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Premature atrial contractions (PACs) are common in the general population, and increase with age. [5] Over 99% of individuals in the general population will have at least one PAC in a 24-hour period. [6] Many PACs can indicate increased risk of atrial fibrillation and/or ischemic stroke. [6]
As this PAC conducts down the left bundle, it will depolarize the septum then proceed retrograde up the right bundle. Eventually, this will reach refractory conduction tissue and stop. The subsequent beat — if early enough — will find the right bundle still refractory and the process will repeat yielding a continued RBBB morphology.
Ectopic beat is a disturbance of the cardiac rhythm frequently related to the electrical conduction system of the heart, in which beats arise from fibers or group of fibers outside the region in the heart muscle ordinarily responsible for impulse formation (i.e., the sinoatrial node).
In comparison to second-degree atrioventricular block, in first-degree block there is an absence of non-conduction or "dropped beats." In an electrophysiology study , this corresponds to a prolonged A-H interval that shows the time between atrial depolarization and His bundle depolarization near the AV node.
Second-degree atrioventricular block (AV block) is a disease of the electrical conduction system of the heart. It is a conduction block between the atria and ventricles . The presence of second-degree AV block is diagnosed when one or more (but not all) of the atrial impulses fail to conduct to the ventricles due to impaired conduction.
By contrast, an AV block occurs in the AV node and delays ventricular depolarization. The term "Wenckebach block" is also used for some heart blocks, and can refer to a second degree type I block in either the SA node or the AV node, however the ECG features of the two are quite distinctly different.
Wandering atrial pacemaker (WAP) is an atrial rhythm where the pacemaking activity of the heart originates from different locations within the atria. [1] This is different from normal pacemaking activity, where the sinoatrial node (SA node) is responsible for each heartbeat and keeps a steady rate and rhythm.
First-degree AV block occurs when there is a delay, but not disruption, as the electrical signal moves between the atrium and the ventricles through the AV node. [3] On ECG, this is defined by a PR interval greater than 200 msec. Additionally, there are no dropped, or skipped, beats.