Ecg Recognition

ECG is a powerful tool in the diagnosis of heart disease. It is exciting to unlock the codes behind the squiggles and spikes and actually decipher a patient's heart patterns. However, I was having trouble identifying atrioventricular (AV) heart blocks. Therefore, I was extremely reassured by the first sentence of this article. Apparently, it is common to have difficulty decoding these rhythms, which gives me hope that with knowledge and practice, I will master them. Part of the difficulty in depicting AV blocks, is that they present in different ways for different degrees. Once again, in order to determine any irregularity, we need to study what is healthy, and find the discrepancies. Heart rhythms are measured in waves, complexes (spikes) and intervals (time lapses), which are assigned the letters P-T. P is a wave representing atrial depolarization, which causes the atria to contract, in response to electrical impulses sent from the
SA node. The PR interval shows the time from the start of atrial depolarization to the start of the ventricular depolarization which follows it, which comes after a slight delay in receiving the impulses through the AV node. The QRS complex represents ventricular depolarization, and is always followed by a T wave which indicates the relaxation of the ventricles, called repolarization, in order to build up energy to repeat the cycle. In a healthy ECG reading in lead II, the P wave is small, round, and positive. One will always appear just before each QRS complex. The PR interval should fall into a range of .12 to .20 second. The QRS complex should take .10 second or less, and be followed by a T wave. Of course, this is not the pattern that will occur when an AV block is present. In a first degree
AV block, the delay in the AV node will be longer than normal, marked by a longer PR interval.
Over .30 second is considered significant delay. First degree AV block is