At first glance, the subject of heart disease can seem exceptionally complex consisting of several different conditions, medical jargon and very scary sounding terminology. However when we really examine heart disease closely there are in general mainly 3 things that can go wrong with the heart and cause harm and if we know this then we are able to firstly understand the different conditions better but also get our head around why certain tests are done and what they tell us. This is important because there are many unscrupulous professionals and organizations which will offer expensive heart health tests which really dont tell us very much but other than cause unnecessary anxiety. I will go through these three things and the tests that give us insight into them.

First and foremost, the heart is a pump and its job is to deliver oxygen rich blood around the body and to our vital organs. If the pump is unable to pump blood out (either because it is defective or because something is making it more difficult to pump blood out in some way) then less blood goes around and this can damage our vital organs and be dangerous.

Common conditions that can cause our pump to become defective are:

A previous heart attack a heart attack means that a part of the heart has died and therefore, the pump has in some way become weaker

Heart valve disease if our heart valves are abnormally narrowed then they make it a lot more difficult for the heart to pump blood out. If our valves are leaky then again, a smaller volume of blood is effectively ejected because some leaks back

Cardiomyopathies if the heart muscle itself is defective in some way then that makes it weaker. This includes conditions like familial hypertrophic cardiomyopathy, familial dilated cardiomyopathy etc.

Infections and inflammation of the heart eg myocarditis will cause acute inflammation of the heart and therefore may compromise the pumping ability of the heart

Conditions such as high blood pressure will make the heart work harder and as it does so it will become more muscular. As the heart becomes more muscular, it becomes stiffer and therefore does not fill with as much blood and therefore pumps less blood out. This is termed as diastolic dysfunction.


So what tests tell us about the heart as a pump?

Echocardiography We can use ultrasound to visualize the heart and look at how well it pumps. This is crude but is easily available and gives us a good basic visualization of the pumping abilities of the heart. A more sophisticated test would be an MRI scan because whilst on echo you will get a general overview.

MRI has much better spatial resolution and therefore you can even detect smaller areas of abnormal or reduced motion i.e. damage. In addition, MRI can actually characterize abnormal tissue and tell us whether the areas of the heart that are not moving are due to inflammation or scar. The problem with both these tests are that they study the heart at rest and sometimes abnormalities may be picked up only when the heart is stressed and therefore combining these modalities with a stress test can be even more helpful and by far the best form of stress is exercise.

Hence to my mind a really good way of assessing the heart as a pump is a test called an exercise stress echo. With this test, an echocardiogram is done at rest to study the pumping ability of the heart. The patient is then exercised on the treadmill and once peak stress is reached, the patient is taken off the treadmill and the heart is studied again by a repeat echo and the pumping function of the heart at rest is compared with peak exercise. If the heart looks strong at rest and gets even better at peak exercise then this indicates that the heart as a pump is strong.




I hope you found this useful and I would love to hear your thoughts.