摘要:

The definition of chronic heart failure (CHF) in clinical practice concentrates on two essential features, namely symptoms suggesting CHF and the objective demonstration of a sufficient severity of cardiac dysfunction. The cardiac dysfunction may be endocardial, myocardial, pericardial, valvular or arrhythmic in nature.Relief of symptoms, at least by the use of diuretic therapy, supports the relationship between cardiac dysfunction and symptoms. However, asymptomatic left ventricular (LV) dysfunction is also common, is associated with a high morbidity and mortality and is amenable to treatment. Therefore it is appropriate to try and identify asymptomatic LV dysfunction.Estimates of the prevalence of CHF in the adult population range from 4 to 20 per 1000 people, rising with age up to 170 per 1000 people aged 70 years and over. Previous estimates of a prevalence of CHF of about 1% (10 per 1000) are broadly supported by more recent data. Estimates of the prevalence of asymptomatic LV dysfunction range from 8 to 59 per 1000, depending on age, the echocardiographic method for measuring ventricular dysfunction and the threshold value of ejection fraction used to separate those with and without LV dysfunction. Asymptomatic LV dysfunction is at least as common and possibly twice as common as CHF.The first step in screening for CHF and LV dysfunction is the recognition of symptoms of CHF and knowledge of the past medical history, in particular a history of myocardial infarction. However, many patients with LV dysfunction will be asymptomatic and in at least 50% of patients with some of the clinical features of CHF the diagnosis cannot be sustained by more detailed investigation.Echocardiography is currently the tool of choice to investigate LV dysfunction although important problems of interpretation of many echocardiographic measurements exist. Echocardiographic examination should be performed on all patients suspected of having CHF before the diagnosis is accepted. It does not generally appear an effective use of resources to screen the general population for asymptomatic LV dysfunction echocardiographically. Screening patients who have had a myocardial infarction (recent or remote) increases the yield of LV dysfunction, with up to 40% of patients surviving hospital admission having important ventricular dysfunction. It is less clear if screening patients with longstanding hypertension or diabetes mellitus is appropriate.Access to echocardiography is restricted in some communities. In these cases, a normal ECG may identify patients at low risk of LV dysfunction. A normal chest x-ray is probably less effective than the ECG in excluding LV dysfunction. However, it should be recognised that it is probably often simpler, more accurate and less expensive to perform echocardiography as the initial investigation.More recently, the potential for natriuretic peptides to identify LV dysfunction has been investigated. Currently, there is sufficient evidence to indicate that these biochemical measures are a useful way of confirming LV dysfunction or CHF in cohorts of patients. Whether natriuretic peptides will prove sufficiently accurate to be used to exclude CHF in individuals remains to be determined. Echocardiography will still be required in those with elevated levels of natriuretic peptides to identify the cause of the cardiac dysfunction.

ISSN:1173-8790    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

At a time when death from myocardial infarction, hypertension and stroke is falling, the impact of chronic heart failure (CHF) is escalating relentlessly and it now constitutes a major public health problem. The clinical impact of CHF, both on quality of life and survival is enormous and, because of this, it is also of growing economic importance.Medical treatment, particularly with ACE inhibitors, improves symptoms and survival rate, and is cost effective. Somewhat surprisingly, ACE inhibitors are still underutilised. Other treatments may also be effective but at present their use in CHF is not clearly defined. Medical therapy in established left ventricular dysfunction may not ultimately be as important as strategies which aim to prevent its occurrence or progression. This article reviews the clinical trials data relating to the effectiveness of current and possible future treatments for CHF.

ISSN:1173-8790    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

The relative explosion in the volume and complexity of research data has made it increasingly difficult for healthcare professionals to assimilate important new findings into daily practice. This has contributed to uncertainty about the optimal management of certain conditions and, on occasion, to undesirable variation in clinical practice.Clinical practice guidelines have been proposed as a tool to help address these problems by using carefully summarised scientific data in an easy-to-understand format. The processes required to develop and implement ‘good’ guidelines are more complex than is generally recognised, however. This underlies the need for ‘guidelines for guidelines’.The article explores some of the issues surrounding the international guidelines movement and summarises key principles on which to evaluate existing clinical practice guidelines. These principles may also be used as a preliminary basis for formulating new guidelines.It is recognised that the principles set out in this document describe high standards for clinical practice guidelines. We suggest that this should not deter groups from attempting to develop guidelines, even if they do not meet all standards simultaneously. The principles embodied herein will help to define ‘good’ guidelines and ultimately lead to better standards of care for patients.

ISSN:1173-8790    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Hypertension is a major independent risk factor for cardiovascular events and death. Moreover, it generally occurs in conjunction with other cardiovascular risk factors (e.g. dyslipidaemia, diabetes, obesity, left ventricular hypertrophy) which greatly increase the overall risk of adverse cardiovascular outcomes.Diet and lifestyle modifications are recommended for all patients with hypertension; however, most will also require pharmacological therapy. To date, only diuretic- and &bgr;-blocker-based regimens have been shown to reduce cardiovascular morbidity and mortality in long term outcome studies; therefore, these agents are the preferred first-line drugs in patients with hypertension according to most expert committee guidelines. Newer agents (i.e. ACE inhibitors, calcium antagonists, &agr;1-blockers) show antihypertensive efficacy equivalent to diuretics and &bgr;-blockers, but long term outcome data are not yet available for the newer drugs. The newer drugs also appear to have important roles in the treatment of hypertensive patients with concomitant disorders (e.g. ACE inhibitors in patients with congestive heart failure).Losartan (losartan potassium) is the first angiotensin II antagonist available for clinical use. It has been shown to be as effective as the well established agents atenolol, enalapril, amlodipine and long-acting formulations of felodipine and nifedipine in reducing blood pressure in patients with hypertension. It has additive effects when used in combination with hydrochlorothiazide. Losartan has been well tolerated in clinical trials to date and, in contrast with ACE inhibitors, does not cause cough. However, the results of ongoing long term studies, as well as studies in special patient populations, are needed to clarify the role of losartan in the management of hypertension. Pending these results, losartan should have the same positioning as ACE inhibitors, calcium antagonists and &agr;1-blockers in most management protocols for hypertension, i.e., as an alternative first-line agent to diuretics and &bgr;-blockers and for patients who are not adequately managed with, or who are intolerant of, their current therapy. It is likely that losartan will find a particular niche in patients unable to tolerate ACE inhibitors because of persistent cough.

ISSN:1173-8790    

出版商:ADIS    

年代:1997

数据来源: ADIS

ISSN:1173-8790    

出版商:ADIS    

年代:1997

数据来源: ADIS