Shortness of Breath
According to NHS shortness of breath ‘might not be anything to worry about, but sometimes it can be serious, and you’ll need to get medical help’.
You may need to consider calling 999 if you are struggling to breathe or have a sudden onset of shortness of breath and:
Your chest feels tight or heavy
You have pain that spreads to your arms, back, neck and jaw
You feel or are being sick.
In all other circumstances shortness of breath could be a symptom of many other conditions related to the heart, lungs, ongoing viral or even bacterial infections, being overweight, blood conditions (for example anaemia). It also can be a sign of a panic attack.
When I see a patient, my main aim is to establish if a heart condition causes shortness of breath.
The most common scenario is when there is a weakening of the pumping function of the heart and the heart muscle is not able to push enough blood around the body to satisfy oxygen demand. One of the most important tests to establish a pumping function of the heart is the ultrasound (echo) scan. A value called Ejection Fraction (EF) describes the pumping function of the heart. The normal value of EF is 55% – 75%.
Sometimes when we say to the patient that the pumping function of the heart is 55%, they may be taken aback as they automatically assume that the normal pumping function of the heart should be 100%. The essential concept here is that the heart never completely empties itself and after systole (pushing the blood into the circulation) some of the blood always remains in the heart chamber during the rest period (diastole). The formula for how EF calculated is straightforward
End-diastolic volume – End- Systolic volume
———————————————————— x 100 %
Several heart conditions can cause weakening of the heart muscle:
Atherosclerosis causing coronary artery disease and resulting in angina symptoms or sometimes in Acute Heart Attack.
Heart valve problems. The most common valve problems are Aortic Stenosis (narrowing of Aortic Valve), Aortic Valve Regurgitation (leakage) or Mitral Valve regurgitation (leakage).
Arrhythmias, Atrial Fibrillation being the most common.
Cardiomyopathies. There are several types of Cardiomyopathies. In essence, they can be either inherited or as a result of the other disease (viral myocarditis, arrhythmias, coronary artery disease, etc.)
Poorly controlled hypertension.
Various rare inherited heart conditions.
There might be a scenario when a patient has normal pumping function of the heart and can still complain of shortness of breath despite ruling out pathologies.
The heart has two cycles: systole (1/3 of the time) and diastole (2/3 of the time). During diastole, the heart muscle has to relax well to allow adequate blood to fill the main chamber of the heart (left ventricle). If the heart muscle is not able to relax fully, then the left ventricle is not in a position to accept enough blood from the lungs. With each contraction, the heart releases less blood into circulation, slightly more blood remains in the lungs, and this can cause shortness of breath. The medical term for this condition is diastolic dysfunction.
Most heart conditions, as well as significant excess weight, can cause diastolic dysfunction. Diastolic dysfunction can be diagnosed during an ultrasound scan of the heart.