The differential diagnosis of the patient presenting with shortness of breath is challenging, and incorporates not only cardiovascular disease, but also pulmonary, neurological, gastrointestinal and psychiatric causes. With this in mind, in every patient it is vital to establish a comprehensive clinical picture, drawn from a detailed history and the associated profile of signs and symptoms. This article introduces the clinical features and initial management of the cardiac conditions that manifest in shortness of breath.


A breathless patient

Causes of Shortness of Breath


The causes of shortness of breath are best considered systematically; below is a diagram listing the key conditions to think of when faced with a breathless patient:

Initial Approach


Many of the acute conditions listed above can be life-threatening if not treated promptly. Your initial management should therefore consist of 3 elements:


1.     ABC! The source of a patient's breathlessness may not be immediately obvious, but basic resuscitation strategies apply regardless. Patients may present severely hypoxic or shocked; do not start to consider specific investigations until you are happy with their airway, have provided adequate oxygenation and initiated circulatory support if necessary.

2.      Find the cause - once the patient is stabilised obtain a history, perform a more thorough examination and order the appropriate tests.

3.     Treat the most likely diagnosis.


Making a Diagnosis


Despite the breadth of the differential diagnosis, dealing with these patients need not be distressing; by remaining systematic in your inquiry, the relevant conditions can be singled out and addressed in turn. The following diagram is provided as an example of how to think in such situations, and considers two different patients with acute shortness of breath:


This demonstrates how to delineate patients through focused history taking, appropriate examination and quick, non-invasive investigations. The figure below repeats the exercise for two patients with more long-term breathlessness: 


Again, this structured method of inquiry can reliably separate two patients with similar presenting complaints. Once this framework has been applied, a knowledge of the classical signs, symptoms and test results from each of the key conditions will enable us to suggest diagnoses for patients A, B, C and D.  The essential facts are tabulated below:



With this, the diagnoses become clear:


  • Patient A = ST-elevation Myocardial Infarction.
  • Patient B = Cardiac tamponade.
  • Patient C = Infective endocarditis.
  • Patient D = Congestive cardiac failure.


    Initial Management


    The detailed management strategies for the diseases mentioned in this article are described elsewhere on Fastbleep, but the basics of managing acute cardiogenic breathlessness follow below. Remember that an initial ABC approach is vital in all cases, and that help from one's seniors is often warranted:



    • Algorithms differ by Hospital Trust and can vary depending on the presence of a Catheterisation Laboratory/nearby Tertiary Centre.
    • Unless contraindicated, patients should get aspirin, clopidogrel, morphine, nitrates and oxygen if hypoxic. Also consider a LMWH or fondaparinux if angiography is unlikely.
    • STEMI: aim to get patients to the Catheter Lab for PCI within 90 minutes.
    • NSTEMI/Unstable angina: stratify patients according to their risk (use the GRACE score). High risk patients should undergo Angiography within 12-24 hours for revascularisation. Consider Glycoprotein IIb/IIIa inhibitors in intermediate risk patients and perform Angiography within 96 hours. Low risk patients should continue on medical therapies and a stress ECG should guide further management.



    • Sit the patient forward.
    • Administer high-flow oxygen.
    • Give morphine to reduce discomfort and myocardial oxygen demand, nitrates (provided systolic BP is >90mmHg), and IV furosemide (20-40mg)
    • Monitor blood gases and aim to keep PaO2 > 10kPa.
    • Consider non-invasive positive pressure ventilation early to reduce mortality.



    • Consult the UK resuscitation council tachycardia algorithm:  


    • Seek surgical help.
    • Give morphine for analgesia and beta blockers to keep systolic BP at 100-120.



    • Seek the help of an expert capable of pericardiocentesis.
    • Improve venous return by administering fluids/bloods, raising the patient's legs and avoiding mechanical ventilation.
    • Consider inotropes (e.g. dobutamine)



    A Pericardial Effusion


    To conclude, when faced with a breathless patient:


    • Be methodical with your inquiry.


    • Don't be afraid to seek help.


    • Always remember: A B C!



    1. Braunwald's Heart Disease - A Textbook of Cardiovascular Medicine. 8th Edition: Libby, Bonow, Mann & Zipes. Saunders Elsevier, 2008

    2. National Institute for Health & Clinical Excellence:




    2-5. Author's own

    6. UK Resuscitation Council:

    7. Learning Radiology -


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