diabetic and nondiabetic hypertensive subjects remain incompletely described in population-based samples. Therefore, we compared clinical and metabolic characteristics, LV geometry, and systolic function between diabetic and nondiabetic hypertensive participants in the Hypertension Genetic Epidemiology Network (HyperGEN) Study.  (+info)

Effects of combination of ACE inhibitor and angiotensin receptor blocker on cardiac remodeling, cardiac function, and survival in rat heart failure. (50/927)

BACKGROUND: The mechanism and treatment of diastolic heart failure are poorly understood. We compared the effects of an ACE inhibitor, an angiotensin receptor blocker (ARB), and their combination on diastolic heart failure in Dahl salt-sensitive (DS) rats. METHODS AND RESULTS: DS rats fed an 8% NaCl diet from 7 weeks of age were treated with benazepril 10 mg/kg alone, valsartan 30 mg/kg alone, or combined benazepril and valsartan at 5 and 15 mg/kg, respectively, or at 1 and 3 mg/kg, respectively. At 16 weeks of age, DS rats exhibited prominent concentric left ventricular (LV) hypertrophy and diastolic dysfunction with preserved systolic function, as estimated by echocardiography. Despite comparable hypotensive effects among all drug treatments, the combination of benazepril 5 mg/kg and valsartan 15 mg/kg improved diastolic dysfunction and survival in DS rats more effectively than ACE inhibitor or ARB alone. Furthermore, the increase in LV endothelin-1 levels and hydroxyproline contents in DS rats was significantly suppressed only by combined benazepril and valsartan, and LV atrial natriuretic peptide mRNA upregulation in DS rats was suppressed to a greater extent by the combination therapy than monotherapy. CONCLUSIONS: The combination of ACE inhibitor and ARB, independently of the hypotensive effect, improved LV phenotypic change and increased LV endothelin-1 production and collagen accumulation, diastolic dysfunction, and survival in a rat heart failure model more effectively than either agent alone, thereby providing solid experimental evidence that the combination of these 2 agents is more beneficial than monotherapy for treatment of heart failure.  (+info)

Midwall mechanics are improved after regression of hypertensive left ventricular hypertrophy and normalization of chamber geometry. (51/927)

BACKGROUND: It is still unclear whether substantial regression of hypertensive left ventricular hypertrophy (LVH) and normalization of chamber geometry are associated with improved left ventricular (LV) myocardial function. METHODS AND RESULTS: Midwall mechanics were evaluated in 152 patients undergoing 1 year of effective antihypertensive treatment. Two-dimensionally directed M-mode echocardiography was performed as follows: (1) after a 4-week placebo "run-in" period, (2) after 1 year of treatment with 20 mg/d lisinopril (alone or associated with 12.5 to 25 mg/d hydrochlorothiazide), and (3) after a final 1-month placebo period to allow blood pressure (24-hour average ambulatory monitoring) to return to pretreatment levels. Treatment-induced reductions in blood pressure (from 149+/-16/95+/-11 to 131+/-12/83+/-10 mm Hg, P:<0.05) and circumferential end-systolic wall stress (from 84+/-22 to 72+/-19 g/cm(2), P:<0.05) were associated with a marked reduction in LV mass index (from 159+/-30 to 133+/-26 g/m(2), P:<0.05). LVH regression was accompanied by an increase in midwall fractional shortening (from 19.7+/-2.7% to 20.9+/-2.7%, P:<0.05) and by a decrease in relative wall thickness (from 48.2+/-7.7% to 44.1+/-6.7%, P:<0.05). The improvement in midwall function associated with afterload reduction and substantial LVH regression persisted after antihypertensive therapy withdrawal and restoration of the hypertensive state. Despite a significant increase in end-systolic wall stress, further LV chamber remodeling did not occur. The preservation of relative wall thickness was associated with a persistent improvement in midwall systolic function. CONCLUSIONS: Regression of concentric LVH is associated with an improvement of midwall systolic function, which is more dependent on the normalization of LV geometry than on the reduction in LV systolic stress.  (+info)

Effects of early angiotensin-converting enzyme inhibition on cardiac gene expression after acute myocardial infarction. (52/927)

BACKGROUND: ACE inhibition after myocardial infarction (MI) has been shown to have beneficial effects on cardiac anatomy and function. The purpose of this study was to examine the effects of ACE inhibition on cardiac gene expression after MI. METHODS AND RESULTS: Rats were randomized to receive captopril or no treatment 1 day after MI. Eight weeks later, cardiac function and hemodynamics were measured by use of indwelling catheters and perivascular flow probes. Myocardial gene expression was assessed with DNA microarrays and real-time reverse transcription-polymerase chain reaction. The ratios of heart and left ventricular weights to body weight were significantly increased by MI and normalized by captopril. Cardiac index and stroke volume index were lower in the untreated MI group than in sham controls but were normal in the MI+captopril group. Thirty-seven genes were found to be differentially expressed between the untreated MI group and sham controls; 31 were induced and 6 repressed. Captopril partially or completely inhibited changes in 10 of the genes. The 37 genes clustered into 11 functional groups, and 6 had >/=1 genes whose expression was modified by ACE inhibition. CONCLUSIONS: ACE inhibition after MI inhibits cardiac hypertrophy, preserves cardiac function, and attenuates changes in myocardial gene expression. Gene expression profiling reveals, however, that some elements of the pathophysiology may be unaffected by the treatment and be targets for new therapies.  (+info)

Pulsed Doppler tissue imaging of the velocity of tricuspid annular systolic motion; a new, rapid, and non-invasive method of evaluating right ventricular systolic function. (53/927)

AIMS: Rapid, accurate, and widely available non-invasive evaluation of right ventricular function still presents a problem. The purpose of the study was to determine whether the parameters derived from Doppler tissue imaging of tricuspid annular motion could be used as indexes of right ventricular function in patients with heart failure. METHODS: Standard and pulsed Doppler tissue echocardiography were obtained in 44 patients with heart failure (mean left ventricular ejection fraction 24 +/- 7%) and in 30 age- and sex-matched healthy volunteers. The tricuspid annular systolic and diastolic velocities were acquired in apical four-chamber views at the junction of the right ventricular free wall and the anterior leaflet of the tricuspid valve using Doppler tissue imaging. Within 2 h of Doppler tissue imaging, the first-pass radionuclide ventriculogram, determining right ventricular ejection fraction and equilibrium gated radionuclide ventriculography single photon emission computed tomography, were performed in all patients. RESULTS: In patients with heart failure, the peak systolic annular velocity was significantly lower and the time from the onset of the electrocardiographic QRS complex to the peak of systolic annular velocity was significantly greater than the corresponding values in healthy subjects (10.3 +/- 2.6 cm. s(-1) vs 15.5 +/- 2.6 cm.s(-1), P < 0.001, and 198 +/- 34ms vs 171 +/- 29 ms, P < 0.01, respectively). There was a good correlation between systolic annular velocity and right ventricular ejection fraction (r = 0.648, P <0.001). A systolic annular velocity < 11.5 cm.s(-1)predicted right ventricular dysfunction (ejection fraction < 45%) with a sensitivity of 90% and a specificity of 85%. CONCLUSION: We conclude that the evaluation of peak systolic tricuspid annular velocity using Doppler tissue imaging provides a simple, rapid, and non-invasive tool for assessing right ventricular systolic function in patients with heart failure.  (+info)

Gender-related differences in left ventricular chamber function. (54/927)

OBJECTIVES: While women have lower rates of atherosclerotic disease than men, they are more likely to suffer cardiac failure following infarction or cardiac surgery, despite typically having a greater left ventricular (LV) ejection fraction. We hypothesised that gender differences in systolic chamber function and ventriculo-vascular coupling may contribute to these clinical findings. METHODS: LV chamber function was determined in a cohort of 30 patients (16 women) aged 48-75 years with normal LV function using pressure-volume loops obtained by simultaneous conductance catheter volumetry and micromanometer pressure. End-systolic and end-diastolic pressure volume (ESPVR, EDPVR) and preload recruitable stroke work relations (PRSWR) were derived. Results were analysed according to gender, and the effects of body size and chamber dimensions were examined. RESULTS: The groups were closely matched for age (60+/-6 vs. 60+/-8 years) and co-morbid conditions. Women had higher end-systolic blood pressure (139.7+/-21.1 vs. 123.6+/-12.6 mmHg, P=0.001), and smaller LV cavity volume (end-diastolic volume 96.4+/-30.6 vs. 139+/-30.7 ml, P=0.001). Women had significantly higher LV end-systolic elastance (Ees, 2.65+/-0.10 vs. 1.96+/-0.09 mmHg ml(-1), P<0.002), arterial elastance (2.41+/-1.13 vs. 1.54+/-0.55 mmHg ml(-1), P=0.01) and lower passive LV diastolic compliance (slope EDPVR, 6.12+/-0.37 vs. 10.0+/-0.50 ml mmHg(-1), P<0.001). While there was a strong relationship between end-systolic elastance and chamber volume (r=0.69, P<0.001), gender differences in chamber function all persisted after indexing to body size. Higher LV systolic function in women was also shown in PRSWR analysis (slope, M(SW); 101.4+/-3.8 vs. 90.4+/-2.8 mmHg, P<0.05), which is independent of chamber size. After normalising volumes to resting diastolic volume, the greater systolic and diastolic elastance in women was accounted for. The ratio of end-systolic to arterial elastance, a measure of ventriculo-vascular coupling, was similar in women and men (1.19+/-0.40 vs. 1.54+/-0.30, respectively, P=0.23). CONCLUSIONS: This study demonstrates greater systolic chamber function and lower diastolic compliance in women. Within the range of chamber dimensions seen in patients with normal LV function, a strong relationship was found between cardiac size and end-systolic elastance. While these differences were not accounted for by indexing to body size, the greater ventricular elastance in women was removed after normalising to chamber size. Despite differences in resting ventricular elastance, appropriate ventriculo-vascular coupling was maintained in both genders as the greater end-systolic elastance in women was matched by similarly elevated arterial elastance.  (+info)

Enhanced ventilatory response to exercise in patients with chronic heart failure and preserved exercise tolerance: marker of abnormal cardiorespiratory reflex control and predictor of poor prognosis. (55/927)

BACKGROUND: In patients with chronic heart failure (CHF) and preserved exercise tolerance, the value of cardiopulmonary exercise testing for risk stratification is not known. Elevated slope of ventilatory response to exercise (VE/VCO(2)) predicts poor prognosis in advanced CHF. Derangement of cardiopulmonary reflexes may trigger exercise hyperpnea. We assessed the relationship between cardiopulmonary reflexes and VE/VCO(2)and investigated the prognostic value of (VE/VCO(2)) in CHF patients with preserved exercise tolerance. METHODS AND RESULTS: Among 344 consecutive CHF patients, we identified 123 with preserved exercise capacity, defined as a peak oxygen consumption (PEAK VO(2)) >/=18 mL. kg(-1). min(-1) (age 56 years; left ventricular ejection fraction 28%; peak VO(2) 23.5 mL. kg(-1). min(-1)). Hypoxic and hypercapnic chemosensitivity (n=38), heart rate variability (n=34), baroreflex sensitivity (n=20), and ergoreflex activity (n=20) were also assessed. We identified 40 patients (33%) with high VE/VCO(2) (ie, >34.0). During follow-up (49+/-22 months, >3 years in all survivors), 34 patients died (3-year survival 81%). High VE/VCO(2) (hazard ratio 4.3, P<0.0001) but not peak f1.gif" BORDER="0">O(2) (P=0.7) predicted mortality. In patients with high VE/VCO(2), 3-year survival was 57%, compared with 93% in patients with normal VE/VCO(2) P<0.0001). Patients with high VE/VCO(2) demonstrated impaired reflex control, as evidenced by augmented peripheral (P=0.01) and central (P=0.0006) chemosensitivity, depressed low-frequency component of heart rate variability (P<0.0001) and baroreflex sensitivity (P=0.03), and overactive ergoreceptors (P=0.003) compared with patients with normal VE/VCO(2). CONCLUSIONS: In CHF patients with preserved exercise capacity, enhanced ventilatory response to exercise is a simple marker of a widespread derangement of cardiovascular reflex control; it predicts poor prognosis, which VO(2) does not.  (+info)

Hemodynamic effects of tezosentan, an intravenous dual endothelin receptor antagonist, in patients with class III to IV congestive heart failure. (56/927)

BACKGROUND: Endothelin-1, a powerful mediator of vasoconstriction, is increased in patients with congestive heart failure and appears to be a prognostic marker that strongly is correlated with the severity of disease. However, little is known about the potential immediate beneficial effects of acute blockade of the endothelin system in patients with symptomatic left ventricular dysfunction. We assessed the hemodynamic effects and safety of tezosentan, an intravenous dual endothelin receptor antagonist, in patients with moderate to severe heart failure. METHODS AND RESULTS: This randomized placebo-controlled study evaluated the hemodynamic effects of 6-hour infusions of tezosentan at 5, 20, 50, and 100 mg/h compared with placebo in 61 patients with New York Heart Association class III to IV heart failure. Plasma endothelin-1 and tezosentan concentrations were also determined. Treatment with tezosentan caused a dose-dependent increase in cardiac index ranging from 24.4% to 49.9% versus 3.0% with placebo. Tezosentan also dose-dependently reduced pulmonary capillary wedge pressure and pulmonary and systemic vascular resistances, with no change in heart rate. No episodes of ventricular tachycardia or hypotension requiring drug termination were observed during tezosentan infusion. Tezosentan administration resulted in dose-related increased plasma endothelin-1 concentrations. CONCLUSIONS: The present study demonstrated that tezosentan can be safely administered to patients with moderate to severe heart failure and that by virtue of its ability to antagonize the effects of endothelin-1, it induced vasodilatory responses leading to a significant improvement in cardiac index. Further studies are under way to determine the clinical effects of tezosentan in the setting of acute heart failure.  (+info)