What All Those Lines in an Electrocardiogram Test Mean

Late last year, I was convinced by the missus to undergo an electrocardiogram test after weeks of complaining that something's not right with the way my heart was beating as I felt then. It turned out after the test that my heart was just fine, and that perhaps the unusual palpitations I was feeling were caused by the extra cups of coffee I took each night for some weeks to help me stay up a little longer to finish on time a very important project.

I remember that several years ago, I accompanied my father to at least two electrocardiogram tests; the last one I still recall showed abnormal results. Less than two years after that, my father died of a heart attack.

During those electrocardiogram tests done on my father, I wasn't yet interested on what all the lines that appear on the tests mean. But remembering how his last test turned out made me decide that I should know and learn what the lines that appeared on my own electrocardiogram test exactly revealed. My doctor not only explained what the lines in my own test revealed; he also took my learning a step further by expounding on the meanings of the blips and spikes in an electrocardiogram test.

For the laymen or those who have not had an electrocardiogram test done on them, it is first important to explain how this test works and what it can reveal. The heart, as we know, is likened to a modern well pump in that besides what they do (the latter pumps water, while the heart pumps blood), they both work with electricity which is the basis for the electrocardiogram test. In the heart's case, a tiny electric current is released in the upper right chamber every second or so. This tiny electric current, or pulse, is then transmitted through the heart in a prognostic way, consequently arousing parts of the heart to contract in a certain rhythm.

In an electrocardiogram test, the doctor attaches electrodes to the skin and leads them to a machine known as an electrocardiograph. In this way, the doctor can measure the changes in the heart's electric current, which are reproduced on a graph. This graph, which appears either on sheets of paper or on a monitor, is called an electrocardiogram, or ECG for short. ECG consists of a series of jiggly lines that seem like a landscape of deep valleys and steep mountains. The doctor can often tell whether or not the person's heart is sound by examining these lines.

So what do the lines in an ECG test exactly mean? First, let's make some clear representations, keeping in mind the landscape described above: Each beat of the heart is made up of a small blip; followed by a sharp, declining spike (deep valley); then a sharp, rising spike (steep mountain); another sharp, declining spike; and, finally, another small blip. The first small blip is produced as the atria (the heart's two upper chambers) contract; the declining-rising-declining series of sharp spikes that follows is produced as the ventricles (the heart's two lower chambers) contract and relax; finally, the last small blip takes place during the space between beats, while the heart is recovering and preparing for the next beat.

By examining the subtly varying blips and spikes, the doctor can say a lot about the condition of the person's heart. If, for example, the atria are moving in a rapid, uncoordinated way (fibrillating), the first small blip will disappear. If a person has a heart block (loss of coordination in heartbeat, in which the atria and ventricles beat independently), the interval between the first small blip and the three sharp spikes will become longer. If a person has suffered from a heart attack and the heart muscle has died, the damage may appear as a deeper spike (the first one in the three-spike series).

According to my doctor, electrocardiogram tests are likewise helpful in at least three other ways: in detecting heart valve disease (in which case the heart chambers are enlarged); in checking on the possible presence of pulmonary emboli (blood clots that move through the blood and reach the lungs); and in diagnosing pericarditis (inflammation of the pericardium, the bag-like membrane that encloses the heart and the roots of the great blood vessels). [Read the Original Article]