Left ventricular hypertrophy and antihypertensive therapy.

Left ventricular hypertrophy is more common in hypertensive individuals than in normotensive persons. Its presence in hypertensive patients is associated with an increased incidence of ventricular arrhythmias, myocardial infarction, congestive heart failure, stroke and cardiovascular mortality. Echocardiography is more sensitive than electrocardiography in detecting left ventricular hypertrophy. Echocardiographic evidence of this condition in patients with borderline hypertension may identify those who need treatment. Weight reduction and drug therapy can prevent or reverse ventricular hypertrophy in hypertensive patients. Recent studies suggest that some antihypertensive drugs are more effective than others in reducing left ventricular hypertrophy. These agents include beta-adrenergic blockers, angiotensin converting enzyme inhibitors, calcium channel blockers and sympatholytic agents. Although little evidence exists to show that reduction of left ventricular mass decreases cardiovascular morbidity and mortality, avoidance of antihypertensive agents that may aggravate hypertrophy would seem prudent.     

Left ventricular hypertrophy. A crucial target for antihypertensive therapy

The development of left ventricular hypertrophy (LVH) is one way that the heart compensates for the hemodynamic burden of sustained hypertension. However, this adaptation itself contributes to increased cardiovascular morbidity and mortality. In this article, Dr Messerli describes the causes and consequences of LVH and discusses the current therapeutic approach to patients with the condition.     

Characteristics and prognosis of normoalbuminuric type 1 diabetic patients

Intervention in type 1 diabetic patients with increased urinary albumin excretion (UAE) represents a great step forward in modern diabetology. At the moment, the consensus calls for antihypertensive treatment in normotensive type 1 diabetic patients with persistent microalbuminuria. However, recent data indicate that substantial pathophysiological changes have already taken place at the microalbuminuric stage. Thus, prevention of progression from normo- to microalbuminuria would be a major clinical turning point. A considerable number of potential risk factors for progression to microalbuminuria have been proposed, among which are blood pressure elevation and disturbancies in circadian blood pressure variation. We performed 24-h ambulatory blood pressure (AMBP) monitoring in 115 normoalbuminuric (UAE < 20 micrograms/min) patients, along with performing an assessment of circadian blood pressure and heart rate (HR) variation and a short-term power spectral analysis of RR interval oscillations. Patients with UAE above the median had significantly higher systolic and diastolic AMBP compared to the low normoalbuminuric group. The difference in blood pressure between the two groups was most pronounced for the night blood pressure (P < 0.01 and 0.02). A positive correlation between UAE and circadian variation (described as diastolic night/day ratio) was present--that is, the higher the normoalbuminuria, the more blunted the night/day ratio. The patients characterized by a combination of high-normal UAE and blunted circadian variation also proved to have significantly higher HbA1c values, higher 24-h mean arterial blood pressure, and lower vagal activity. In conclusion, high-normal UAE, poor metabolic control, and cigarette smoking are at present the only established risk factors for progression from normo- to microalbuminuria. However, new data emphasizes the close relation between blood pressure and albumin excretion. Pathophysiological abnormalities (poorer glycemic control, higher blood pressure, and attenuated vagal activity) tend to cluster in patients characterized by high-normal UAE and blunted circadian variation of blood pressures, and this patient group might constitute a putative high-risk group.     

Left ventricular function in young type I diabetic patients. A Doppler echocardiography study

Systolic and diastolic left ventricular function was assessed by M-mode and pulsed Doppler echocardiography in 10 young type I diabetic patients without late complications and maximal diabetes duration of 5 years and in 10 healthy persons. Fractional shortening, a measure of systolic ventricular function, was significantly lower in diabetics than in controls (33.9 +/- 2.9 vs. 37.9 +/- 4.9; p less than 0.05). Fractional shortening decreased significantly with advancing diabetes duration (R = -0.819; p less than 0.01). Indexes of diastolic ventricular function (isovolumetric relaxation period and transmitral flow velocity pattern) were not significantly different in the two groups, but 3 patients had 1 parameter (3x isovolumetric relaxation period) and another patient had 2 parameters (isovolumetric relaxation period and early diastolic peak velocity E-E') outside the normal range. Follow-up studies should define the clinical significance of these alterations of systolic and diastolic left ventricular function.     

Urinary albumin excretion rate is associated with increased ambulatory blood pressure in normoalbuminuric type 2 diabetic patients

OBJECTIVE: To evaluate the 24-h blood pressure profile in normoalbuminuric type 2 diabetic patients. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted in 90 type 2 diabetic patients with a urinary albumin excretion rate (UAER) <20 microg/min on two occasions, 6 months apart (immunoturbidimetry). Patients underwent clinical and laboratory evaluations. Ambulatory blood pressure monitoring and echocardiograms were also performed. RESULTS: UAER was found to correlate positively with systolic doctor's office blood pressure measurements (r = 0.243, P = 0.021) and ambulatory blood pressure (24 h: r = 0.280, P = 0.008) and left ventricular posterior wall thickness (r = 0.359, P = 0.010). Patients were divided into four groups according to UAER (<5, > or =5-10, > or =10-15, and > or =15-20 microg/min). Systolic blood pressure parameters for the 1st, 2nd, 3rd, and 4th groups, respectively, were 123.0 +/- 10.6, 132.5 +/- 15.0, 139.0 +/- 23.4, and 130.7 +/- 8.0 mmHg for 24-h blood pressure (ANOVA P = 0.004) and 48.4 +/- 6.0, 54.5 +/- 11.2, 58.8 +/- 15.6, and 57.6 +/- 8.0 mmHg for 24-h pulse pressure (ANOVA P = 0.003). A progressive increase in the prevalence of diabetic retinopathy was observed from the 1st to the 4th UAER group: 27.3, 43.8, 45.5, and 66.7% (P = 0.029 for trend). CONCLUSIONS: In type 2 diabetic patients, UAER in the normoalbuminuric range is positively associated with systolic ambulatory blood pressure indexes, left ventricular posterior wall thickness, and diabetic retinopathy, suggesting that intensive blood pressure treatment may prevent diabetes complications in these patients.     

A longitudinal evaluation of urinary glycosaminoglycan excretion in normoalbuminuric type 1 diabetic patients.

BACKGROUND: Previously, we found high urinary glycosaminoglycan (GAG) concentration, together with an altered electrophoretic pattern, in normoalbuminuric type 1 diabetic subjects with hemoglobin A(1c) (HbA(1c)) > or =8.0%. The purpose of this study was long-term evaluation of GAG excretion variations in these patients compared to those with HbA(1c) < 8.0% at baseline who maintained better metabolic control over time. METHODS: We enrolled 26 normotensive, normoalbuminuric type 1 diabetic patients and divided them into two groups according to mean HbA(1c) levels during the follow-up period. GAGs were isolated from 24-h urine samples on two separate occasions, at baseline and after a mean (+/-SD) follow-up of 6.8+/-1.1 years. RESULTS: All patients remained normoalbuminuric at follow-up, and had normal urinary alpha(1)-microglobulin levels. In patients with HbA(1c) <8.0%, total GAG levels and low sulfated chondroitin sulfate-proteoglycan/chondroitin sulfate ratio were almost unchanged during the follow-up period. In contrast, these increased in patients with HbA(1c) > or =8.0% and were significantly related to both HbA(1c) levels and the duration of poor glycemic control. CONCLUSIONS: Our results show a strong influence of hyperglycemic environment on GAG metabolism in diabetes and indicate that the distribution pattern of urinary GAGs, besides their total concentration, may be predictive of altered GAG metabolism in type 1 diabetes.     

Effect of antihypertensive treatment on the prevalence of ventricular arrhythmias among patients with isolated systolic hypertension without left ventricular hypertrophy

Background: The high incidence of ventricular arrhythmias in patients with hypertension and left ventricular hypertrophy (LVH) is well documented. However, few studies have been conducted on the prevalence of ventricular arrhythmias in patients with isolated systolic hypertension without LVH.Objectives: The objectives of this study were to (1) determine the prevalence of ventricular arrhythmias in patients with systolic hypertension without LVH and (2) estimate the effect of a perindopril/indapamide combination, which does not have an antiarrhythmic effect, on the incidence of ventricular arrhythmias.Methods: Patients with newly diagnosed isolated systolic hypertension (systolic blood pressure [SBP] >160 mm Hg) and a control group of normotensive patients were enrolled. During the 2-week washout period, patients underwent physical examination (including blood pressure measurements), ambulatory electrocardiography monitoring, echocardiography, and laboratory urine and blood tests. Absence of LVH was confirmed by echocardiographic examination. The group of hypertensive patients received 1 tablet of 2 mg perindopril/0.625 mg indapamide per day for a total of 4 weeks. Physical examinations and ambulatory electrocardiographic monitoring were repeated after treatment.Results: A total of 60 hypertensive (mean age, 63.1 years; mean SBP, 176.8 ± 3.1 mm Hg; mean diastolic blood pressure, 82.6 ± 2.9 mm Hg) and 60 normotensive patients were enrolled. Ambulatory electrocardiographic monitoring indicated that 18 of the 60 hypertensive patients (30%) had ventricular arrhythmias: 17 had ventricular premature contractions (>100/24 h) and 1 had ventricular tachycardia plus ventricular premature contractions. In the control group, 7 of 60 subjects (11.7%) had ventricular premature contractions. The difference between the 2 groups in incidence of ventricular arrhythmias was significant (P < 0.01). After treatment, mean SBP decreased to 136.1 ± 3.2 mm Hg, and ventricular premature contractions were found in 9 of 60 hypertensive patients (15%) (P < 0.02 vs pretreatment).Conclusions: The results of this study suggest that in patients with isolated systolic hypertension without LVH, (1) the prevalence of ventricular arrhythmia is higher than in normotensive patients and (2) treatment with perindopril/indapamide decreases the incidence of ventricular arrhythmias.     

Left ventricular hypertrophy, compliance and ventricular filling.

A total of 20 untreated hypertensive patients were divided into two equal groups matched for sex, age and blood pressure but with [mean diastolic wall thickness (MDWT) greater than 1.2 cm] or without (MDWT greater than 1.2 cm) left ventricular hypertrophy (LVH). All patients underwent pulsed doppler echocardiography and 99Tc radionuclide ventriculography at rest to assess diastolic and systolic abnormalities. In hypertensives with LVH the interventricular wall thickness, posterior wall thickness and relative diastolic wall thickness were significantly (P less than 0.01) higher and peak filling rate was significantly (P less than 0.01) lower than in hypertensives without LVH. The indices of systolic function, however, were not significantly different in the two patient groups. In hypertensives without LVH peak filling rate directly correlated with heart rate, whereas in those with LVH peak filling rate directly correlated with heart rate and the ratio of peak velocity of early left ventricular filling : peak velocity of late left ventricular filling due to atrial contraction. It is concluded that diastolic parameters may be useful tools for assessing myocardial compliance and may be effective markers of diastolic dysfunction.     

Left ventricular hypertrophy in renal failure a review

Renal failure is becoming increasingly common in our enironment. Advances in management like availability of dialysis and transplantation is prolonging the live of patients. As a consequence complication are increasingly being encountered. Cardiovascular complication is one of the commonest; and left ventricular hypertrophy is one of the major cardiovascular complications of end stage renal failure. It is an independent predictor of survival in patients with chronic renal failure and is present in a large number of patients entering maintenance haemodialysis. This review summarizes the occurrences of left ventricular hypertrophy, its pathomechhanism, clinical significance, evaluation and interventional strategies. This information is useful to us as we grapple with this problem.     

Sulfonylurea treatment of type 2 diabetic patients does not reduce the vasodilator response to ischemia

OBJECTIVE: Sulfonylureas block the activation of vascular potassium-dependent ATP channels and impair the vasodilating response to ischcmia in nondiabetic individuals, but it is not know whether this occurs in type 2 diabetic patients under chronic treatment with these drugs. Glimepiride, a new sulfonylurea, apparently has no cardiovascular interactions. The aim of our study was to compare the effect of the widely used compound glibenclamide, the pancreas-specific glimepiride, and diet treatment alone on brachial artery response to acute forearm ischemia. RESEARCH DESIGN AND METHODS: Brachial artery examination was performed by a high-resolution ultrasound technique on 20 type 2 diabetic patients aged mean +/- SD) 67 +/- 2 years and on 18 nondiabetic patients matched for age, hypertension, and dislipidemia. Diabetic subjects underwent three separate evaluations at the end of each 8-week treatment period, during which they received glibenclamide, glimepiride, or diet alone according to crossover design. Scans were obtained before and after 4.5 min of forearm ischemia. Postischemic vasodilation and hyperemia were expressed as percent variations in vessel diameter and blood flow. RESULTS: Postischemic vasodilation and hyperemia were, respectively, 5.42 +/- 0.90 and 331 +/- 38% during glibenclamide, 5.46 +/- 0.69 and 326 +/- 28% during glimepiride, and 5.17 +/- 0.64 and 357 +/- 35% during diet treatment (NS). These results were similar to those found in the nondiabetic patients (6.44 +/- 0.68 and 406 +/- 42%, NS). CONCLUSIONS: In type 2 diabetic patients, the vasodilating response to forearm ischemia was the same whether patients were treated with diet treatment alone or with glibenclamide or glimepiride at blood glucose-lowering equipotent closes.     

Haemorheological disturbances in hypertensive type 2 diabetic patients--influence of antihypertensive therapy

Haemorheological changes have been described in hypertension as well as in diabetes mellitus. Antihypertensive treatment improves rheology in hypertensive patients. The aim of this study was to describe the haemorheological profile and its impact on shear stress in hypertensive type 2 diabetes mellitus patients (HT + DM) and to investigate the effect of antihypertensive therapy on blood rheology using a double-blind randomized protocol, comparing the calcium antagonist amlodipine with the angiotensin-converting enzyme (ACE) inhibitor enalapril. A total of 144 patients with hypertension and type 2 diabetes (64 of transversal study and 80 of randomized clinical trial) were compared with 92 controls belonging to a transversal study. Secondarily, in a separate analysis, therapeutic effects of calcium antagonist amlodipine and ACE inhibitor enalapril were compared in a longitudinal, randomized trial in the patients. We assessed whole-blood viscosity, plasma viscosity, partial and total disaggregation times, haematocrit and fibrinogen. Radial artery systolic flow velocity was measured by pulsed Doppler. Shear stress was calculated as the product of flow velocity x whole-blood viscosity. Compared with controls, patients had significantly higher whole-blood viscosity for all shear rates (P < 0.001) as well as higher arterial diameter and systolic blood flow velocity (2.8 +/- 0.3 vs. 2.6 +/- 0.3 mm, P < 0.001; and 50.8 +/- 11.6 vs. 45.6 +/- 9.8 cm/s, P = 0.01, respectively). Whole-blood viscosity at shear rate gamma = 128/s tended to increase with amlodipine (+1.13%) and decrease with enalapril (-2.47%) (P = 0.028 for inter-group difference). In hypertensive diabetic patients, hyperviscosity contributes to increased shear stress. Haemorheological disturbances in these patients are not significantly influenced by blood pressure lowering with antihypertensive therapy by ACE inhibitor enalapril or calcium antagonist amlodipine. Other factors potentially contributing to rheology and arterial changes may be more critical in HT + DM patients and need further investigation.     

实时三维超声心动图评价射血分数正常高血压左心室肥厚患者左心室协调性

目的应用实时三维超声心动图评价左心室射血分数正常的高血压左心室肥厚患者左心室协调性。方法选取30例正常人(正常对照组)和50例高血压左心肥厚患者(左心室肥厚组),应用实时三维超声心动图测量左心室室壁17个节段容积-时间曲线,计算左心室特定节段达到最小收缩容积时间(Tmsv)的标准偏差和最大差值被标准化为心动周期的百分比Tmsv16-SD%、Tmsv12-SD%、Tmsv6-SD%、Tmsv16-Dif%、Tmsv12-Dif%、Tmsv6-Dif%。结果与正常对照组比较,高血压左心室肥厚患者的Tmsv16-SD%、Tmsv12-SD%、Tmsv6-SD%、Tmsv16-Dif%、Tmsv12-Dif%、Tmsv6-Dif%均显著增加(P<0.05)。结论高血压患者即使左心室射血分值正常,左心室协调性也较正常人显著减低,尤其是在高血压左心室肥厚患者。室壁运动的协调性是反映心功能的一项重要指标,利用实时三维超声心动图能发现高血压左心室肥厚非心力衰竭患者左心室协调性变化,对于明确高血压左心室肥厚患者心脏功能变化有帮助。