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

Oxidative stress and stress signaling: menace of diabetic cardiomyopathy

Cardiovascular disease is the most common cause of death in the diabetic population and is currently one of the leading causes of death in the United States and other industrialized countries. The health care expenses associated with cardiovascular disease are staggering, reaching more than 350 billion dollars in 2003. The risk factors for cardiovascular disease include high fat/cholesterol levels, alcoholism, smoking, genetics, environmental factors and hypertension, which are commonly used to gauge an individual's risk of cardiovascular disease and to track their progress during therapy. Most recently, these factors have become important in the early prevention of cardiovascular diseases. Oxidative stress, the imbalance between reactive oxygen species production and breakdown by endogenous antioxidants, has been implicated in the onset and progression of cardiovascular diseases such as congestive heart failure and diabetes-associated heart dysfunction (diabetic cardiomyopathy). Antioxidant therapy has shown promise in preventing the development of diabetic heart complications. This review focuses on recent advances in oxidative stress theory and antioxidant therapy in diabetic cardiomyopathy, with an emphasis on the stress signaling pathways hypothesized to be involved. Many of these stress signaling pathways lead to activation of reactive oxygen species, major players in the development and progression of diabetic cardiomyopathy.

Insulin resistance, dietary fat intake and blood pressure predict left ventricular diastolic function 20 years later

BACKGROUND AND AIMS

Our knowledge on the development of left ventricular diastolic dysfunction is scarce. Thus, we aimed to investigate the relationship between left ventricular diastolic function and a wide variety of cardiovascular risk factors, including dietary factors using both cross-sectional and longitudinal data with 20 years follow-up.

METHOD AND RESULTS

A population-based cohort of 505 50-year-old men was examined with determinations of blood pressure, insulin, glucose and fatty acid composition of serum cholesterol esters. A reinvestigation 20 years later also included hyperinsulinaemic euglycaemic clamp, 7-day diet record and Doppler echocardiography with determination of left ventricular diastolic function (early (E) and late (A) peak mitral velocities and left atrial diameter). Blood pressure both at age 50 and 70 was negatively correlated to the E/A ratio (r=-0.15, p<0.001 and r=-0.23, p<0.001) at age 70. Insulin resistance at age 50 and 70 were negatively correlated to the A-wave and left atrial diameter at follow-up. A fatty acid profile indicating a diet high in saturated fats at age 50 was correlated to an increased left atrial diameter 20 years later and the dietary intake of fat was negatively correlated to the E/A ratio (r=-0.09, p<0.05) at age 70. All findings were independent of myocardial infarction and cardiovascular medication.

CONCLUSION

Apart from blood pressure, insulin resistance and dietary fat intake predicted left ventricular diastolic function after 20 years. These findings suggest that both hemodynamic and metabolic factors may play a role for left ventricular diastolic function and disclose new possibilities for prevention of left ventricular diastolic dysfunction.

Impairment of cardiac function in hypertensive patients with Type 2 diabetes: a LIFE study

AIMS

Type 2 diabetic patients with hypertension have an increased left ventricular (LV) mass and impaired cardiac function compared to hypertensive patients without diabetes. However, it is unknown if the impaired cardiac function can be explained solely by LV hypertrophy, or is independently related to diabetes. The aim of the present study was to compare LV function between diabetic and non-diabetic hypertensive patients with electrocardiographic LV hypertrophy.

METHODS

In 937 patients participating in the LIFE echocardiographic substudy, all echocardiograms were centrally evaluated by a core reading centre measuring LV mass, systolic and diastolic LV function. Known diabetes was present in 105 patients.

RESULTS

Left ventricular mass was similar in diabetic and non-diabetic patients. Endocardial systolic LV function, estimated by LV ejection fraction, was reduced and indices of midwall systolic LV function were impaired in the diabetic patients. Diastolic LV filling pattern was impaired and arterial stiffness, measured by pulse pressure/stroke index, was increased in diabetic patients.

CONCLUSIONS

Systolic and diastolic LV function in hypertensive patients with electrocardiographic LV hypertrophy and diabetes are impaired independent of LV mass, most likely reflecting the adverse effects of diabetes per se.

Left ventricular diastolic function in normotensive subjects 2 months after acute myocardial infarction is related to glucose intolerance

BACKGROUND

Both glucose intolerance and myocardial infarction are independently associated with impaired left ventricular (LV) function. This study was carried out to relate LV diastolic function in normotensive subjects 2 months after acute myocardial infarction (AMI) to glucose tolerance status.

METHODS

Left ventricular ejection fraction (LVEF), LV mass index, peak velocity of the early phase/atrial contraction wave, deceleration time of E wave, and isovolumic relaxation time were measured during echocardiograph/Doppler cardiography in 200 normotensive patients 2 months after AMI. Twenty-nine patients were known to be diabetic on admission with AMI. Glucose tolerance test was carried out in the 171 patients who are not known to be diabetic.

RESULTS

Independent of LVEF, restrictive LV filling (peak velocity of the early phase/atrial contraction wave > 1 but < 2 associated with deceleration time of E wave < or = 140 milliseconds) was found in 72% of the known-diabetic patients, 70% of the 20 preclinical diabetic patients, 23% of the 35 patients with impaired glucose tolerance, 13% of the 15 patients with stress hyperglycemia, and 7% of the euglycemic patients (P < .01). In the rest of these patients, LV filling was nonrestrictive. No significant difference was observed in LVEF and LV mass index between patient groups.

CONCLUSION

Independent of LVEF, the pattern of abnormal LV filling in normotensive subjects 2 months after AMI is a function of the severity of glucose intolerance, restrictive in the majority of the diabetic patients and nonrestrictive in the majority of the euglycemic patients, impaired glucose tolerance, and stress hyperglycemia. After AMI, abnormal LV filling occurs even in the absence of detectable systolic dysfunction or left ventricular hypertrophy.

Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases: Results of the Myocardial Doppler in Diabetes (MYDID) Study 1

AIMS

Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension (HTN).

SUBJECTS AND METHODS

Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n = 23), patients with HTN (n = 20), CAD (n = 35), uncomplicated DM (n = 59), DM+HTN (n = 27), DM+CAD (n = 16) and DM+CAD+HTN (n = 20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables.

RESULTS

Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls.

CONCLUSION

The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

Left ventricular diastolic dysfunction in patients with chronic renal failure: impact of diabetes mellitus

AIMS

Left ventricular (LV) hypertrophy and LV diastolic dysfunction are cardiac changes commonly observed in patients with chronic renal failure (CRF) as well as hypertension. Although the impairment of LV diastolic function in patients with diabetes mellitus has been shown, little is known about the specific effect of diabetes on LV diastolic function in patients with CRF. The present study was designed to investigate the impact of diabetic nephropathy on LV diastolic dysfunction, independent of LV hypertrophy, in CRF patients.

METHODS

In 67 patients with non-dialysis CRF as a result of chronic glomerulonephritis (n = 33) or diabetic nephropathy (n = 34), and 134 hypertensive patients with normal renal function, two-dimensional and Doppler echocardiographic examinations were performed, and LV dimension, mass, systolic function, and diastolic function were evaluated.

RESULTS

LV mass was increased and LV diastolic dysfunction was advanced in subjects with CRF compared with hypertensive controls. In the comparison of echocardiographic parameters between the two groups of CRF patients, i.e. chronic glomerulonephritis and diabetic nephropathy groups, all indices of LV diastolic function were more deteriorated in the diabetic nephropathy group than in the chronic glomerulonephritis group, although LV structure including hypertrophy and systolic function did not differ between the groups. In a multiple regression analysis, the presence of diabetes (i.e. diabetic nephropathy group) was a significant predictor of LV diastolic dysfunction in CRF subjects, independent of other influencing factors such as age, blood pressure, renal function, anaemia and LV hypertrophy.

CONCLUSION

The present findings suggest that LV diastolic dysfunction, independent of LV hypertrophy, is specifically and markedly progressed in patients with CRF as a result of diabetic nephropathy.

Diastolic dysfunction and diastolic heart failure: diagnostic, prognostic and therapeutic aspects

Left ventricular (LV) diastolic dysfunction (DD) and diastolic heart failure (HF), that is symptomatic DD, are due to alterations of myocardial diastolic properties. These alterations involve relaxation and/or filling and/or distensibility. Arterial hypertension associated to LV concentric remodelling is the main determinant of DD but several other cardiac diseases, including myocardial ischemia, and extra-cardiac pathologies involving the heart are other possible causes. In the majority of the studies, isolated diastolic HF has been made equal to HF with preserved systolic function (= normal ejection fraction) but the true definition of this condition needs a quantitative estimation of LV diastolic properties. According to the position of the European Society of Cardiology and subsequent research refinements the use of Doppler echocardiography (transmitral inflow and pulmonary venous flow) and the new ultrasound tools has to be encouraged for diagnosis of DD. In relation to uncertain definitions, both prevalence and prognosis of diastolic heart failure are very variable. Despite an apparent lower death rate in comparison with LV systolic HF, long-term follow-up (more than 5 years) show similar mortality between the two kinds of HF. Recent studies performed by Doppler diastolic indexes have identified the prognostic power of both transmitral E/A ratio < 1 (pattern of abnormal relaxation) and > 1.5 (restrictive patterns). The therapy of LV DD and HF is not well established but ACE-inhibitors, angiotensin inhibitors, aldosterone antagonists and β-blockers show potential beneficial effect on diastolic properties. Several trials, completed or ongoing, have been planned to treat DD and diastolic HF.

Diabetes mellitus and heart failure: basic mechanisms, clinical features, and therapeutic considerations

Diabetic cardiomyopathy encompasses the spectrum from subclinical disease to the full-blown syndrome of congestive heart failure. The prevalence of type 2 diabetes mellitus is increasing at an alarming rate in the western world. and with it, the frequency of diabetes-related heart failure. There is at least early suggestion that target-driven, long-term, intensified intervention that is aimed at multiple risk factors in patients who have type 2 diabetes and microalbuminuria may reduce the risk of macrovascular (cardiovascular) and micro-vascular complications by approximately 50%. Thus, it is imperative that patients, particularly those who are at risk for the cardiovascular dysmetabolic syndrome, be screened aggressively for the presence of glucose intolerance and diabetes. When detected, all metabolic and cardio-vascular parameters should be evaluated and treated aggressively to reach currently recommended clinical targets. Such action will result in great benefit for patients by reducing morbidity and mortality and improving quality of life and will reduce the financial burden that is associated with this epidemic disease.

Tissue Doppler imaging for the detection and quantitation of myocardial dysfunction in patients with type 2 diabetes mellitus

The prevalence of type 2 diabetes mellitus is rapidly increasing. Myocardial dysfunction may be a consequence of diabetic cardiomyopathy and it contributes to the poor prognosis of diabetic patients.

AIMS

This study was designed to test whether tissue Doppler imaging might be a suitable tool for early detection of myocardial dysfunction in diabetic patients.

METHODS

Forty-three diabetic patients and 33 non-diabetic controls, including age-matched subgroups without evidence of coronary artery disease (n=12), were recruited if they had normal LV-function by standard 2-D echocardiography and no clinical signs of heart failure. They were investigated with tissue Doppler imaging at rest and during pharmacological stress with dipyridamole and/or dobutamine. Myocardial function was calculated as the mean value from six basal myocardial segments for peak velocity at systole (Vs), early diastole (Ve) and atrial contraction (Va).

RESULTS

Compared to controls, diabetic patients had compromised Ve at rest (8.5 +/- 1.7 vs. 9.6 +/- 1.9 cm/sec, p < 0.02), as did the subgroups without coronary artery disease (9.3 +/- 1.7 vs. 10.7 +/- 1.5 cm/sec, p < 0.05). Dobutamine stress resulted in lower Vs (10.7 +/- 2.7 vs. 13.6 +/- 3.4 cm/sec, p < 0.05) and Ve (10.0 +/- 2.1 vs. 13.1 +/- 3.8 cm/sec, p < 0.05) in the diabetic patients, demonstrating an impaired increase of Vs, Vd and Va (p < 0.05, p < 0.0003 and p < 0.03, respectively). An inverse correlation was observed between Ve and age in both control and diabetic individuals. Thus, abnormal values were defined in relation to age.

CONCLUSIONS

Diastolic and systolic myocardial dysfunction in patients with type 2 diabetes may be identified by quantitative tissue Doppler imaging before the onset of clinical signs of heart failure and before the appearance of traditional echocardiographic indices of systolic myocardial dysfunction.

NT-proBNP in normoalbuminuric patients with Type 2 diabetes mellitus

OBJECTIVE

To examine levels of NT-proBNP and its relation to hypertension, as well as diastolic function in normoalbuminuric patients with Type 2 diabetes.

RESEARCH DESIGN AND METHODS

The study comprised 60 Type 2 diabetic patients without albuminuria. Thirty patients were normotensive and 30 had hypertension. Exclusion criteria were cardiac symptoms and an ejection fraction < 55%. Thirty age- and sex-matched normal subjects served as controls. Diastolic dysfunction was assessed with echocardiography, by means of mitral inflow and colour M-Mode flow propagation recordings.

RESULTS

Overall NT-proBNP was significantly elevated in the Type 2 diabetes group, compared with the controls [54.5 pg/ml (5-162) vs. 32.7 pg/ml (5-74.3) P = 0.02]. NT-proBNP was significantly higher among hypertensive patients compared with both normotensive patients and controls but no difference was found between the normotensive patients and the controls [58.0 pg/ml (8.5-162), P < 0.05 vs. 50.8 pg/ml (5-131) P = 0.4]. Patients with concentric and eccentric hypertrophy had significantly higher NT-proBNP levels compared with the control group [81.0 pg/ml (5-147), P < 0.001 and 66.8 pg/ml (42-128), P < 0.001], whereas patients with left ventricular remodelling (enlarged relative wall diameter but normal left ventricular mass) were comparable with the control group [42.3 pg/ml (8.3-142) P = 0.55]. Patients with left atrial enlargement also had incremental NT-proBNP values. NT-proBNP was only moderately correlated to age (r = 0.33, P < 0.05) and left ventricular diastolic diameter (r = 0.41, P < 0.05), but unrelated to diastolic function.

CONCLUSIONS

NT-proBNP is significantly increased in hypertensive, normoalbuminuric patients with Type 2 diabetes. These findings were related to left ventricular hypertrophy and increased left atrial and ventricular diameters.

Cardiac dysfunction in the euglycemic diabetic-prone BB Wor rat

The purpose of this study was to examine cardiac function in the diabetic-prone BB Wor rat. The study involved 2 groups: diabetic resistant control littermates of BB rats and diabetic-prone BB rats that had yet to demonstrate overt signs of diabetes. Hearts from these animals were isolated and cardiac function examined in response to incremental increases in left atrial filling pressure. Hearts were also perfused at an increased aortic afterload resistance with buffer consisting of glucose alone or glucose in the presence of palmitate. Hearts from diabetic-prone rats exhibited depressed contractility and ventricular relaxation at high filling pressures. Ventricular function, expressed as cardiac output, was also depressed in diabetic-prone rats perfused at increased afterload resistance, but only in the presence of palmitate. Our results indicate that hearts from diabetic-prone BB Wor rats demonstrate abnormalities in contractile performance and thus may be a useful model for the study of cardiac function in the prediabetic state.

Left ventricular dysfunction in normotensive Type 1 diabetic patients: the impact of autonomic neuropathy

AIMS

The pathophysiological mechanisms responsible for increased cardiovascular mortality in diabetic autonomic neuropathy (AN) are largely unknown. The aim was to determine the relative role of AN in the pathogenesis of cardiac diastolic dysfunction and left ventricular hypertrophy in Type 1 diabetes.

METHODS

Ten Type 1 diabetic patients with AN, defined by cardiovascular tests (AN+) and 10 age- and sex-matched patients without neuropathy (AN-) as well as 10 healthy subjects (C) participated in the study. Left ventricular diastolic function was assessed by Doppler echocardiography, whilst systolic function was evaluated by cine magnetic resonance (MR) imaging.

RESULTS

Doppler echocardiography showed a significant decrease in E/A ratio, i.e. the ratio between peak Early transmitral filling velocity during early diastole (E-wave) and peak transmitral Atrial filling velocity during late diastole (A-wave), in AN+ compared with C (P < 0.01) [0.95 +/- 0.08 (mean +/- sem) (AN+); 1.19 +/- 0.09 (AN-); 1.33 +/- 0.10 (C)]. The E-wave deceleration time was significantly shorter in AN+ compared with AN- and C (P < 0.02) [178 +/- 7 ms (AN+); 203 +/- 9 ms (AN-); 205 +/- 9 ms (C)]. Cine MR imaging showed a significantly greater left ventricular mass index in AN+ compared with C [103 +/- 4 g/m(2) (AN+) vs. 98 +/- 7 (AN-) and 92 +/- 4 g/m(2) (C), P < 0.05].

CONCLUSION

Autonomic neuropathy is associated with left ventricular hypertrophy and diastolic dysfunction in Type 1 diabetic patients.

The diabetes epidemic: a national and global crisis

Diabetes mellitus is a serious problem that will soon reach epidemic proportions in the United States and throughout the world. The incidence of this condition will skyrocket in the next quarter century as demographic changes increase the size of highly susceptible populations (e.g., the elderly and Hispanic communities) and sociocultural developments create a more sedentary populace as well as expose people in developing nations to new risk factors for this disease. Along with substantial direct morbidity and mortality, diabetes is independently associated with the incidence and severity of a variety of cardiovascular illnesses. Individuals with diabetes are substantially more likely than their nondiabetic counterparts to suffer stroke, myocardial infarction, or heart failure, with a worse prognosis following any of these conditions. Many factors may be relevant to this association, but recent studies have elucidated a major role for the metabolic syndrome, which has been shown to be predictive of both diabetes and cardiovascular disease. Consequently, early intervention to control blood glucose levels and other risk factors may mitigate the severity of these conditions, possibly even before the disease begins.

New insights into diastolic heart failure: role of diabetes mellitus

Heart failure affects nearly 5 million people in the United States and is a major contributor to mortality, hospitalization, and medical costs. Approximately 40% of patients with heart failure have preserved left ventricular systolic function, thus exhibiting diastolic heart failure. More common in women and the elderly, this condition is associated with hypertension, coronary artery disease, and/or atrial fibrillation. With the exception of the Digitalis Investigation Group (DIG) and the Candesartin in Heart Failure: Assessment of Reduction in Mortality and Morbidity (CHARM)-Preserved trials, no completed large randomized clinical trial has addressed the management of such patients. Symptomatic treatment involves administration of diuretics and nitrates, but long-term management with angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, aldosterone antagonists, beta-blockers, and calcium channel blockers targets the underlying disorders. Recent studies found that diabetes mellitus produces functional, biochemical, and morphologic myocardial abnormalities independent of coronary atherosclerosis and hypertension. These abnormalities may result in impaired left ventricular diastolic function, contributing importantly to heart failure with normal systolic function. Although tight glycemic control decreases the risk of heart failure in patients with diabetes, the effects of different diabetic treatment regimens on heart failure with normal systolic function are unknown and remain subject to future investigation.

Electrocardiographic repolarization complexity and abnormality predict all-cause and cardiovascular mortality in diabetes: the strong heart study

Type 2 diabetes is associated with increased risk of cardiovascular (CV) and all-cause mortality. Although electrocardiographic measures of repolarization abnormality and complexity stratify risk in the general population, their prognostic value in diabetes has not been well characterized. Digital electrocardiogram (ECG) readings were acquired for 994 American Indians with type 2 diabetes. ST segment depression (STD) >/=50 micro V and rate-corrected QT interval (QTc) >460 ms were examined as measures of repolarization abnormality. The principal component analysis (PCA) of the ratio of the second to first eigenvalues of the T-wave vector (PCA ratio) (>32.0% in women and >24.6% in men) was examined as a measure of repolarization complexity on the ECG. After a mean follow-up of 4.7 +/- 1.0 years, there were 56 CV deaths and 155 deaths from all causes. In univariate analyses, STD, QTc, and the PCA ratio predicted CV and all-cause mortality. After multivariate adjustment for age, sex, and other risk factors, STD (hazard ratio 3.68, 95% CI 1.70-7.96) and PCA ratio (2.61, 1.33-5.13) remained predictive of CV mortality and both STD (2.36, 1.38-4.02) and QTc (2.03, 1.32-3.12) predicted all-cause mortality. Computerized ECG measures of repolarization abnormality and complexity predict CV and all-cause mortality in type 2 diabetes, supporting their use to identify high-risk individuals with diabetes.

The Role of Exercise in the Treatment of Cardiovascular Disease Associated with Type 2 Diabetes Mellitus

The role of exercise training in the prevention and treatment of type 2 diabetes mellitus has been studied extensively over the past two decades. Although the primary treatment aim for patients with type 2 diabetes is metabolic control, the morbidity and mortality associated with the disease is more a function of cardiovascular disease. As exercise is associated with favourable reductions in the risk for cardiovascular disease in other high-risk populations, here we explore the role of exercise in the treatment of cardiovascular maladaptations associated with type 2 diabetes. The cardiovascular adaptation to type 2 diabetes is characterised by hypertrophy, stiffening and loss of functional reserve. Clinically, the cardiovascular adaptations to the diabetic state are associated with an increased risk for cardiovascular disease. Functionally, these adaptations have been shown to contribute to a reduced exercise capacity, which may explain the reduced cardiovascular fitness observed in this population. Exercise training is associated with improved exercise capacity in various populations, including type 2 diabetes. Several structural and functional adaptations within the cardiovascular system following exercise training could explain these findings, such as reductions in ventricular and vascular structural hypertrophy and compliance coupled with increased functional reserve. Although these cardiovascular adaptations to aerobic exercise training have been well documented in older populations with similar decrements in cardiovascular fitness and function, they have yet to be examined in patients with type 2 diabetes. For this reason, we contend that exercise training may be an excellent therapeutic adjunct in the treatment of diabetic cardiovascular disease.

Diabetes Mellitus and Heart Failure

The metabolic abnormalities associated with diabetes mellitus result in macrovascular and microvascular complications in multiple organ systems; it is the cardiovascular impact that accounts for the greatest morbidity and mortality associated with this disease. Heart failure, both with reduced and preserved systolic function, is a major complication, arising from the frequent associations with coronary atherosclerosis, hypertension, and a specific heart muscle dysfunction (cardiomyopathy) that occurs independently of coronary artery disease. Hyperglycemia, insulin resistance, and hypertension, together with activation of both the circulating and the tissue renin-angiotensin-aldosterone systems, contribute to structural fibrosis and autonomic neuropathy. Thus, it becomes imperative to identify cardiac abnormalities early in the course of both type 1 and type 2 diabetes to allow early and aggressive intervention to control glucose and blood pressure and to normalize blood lipid profiles. Patients with diabetes should be treated to secondary prevention targets, including blood pressure less than 130/80 mm Hg and low-density lipoprotein cholesterol level less than 100 mg/dL. Angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers,beta blockers, calcium channel-blockers, statins, and aspirin have all been demonstrated to significantly reduce cardiovascular morbidity and mortality in patients with diabetes.

Relation of left ventricular hypertrophy to inflammation and albuminuria in adults with type 2 diabetes: the strong heart study

OBJECTIVE

To evaluate in adults with type 2 diabetes the extent to which the relation of left ventricular hypertrophy (LVH) to markers of systemic inflammation (fibrinogen and high-sensitivity C-reactive protein [hsCRP]) are affected by microangiopathy.

RESEARCH DESIGN AND METHODS

We selected adults with type 2 diabetes using American Diabetes Association criteria from a population-based cohort, excluding those with medical history or electrocardiographic evidence of coronary heart disease or dialysis-dependent renal failure. LVH was assessed by echocardiogram.

RESULTS

Of the 1299 eligible participants, 384 (29.6%) had LVH, which was associated with higher BMI, hsCRP, fibrinogen, and albuminuria in univariate analyses. After controlling for significant confounders, fibrinogen and albuminuria were higher in the presence of LVH (both P < 0.01), whereas hsCRP was not (P = 0.2), mostly because of the confounding effect of BMI. Adjustment for albuminuria abolished the relation of LVH to higher fibrinogen (P = 0.2). However, fibrinogen was significantly higher in participants with LVH among those without pathologic levels of albuminuria (<30 mg/g creatinuria), but not independent of BMI. Although hsCRP and fibrinogen were moderately correlated, fibrinogen, but not CRP, showed a significant relation with albuminuria.

CONCLUSIONS

In adults with type 2 diabetes, echocardiographic LVH is associated with susceptibility to atherothrombosis and increased albuminuria, which is a marker of microangiopathy and endothelial dysfunction that appears in turn to be a relevant pathogenetic link between LVH and inflammation. However, in the absence of significant microalbuminuria, elevated BMI is a relevant pathogenetic factor in the relation of LVH to increased levels of markers of inflammation, potentially preceding development of significant albuminuria. In the presence of microangiopathy, we found that the atherothrombotic risk profile associated with LVH was independent of BMI and possibly reflected the association of LVH with a higher degree of endothelial dysfunction.

Preclinical diabetic cardiomyopathy: relation of left ventricular diastolic dysfunction to cardiac autonomic neuropathy in men with uncomplicated well-controlled type 2 diabetes

Diabetic cardiomyopathy is an ill-defined entity. This study was designed to explore the possible association between left ventricular diastolic dysfunction (LVDD) and cardiac autonomic neuropathy (CAN) independently from metabolic control. Three groups of 10 age-matched men each with well-controlled type 2 diabetes were studied: (1) subjects with normal diastolic function, (2) subjects with LVDD characterized by impaired LV relaxation, and (3) subjects with a more severe form of LVDD characterized by a pseudonormalized pattern of LV filling. No subject had evidence of clinical diabetic complications, coronary artery disease (CAD), hypertension, congestive heart failure, or thyroid or overt renal disease, and all had a negative maximal exercise test. LVDD was evaluated by Doppler echocardiographic and CAN was evaluated using spectral analysis of heart rate variability (HRV; time and frequency domains) from 24-hour Holter recordings. Findings showed that the high frequency power (HF: 0.15 to 0.4 Hz) tends to decrease with worsening diastolic function; 5.0 +/- 0.2 ms(2) (mean +/- SE) in group 1, 4.2 +/- 0.3 ms(2) in group 2, and 3.9 +/- 0.4 ms(2) (P =.03) in group 3, respectively, whereas the low frequency power (LF: 0.04 to 0.15 Hz) was similar between groups. In the time domain, the mean squared differences of the successive RR intervals (rMSDD) also showed the same pattern, ie, 31.0 +/- 2.8 ms, 23.8 +/- 1.6 ms, and 21.5 +/- 2.9 ms in groups 1, 2, and 3, respectively (P =.03). The E/A ratio correlated significantly with indices of parasympathetic modulation (HF; r = 0.448, P =.013; rMSDD: r = 0.457, P =.011; pNN50: r = 0.425, P =.019). LVDD and CAN are associated in patients with otherwise uncomplicated well-controlled type 2 diabetes. The parameters defining these 2 abnormalities may serve to better define diabetic cardiomyopathy as a distinct entity and could eventually become useful prognostic indicators as it has been shown in nondiabetic populations.

Left ventricular systolic and diastolic function in normotensive type 1 diabetic patients with or without autonomic neuropathy: a radionuclide ventriculography study

OBJECTIVE

To investigate the relation between diabetic autonomic neuropathy (DAN) and left ventricular (LV) function in type 1 diabetic patients.

RESEARCH DESIGN AND METHODS

A total of 57 type 1 diabetic patients free of coronary artery disease and arterial hypertension were studied. Diagnosis of DAN was established by autonomic nervous function (ANF) tests, and LV systolic and diastolic functions were assessed by radionuclide ventriculography at rest.

RESULTS

There were 24 patients who had definite DAN, established by the presence of two or more abnormal ANF tests, and 33 subjects were without DAN. DAN patients had impaired LV filling pattern, obvious by a reduced peak filling rate (3.1 +/- 1.1 vs. 3.7 +/- 0.7 end-diastolic volume [EDV]/s, P = 0.011) and first third filling fraction (35.3 +/- 19.5 vs. 50.8 +/- 16%, P = 0.002) as well as an increased time to peak filling (159.4 +/- 45.1 vs. 134.2 +/- 33.4 ms, P = 0.02) after correction for age and heart rate. There were no differences between the two groups with regard to ejection fraction, cardiac output, and cardiac index, whereas the peak emptying rate was greater in DAN patients (4.1 +/- 0.8 vs. 3.6 +/- 0.8 EDV/s, P = 0.019), suggesting LV hypercontractility. DAN patients had an increased heart rate (83.4 +/- 11.9 vs. 72.7 +/- 9.3 bpm, P = 0.001) and slightly higher systolic blood pressure. As a result, LV working load at rest was higher in DAN patients (11,109 vs. 9,096 bpm x mmHg, P < 0.001). Moreover, a correlation was found between abnormal LV systolic and diastolic indexes and the number of abnormal ANF tests.

CONCLUSIONS

At rest, DAN patients have impaired LV filling pattern, slightly increased LV systolic function, and a higher LV working load, in comparison to non-DAN type 1 diabetic patients.

Screening for treatable left ventricular abnormalities in diabetic patients

Cardiovascular disease is the leading cause of death in patients with diabetes mellitus. Attempts to improve this statistic tend to focus primarily on the prevention of coronary artery disease. However, coronary artery disease is not the sole cause of cardiac death in diabetic patients; left ventricular dysfunction (LVD) and left ventricular hypertrophy (LVH) are also implicated and, unlike coronary artery disease, are ideal targets for screening. The treatment of left ventricular abnormalities, even when these are asymptomatic, is associated with prognostic benefit. Prescreening diabetic patients with plasma B-type natriuretic peptide (BNP) may permit identification of those who are likely to have left ventricular abnormalities, so that they may be put forward for echocardiography and receive targeted therapy.

Ventricular remodeling does not accompany the development of heart failure in diabetic patients after myocardial infarction

BACKGROUND

Diabetic patients are at increased risk for heart failure (HF) and other adverse events after myocardial infarction (MI). Left ventricular (LV) enlargement after MI is also associated with the same increased risk. We used data from the Survival and Ventricular Enlargement (SAVE) echocardiographic substudy to test the hypothesis that diabetes was associated with increased LV enlargement after MI.

METHODS AND RESULTS

Four hundred twelve nondiabetic and 100 diabetic patients underwent echocardiographic assessment at baseline and 3 months, 1 year, and 2 years after MI. HF developed in 30% of diabetic and 17% of nondiabetic patients during follow-up (P<0.001). Baseline LV diastolic size, ejection fraction, and infarct segment length were similar between diabetic and nondiabetic patients. Diabetic patients demonstrated less LV enlargement between baseline and 2 years than nondiabetic patients (0.9+/-11.1 cm2 versus 3.8+/-10.9 cm2, P=0.047). In patients who developed HF, LV diastolic dilatation (10.0+/-12.4 cm2 versus 3.7+/-13.1 cm2, P=0.06) and systolic dilatation (4.6+/-11.8 versus 0.91+/-12.1, P=0.017) were greater in nondiabetic than in diabetic patients. LV dilatation between baseline and 2 years was a predictor of HF in nondiabetic patients, but not in diabetic patients, even after excluding patients with recurrent MI and adjusting for history of hypertension, prior MI, age, treatment group, and smoking. Diabetes modified the relationship between ventricular enlargement and the risk of HF (P=0.011).

CONCLUSIONS

The increased incidence of HF after MI in diabetic patients is not explained by a greater propensity for LV remodeling.

Prevalence of gallbladder disease in American Indian populations: findings from the Strong Heart Study

American Indians are believed to be at high risk of gallbladder disease (GBD), but there has been no systematic evaluation of its prevalence among diverse groups of American Indians. Therefore, we determined the prevalence of GBD and associated risk factors among specified American Indian populations using ultrasonography of the gallbladder and standardized diagnostic criteria. Enrolled members, aged 47 years and older, of 13 American Indian tribes or communities in Arizona, Oklahoma, and South and North Dakota who participated in the Strong Heart Study were analyzed. GBD was the sum of gallstones (determined by ultrasound examination) and cholecystectomy (determined by ultrasound and self-report). The proportion of American Indian heritage was based on the heritage of the grandparents of participants. GBD prevalence was determined among 3,296 participants at the 3 sites. Among women, 17.8% had gallstones, and 46.3% had evidence of a cholecystectomy, for a total of 64.1% with GBD. Among men, 17.4% had gallstones, and 12.1% had evidence of a cholecystectomy, for a total of 29.5% with GBD. When figures were adjusted for age and Indian heritage, there was no significant difference in GBD prevalence across the 3 geographical areas. In multivariate logistic regression analysis, age, American Indian heritage, and waist circumference were associated with GBD among men, and age, American Indian heritage, diabetes, and parity were associated with GBD among women. Body mass index was not independently associated with GBD in either sex. In conclusion, GBD was found in epidemic proportions in diverse American Indian populations.

Echocardiographic abnormalities in normotensive obese patients: relationship with visceral fat

OBJECTIVE

To evaluate the relationship of echocardiographic characteristics and visceral adipose tissue (VAT) distribution in normotensive obese patients.

RESEARCH METHODS AND PROCEDURES

Echocardiographic parameters were assessed in 28 normotensive obese patients [7 men, 21 women, mean age, 43.2 years; mean body mass index (BMI), 37.2 kg/m(2); 10 with impaired glucose tolerance (IGT); 6 with type 2 diabetes] and 18 sex- and age-matched healthy, normal-weight controls (4 men, 14 women; mean age, 45.8 years; mean BMI, 22.4 kg/m(2)) by an M-mode, color-doppler videofluoroscope. VAT in the obese patients was assessed by computed tomography (at L4 level).

RESULTS

The obese patients had a significantly larger internal diastolic left ventricular (LV) diameter (p < 0.05), a thicker end-diastolic septum (p < 0.001) and posterior wall (p < 0.001), a greater indexed (g/m(2.7)) LV mass (p < 0.001), a higher atrial diastolic filling wave velocity (p < 0.001), a lower ratio between early and atrial diastolic filling wave velocities (p < 0.01), and a prolonged isovolumic relaxation time (p < 0.05). End-diastolic septum and posterior wall thickness and the LV mass were significantly greater in patients with a VAT area >130 cm(2) than with <130 cm(2). In the multivariate regression analysis, only VAT (p < 0.0001), waist-to-hip ratio (p < 0.001), and sex (p < 0.001) were associated with the most important echocardiographic alterations.

DISCUSSION

The morphological and functional echocardiographic alterations usually found in normotensive obese patients closely correlate with the amount of intra-abdominal fat deposition, even in the presence of diabetes or IGT.

Fasting plasma glucose is an independent determinant of left ventricular diastolic dysfunction in nondiabetic patients with treated essential hypertension

Left ventricular (LV) hypertrophy and LV diastolic dysfunction are common cardiac changes in hypertensive patients, and these changes are modified by various factors other than blood pressure. The present study was conducted to investigate the influence of mild abnormalities in glucose metabolism on LV structure and function in essential hypertension. In 193 nondiabetic patients with treated essential hypertension, two-dimensional and Doppler echocardiographic examinations were performed, and relative wall thickness (RWT), LV mass index (LVMI), fractional shortening, and the ratio of the peak velocity of atrial filling to early diastolic filling (A/E) were calculated. Fasting plasma glucose (FPG) and HbA1c levels were positively correlated with the A/E ratio and the deceleration time of the E wave. However, these plasma levels had no correlation with RWT, LVMI, or fractional shortening. Peak A wave velocity and the A/E ratio were significantly higher in patients who had FPG of > or = 100 mg/dl (and <126 mg/dl) than those who had FPG of <100 mg/dl, although age, blood pressure, RWT, LVMI, and fractional shortening did not differ between the two groups. In a multiple regression analysis of all subjects, only FPG and age were independent determinants of the A/E ratio. These observations suggest that FPG is a sensitive predictor for LV diastolic dysfunction in nondiabetic patients with treated hypertension. Since a slight increase in plasma glucose levels is associated with abnormalities in diastolic function independent of LV hypertrophy, an early stage of impaired glucose metabolism in hypertensive patients may specifically deteriorate cardiac diastolic function.

Gender difference in diastolic function in hypertension (the HyperGEN study)

Although several studies indicate that there are gender differences in left ventricular (LV) systolic function, it remains unclear whether similar differences exist with regard to diastolic function. Accordingly, Doppler echocardiograms were analyzed in 515 male and 839 female, mostly treated (95%) hypertensive participants enrolled in the Hypertension Genetic Epidemiology Network (HyperGEN) study with no evidence of abnormal wall motion or significant valvular heart disease. There was no difference in age between genders, but after adjusting for age and race, men had lower body mass indexes (29.8 +/- 5.2 vs 32.3 +/- 7.6 kg/m(2)) and heart rates (67 +/- 12 vs 69 +/- 11 beats/min) and higher systolic and diastolic blood pressures (BP) than women (134 +/- 20 vs 130 +/- 21 and 80 +/- 11 vs 72 +/- 11 mm Hg, all p <0.001). LV mass/height(2.7) was slightly greater in women than in men (43 +/- 10 vs 42 +/- 9 g/m(2.7), p <0.05). After adjusting for age, race, systolic BP, body mass index, heart rate, and LV hypertrophy, both mitral E-wave (70 +/- 18 vs 77 +/- 19) and A-wave (74 +/- 15 vs 79 +/- 17, both p <0.001) velocities were lower in men than in women, but the mitral E/A ratio and atrial filling fraction were nearly identical in both genders. Deceleration time (221 +/- 55 vs 214 +/- 46 cm/s, p = 0.018) and isovolumic relaxation time (IVRT) were longer in men than in women (85 +/- 18 vs 81 +/- 17 cm/s, p <0.001). Prolonged IVRT was present in more men than women (14% vs 7%, p <0.05). In analyses of covariance, adjusting for age, race, systolic BP, body mass index, heart rate, and medications, male gender remained related to prolonged deceleration time and IVRT. Thus, in this population-based sample of hypertensive adults, men had evidence of slower early diastolic LV filling than women. This gender difference in diastolic function may provide insight into gender differences in congestive heart failure and other specific cardiovascular diseases.