Atypical features make echocardiography mandatory in suspected heart failure
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《英国医生杂志》
1 Ninewells Hospital, Dundee DD1 9SY a.d.struthers@dundee.ac.uk
One of the key skills of a good diagnostician is to spot when a patient's case has enough atypical features for there to be a strong chance that the "obvious" diagnosis might be wrong. This suspicion would lead a good diagnostician to perform extra investigations.
In this case, the normal electrocardiographic appearance virtually excluded the possibility of left ventricular systolic dysfunction (figure). The other less reliable atypical features were the lack of any history of ischaemic heart disease and the lack of any response to furosemide (although the dose might not have been high enough). Of course, these alerting, atypical features had to be balanced against all the positive features suggesting heart failure: hypertension, pansystolic murmur, raised jugular venous pressure, pleural effusions, and possible cardiomegaly.
Patient's initial 12 lead electrocardiogram
It was somewhat unusual that an angiotensin converting enzyme inhibitor was given before the result of echocardiography was available. However, the drug could have been justified anyway as an excellent addition to the diuretic to treat hypertension. The only slight risk might have been that the systolic murmur was aortic stenosis; but the pansystolic nature of the murmur and the lack of left ventricular hypertrophy on electrocardiography would make that a risk probably worth taking.
The left ventricular ejection fraction was 44%, neither entirely normal (> 50%), nor entirely abnormal (< 40%). Even if this finding did represent mild systolic dysfunction, it would be far too mild to produce such large pleural effusions. A good diagnostician also relies on proportionality—that is, is the detected abnormality likely to cause the severity of symptoms or signs found or are the diagnostic test results disproportionate to the clinical picture?
In view of all the atypical features, it was sensible to aspirate pleural fluid to see if it was a transudate or an exudate. Indeed, you could argue that all pleural effusions should be aspirated. Even if the echocardiogram shows left ventricular systolic dysfunction, pleural effusion has many other causes (such as bronchial carcinoma, particularly in a smoker) that might coexist with heart failure. I remember being caught out many years ago by a patient with heart failure who eventually turned out also to have a mesothelioma. On the other hand, there is always a small risk of producing a pneumothorax when aspirating pleural fluid, so it should not be done if a good explanation already exists for the effusion. I ask the junior staff to obtain an aspirate only if the fluid is aspirated easily and clearly; they should not poke around for it and increase the chance of a pneumothorax.
This case confirms echocardiography as the standard for diagnosing heart failure. In an ideal world, this would be available quickly. However, in the real world, the lack of availability of echocardiography means that it is often necessary to start treatment before the diagnosis is confirmed. Furosemide is thought of as safe enough to be used even if the eventual diagnosis is different. But it often ruins the quality of life of patients, forcing them to rush to the toilet for a lot of the day. Causing unpleasant urgency in this way seems even more perverse when, as in this case, it adds to their original symptoms and eventually turns out to be unnecessary. This is one of many arguments for increasing the availability of echocardiography in the United Kingdom.(Allan D Struthers, profes)
One of the key skills of a good diagnostician is to spot when a patient's case has enough atypical features for there to be a strong chance that the "obvious" diagnosis might be wrong. This suspicion would lead a good diagnostician to perform extra investigations.
In this case, the normal electrocardiographic appearance virtually excluded the possibility of left ventricular systolic dysfunction (figure). The other less reliable atypical features were the lack of any history of ischaemic heart disease and the lack of any response to furosemide (although the dose might not have been high enough). Of course, these alerting, atypical features had to be balanced against all the positive features suggesting heart failure: hypertension, pansystolic murmur, raised jugular venous pressure, pleural effusions, and possible cardiomegaly.
Patient's initial 12 lead electrocardiogram
It was somewhat unusual that an angiotensin converting enzyme inhibitor was given before the result of echocardiography was available. However, the drug could have been justified anyway as an excellent addition to the diuretic to treat hypertension. The only slight risk might have been that the systolic murmur was aortic stenosis; but the pansystolic nature of the murmur and the lack of left ventricular hypertrophy on electrocardiography would make that a risk probably worth taking.
The left ventricular ejection fraction was 44%, neither entirely normal (> 50%), nor entirely abnormal (< 40%). Even if this finding did represent mild systolic dysfunction, it would be far too mild to produce such large pleural effusions. A good diagnostician also relies on proportionality—that is, is the detected abnormality likely to cause the severity of symptoms or signs found or are the diagnostic test results disproportionate to the clinical picture?
In view of all the atypical features, it was sensible to aspirate pleural fluid to see if it was a transudate or an exudate. Indeed, you could argue that all pleural effusions should be aspirated. Even if the echocardiogram shows left ventricular systolic dysfunction, pleural effusion has many other causes (such as bronchial carcinoma, particularly in a smoker) that might coexist with heart failure. I remember being caught out many years ago by a patient with heart failure who eventually turned out also to have a mesothelioma. On the other hand, there is always a small risk of producing a pneumothorax when aspirating pleural fluid, so it should not be done if a good explanation already exists for the effusion. I ask the junior staff to obtain an aspirate only if the fluid is aspirated easily and clearly; they should not poke around for it and increase the chance of a pneumothorax.
This case confirms echocardiography as the standard for diagnosing heart failure. In an ideal world, this would be available quickly. However, in the real world, the lack of availability of echocardiography means that it is often necessary to start treatment before the diagnosis is confirmed. Furosemide is thought of as safe enough to be used even if the eventual diagnosis is different. But it often ruins the quality of life of patients, forcing them to rush to the toilet for a lot of the day. Causing unpleasant urgency in this way seems even more perverse when, as in this case, it adds to their original symptoms and eventually turns out to be unnecessary. This is one of many arguments for increasing the availability of echocardiography in the United Kingdom.(Allan D Struthers, profes)