Left ventricular performance in the early stages of systemic hypertension. HARVEST Study Group. Hypertension and Ambulatory Recording Venetia Study

The HARVEST. Looking for optimal management of young people with stage 1 hypertension

In the last few decades there has been much debate about the management of low-risk stage 1 hypertension in youth. In this article, we review the main findings of the HARVEST cohort accrued over 30 years, highlighting the contribution of this study to the existing literature. Tachycardia and sympathetic overdrive were closely intertwined in our HARVEST participants, promoting the development of sustained hypertension, metabolic abnormalities, and increased susceptibility to vascular complications. Short-term blood pressure variability in this age group had a prognostic power even greater than that of average 24h blood pressure. In the HARVEST participants, changes in left ventricular anatomy and contractility were the earliest signs of hypertensive cardiac involvement, whereas left ventricular filling was only marginally affected. Our results highlighted the role of glomerular hyperfiltration in determining microalbuminuria and renal damage in the early stage of hypertension. The genetic approach provided an important contribution to risk stratification and patient management. The HARVEST confirmed the importance of maintaining a good lifestyle for preventing the onset of hypertension, diabetes and cardiovascular events. Isolated systolic hypertension in the first decades of life appeared as a heterogeneous condition. To establish whether antihypertensive drug treatment should be started in this condition the clinician should consider the individual cardiovascular risk profile, the level of office mean BP and central BP. Despite recent progress in our knowledge, systolic hypertension still represents a challenging issue for the clinician. Hopefully, the HARVEST will continue to contribute data that help to fill the present gaps in evidence.

The association of echocardiographic parameters on renal outcomes in chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) often have structural abnormalities of the heart due to pressure and volume overload. The aim of this study was to evaluate associations between echocardiographic parameters and renal outcomes (estimated glomerular filtration rate [eGFR] slope and progression to dialysis) in patients with stage 3-5 CKD.

METHODS

This longitudinal study enrolled 419 patients. Changes in renal function were assessed using the eGFR slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min/1.73 m²/year, and the renal endpoint was defined as commencing dialysis.

RESULTS

Increased left atrial diameter (LAD), ratio of left ventricular mass to body surface area (LVM/BSA), ratio of LVM to height^2.7 (LVM/ht^2.7), and ratio of observed to predicted LVM (o/p LVM) were associated with eGFR slope in an adjusted model, but left ventricular ejection fraction (LVEF) was not. Furthermore, LAD ≥ 4.7 cm, LVM/BSA > 115 g/m² in males and > 95 g/m² in females, and LVM/ht^2.7 > 48 g/ht^2.7 in males and > 44 g/ht^2.7 in females were correlated with progression to dialysis, but o/p LVM and LVEF were not. The maximum change in χ² change to predict renal outcomes was observed for LAD, followed by LVM/BSA and LVM/ht^2.7.

CONCLUSIONS

A large LAD and increased LVM, regardless of how it was measured (LVM/BSA, LVM/ht^2.7 and o/p LVM), were correlated with adverse renal outcomes in patients with CKD stage 3-5. LAD had superior prognostic value to LVM and LVEF.

Office Pulse Pressure Is a Predictor of Favorable Outcome in Young- to Middle-Aged Subjects With Stage 1 Hypertension

The role of pulse pressure in young individuals remains controversial. The aim of the present study was to investigate the clinical significance of elevated pulse pressure in young- to middle-aged subjects screened for stage 1 hypertension. We examined 1241 subjects (mean age, 33.1±8.4 years) from the HARVEST (Hypertension Ambulatory Recording Venetia Study), during a median follow-up of 12.1 years. To evaluate the predictive value of pulse pressure and mean blood pressure for future hypertension needing treatment and for cardiovascular events, participants were grouped into pressure tertiles. Significant determinants of pulse pressure were male sex (P=0.029), younger age (P<0.001), physical activity (P=0.003), heart rate (P<0.001), systolic white coat effect (P<0.001), and stroke volume (n=829; P<0.001). During follow-up, 65.1% of participants developed hypertension requiring pharmacological treatment and 5.1% experienced a cardiovascular event. Participants in the highest pulse pressure tertile had a reduced risk of incident hypertension compared with those of the bottom tertile (hazard ratio, 0.75; 95% confidence interval, 0.62-0.91; P=0.003). In contrast, participants in the top mean blood pressure tertile had an increase in risk (1.91; 1.57-2.33; P<0.001). In addition, participants in the highest pulse pressure tertile had a reduced risk of cardiovascular events (0.35; 0.17-0.73; P=0.005) and those in the top mean blood pressure tertile had an increase in risk (3.06; 1.32-7.09; P=0.009). Our data show that in subjects <45 years, only mean blood pressure is a predictor of adverse outcome whereas high pulse pressure even carries a reduced risk.

Left Ventricular Function Assessed by One-Point Carotid Wave Intensity in Newly Diagnosed Untreated Hypertensive Patients

OBJECTIVES

To investigate whether newly diagnosed untreated hypertensive patients show higher left ventricular (LV) contractility, as assessed by traditional echocardiographic indices and carotid wave intensity (WI) parameters, including amplitude of the peak during early (W₁ ) and late systole (W₂ ).

METHODS

A total of 145 untreated hypertensive patients were compared with 145 age- and sex-matched normotensive subjects. They underwent comprehensive echocardiography and WI analysis. WI analysis was performed at the level of the common carotid artery. The diameter changes were the difference between the displacement of the anterior and posterior walls, with the cursors set to track the media-adventitia boundaries 2 cm proximal to the carotid bulb and calibrated by systolic and diastolic BP. Peak acceleration was derived from blood flow velocity measured by Doppler sonography with the range-gate positioned at the center of the vessel diameter. WI was based on the calculation of (dP/dt)×(dU/dt), where dP/dt and dU/dt were the derivatives of BP (P) and velocity (U) with respect to time. One-point pulse wave velocity (PWVβ) and the interval between the R wave on ECG and the first peak of WI (R-W₁ ), using a high definition echo-tracking system implemented in the ultrasound machine (Aloka), were also derived.

RESULTS

After adjustment for body weight, heart rate, and physical activity, the two groups had similar general characteristics and diastolic function. However, hypertensives showed significantly higher LV mass, LV ejection fraction (LVEF), circumferential and LV end-systolic stress, and one-point PWV as well as W₁ (13.646 ± 7.368 vs 9.308 ± 4.675 mmHg m/s³ , P =.001) and W₂ (4.289 ± 2.017 vs 2.995 ± 1.868 mmHg m/s³ , P =.001). Hypertensives were divided into tertiles according to LVEF: W₁ (11.934 ± 5.836 vs 11.576 ± 5.857 vs 17.227 ± 8.889 mmHg m/s³ , P <.0001) was higher in the highest LVEF tertile along with relative wall thickness, midwall fractional shortening, endocardial fractional shortening, and R-W₁ .

CONCLUSIONS

Newly diagnosed hypertensives show increased LVM and LV contractility, including carotid WI parameters and R-W₁ values, as compared with normotensive subjects, but no differences in LV diastolic function.

Interankle systolic blood pressure difference and renal outcomes in patients with chronic kidney disease

AIM

Interankle blood pressure (BP) difference has been associated with peripheral artery disease and adverse cardiovascular outcomes. However, the relationship between interankle BP difference and renal outcomes in chronic kidney disease (CKD) has never been evaluated. The purpose of this study was to determine whether interankle BP difference is associated with the rate of renal function decline and progression to renal end points in patients with stage 3-5 CKD.

METHODS

We enrolled 144 patients with CKD from one regional hospital. The BP in four limbs was simultaneously measured using an ABI-form device. The decline in renal function was evaluated using an estimated glomerular filtration rate (eGFR) slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min per 1.73 m(2) per year. The renal end points were defined as ≥ 25% decline in eGFR or commencement of dialysis during the follow-up period.

RESULTS

During a mean follow-up period of 3.1 years, 90 patients (62.5%) reached renal end points. Multivariate analysis showed that an increased interankle systolic BP difference (per 5 mmHg) was associated with a worse eGFR slope (regression β, -0.292; 95% confidence interval [CI], -0.482 to -0.102; P = 0.003), rapid renal progression (odds ratio, 1.189; 95% CI, 1.015-1.394; P = 0.032), and an increased risk of progression to renal end points (hazard ratio, 1.126; 95% CI, 1.052-1.204, P = 0.001).

CONCLUSION

Interankle systolic BP difference was associated with rapid renal progression and progression to renal end points in patients with stage 3-5 CKD in our study.

Echocardiographic parameters are independently associated with rate of renal function decline and progression to dialysis in patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Cardiac abnormalities were frequently noted in patients with chronic kidney disease (CKD). This study is designed to assess whether echocardiographic parameters are associated with rate of renal function decline and progression to dialysis in CKD stage 3 to 5 patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This longitudinal study enrolled 415 patients. The renal end point was defined as commencement of dialysis. The change in renal function was measured by estimated GFR (eGFR) slope.

RESULTS

Progression to dialysis was predicted by wide pulse pressure, low albumin, low hemoglobin, high calcium-phosphorous product, proteinuria, diuretics use, and concentric left ventricular hypertrophy (LVH) (hazard ratio, 2.03; 95% confidence interval [CI], 1.00 to 4.10; P = 0.05). The eGFR slope was negatively associated with total cholesterol, uric acid, proteinuria, diuretics use, and left atrial (LA) diameter (change in slope, -0.50; 95% CI, -0.89 to -0.11; P = 0.01) and positively associated with albumin and left ventricular ejection fraction (LVEF) (change in slope, 0.06; 95% CI, 0.03 to 0.08; P < 0.001).

CONCLUSIONS

Our study in patients of CKD stage 3 to 5 demonstrated that concentric LVH was associated with progression to dialysis, and that increased LA diameter and decreased LVEF were associated with faster renal function decline. Echocardiography may help identify high-risk groups with progressive decline in renal function to dialysis and rapid progression of renal dysfunction in CKD stage 3 to 5 patients.

Early Target Organ Damage and Its Reversibility: The Heart

Left ventricular hypertrophy (LVH) represents not only an adaptation to increased load, but also a risk factor and a marker of risk of cardiovascular diseases. It may be detected early in the development of the disease by electrocardiography or echocardiography. LVH is often associated to abnormalities of systolic and diastolic function, and its presence clearly predisposes not only to cardiac ischemia and to congestive heart failure, but also to a higher incidence of stroke. A large number of clinical and experimental studies have shown that long-term antihypertensive treatment may be associated with regression of LVH. Long-term antihypertensive treatment is associated with a progressive decrease of LV mass. Differences on reduction of LV mass using different classes of antihypertensive drugs for the same decrease of blood pressure are usually mild, although the effect on cardiac structure and tissue composition are probably not the same. In fact, not only the quantity of left ventricular mass, but also its quality (i.e., collagen content, contractile machinery) should be evaluated and improved by treatment. The incidence of cardiovascular events in hypertensive patients is clearly related to the value of LV mass achieved during treatment; in fact, a reduction in LVH by antihypertensive treatment is associated with improvement in outcome and with decrease of the risk of cardiovascular morbidity and mortality, even independently from changes of other risk factors, including blood pressure. In patients with LVH at baseline, the decrease of LV mass is associated with a number of pathophysiological changes such as 1) improved systolic performance at the midwall, 2) possible improvement of diastolic filling, 3) autonomic nervous system changes toward normalization, 4) possible reduction or ventricular arrhythmias and 5) coronary reserve improvement. All these changes might explain an improvement of clinical prognosis in hypertensive patients. Ongoing studies will more precisely assess the quantitative relation between development or regression of LV mass, improvement of systolic and diastolic function and incidence of cardiovascular events. At present time detection, prevention and reversal of LVH represent a major goal in the management of hypertensive patients.

Left ventricular hypertrophy differences in male professional runners and in young patients suffering from mild hypertension

AIMS

This study was executed to evaluate left ventricular (LV) geometry, diastolic and systolic function assessed by B- and M-mode and pulsed Doppler echocardiography in a group of professional sprinter runners (group I), in young patients suffering from mild hypertension (group II) and in control young adults (group III). Twenty-one male sprinter runners were checked during a period of training and compared with 19 young patients suffering from mild hypertension and 15 healthy controls matched for gender and body size.

FINDINGS

LV septum thickness, LV posterior wall thickness, LV ejection fraction, LV shortening fraction, midwall fractional shortening and stroke volume were significantly higher in runners compared to hypertensive patients and controls (p < 0.001). A significant increase of diastolic function parameters of the early peak flow velocity, E, and the early/late diastolic wave ratio, E/A, and in the isovolumic relaxation time or in the E velocity deceleration time wave was observed in hypertensive patients when compared to runners and controls (p < 0.05). The study of the pulmonary venous flow revealed a significant increase in the early systolic flow velocity, S, in hypertensive patients compared to runners (p < 0.05); the late diastolic flow velocity, D, appeared to be similar in all groups, while atrial backward flow velocity, Ar, was higher in group I and II respect to control (p < 0.001).

CONCLUSIONS

Our data indicate that LV concentric hypertrophy in sportsmen is associated with improvement of systolic and diastolic performance, whereas diastolic dysfunction can occurs even in the early stages of hypertension in young patients, in whom an alteration in the LV filling appears even in absence of systolic dysfunction and evident concentric myocardial hypertrophy.

Left Ventricular Concentric Geometry During Treatment Adversely Affects Cardiovascular Prognosis in Hypertensive Patients

Left ventricular (LV) mass and geometry predict risk for cardiovascular events in hypertension. Regression of LV hypertrophy (LVH) may imply an important prognostic significance. The relation between changes in LV geometry during antihypertensive treatment and subsequent prognosis has not yet been determined. A total of 436 prospectively identified uncomplicated hypertensive subjects with a baseline and follow-up echocardiogram (last examination 72+/-38 months apart) were followed for an additional 42+/-16 months. Their family doctor gave antihypertensive treatment. After the last follow-up echocardiogram, a first cardiovascular event occurred in 71 patients. Persistence of LVH from baseline to follow-up was confirmed as an independent predictor of cardiovascular events. Cardiovascular morbidity and mortality were significantly greater in patients with concentric (relative wall thickness > or =0.44) than in those with eccentric geometry (relative wall thickness <0.44) in patients presenting with LVH (P=0.002) and in those without LVH (P=0.002) at the follow-up echocardiogram. The incidence of cardiovascular events progressively increased from the first to the third tertile of LV mass index at follow-up (partition values 91 and 117 g/m2), but for a similar value of LV mass index it was significantly greater in those with concentric geometry (OR: 4.07; 95% CI: 1.49 to 11.14; P=0.004 in the second tertile; OR: 3.45; 95% CI: 1.62 to 7.32; P=0.001 in the third tertile; P<0.0001 in concentric versus eccentric geometry). Persistence or development of concentric geometry during follow-up may have additional prognostic significance in hypertensive patients with and without LVH.

Left ventricular structural and functional characteristics in Cushing's syndrome

OBJECTIVES

This study was designed to evaluate left ventricular (LV) anatomy and function in patients with Cushing's syndrome.

BACKGROUND

A high prevalence of LV hypertrophy and concentric remodeling has been reported in Cushing's syndrome, although no data have been reported on LV systolic and diastolic function.

METHODS

Forty-two consecutive patients with Cushing's syndrome and 42 control subjects, matched for age, gender, and blood pressure, were studied. Left ventricular mass index (LVMI) and relative wall thickness (RWT) were measured by echocardiography, endocardial and midwall fractional shortening (FS) were assessed, and diastolic filling was measured by Doppler transmitral flow.

RESULTS

The RWT was significantly greater in Cushing patients than in controls. Left ventricular hypertrophy and concentric remodeling were observed in 10 and 26 patients with Cushing's syndrome, respectively. In Cushing patients, midwall FS was significantly reduced compared with controls (16.2 +/- 3% vs. 21 +/- 4.5%, p = 0.01). The ratio of transmitral E and A flow velocities was reduced and E deceleration time was prolonged in Cushing patients compared with controls (p = 0.03 and p < 0.001, respectively).

CONCLUSIONS

In patients with Cushing's syndrome, cardiac structural changes are associated with reduced midwall systolic performance and with diastolic dysfunction that may contribute to the high risk of cardiovascular events observed in these patients.

Antihypertensive effects of lacidipine during effort in mild to moderate hypertension

The aim of this study was to evaluate the effects of chronic treatment with lacidipine on blood pressure, heart rate and double product during and immediately after physical effort in mild to moderate hypertensive patients. This was a single-center, randomized, double-blind, crossover, placebo-controlled clinical trial. Eighteen hypertensive patients (56% males, median age 53 years) were randomized to lacidipine 4 mg o.i.d. followed by placebo or to placebo followed by lacidipine 4 mg o.i.d. Lacidipine compared with placebo exerted a significant antihypertensive effect, lowering SBP and DBP both at baseline and either during or after exercise test. The average incremental changes of SBP and DBP between pre-exercise stage and maximal effort did not show any significant differences between treatments. HR during treatment with lacidipine was higher than during treatment with placebo both at rest and after exercise, but at maximal effort, HR was not different from placebo. The average values of DP at maximal effort, and during recovery, did not show any significant differences. Lacidipine 4 mg was effective in lowering blood pressure and in maintaining its antihypertensive effect throughout and after physical exercise, without enhancing double product value, which is an indirect index of myocardial oxygen consumption.

Echocardiographic evaluation of left and right ventricular function in mild hypertension

Thirty-one cases of untreated 'mild hypertension' and equal number of age and sex matched controls with 'normal' blood pressure were evaluated by echocardiography. Patients with mild hypertension had significantly increased left ventricular mass index, concentric remodeling, and diastolic dysfunction. Thickness of right ventricular anterior wall, flow velocities across tricuspid and pulmonary valves were also significantly higher in hypertensives. Pulmonary flow acceleration time was significantly less in hypertensives. On multiple regression analysis, mitral valve 'A' wave velocity alone correlated with systolic blood pressure. Other echocardiographic variables did not have any relation with blood pressure readings. Height, weight, body surface area and body mass index could also explain only around 50% of variability in echocardiographic parameters. Cardiac structure and functions in hypertensives are affected by factors other than blood pressure reading, body surface area or body mass index. Routine echocardiography can be useful in identifying those patients of mild hypertension who have disproportionate increase in left ventricular mass or disproportionate impairment of diastolic functions.

Independent predictors of isolated clinic ('white-coat') hypertension

BACKGROUND

Hypertension guidelines recommend 24 h ambulatory blood pressure (ABP) monitoring in hypertensive subjects with suspected isolated clinic hypertension (ICH). However, the pre-test probability of ICH based on the distribution of its independent predictors has not yet been estimated in hypertensive subjects with mildly elevated blood pressure.

OBJECTIVE

To ascertain the independent predictors of ICH in mildly hypertensive subjects.

METHODS

In the setting of the HARVEST-PIUMA collaboration, we studied 1564 subjects with hypertension stage I. At entry, all subjects were untreated and all underwent ABP monitoring and echocardiography. Diabetes, hypertension grade > I, renal failure or previous cardiovascular morbid events were exclusion criteria. Clinic BP was 143/92 mmHg (SD 9/5) and 24 h ABP was 128/81 mmHg (SD 10/8).

RESULTS

Prevalence of ICH (daytime ABP < 130 mmHg systolic and 80 mmHg diastolic) was 10.4%. In a multivariate logistic regression analysis, sex (P = 0.002), smoking (P = 0.038) and clinic diastolic BP (P = 0.0002) were the sole independent predictors of ICH according to the following equation: Y = 2.6438 + 0.5128 x sex (0 = men; 1 = women) + 0.4543 x current smoking (0 = yes; 1 = no) - 0.0531 x clinic diastolic BP (mmHg) and P (probability of ICH) = exp(Y)/[1 + (exp(Y)]. Left ventricular (LV) mass at echocardiography was a further independent predictor (P = 0.002) of ICH according to the following equation: Y= 3.4343 + 0.4603 x sex + 0.5989 x current smoking - 0.0482 x clinic diastolic BP - 0.0312 x LV mass [g/height (m)2.7]. LV mass was greater (P < 0.01) in the group with ambulatory hypertension [42.3 g/height (m)2.7] than in that with ICH [39.2 g/height (m)2.7] and not dissimilar between the ICH group and a control group of 370 healthy normotensive subjects [38.1 g/height (m)2.7].

CONCLUSIONS

In untreated subjects with stage I hypertension, ICH is most frequent among women, nonsmokers and subjects with low clinic BP and smaller LV mass. These findings allow identification of subjects with indication to ABP monitoring because of suspected ICH.

Decreased left ventricular contractility reserve in patients with never-treated essential hypertension

1. Left ventricular diastolic dysfunction is often present in patients with essential hypertension. To determine whether left ventricular systolic function is normal or subnormal, we evaluated the global left ventricular contractile reserve in patients with untreated essential hypertension. 2. Thirty-one untreated men with essential hypertension and 12 normotensive healthy men were evaluated. Hypertensives were divided into two groups based on the presence (group Hc; n = 21) or absence (group Hn; n = 10) of concentric left ventricular geometric remodelling, which was defined as a relative wall thickness > or = 0.45 on M-mode echocardiography. We compared echocardiographic data of left ventricular function in hypertensive men with those in healthy men under beta-adrenoreceptor activation by up to 10 microg/kg per min dobutamine infusion. 3. At baseline, endocardial (eFS) and midwall fractional shortening of the left ventricle, the early peak filling velocity (E), the peak late filling velocity (A) and the ratio E/A were similar in the three groups. During dobutamine infusion, eFS was significantly lower in groups Hc and Hn (54.1+/-9.2 and 54.1+/-7.9%, respectively) than that observed in group N (61.7+/-7.4%). In addition, eFS was highly correlated with circumferential end-systolic wall stress (ESS) during dobutamine infusion in the three groups. In 11 subjects in group Hc (52%), the eFS-ESS relationship was lower than the 95% confidence limit of the normal regression. Comparing group Hc with groups N and Hn, it was found that E (0.52+/-0.12, 0.71+/-0.16 and 0.63+/-0.15 m/s, respectively) and E/A (0.74+/-0.23, 1.24+/-0.53 and 0.98+/-0.37, respectively) were significantly lower. 4. Our results suggest that, in addition to diastolic dysfunction, the reserve of systolic function decreased under beta-adrenoceptor activation in patients with essential hypertension.

Changes in midwall systolic performance and cardiac hypertrophy reduction in hypertensive patients

OBJECTIVE

To investigate changes in left ventricular (LV) performance, as evaluated by measurement of midwall LV fractional shortening (FS), after reduction of cardiac hypertrophy.

DESIGN AND METHODS

Echocardiographic evaluation of LV anatomy and function was performed by M-mode echocardiography at baseline, after long-term antihypertensive therapy, and after treatment withdrawal in 68 asymptomatic hypertensive patients (50 males, 18 females, age range 22-62 years). Patients were divided according to the presence of LV hypertrophy (LVH) at baseline (LV mass index, LVMI, > or = 51 g/m(2.7)).

RESULTS

At baseline patients with concentric (relative wall thickness > 0.44) LV hypertrophy (n = 38) or remodelling (n = 7) had reduced midwall shortening with respect to patients with normal LV geometry (n = 4) or eccentric LVH (n = 19); no differences were observed for endocardial FS. After long-term treatment (average 15 months), in 11 patients LV mass remained within normal limits, in 45 patients LVH reduction was obtained, while in 12 patients LV mass remained persistently elevated. Midwall FS was significantly increased in patients with reduction of LVH both during treatment and after withdrawal of treatment, while it remained significantly lower in patients with persistently elevated LV mass. Changes in midwall fractional shortening were independently associated with modifications in relative wall thickness (P < 0.00001), with changes in end-diastolic dimensions (P < 0.0001) and those of LVMI (P< 0.02) as shown by multivariate analysis.

CONCLUSION

LV midwall systolic performance significantly improved after reduction of LVH, even in the presence of high blood pressure values. Modifications in relative wall thickness are more independently associated with changes, in LV diastolic dimensions and mass, to midwall improvement

Relation of left ventricular diastolic properties to systolic function in arterial hypertension

BACKGROUND

It is unclear whether impairment of left ventricular (LV) diastolic characteristics is independent of systolic dysfunction.

METHODS AND RESULTS

To address this issue, 159 consecutive hypertensive patients (44+/-11 years, 78 obese, 96 women) and 165 normotensive subjects (32+/-11 years, 84 obese, 110 women) were studied with the use of Doppler echocardiography. After adjustment for age, body mass index (BMI), and sex, we found that ejection fraction (EF; M-mode, z-derived) was higher in hypertensive (66. 6+/-5.2%) than in normotensive (63.9+/-4.4%, P<0.0001) subjects, whereas midwall shortening (MS) was lower (hypertensive patients 16. 9+/-2.0%, normotensive subjects 17.8+/-2.2%, P<0.02), even after correction for end-systolic wall stress (P<0.05). Isovolumic relaxation time (IVRT) was greater in hypertensive patients (103+/-14 ms) than in normotensive subjects (78+/-19 ms), as was deceleration time of E velocity and peak A velocity (all P<0.0001). In multivariate analysis, IVRT was unrelated to EF, but a negative relation was found with MS (P<0.001), independent of age, BMI, presence of arterial hypertension, LV geometry, and load (multiple R(2)=0.58). For comparable age, sex distribution, BMI, and blood pressure values, hypertensive patients with lower afterload-adjusted MS exhibited longer IVRT than patients with normal MS (P<0.005). However, IVRT remained higher than in normotensive control subjects after control for LV geometry and load.

CONCLUSIONS

Doppler indices of delayed LV relaxation can be detected in the presence of normal or supranormal EF but are independently related to impaired MS. A less severely abnormal relaxation, however, can be also detected in the presence of normal midwall function, independent of LV geometry and load. Thus, diastolic abnormalities may occur before systolic dysfunction even when it is measured at the midwall.

Relevance of heart rate as a risk factor in hypertension

Numerous studies have shown that resting heart rate is closely correlated with blood pressure and that it is prospectively related to the development of hypertension. Moreover, there is mounting evidence to indicate that a high heart rate is associated with increased cardiovascular morbidity and mortality. In this respect, heart rate can be considered both as a marker of risk and as an independent factor in the induction of risk. Sympathetic overactivity seems to be responsible for the increase in blood pressure and hematocrit, and for the metabolic abnormalities often observed in subjects with tachycardia. Experimental studies in monkeys have shown that heart rate can also exert a direct atherogenic action on the arteries through increased wall stress. Furthermore, tachycardia can favor the occurrence of ventricular arrhythmias and sudden death. Reduction of heart rate appears to be a reasonable additional goal of antihypertensive therapy, especially in subjects with increased sympathetic tone. Nondihydropyridine calcium antagonists and drugs with agonistic properties at the I1-imidazoline receptors of the rostral ventrolateral medulla may be drugs of choice for this purpose, but whether they offer a significant morbidity-mortality advantage must be proven in prospective trials.

Heart rate as a risk factor for atherosclerosis and cardiovascular mortality: the effect of antihypertensive drugs

The aim of this review is to highlight the importance of heart rate (HR) as a risk factor for cardiovascular disease, and to discuss the classes of drugs which can be potentially useful in clinical conditions in which an elevated HR may be present. Numerous studies have shown that high resting HR is prospectively related to the development of atherosclerosis and of cardiovascular events. This relationship was independent of other major risk factors for atherosclerosis and was observed in the general population, in elderly people, in hypertensive cohorts and in patients with myocardial infarction or heart failure. The clustering of several risk factors in individuals with fast heart rate may explain why cardiovascular morbidity is higher in individuals with tachycardia. Sympathetic overactivity seems to be responsible for both the increase in HR, blood pressure and the metabolic abnormalities. Experimental studies in monkeys have shown that HR can also exert a direct atherogenetic action on the arteries through increased wall stress. Moreover, tachycardia can favour the occurrence of ventricular arrhythmias and sudden death. Reduction of HR appears as an additional goal of antihypertensive therapy. If fast HR in hypertension is a marker of increased sympathetic tone, agents which decrease HR through a decline of sympathetic outflow should be particularly efficacious. Beta-blockers retard the development of coronary atherosclerosis in cholesterol-fed monkeys and have proven to be beneficial in patients with myocardial infarction or with heart failure, but their efficacy appear limited in hypertension, probably on account of their unfavourable metabolic profile. Phenylalkylamines are devoid of this untoward effect, and seem to act also through inhibition of sympathetic discharge from the CNS. Mibefradil, a more recent calcium antagonist that selectively blocks voltage-dependent T-type calcium channels decreases HR without affecting left ventricular contractility. New drugs with agonistic properties at the I1-imidazoline receptors of the rostral ventrolateral medulla are effective in reducing blood pressure and HR by inhibiting the sympathetic outflow and improved metabolic parameters in obese or fructose-fed rats. The goal of antihypertensive therapy in the future will be to prevent or reverse those functional abnormalities which accompany the hypertensive condition. In patients with tachycardia the reduction of HR appears a desirable additional goal of therapy.