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Ectopic Complexes: Difference between revisions
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[[Image:Rhythm_premature.png|thumb| An [[Atrial_Premature_Complexes|atrial]] with a noncompensatory pause.]] | [[Image:Rhythm_premature.png|thumb| An [[Atrial_Premature_Complexes|atrial]] with a noncompensatory pause.]] | ||
[[Image:Rhythm_ventricular_premature.png|thumb|A [[Premature ventricular beats(PVB) / Venticular extrasystoles (VES)|ventricular extrasystole]] with a compensatory pause]] | [[Image:Rhythm_ventricular_premature.png|thumb|A [[Premature ventricular beats(PVB) / Venticular extrasystoles (VES)|ventricular extrasystole]] with a compensatory pause]] | ||
[[Image:pacemaker_rates. | [[Image:pacemaker_rates.svg|thumb|Mycoardial cells with pacemaker activity]] | ||
The pacemaker cells in the sinus node are not the only cells in the heart that can depolarize spontaneously. Actually all cardiomyoctyes have this capacity. The only reason why the sinus node 'rules' is that it is the fastest pacemaker of the heart. All healthy cardiomyocytes from the sinus node to the ventricles can function as ectopic pacemakers. Ectopic pacemaker activity can originate from the atria (60-80 bpm), AV-node (40-60 bpm) and the ventricles (20-40 bpm). So, as the sinus rate drops (e.g. during atrial infarction), other cells can take over. The configuration of ectopic | The pacemaker cells in the sinus node are not the only cells in the heart that can depolarize spontaneously. Actually all cardiomyoctyes have this capacity. The only reason why the sinus node 'rules' is that it is the fastest pacemaker of the heart. All healthy cardiomyocytes from the sinus node to the ventricles can function as ectopic pacemakers. Ectopic pacemaker activity can originate from the atria (60-80 bpm), AV-node (40-60 bpm) and the ventricles (20-40 bpm). So, as the sinus rate drops (e.g. during atrial infarction), other cells can take over. The configuration of ectopic complexes, or extrasystoles, as seen on the ECG, reveals its origin, whether they are [[Atrial_Premature_Complexes|atrial]], nodal or [[ves|ventrical]]. | ||
==Ectopic pacemakers== | ==Ectopic pacemakers== | ||
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==Compensatory or noncompensatory pause== | ==Compensatory or noncompensatory pause== | ||
[[File:comppause.svg|thumb|A ladder diagram showing a non-compensatory pause following an atrial premature beat that resets the sinus node and fully compensatory pause following a ventricular premature beat that does not reach the sinus node.]] | |||
The duration of the interval following a premature complex can help in the differentiation of a atrial or ventricular premature complex. | The duration of the interval following a premature complex can help in the differentiation of a atrial or ventricular premature complex. | ||
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[[Image:parasystole_12lead.jpg|thumb|An example of parasystole on a 12 lead ECG]] | [[Image:parasystole_12lead.jpg|thumb|An example of parasystole on a 12 lead ECG]] | ||
[[Image:Paraystole_rhythmstrip.jpg|thumb|This rhythm strip shows clear parasystole. Here the origin of the ectopic beats is somewhat distal to the HIS bundle.]] | [[Image:Paraystole_rhythmstrip.jpg|thumb|This rhythm strip shows clear parasystole. Here the origin of the ectopic beats is somewhat distal to the HIS bundle.]] | ||
Parasystole is the phenomenon that results from two competing pacemakers in the heart. Usually a supraventricular and nodal/ventricular pacemaker compete. For example, sinus rhythm might be interfered with by ventricular ectopic beats. The basic rhythm in this example would be sinus rhythm with a rate of 60/min. Ectopic ventricular complexes can be seen interfering with this rate and rhythm. Parasystole is diagnosed when the ectopic | Parasystole is the phenomenon that results from two competing pacemakers in the heart. Usually a supraventricular and nodal/ventricular pacemaker compete. For example, sinus rhythm might be interfered with by ventricular ectopic beats. The basic rhythm in this example would be sinus rhythm with a rate of 60/min. Ectopic ventricular complexes can be seen interfering with this rate and rhythm. Parasystole is diagnosed when the ectopic complexes have a constant RR interval, e.g. 1500ms, resulting in a rate of 20 ventricular ectopic complexes per minute. [[Fusion complexes]] are often present as the two rhythms are dissociated. | ||
{{clr}} | {{clr}} | ||