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The most obvious abnormal finding will be abnormal P waves. One of three options can occur: [12] 1. There are no P waves. This is because of either failure of retrograde flow to the atria or the P wave is hidden in the QRS. If the P wave is hidden that implies the atria depolarize at the same time as the ventricles. 2.
The depolarization front is carried through the atria along semi-specialized conduction pathways including Bachmann's bundle resulting in uniform shaped waves. Depolarization originating elsewhere in the atria (atrial ectopics) result in P waves with a different morphology from normal.
Anoxic depolarization is a progressive and uncontrollable depolarization of neurons during stroke or brain ischemia in which there is an inadequate supply of blood to the brain. [1] Anoxic depolarization is induced by the loss of neuronal selective membrane permeability and the ion gradients across the membrane that are needed to support ...
The P wave represents depolarization of the atria. Atrial depolarization spreads from the SA node towards the AV node, and from the right atrium to the left atrium. The P wave is typically upright in most leads except for aVR; an unusual P wave axis (inverted in other leads) can indicate an ectopic atrial pacemaker. If the P wave is of ...
The process of depolarization is entirely dependent upon the intrinsic electrical nature of most cells. When a cell is at rest, the cell maintains what is known as a resting potential. The resting potential generated by nearly all cells results in the interior of the cell having a negative charge compared to the exterior of the cell.
Now, normally the depolarization wave originates in the SA node and produces what’s called a P-wave. The normal firing rate from the SA node is 60-100 beats per minute. But in atrial flutter the electrical signals are coming from a reentrant circuit which moves much faster, let’s say 350 beats per minute. In this case, there are no normal P ...
Cardiac cells have two refractory periods, the first from the beginning of phase 0 until part way through phase 3; this is known as the absolute refractory period during which it is impossible for the cell to produce another action potential. This is immediately followed, until the end of phase 3, by a relative refractory period, during which a ...
Schematic representation of a normal sinus rhythm EKG wave. In electrocardiography, the PR interval is the period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200 ms in duration.