Listening to repeated choruses of Disco Science can improve the rate of chest compressions in subjects carrying out cardiopulmonary resuscitation (CPR) but does not help to achieve the correct depth of compressions, a study has found.

Warfarin consistently lowers the risk of thromboembolism in high-risk patients with atrial fibrillation compared with aspirin and no treatment, a meta-analysis has found.

Overweight and obese patients who were referred to Weight Watchers lost twice as much weight as those who received standard care in general practice, a study in The Lancet has shown. A total of 772 adults, with a BMI 27-35 kg/m² and at least one additional risk factor for obesity-related disease, were recruited from primary care practices in the UK, Australia and Germany. The study was a parallel group, non-blinded, randomised controlled trial. The authors concluded that a commercial weight loss programme that provides regular weighing, advice about diet and physical activity, motivation, and group support could offer a clinically useful early intervention for weight management in overweight and obese people.

Effort-related pain and two or more episodes of pain in 24 hours are associated with poor outcomes in patients presenting with chest pain of uncertain origin, according to a study, from Spain, in the BMJ. Dr Peter Savill comments:'Patients presenting with chest pain can be a real challenge. Furthermore, an ECG is rarely helpful although often advocated in guidelines. Although this research comes from an acute settingI think the message carries some relevance for primary care physicians as they try to navigate a path through the potential minefield of chest pain.'

Exercising at a moderate intensity for 300 minutes a week is associated with a 20% reduction in CHD risk. Halving this amount of physical activity reduced CHD risk by 14% and a significant risk reduction was also achieved with lower levels of exercise. A meta-analysis was carried out on 33 prospective cohort studies looking at physical activity and primary prevention of CHD, published since 1995. Nine of the studies allowed quantitative estimates of leisure-time physical activity.The researchers found that people who reported the equivalent of 150 minutes per week of moderate-intensity activity had a 14% lower CHD risk, relative risk (RR)=0.86 (95% CI: 0.77-0.96) compared with those reporting no exercise. Those who undertook 300 minutes per week of moderate-intensity activity had a 20% lower risk, RR=0.80 (95% CI: 0.74-0.88). Increasing exercise above 300 minutes per week only produced a modest increase in benefit.

A recent meta-analysis, published in JAMA, has suggested an increase in the risk of developing diabetes with high-dose statin therapy compared with moderate-dose therapy. However, the cardiovascular benefits appear to outweigh the risk of diabetes.The researchers analysed large, randomised controlled, hard end point studies that compared intensive with moderate-dose statin therapy and included more than 1,000 patients followed up for longer than a year. The trials studied in the meta-analysis were PROVE IT-TIMI 22, A to Z, TNT, IDEAL, and SEARCH. These five trials included 32,752 patients without diabetes mellitus at baseline.

A large systematic review has found no evidence that angiotensin receptor blockers (ARBs) increase the risk of MI. Compared with patients on other active treatment or placebo, those on ARBs also had a lower risk of stroke, heart failure and diabetes. The researchers analysed a total of 37 randomised controlled trials (39 comparator arms) with 147,020 patients. Dr Peter Savill comments: 'This is a large and comprehensive analysis and has produced firm evidence to refute the hypothesis that ARBs increase the risk of MI. The authors comment that they were able to rule out as low as a 0.3% absolute increase. Furthermore, compared with controls, ARBs reduced the risk of stroke, heart failure, and new onset diabetes. The concern that ARBs may increase the risk of MI has mainly arisen from under-powered observations and secondary endpoint analysis of several ARB trials but such observations can cause clinicians some concern. I am not certain to what degree this has influenced the prescribing of this class of drugs but this recent meta-analysis should now lay this concern to rest. From a practical perspective, I would still stick with ACEIs as the first-line renin angiotensin system drug for the indications discussed above but when ACEIs are genuinely not tolerated, and cardioprotection is not the sole aim of treatment, then ARBs would appear to be a safe and effective alternative.'

Tai chi can improve mood, quality of life and exercise self-efficacy in patients with heart failure although it does not appear to increase functional capacity, a study from the US has found. A single-blind, parallel-group, randomised controlled trial evaluated 100 outpatients with systolic heart failure (New York Heart Association class I-III, left ventricular ejection fraction <40%). The mean age of patients enrolled was 67 and the mean ejection fraction 29% (SD 8%). ' The authors conclude that tai chi, as an adjunct to standard medical care, may improve the quality of life, mood, and exercise self-efficacy of patients with heart failure. However, they acknowledge the limitations of this study such as the small sample size and single blind nature of the randomisation. Furthermore, the lack of impact on functional measures may be seen as a lack of meaningful benefit. However, we must not underestimate the value of even a small improvement in the quality of life to such patients. This should certainly lead to further consideration of the role of mind-body interventions in cardiac rehabilitation programmes.'

Guidance from NICE on stopping antibiotic prophylaxis before invasive procedures in patients at risk has not resulted in an increase in cases of infective endocarditis. In March 2008, NICE released new guidance on the role of antibiotic prophylaxis in the prevention of infective endocarditis. This caused quite a stir as it proposed a radical shift in clinical practice by suggesting that such prophylaxis, before dental and other invasive procedures, should be stopped. Furthermore, it was not based on any new evidence. It had been accepted practice to recommend antibiotic prophylaxis before potentially bacteraemic procedures for patients with underlying cardiac conditions which could result in turbulent blood flow such as valve disease and congenital defects. Despite the initial furore this guidance has generally been adopted and a recent study in the BMJ set out to investigate its impact. The authors stated aim was to quantify the change in prescribing of antibiotic prophylaxis before invasive dental procedures for those at risk of infective endocarditis, and any concurrent change in the incidence of infective endocarditis following the introduction of the NICE guidance. The results showed that following the introduction of the NICE guidance there was a highly significant 78.6% reduction (p<0.001) in the prescribing of antibiotic prophylaxis, from a mean of 10,277 prescriptions per month to 2,292. They also found that despite a general upward trend in the number of cases of infective endocarditis before the guidance that there was no significant change in this trend after the guidance was introduced (p=0.61). Dr Peter Savill writes: 'This would seem to support NICE and silence the critics, of which I was one, but it should be remembered that we must continue to monitor the situation as trends may appear over time.'

A 30-minute office-based automated blood pressure measurement is as effective at identifying white coat hypertension and sustained hypertension as conventional daytime ambulatory blood pressure measurement (ABPM), according to a Dutch study. 'The authors support the use of ABPM and home blood pressure monitoring but point out that these methods are not without problems. Patient compliance can affect home blood pressure monitoring and ABPM is laborious, costly and not tolerated by all patients. They accept that any clinic-based method will be unable to identify diurnal blood pressure patterns, blood pressure variability, and mean nocturnal blood pressure but conclude that their protocol is as accurate as daytime ABPM and will be more cost effective and tolerable. You may wonder how a busy practice could set aside a room for such monitoring on a regular basis but given the trend towards ABPM as a first-line investigation in hypertension this could be a more cost-effective solution.'

Arrhythmia-free survival rates after a single catheter ablation procedure for atrial fibrillation (AF) were 40% after a year but dropped to below 30% after five years' follow-up, a study from France has found.

The CHA₂DS₂-VASc score appears to be better than the CHADS₂ score at predicting patients with atrial fibrillation (AF) who will have a stroke over the next 10 years. It is also more accurate in identifying those at very low risk who do not need anticoagulation, a registry-based study has found.

Statins have no effect on survival rates in high-risk patients who do not have established cardiovascular disease, a comprehensive meta-analysis has demonstrated. The huge meta-analysis published in Archives of Internal Medicine included eleven randomised, controlled trials involving 65,229 patients. 'This was the largest analysis of statin therapy in a purely primary prevention setting and probably includes the totality of evidence available for primary prevention. However, it is important to consider that mortality rates are low in primary prevention trials and it is therefore difficult to show a mortality benefit. It must also be remembered that the analysis looked at the short term, <4 years, benefit of statin therapy and it is possible that longer-term trials may reveal important benefits. Statin use in these populations can significantly reduce the incidence of non-fatal cardiovascular events. Therefore, from a practical perspective I would not necessarily look to statins to help people without established cardiovascular disease live longer but they might reduce the incidence of other, not necessarily fatal, outcomes such as MI and stroke and this may be just as important to our patients.'

Green but not black tea may lower the risk of coronary artery disease (CAD), the limited evidence suggests. The researchers performed a meta-analysis of 18 observational studies identified from a search of PubMed and EMBASE databases from 1966 through November 2009. Thirteen studies were on black tea and five on green. 'The authors do recognise several limitations to this analysis such as a small number of included studies, observational study designs prone to confounding and differing methods for measuring tea consumption. They therefore conclude that additional studies are needed before firm conclusions can be drawn. So no need to switch teas just yet then. '

Uninterrupted chest compressions can improve the likelihood of a good outcome after cardiac arrest compared with standard CPR, a meta-analysis has shown. The delivery of rescue breaths during CPR is time-consuming particularly for lay bystanders and prevents the maintenance of a continuous uninterrupted coronary perfusion pressure. The notion that rescue breaths may be detrimental to the success of adult CPR is not a new one and a recent meta-analysis published in The Lancet explored the current evidence. The authors reviewed studies published over the past 25 years comparing chest compression only bystander CPR with standard CPR with ventilations for adults with prehospital cardiac arrest. 'The takehome message is that emergency medical services dispatchers should instruct bystanders to focus on chest compression only CPR in adults with prehospital cardiac arrest. However, the situation for unassisted lay bystander CPR is unclear. I was also interested to read that the American Heart Association is telling the public to remember CAB (Compressions Airway Breathing) rather than ABC.'

Around three-quarters of patients are still taking all their prescribed medications three months after hospitalisation for stroke, a study from the US has found. Researchers used the Adherence Evaluation After Ischemic Stroke-Longitudinal (AVAIL) Registry, which included 3,068 adult stroke patients at 106 hospitals participating in the American Heart Association/American Stroke Association ‘Get with the Guidelines'-Stroke program. Overall, 2,598 patients were contacted three months after hospital discharge and asked about adherence to prescribed antiplatelet drugs, warfarin, antihypertensives, lipid-lowering drugs, and diabetes treatments.