Hypertension, antihypertensive treatment, and sudden coronary death. The Framingham Study

Sex Differences in the Inflammatory Response: Pharmacological Opportunities for Therapeutics for Coronary Artery Disease

Coordinated molecular responses are key to effective initiation and resolution of both acute and chronic inflammation. Vascular inflammation plays an important role in initiating and perpetuating atherosclerotic disease, specifically at the site of plaque and subsequent fibrous cap rupture. Both men and women succumb to this disease process, and although management strategies have focused on revascularization and pharmacological therapies in the acute situation to reverse vessel closure and prevent thrombogenesis, data now suggest that regulation of host inflammation may improve both morbidity and mortality, thus supporting the notion that prevention is better than cure. There is a clear sex difference in the incidence of vascular disease, and data confirm biological differences in inflammatory initiation and resolution between men and women. This article reviews contemporary opinions describing the sex difference in the initiation and resolution of inflammatory responses, with a view to explore potential targets for pharmacological intervention.

Intrinsic frequency for a systems approach to haemodynamic waveform analysis with clinical applications

The reductionist approach has dominated the fields of biology and medicine for nearly a century. Here, we present a systems science approach to the analysis of physiological waveforms in the context of a specific case, cardiovascular physiology. Our goal in this study is to introduce a methodology that allows for novel insight into cardiovascular physiology and to show proof of concept for a new index for the evaluation of the cardiovascular system through pressure wave analysis. This methodology uses a modified version of sparse time-frequency representation (STFR) to extract two dominant frequencies we refer to as intrinsic frequencies (IFs; ω1 and ω2). The IFs are the dominant frequencies of the instantaneous frequency of the coupled heart + aorta system before the closure of the aortic valve and the decoupled aorta after valve closure. In this study, we extract the IFs from a series of aortic pressure waves obtained from both clinical data and a computational model. Our results demonstrate that at the heart rate at which the left ventricular pulsatile workload is minimized the two IFs are equal (ω1 = ω2). Extracted IFs from clinical data indicate that at young ages the total frequency variation (Δω = ω1 - ω2) is close to zero and that Δω increases with age or disease (e.g. heart failure and hypertension). While the focus of this paper is the cardiovascular system, this approach can easily be extended to other physiological systems or any biological signal.

Uric acid increases the incidence of ventricular arrhythmia in patients with left ventricular hypertrophy

BACKGROUNDS

Elevated uric acid (UA) level is reported to be related to the development of left ventricular hypertrophy (LVH) which is associated with high incidence of ventricular tachycardia (VT) and sudden cardiac death. However, little is known about the association between serum UA levels and the occurrence of VT. Thus, we examined the relationship between serum UA levels and the appearance of VT in patients with LVH.

METHODS

The study subjects consisted of 167 patients (110 males, mean age 67.4 ± 12.7 years) with LVH detected by echocardiography. These patients were divided into two groups based on whether VT was presented (defined by more than 5 beats, n = 27) or not (n = 140) by 24-hour Holter ECG monitoring. Left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVDd), the E/A ratio and deceleration time of transmitral flow velocity were assessed by echocardiography in each group. In addition, blood urea nitrogen (BUN), creatinine, estimated glomerular filtration rate (eGFR), sodium, potassium, hemoglobin, total bilirubin and UA were compared in each group.

RESULTS

Echocardiographic findings did not show the difference between the two groups. However, BUN and UA levels in the VT group were significantly higher than those in the Non-VT group (p < 0.01). eGFR was significantly lower in the VT group than that in the Non-VT group (p < 0.01). A multivariate logistic regression analysis identified the UA level as an independent predictive factor for the occurrence of VT (odds ratio 1.61, 95% confidence interval 1.1-2.2, p < 0.01).

CONCLUSIONS

These results suggest that serum UA level is a useful marker for predicting ventricular arrhythmias in patients with LVH.

Hypertension and acute myocardial infarction: an overview

History of hypertension is a frequent finding in patients with acute myocardial infarction (AMI) and its recurring association with female sex, diabetes, older age, less frequent smoking and more frequent vascular comorbidities composes a risk profile quite distinctive from the normotensive ischemic counterpart.Antecedent hypertension associates with higher rates of death and morbid events both during the early and long-term course of AMI, particularly if complicated by left ventricular dysfunction and/or congestive heart failure. Renin-angiotensin-aldosterone system blockade, through either angiotensin-converting enzyme inhibition, angiotensin II receptor blockade or aldosterone antagonism, exerts particular benefits in that high-risk hypertensive subgroup.In contrast to the negative implications carried by antecedent hypertension, higher systolic pressure at the onset of chest pain associates with lower mortality within 1 year from coronary occlusion, whereas increased blood pressure recorded after hemodynamic stabilization from the acute ischemic event bears inconsistent relationships with recurring coronary events in the long-term follow-up.Whether antihypertensive treatment in post-AMI hypertensive patients prevents ischemic relapses is uncertain. As a matter of fact, excessive diastolic pressure drops may jeopardize coronary perfusion and predispose to new acute coronary events, although the precise cause-effect mechanisms underlying this phenomenon need further evaluation.

Echocardiographic abnormalities in familial dysautonomia

Sudden death accounts for up to 43% of all deaths in patients with familial dysautonomia (FD). The classic features of FD, namely, autonomic dysfunction, high blood pressure, and blood pressure labiality, are all risk factors for cardiac remodeling and hypertrophy. Myocardial remodeling and hypertrophy are independent risk factors for arrhythmias, cardiovascular events, and sudden death. An extensive review of the medical literature found no documentation of structural heart defects or myocardial remodeling in patients with FD. Sixteen patients with FD underwent physical examination, in-clinic blood pressure measurements, and echocardiographic study. On the basis of the findings, the patients were categorized by left ventricular geometric pattern. Twenty-four-hour ambulatory blood pressure monitoring was recommended to all participants. The majority of FD patients were found to have very high blood pressure values both during in-clinic measurements and during ambulatory blood pressure monitoring. Echocardiographic abnormalities were found in 43.75% of the study group; 18.75% of the study group had concentric hypertrophy, among which severe hypertrophy was found in 2 patients. Unknown previously, cardiac remodeling or hypertrophy is common in FD. We recommend that routine cardiac echocardiography be performed in this population, and attempts to treat high blood pressure should begin earlier in life.

Menopause and cardiovascular disease: the evidence

Menopause is a risk factor for cardiovascular disease (CVD) because estrogen withdrawal has a detrimental effect on cardiovascular function and metabolism. The menopause compounds many traditional CVD risk factors, including changes in body fat distribution from a gynoid to an android pattern, reduced glucose tolerance, abnormal plasma lipids, increased blood pressure, increased sympathetic tone, endothelial dysfunction and vascular inflammation. Many CVD risk factors have different impacts in men and women. In postmenopausal women, treatment of arterial hypertension and glucose intolerance should be priorities. Observational studies and randomized clinical trials suggest that hormone replacement therapy (HRT) started soon after the menopause may confer cardiovascular benefit. In contrast to other synthetic progestogens used in continuous combined HRTs, the unique progestogen drospirenone has antialdosterone properties. Drospirenone can therefore counteract the water- and sodium-retaining effects of the estrogen component of HRT via the renin-angiotensin-aldosterone system, which may otherwise result in weight gain and raised blood pressure. As a continuous combined HRT with 17beta-estradiol, drospirenone has been shown to significantly reduce blood pressure in postmenopausal women with elevated blood pressure, but not in normotensive women. Therefore, in addition to relieving climacteric symptoms, drospirenone/17beta-estradiol may offer further benefits in postmenopausal women, such as improved CVD risk profile.

Demographic and temporal trends in out of hospital sudden cardiac death in Belfast

OBJECTIVE

To determine the epidemiology of out of hospital sudden cardiac death (OHSCD) in Belfast from 1 August 2003 to 31 July 2004.

DESIGN

Prospective examination of out of hospital cardiac arrests by using the Utstein style and necropsy reports. World Health Organization criteria were applied to determine the number of sudden cardiac deaths.

RESULTS

Of 300 OHSCDs, 197 (66%) in men, mean age (SD) 68 (14) years, 234 (78%) occurred at home. The emergency medical services (EMS) attended 279 (93%). Rhythm on EMS arrival was ventricular fibrillation (VF) in 75 (27%). The call to response interval (CRI) was mean (SD) 8 (3) minutes. Among patients attended by the EMS, 9.7% were resuscitated and 7.2% survived to leave hospital alive. The CRI for survivors was mean (SD) 5 (2) minutes and for non-survivors, 8 (3) minutes (p < 0.001). Ninety one (30%) OHSCDs were witnessed; of these 91 patients 48 (53%) had VF on EMS arrival. The survival rate for witnessed VF arrests was 20 of 48 (41.7%): all 20 survivors had VF as the presenting rhythm and CRI < or = 7 minutes. The European age standardised incidence for OHSCD was 122/100,000 (95% confidence interval 111 to 133) for men and 41/100,000 (95% confidence interval 36 to 46) for women.

CONCLUSION

Despite a 37% reduction in heart attack mortality in Ireland over the past 20 years, the incidence of OHSCD in Belfast has not fallen. In this study, 78% of OHSCDs occurred at home.

[Epidemiology of sudden cardiac death]

Sudden cardiac death remains a major challenge that we are still facing today. The complexity of the trigger mechanisms makes it difficult to achieve a reliable identification of high-risk patients. Three suggestions are made that might help to overcome this epidemiological catastrophe "Sudden Cardiac Death". 1. In patients with known heart disease risk stratification has to be improved by developing new methods to identify specifically those individuals, who are at risk for sudden rather than non-sudden cardiac death. 2. The general population contains an unknown proportion of individuals with advanced coronary disease, which is commonly asymptomatic. In these so called "normal population" classical risk stratification does not work. However, since there is a close relationship between the prevalence of risk factors for coronary disease and sudden death, a consequent treatment of risk factors should have a positive effect on sudden death rate as well. 3. The success rate of resuscitation has to be improved by strengthening each single link of the "chain of survival". Laypersons trained in basic and advanced life support techniques have to play a much major role on this scene.

Ventricular repolarization is prolonged in nondipper hypertensive patients: role of left ventricular hypertrophy and autonomic dysfunction

OBJECTIVE

The aim of this study was to investigate the influence of circadian behavior of blood pressure, left ventricular hypertrophy, and autonomic function on QTc interval duration in untreated hypertensive patients.

DESIGN

Hypertensive patients underwent simultaneous blood pressure and ECG 24-h ambulatory monitoring. Patients were classified into two groups on the basis of a lack of nocturnal fall in blood pressure, as dippers and nondippers. A group of normotensive healthy subjects was studied as controls.

METHODS

QT and QTc intervals were automatically computed and spectral analysis was applied to RR interval time series from the same electrocardiogram (ECG) recordings. Left ventricular mass index (LVMI) was computed by echocardiogram.

RESULTS

No difference among the three groups was found concerning mean values and circadian pattern of heart rate; by contrast, QTc was significantly longer in nondippers compared to dippers or to normotensive subjects, particularly at night-time, whereas all groups exhibited similar circadian variations in heart rate. Compared to dippers, nondippers showed significantly higher LVMI, which positively correlated with QTc, and parasympathetic withdrawal, which negatively correlated with QTc.

CONCLUSIONS

Nondippers show a prolonged ventricular repolarization throughout the 24-h period, absent either in dippers or normotensives. The association of left ventricular hypertrophy and vagal deactivation may lead to prolongation of QTc, potentially facilitating ventricular arrhythmias in nondipper hypertensive patients.

Prognostic value of ventricular arrhythmias in systemic hypertension

OBJECTIVE

Hypertensive left ventricular hypertrophy is associated with an increased risk of arrhythmias and mortality. However, no clinical study has demonstrated a significant relationship between ventricular arrhythmias and mortality in systemic hypertension.

DESIGN AND METHODS

To evaluate the prognostic value of arrhythmogenic markers, we included, prospectively, 214 hypertensive patients aged (mean+/-SD) 59.1+/-12.8 years, without symptomatic coronary disease, myocardial infarction, systolic dysfunction or electrolyte disturbances. At inclusion, a 12-lead electrocardiogram (ECG) with QT dispersion calculation, a 24 h Holter ECG (204 patients) with Lown classification of ventricular arrhythmias, echocardiography (reliable in 187 patients) and a signal-averaged ECG (125 patients) with ventricular late potentials were recorded.

RESULTS

At baseline, echocardiographic left ventricular hypertrophy was found in 63 patients (33.7%). Non-sustained ventricular tachycardia (Lown class IVb) was recorded in 33 patients (16.2%) and late potentials in 27 patients (21.6%). After a mean follow-up of 42.4+/-26.8 months, all-cause mortality was 11.2% (24 patients); 17 patients died of cardiac causes (7.9%); of these, nine (4.2%) died suddenly. In univariate analysis, age, Lown class IVb and a QT dispersion > 80 ms were significantly related to global, cardiac and sudden death (P < 0.01). The left ventricular mass index was related to cardiac mortality (P= 0.002). In multivariate analysis, only Lown class IVb was an independent predictor of global and cardiac mortality, increasing the risk of global death 2.6-fold (95% confidence interval 1.2-6.0) and cardiac death 3.5-fold (95% confidence interval 1.2-9.7).

CONCLUSION

In hypertensive patients the presence of non-sustained ventricular tachycardia has prognostic value.

Sudden cardiac death in patients with hypertension. An association with diuretics and beta-blockers?

The cornerstones of current antihypertensive treatment are diuretics and beta-blockers and the efficacy of these drugs in preventing cardiovascular disease is undisputed. This article focuses on the effect of these 2 drug classes on the incidence of sudden death. Numerous studies have shown that thiazide diuretics have a strong, dosage-dependent potassium-depleting effect, and it has been postulated that this may explain why the reduction in risk of coronary heart disease, observed in hypertension trials, was less pronounced than expected. In 7 trials that included sudden death as an end-point; a pooled risk-ratio of sudden death of 1.5 (95% confidence interval 1.1 to 2.0) was observed when non-potassium-sparing diuretics were compared with placebo. Two recent case-control studies have also strongly indicated that the use of thiazides increases the risk of sudden death. Evidence from trials using potassium-sparing diuretic combinations suggests that these may be better tolerated than thiazide monotherapy. Although it was suggested in the 2 recent case-control studies that recipients of beta-blockers are also at an increased risk of sudden death, further studies are required to confirm this finding, particularly since these drugs have several well-documented cardioprotective effects.

Comparison of sudden and nonsudden coronary deaths in the United States

BACKGROUND

The present study was designed to compare risk factor prevalences in coronary heart disease deaths in persons dying within 1 hour of onset of cardiovascular symptoms (sudden coronary death), those dying without such sudden symptoms (nonsudden coronary death), and those with unknown duration of symptoms before death (other coronary death).

METHODS AND RESULTS

Data from the 1986 National Mortality Followback Survey and the US Bureau of the Census were examined to assess death rates for sudden, nonsudden, and other coronary deaths. Multivariate logistic regression methods were used to calculate the odds ratio (OR), compared with nonsudden and other coronary deaths, for sudden coronary death associated with socioeconomic status variables, the person's location at death, and coronary heart disease risk factors. Mortality rates for all coronary deaths increased with age, were higher for men than women, and increased with decreasing years of schooling. The rate of sudden coronary death was highest for Hispanics. In 1986, an estimated 251,000 sudden coronary deaths (95% CI = 238,000 to 263,000) occurred in the United States. Sudden coronary deaths were less likely than nonsudden coronary deaths to occur at home (OR = 0.5, 95% CI = 0.4 to 0.6), but individuals who died of sudden coronary death were more likely to have been current cigarette smokers (OR = 1.3, 95% CI = 1.0 to 1.8). No other modifiable risk factors for coronary heart disease distinguished sudden coronary deaths from nonsudden coronary deaths.

CONCLUSIONS

Contrary to the commonly held view, coronary deaths in the home are more likely to be nonsudden than sudden. Cigarette smoking more likely results in sudden than nonsudden coronary death, perhaps because of nicotine-induced ventricular arrhythmias.

Cardiac consequences of diabetes mellitus

A variety of disciplines including noninvasive and invasive cardiac methodologies, as well as epidemiologic studies, have provided information that has altered our view on the relation of diabetes to cardiac disease. Instead of an exclusive focus on coronary artery disease, it is now recognized that heart muscle can be independently involved in diabetic patients. In diabetics without known cardiac disease, abnormalities of left ventricular mechanical function have been demonstrated in 40 to 50% of subjects, and it is primarily a diastolic phenomenon. Left ventricular hypertrophy may eventually appear in the absence of hypertension. The diastolic dysfunction appears related to interstitial collagen deposition, largely attributable to diminished degradation. The presence of even moderate obesity intensifies the abnormality. Reversibility of this process is not readily achieved with chronic insulin therapy. Experimental studies have indicated normalization of the collagen alteration by endurance training, begun relatively early in the disease process. General measures of management include the control of other cardiac risk factors and a reasonable program of physical activity. The high mortality during an initial acute myocardial infarction has been attributed to heart failure, which is managed as in nondiabetic patients. Recently, the early introduction of aspirin, thrombolysis, and beta-adrenergic blockade has reduced mortality during the initial infarction. Chronic use of the latter agent over the subsequent years has also proven to be more beneficial in diabetic patients with acute myocardial infarction compared with nondiabetic patients.

Antihypertensive therapy targeted to the needs of the patient: focus on the renin-angiotensin system; older and newer agents

Antihypertensive drug therapy can lower blood pressure and prolong life, but many hypertensive patients continue to develop further risk factors and to die prematurely of heart disease. Antihypertensive drugs can also interfere with the patient's quality of life, and many are not compatible with the concomitant medical conditions of the patient and the medications taken to treat them. For these reasons, the antihypertensive therapy selected should meet the specific and complete needs of each patient, not just treat the high blood pressure. An analysis of the drugs that inhibit the renin-angiotensin system suggests that several of these drugs have a more favorable therapeutic profile than other classes of hypotensive agents. The newly developed receptor-site-specific blockers are expected to be tolerated better by hypertensive patients and, consequently, to enhance their quality of life. The first of the new class of nonpeptide blockers of the AT1 receptor, losartan--which has no partial agonist activity--is likely to have the advantages of the angiotensin-converting enzyme inhibitors without their adverse effects, notably cough. In selected patients, the AT1-receptor blockers could become the drugs of first choice for the management of hypertension.

Hypertension and ischemic heart disease. Role of dipyridamole echocardiography test

The aim of this study is to try to evaluate the relationship between arterial hypertension and ischemic heart disease (IHD) in the light of the physiopathologic response pattern to the dipyridamole echocardiography test (DET) in hypertensive patients, in pharmacologic washout, without any electrocardiographic ST segment depression during exercise tests or at rest. Sixty patients affected by mild to moderate asymptomatic essential arterial hypertension were studied: the subjects had a sitting diastolic blood pressure > or = 95 < or = 114 mmHg; there were 38 men and 22 women with a mean age of 49.8 +/- 7.6 years (range twenty-nine to sixty-eight). All patients had undergone high-dose DET (0.84 mg/kg in ten minutes). No patients developed side effects or asynergy in cardiac contractility during the test. In the absence of any significant coronary artery obstruction assessed angiographically, 18 patients (30%) showed ST segment depression > 1.0 mV during DET, sometimes with the presence of ventricular and/or supraventricular extrasystoles. In this group of patients the left ventricular mass index (LVMI) and duration of hypertension (in months) were higher as compared with those of the other 42 patients (respectively: 160.2 +/- 5.1 vs 129.2 +/- 9.2 g/m2, P < 0.02; and 30 +/- 4.8 vs 9 +/- 5.4 months, P < 0.007). In conclusion it is reasonable to speculate from these data that the ischemic-like" dipyridamole-induced ST segment depression, like that shown by patients affected by Syndrome X, might involve a worse prognosis in hypertensive patients. This may be because of increased coronary resistance due to structural modification or anatomic background.

The place of diuretics in the treatment of hypertension in 1993: can we do better?

Diuretics are the only class of antihypertensive drugs that have been conclusively shown to reduce morbidity and mortality in long term outcome trials. However even in these trials there were difficulties with withdrawals, cross contamination, high usage of 2 or more drugs and adverse effects. Low doses of thiazide diuretics should be recommended because they have equal blood pressure lowering effects with less biochemical changes and adverse reactions. In 3 of the 4 outcome trials in the elderly in which there were significant reductions in cardiovascular morbidity and mortality a potassium sparing agent was used in conjunction with the thiazide diuretic, raising the possibility of additional cardioprotection.

The treatment of elderly hypertensive patients

Treatment of hypertension in the elderly has hitherto been considered to be potentially dangerous. Three recent studies have clearly shown that in selected elderly hypertensives, blood pressure reduction very effectively reduces cardiovascular complications without causing unacceptable adverse effects. The impact on non-fatal stroke was most striking although a reduction in coronary events was also achieved. Thiazide diuretics were used in all three trials, and beta-blockers were used in two. Thiazide diuretics had a major beneficial effect. In this review the applicability of these results to the whole unselected population of elderly hypertensives is considered, and the choice of therapy in different subgroups of patients discussed.

Non-pharmacologic measures for lowering blood pressure

Nondrug measures have proven effective, to some extent, in lowering blood pressure, especially in mild hypertensives, in many well-controlled studies. The proven measures are reduction of a) salt (less than 5 g/day), b) alcohol (less than 30 ml/day) intake, and c) obesity, and d) regular physical exercise (30-60 minutes/day) and e) mental relaxation. The reported effectiveness of each of these measures ranges from one third to two thirds in mild hypertensives. Should all these nondrug measures, together with cessation of smoking, be applied in all mild hypertensives, it might help prevent their progression to moderate or even severe hypertension with complications, such as coronary heart disease in particular, thereby solving most of the problems that antihypertensive drugs have left behind.