Ekg what is the p wave

Encyclopaedia Diseases, symptoms, signs and drugs. ECG Basics. The P Wave. View Topic Outline. Overview The P wave on an ECG trace is indicative of atrial depolarisation, which may be initiated by the sinoatrial node or by an ectopic atrial focus. The P wave is directed inferiorly and therefore should be positive in leads I and II. An EKG lead consists of two surface electrodes of opposite polarity positive and negative or one positive surface electrode and one reference point.

A lead composed of two electrodes of opposite polarity is called a Bipolar Lead. A lead composed of a single positive electrode and a reference point is called a Unipolar Lead. All leads of the ECG record the same electrical impulses of the heart muscle. Diagnosis of arrhythmias may be made easier by examination of different leads. The lead ECG tracing is standard. Six leads are recorded by placing wires on each limb.

The other six leads are recorded by placing wires on the chest in six specific positions. Chest Leads: , , , , ,. For diagnosis of most arrhythmias, lead II is most commonly used. Lead II and the chest leads most consistently show the most clear P Wave which can be diagnostic of many common arrhythmias. If changes in the ECG tracing are seen in a group of the above leads, the disease can be localized to a particular area of the heart. If the MD can thus localize the damage to the heart they can also diagnose other possible problems in the heart.

Valvular problems may show up as a specific change in one or more leads of the ECG tracing. Blockages in one of the major arteries of veins may also show up as an altered deflection in the ECG. Below is a diagram of the chest and the placement of leads of the chest so as to trace leads I and II. When the patient is being monitored for a specific arrhythmia, it will help to connect the wires to the spot of the chest that will show that arrhythmia most clearly.

Looking at the EKG tracing, all beats appear similar and are evenly spaced. The information contained within a single lead electrocardiogram can be extensive. Learning how to interpret the subtle differences in characteristic changes that can arise is a specialized skill that can take years to learn.

Fortunately, basic ECG interpretation can be rather straightforward, as long as you know the basics. An electrocardiogram is a tracing of the electrical activity that is taking place within the heart. Under normal circumstances, an electrical impulse will travel from the sinoatrial node, spread across the atrium, to the atrioventricular node and through the ventricular septum of the heart. This electrical impulse causes the four chambers of the heart to contract and relax in a coordinated fashion.

Studying these electrical impulses allows us to understand how the heart is functioning. The P wave represents the depolarization of the left and right atrium and also corresponds to atrial contraction. Strictly speaking, the atria contract a split second after the P wave begins. Because it is so small, atrial repolarization is usually not visible on ECG. In most cases, the P wave will be smooth and rounded, no more than 2. These three waves occur in rapid succession. The QRS complex represents the electrical impulse as it spreads through the ventricles and indicates ventricular depolarization.