How hot are you on... heart failure?
Test your knowledge for the nMRCGP with this Little GEM from GPnotebook
What are the general features of systolic and diastolic heart failure?
Heart failure may be caused by:
• ventricular systolic dysfunction • ventricular diastolic dysfunctionSystolic dysfunction:• results in low blood pressure • is most common • caused by inadequate contractile capacity.Diastolic dysfunction:• results in congestion • caused by inability of the ventricle to relax correctly • caused by myocardial or pericardial disease.
Heart failure may be caused by mixed systolic and diastolic dysfunction. For example in a patient with hypertension and ischaemic heart disease there may be:
• a systolic dysfunction because of previous myocardial infarction • a diastolic dysfunction because of scarring and myocardial hypertrophy.
What is the role of brain natriuretic peptide (BNP) in the diagnosis of chronic heart failure?
NICE suggests BNP measurement be undertaken in conjunction with ECG and history and examination, before referral from primary care for echocardiography to confirm the diagnosis of heart failure.
There is evidence that in patients presenting to emergency departments with dyspnoea and possible congestive heart failure:
• B type natriuretic peptide levels revealed a diagnostic accuracy of 83.4% for congestive heart failure (at a cutoff of 100pg per millilitre); negative predictive value of B-type natriuretic peptide at levels of less than 50pg per millilitre was 96% • this is based on evidence from a blinded comparison of BNP levels with a confirmatory diagnosis of congestive heart failure made by two cardiologists who reviewed medical records • this study included 1,586 casualty department patients who had shortness of breath as the most prominent symptom; exclusion criteria included age <18 years,="" dyspnoea="" clearly="" not="" secondary="" to="" congestive="" heart="" failure="" (for="" instance="" trauma),="" acute="" myocardial="" infarction,="" renal="" failure="" and="" unstable="" angina="" without="" dyspnoea="" as="" the="" primary="">18>
Data suggests serial point-of-care testing of BNP will be of immense help in patients presenting to urgent care clinics with dyspnoea. Additionally, BNP might serve as a screen for patients referred for echocardiography, and might also be an effective way to improve the in-hospital management of patients admitted with decompensated congestive heart failure.Finally, the role of BNP in the outpatient cardiac or primary care clinic may be one of critical importance in titration of therapies.
What ECG changes might be seen in a patient with heart failure?
ECG changes that may be seen include:
• left ventricular hypertrophy which may be caused by chronic hypertension or aortic stenosis • evidence of ischaemic heart disease • p-mitrale of mitral stenosis.
What is the ECG definition of LVH?
If there is left ventricular hypertrophy then this will result in:
• a tall R wave (greater than 25mm in V5 or V6), or R plus S greater than 35mm• a deep S in V1 or V2• if there is significant left ventricular 'strain' then there are also inverted T waves in V5 and V6 and possible ST depression• left axis deviation may also be present• QRS may be slightly prolonged.This series is based on GPnotebook Educational Modules (GEMS). The full version is available via GPnotebook Plus, a service free to UK medics. Register at www.gpnotebook.co.uk.