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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).
Emerging data also suggest that very frequent ventricular ectopy may be associated with cardiomyopathy through a mechanism thought to be similar to that of chronic right ventricular pacing associated cardiomyopathy. For patients with underlying chronic structural heart disease and complex ectopy, mortality is significantly increased. [3]
Since pacemaker correction of the third-degree block requires full-time pacing of the ventricles, a potential side effect is pacemaker syndrome, and may necessitate the use of a biventricular pacemaker, which has an additional 3rd lead placed in a vein in the left ventricle, providing more coordinated pacing of both ventricles. [citation needed]
An ectopic pacemaker located in the atria is known as an atrial pacemaker and can cause the atrial contraction to be faster. [10] An ectopic pacemaker situated near the AV node and the septum is known as a junctional pacemaker. [11] The pacemaker that is operating in the ventricles is known as the ventricular. [12]
The QRS complex is often normal but can also be narrow in LGL syndrome, as opposed to WPW, because ventricular conduction is via the His-Purkinje system. Lown–Ganong–Levine syndrome is a clinical diagnosis that came about before the advent of electrophysiology studies.
Accelerated idioventricular arrhythmias are distinguished from ventricular rhythms with rates less than 40 (ventricular escape) and those faster than 120 (ventricular tachycardia). [2] Though some other references limit to between 60 and 100 beats per minute. [3] It is also referred to as AIVR and "slow ventricular tachycardia."
IVCD can be caused by abnormalities in the structures of bundle of His, Purkinje fibers or ventricular myocardium. [ 5 ] [ 6 ] Nonspecific intraventricular conduction delay (NICD) is a delay with widened QRS complex but without a specific intraventricular block present.
Ashman beats are described as wide complex QRS complexes that follow a short R-R interval preceded by a long R-R interval. [3] This short QRS complex typically has a right bundle branch block morphology and represents an aberrantly conducted complex that originates above the AV node, rather than a complex that originates in either the right or left ventricle.