Some interesting facts from the history of cardiology

It was in 1628 that William Harvey found that blood circulates in the body. He noted valves in veins which prevent backflow of blood and facilitates movement of blood towards the heart, which pumps it back into the body through arteries. A few decades later, Richard Lower found that the dark red blood returning from the veins become bright red when exposed to air in the lungs. In that way, blood can carry oxygen which is vital to the function of all organs. In eighteenth century, Steven Hales measured blood pressure in animals by placing cannulas directly in them. This was a very invasive method of measuring blood pressure, which is followed even now in the intensive care setting to get continuous blood pressure tracings. It was more than one and a half centuries later that Riva Rocci and Korotkoff found that blood pressure could be measured non-invasively by inflating a cuff tied on the arm and hearing the ‘Korotkoff sounds’ in front of the elbow as the cuff pressure was being released.

At the turn of the century, in 1903, Willem Einthoven recorded the electrical activity of the heart using a string galvanometer. Though it was a very cumbersome procedure then, with the subject having to immerse his limbs in salt water, now we have even smart watches which can record ECG tracings. It was in 1952 that Elder and Herz invented the ultrasound imaging of the heart which is now known as echocardiography. Echocardiography has become so versatile that is now used in the emergency room, operating room, intensive care unit as well as in the echocardiography laboratory. Echocardiography has changed our way of understanding structural heart disease a lot, with the recent introduction of 3D and 4D echocardiography.