Clinical articles

Interest in the cardioprotective properties of marine omega-3 polyunsaturated fatty acids (n-3 PUFAs) has been renewed following the publication of three large trials earlier this year demonstrating a reduction in sudden cardiac deaths from the ingestion of marine n-3 PUFAs, along with the recent availability in the UK of its pharmacological equivalent, Omacor™. Secondary prevention trials, such as the Diet and Reinfarction Trial (DART) and the more recent analysis of the GISSI-Prevenzione data, found a reduction in sudden deaths associated with supplementation of n-3 PUFAs in post-myocardial infarction patients.1,2

The low incidence of ischaemic heart disease amongst Greenlandic Eskimos has intrigued researchers for many years. The answer was found in their marine-based diet, very rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs). These have shown anti-arrhythmic, endothelial protective, anti-atherogenic, antithrombotic and antiplatelet effects in many observational studies, which have paved the way for the potential role in secondary prevention post-myocardial infarction.
Many trials have emphasised the importance of oily fish in the secondary prevention of coronary heart disease. Oily fish consumption, however, is poor in the UK. It has the disadvantages of possible toxic chemical contaminants, a large calorific content and some people simply do not like it. The GISSI-Prevenzione trial studied the effect of a highly purified n-3 PUFA supplement and found it conferred a 20% relative risk reduction in mortality and a 45% reduction in the risk of sudden cardiac death. This early protection supports the anti-arrhythmic potential of n-3 PUFAs.
A supplement containing 90% concentrate of the n-3 PUFAs, eicosapentaenoic acid and docosahexanoic acid, known as Omacor™, is now licensed in the UK as adjuvant treatment in secondary prevention post-myocardial infarction, in addition to standard medical treatment including statins.
The prescription of n-3 PUFA supplements are best initiated in secondary care. The index admission is generally the best time to initiate secondary prevention when patients tend to be most receptive.

Our increased understanding of the human immunodeficiency virus (HIV), including elucidation of the processes of transmission and replication, has led to the development of relatively effective therapies to minimise and manage the clinical consequences of HIV infection. These therapeutic developments have undoubtedly improved rates of morbidity and mortality in infected patients. The improvements in quality of life and life expectancy have been accompanied by an increase in the number of patients demonstrating cardiac complications, occurring either as a result of the infection itself or the drugs used to control the virus.
Cardiac involvement occurs frequently in HIV/AIDS patients and it seems likely that the myocardium, pericardium and/or endocardium are involved. Myocarditis, one of the most common types of cardiac involvement observed in HIV patients, the cause of which can be difficult to identify, may be responsible for myocardial dysfunction. Opportunistic infections, including HIV itself, have been suggested as the cause of myocarditis. Dilated cardiomyopathy is usually found in the late stage of HIV infection and myocarditis may be the triggering causative factor. The mechanism behind pericardial effusion remains unclear but it too may be related to infections or neoplasms. Non-bacterial thrombotic endocarditis and infective endocarditis have been described in AIDS patients, both of which cause significant morbidity. Human immunodeficiency virus-related pulmonary hypertension is a diagnosis of exclusion, and symptoms and signs may mimic other pulmonary conditions in AIDS patients. Cardiac Kaposi’s sarcoma and cardiac lymphoma are the frequently encountered malignant neoplasms in AIDS patients – the prognosis is grave in patients with these conditions.

Details of the ‘Fifth report on the provision of services for patients with heart disease’, compiled jointly by the British Cardiac Society and the Royal College of Physicians, were published recently. We recommend that all health workers concerned with the care and management of patients with cardiovascular disorders should be aware of the report and contribute to its implementation.

The innovation of specialist nurses in coronary heart disease prevention across 12 practices in a rural County Durham Primary Care Trust (PCT) with a high rate of premature death from heart disease helped the Trust achieve the National Service Frame-work (NSF) for Coronary Heart Disease (CHD) targets and milestones. The introduction of nurse-led CHD clinics at each practice provided a structured follow-up for all patients with CHD to locally agreed guidelines. Audit data collected showed that after 12 months, the service showed an improved management of secondary prevention: more patients had had their cholesterol measured, more had received lipid-lowering medication and more had achieved target cholesterol levels of < 5.0 mmol/L than at baseline. Aspirin prescribing also increased. The PCT has also recently introduced a specialist heart failure nurse to carry out a similar programme and, in addition, has addressed cardiac rehabilitation to provide a home-based service for some patients.

This article looks at the results of four studies which examined the delivery of early thrombolysis by general practitioners and ambulance paramedics to patients suffering an acute myocardial infarction. The studies found that they could provide early thrombolysis safely.
One study in an isolated rural area in Scotland found general practitioners would have very limited experience of thrombolysis – one case per general practitioner per year – and that use of thrombolysis by local general practitioners fell off sharply after the study. A second study carried out in 15 European countries and Canada, found that there was no significant improvement in mortality and morbidity in the pre-hospital group given thrombolysis at home. This was also found by a Dutch study. An American study using computer-assisted diagnostic ECGs relayed to a physician at the base hospital, found little difference in the pre-hospital and hospital treatment arms but a dramatic improvement in the speed of treatment of both groups. Pre-hospital thrombolysis was also reduced. Two studies found ambulances became ‘tied up’ when thrombolysis was delivered at home.
These studies were used as part of a submission on behalf of the Primary Care Cardiovascular Society to the National Institute for Clinical Excellence. The rest of the submission is discussed in part two of this article next month.

The authors describe a case of a Wolff-Parkinson-White syndrome patient experiencing atrial fibrillation, which was difficult to distinguish from ventricular tachycardia.

Thrombolytic therapy has revolutionised the management of acute myocardial infarction (MI) and saved many thousands of lives. Since these agents first became available nearly 20 years ago, many new pharmacological therapies have been developed to try and improve both short-term and long-term outcome following MI. Surgical interventions too are being considered as a serious option during the immediate post-MI period to avoid the adverse effects of thrombolysis and improve long-term outcome. At the same time, research is focusing on what therapy should follow acute MI treatment to improve the long-term outlook for patients. Both old and new therapeutic options need to be considered to offer patients the best chance of a full recovery and long-term survival after MI.

These images are from a 65-year-old woman referred for stress echocardiography following a history of exercise-induced dizziness and shortness of breath. A dobutamine stress echocardiogram was performed. The resting heart rate was 90 beats per minute and resting blood pressure was 210/90 mmHg. The resting images showed severe concentric left ventricular hypertrophy with normal systolic function.

In the last few years our ideas about the physiological and pathological roles of aldosterone have changed enormously. It is now widely recognised that this hormone not only plays a crucial role in normal salt and water regulation, and its abnormalities in congestive heart failure and some types of hypertension, but also has other effects. These may include the promotion of cardiac and vascular inflammation and fibrosis and increased likelihood of arrhythmias. These perspectives coincide with a revived interest in aldosterone antagonists, particularly since the RALES trial showing the benefits of spironolactone in patients with congestive heart failure. This long-established drug does unfortunately have serious adverse effects, notably gynaecomastia and menstrual abnormalities. New drugs, such as eplerenone, are being developed which are more selective for the aldosterone receptor and have less interaction with receptors for other steroid hormones. Early studies indicate that this drug may have comparable efficacy to spironolactone in patients with hypertension and heart failure, while adverse effects appear to be less frequent and severe. The development of such compounds will encourage greater emphasis on aldosterone antagonism in cardiovascular drug therapy.