Investigating suspected heart failure
BMJ 2013; 346 doi: https://doi.org/10.1136/bmj.f2442 (Published 24 April 2013) Cite this as: BMJ 2013;346:f2442
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Kotecha & Fox are to be congratulated for a pithy & concise overview of investigation of suspected heart failure, however, I'm not sure whom this is aimed at. If, as I suspect, it's aimed at general practitioners, it appears to be of limited usefulness.
The authors appropriately emphasize the usefulness of serum natriuretic peptide measurement, however, I'm not sure how widely available this is in general practice in the UK. It is certainly not directly available to general practitioners in Glasgow.
The authors also suggest coronary angiography, despite a lack of evidence that revascularisation is beneficial in heart failure (& evidence that revascularisation is not beneficial in heart failure[1]).
Finally, I would like to have seen at least a brief mention of the usefulness of a therapeutic trial of treatment, when a diagnosis of heart failure is uncertain. If a patient's symptoms respond to a trial of furosemide, then they're very likely to be due to heart failure, but if they don't, then heart failure is very unlikely indeed. I appreciate that this is not part of the investigation of heart failure, but it's very useful for the patient & general practitioner, whilst waiting for definitive investigation and/or treatment.
References
1. Velazquez EJ, Lee KL, Deja MA, Jain A, Sopko G, Marchenko A, Ali IS, Pohost G, Gradinac S, Abraham WT, Yii M, Prabhakaran D, Szwed H, Ferrazzi P, Petrie MC, O'Connor CM, Panchavinnin P, She L, Bonow RO, Rankin GR, Jones RH & Rouleau JR for the STICH Investigators, N Engl J Med 2011; 364:1607-1616
Competing interests: No competing interests
Kotecha and Fox provided an overview of the contemporary investigation of incident heart failure (HF)[1]. Interestingly, despite advocating the use of invasive angiography only in cases were ischaemic symptoms are present or reversible ischaemia is demonstrated by functional non-invasive investigations, their presented patient proceeded to angiography with neither. This highlights that the current role of invasive coronary angiography is unclear in patients who present with incident HF of unknown aetiology.
In these patients it is not uncommon for angiography to demonstrate normal coronary arteries or, as in the presented case, modest coronary disease requiring medical management only. Such patients have therefore been exposed to the risks associated with invasive cardiac catheterisation without subsequent therapeutic benefit. Given that the accuracy of non-invasive functional tests, such as stress echocardiography, is compromised by left bundle branch block and/or left ventricular systolic dysfunction at baseline (obviously common in HF, and their patient had both), we would suggest that CT coronary angiography should be considered as an effective “gatekeeper” to invasive angiography in suitable patients [2].
References
[1]Kotecha T, Fox K. Investigating suspected heart failure. BMJ, 2013;346:f2442
[2]Andreini D, Pontone G, Bartorelli AL, Agostoni P, Mushtaq S, Bertella E, Trabattoni D, Cattadori G, Cortinovis S, Annoni A, Castelli A, Ballerini G, Pepi M. Sixty-four-slice multidetector computed tomography: an accurate imaging modality for the evaluation of coronary arteries in dilated cardiomyopathy of unknown etiology. Circ Cardiovasc Imaging, 2009;2:199-205.
Competing interests: No competing interests
We read with interest the recent practice article [1] based on 2010 National Institute for Health and Clinical Excellence (NICE) guidance, but would like to add further comments, particularly on the use of electrocardiogram (ECG) in primary care for heart failure diagnosis.
It is recognised that ECG is a poor discriminator for the diagnosis of left ventricular systolic dysfunction (LVSD) [2]. The European Society of Cardiology (ESC) guidelines 2012 state that the ECG can give useful information on rhythm and conduction problems, and may show evidence of LV hypertrophy or Q waves that could give possible clues to the aetiology of heart failure [3]. The ECG is therefore a useful guide to potential treatment options for heart failure, rather than a diagnostic tool for heart failure specifically. The question of reliability of ECG interpretation between general practitioners and cardiologists has previously been addressed [4], and on this basis the ECG has been removed from NICE guidance as a restrictive criteria to echocardiography.
We would also question the validity of the claim that a normal ECG has a 90% negative predictive value (NPV) for excluding systolic heart failure. Using the following equation NPV = number of true negatives/ (number true negatives + number of false negatives) and inputting the data from the quoted reference, we calculate the NPV to be between 4 and 39%. We suspected the authors mean sensitivity rather than NPV, and 90% sensitivity is the highest rather than lowest achievable.
While this is an article using the 2010 NICE guidance, the authors quote B-type natriuretic peptide (BNP) cut off levels recommended by ESC without explanation. Moreover, we also wonder why spironolactone was used so early in management, where the guideline recommends this as a third line agent, after starting a beta-blocker. There have been previous comments in 2010 on up-dated NICE guidelines [5], which prompts the question – what does this latest update really have to add to current practice?
References:
1. Kotecha T, Fox K. Investigating suspected heart failure. British Medical Journal 2013; 346: 34-35
2. Khunti K, Squire I, Abrams K R, Sutton A J. Accuracy of a 12-lead electrocardiogram in screening patients with suspected heart failure for open access echocardiography: a systematic review and meta-analysis. European Journal of Heart Failure 2004; 6(5): 571-576
3. McMurray JJ, Adamopoulos S, Anker SD, Auricchio A, Bohm M, Dickstein K, et al. ESC guidelines for the diagnosis and treatment of acute and chronic heart failure 2012: the Task Force for the Diagnosis and Treatment of Acute and Chronic Heart Failure 2012 of the European Society of Cardiology. Eur Heart J 2012;33:1787-847
4. Whitman M, Layt D, Yelland M. Key findings on ECGs - level of agreement between GPs and cardiologists. Aust Fam Physician. 2012 Jan-Feb; 41(1-2):59-62
5. Al-Mohammad A, Mant J, Laramee P, Swain S. Diagnosis and management of adults with chronic heart failure: summary of updated NICE guidance. British Medical Journal 2010;341:c4130
Competing interests: No competing interests
I can see the benefits of B-type natriuretic peptide (BNP) and echocardiography in cases where heart failure is still suspected but chest radiography and electrocardiogram (ECG) are equivocal. However, in the highlighted case, the patient had several risk factors (hypertension, smoking, family history of heart disease), suggestive signs (oedema, crackles, albeit without an elevated JVP or third heart sound), the ECG showed left bundle branch block and the CXR showed mild pulmonary oedema. In such a setting, empirical treatment for heart failure would surely be initiated and would have resulted in symptomatic improvement confirming the diagnosis. Should we not limit the use of BNP and echocardiography in current resource rationed times to when it will really change management significantly, unless resynchronisation or other cardiac intervention is planned beyond drug therapy?
Competing interests: No competing interests
Re: Investigating suspected heart failure
We thank the many contributors to the correspondence following the publication of our article.
A therapeutic trial as suggested by both Medford and Davie, may be useful and has been used formerly as part of a diagnostic strategy [1]. We would caution relying on response to furosemide as this will reduce oedema from any cause, where as non-cardiac oedema will not respond to ACE Inhibitors. However investigation through BNP and echocardiography provides, in addition to diagnosis, prognostic, aetiological and therapeutic information.
There are a number of possible investigations for coronary disease and an individualised approach is recommended. However invasive coronary angiography is reliable in almost all clinical circumstances with a sensitivity and specificity undiluted by the presence of left bundle branch block and tachycardia which can adversely affect functional imaging and CT angiography respectively.
We fully accept the uncertainty around the role of revascularisation and believe our wording acknowledged this.
Spironolactone has prognostic benefit in systolic heart failure. It also has diuretic and antihypertensive properties. So in cases where the criteria for spironolactone use are fulfilled and hypertension and oedema are present, we believe relatively early introduction can be considered.
With regards to the role of the electrocardiogram (ECG), our article does not suggest the use of the ECG as the sole diagnostic tool for heart failure. We appreciate that general practitioners (and general physicians) do not have the same experience at interpreting ECGs as cardiologists, and that this has been reported in the literature.
Utilising the data within the meta-analysis quoted within our article [2] and the formula for negative predictive value (NPV) correctly quoted by Broughton et al, the negative predictive value for the ECG in the diagnosis of systolic heart failure is 92% (total true negatives = 584, total false negatives = 45). The calculated NPVs for the four studies included within this meta-analysis were 60%, 82%, 95% and 98%. Furthermore, Davie et al [3], who reported NPV of 98%, considered minor abnormalities (atrial enlargement, bradycardia, tachycardia, broadening of QRS complex, poor R wave progression, right axis deviation, myocardial ischaemia, first degree atrioventricular block, nonspecific ST-T wave changes) within the “normal” ECG group.
Ng et al [4] identified peptide levels, major ECG abnormalities, and history of ischaemic heart disease as independent predictors of left ventricular systolic dysfunction, and that the use of these three factors in conjunction improves the prediction of heart failure.
We therefore advocate the use of clinical judgement, the ECG and BNP in conjunction in order to identify those patients who have a low probability of having heart failure.
[1]The Task Force on Heart Failure of the European Society of Cardiology. Guidelines for the diagnosis of heart failure European Heart Journal (1995) 16, 741–751
[2] Khunti K, Squire I, Abrams KR, Sutton AJ. Accuracy of a 12-lead electrocardiogram in screening patients with suspected heart failure for open access echocardiography: a systematic review and meta-analysis. Eur J Heart Fail2004;6:571-6.
[3] Davie AP, Francis CM, Love MP, Caruana L, Starkey IR, Shaw TR, et al. Value of the electrocardiogram in identifying heart failure due to left ventricular systolic dysfunction. BMJ 1996;312:222.
[4] Ng LL, Loke I, Davies JE, Khunti K, Stone M, Abrams KR, et al. Identification of previously undiagnosed left ventricular systolic dysfunction: community screening using natriuretic peptides and electrocardiography. Eur J Heart Fail 2003;5:775 – 82.
Competing interests: No competing interests