Idioventricular RhythmOctober 24, 2021 2021-10-28 12:38
Idioventricular rhythm is a slow regular ventricular rhythm with a rate of less than 50 bpm, absence of P waves, and a prolonged QRS interval.
Idioventricular rhythm refers to an intrinsic rhythm that starts in the ventricles (Figure 1 ). It originates in the ventricular area and the depolarization wave spreads either partially through the electrical conduction system or completely via direct cell-to-cell transmission. The intrinsic rate in idioventricular rhythm is most commonly between 30 and 50 BPM, but the rhythm can be anywhere from 20 to 50 BPM. The idioventricular complexes will have the morphological characteristics of the ectopic ventricular complexes (wider than 0,12 seconds, bizarre appearance, ST and T wave abnormalities).
Figure : 1
Idioventricular rhythm refers to an intrinsic rhythm that starts in the ventricles (Figure 1 ). It originates in the ventricular area and the depolarization wave spreads either partially through the electrical conduction system or completely vi
Based on in which location of the ventrical there is increase automaticity the ECG wave will present in that morphological format as seeen in the figure 2.
Figure : 2
An idioventricular rhythm may develop because of increased automaticity of a ventricular escape focus. An idioventricular rhythm may also develop as an escape mechanism if the supraventricular pacemakers fail, in order to overcome a very slow supraventricular bradycardia, or if there is a block of AV conduction (Figure 3).
Figure : 2
An accelerated idioventricular rhythm is basically a rapid idioventricular rhythm (Figure 4). The rates for accelerated idioventricular rhythm are above the rates typically expected for the ventricular pacemakers and are typically between 50 and 100 BPM.
Figure : 4
Accelerated Idioventricular Rhythm
An accelerated idioventricular rhythm is basically a rapid idioventricular rhythm (Figure 3 ). The rates for accelerated idioventricular rhythm are above the rates typically expected for the ventricular pacemakers and are typically between 50 and 100 BPM. The rhythm is due to increased automaticity of an ectopic ventricular pacer. The ventricular complexes have the morphological characteristics of the intrinsic ventricular rhythms (wider than 0.12 seconds, bizarre appearance, ST and T wave abnormalities).
Accelerated idioventricular rhythm is typically very regular, but there may be some slight irregularity at the onset of the rhythm. The rhythm can usually be overcome by overdrive pacing from an external pacer or by using pharmaceutical agents that speed up the heart or suppress ventricular activity. Once again, be careful of pharmaceutical intervention because the ventricular pacemakers are the last defense against asystole or absence of rhythm. Overdrive pacing can be attempted as long as the patient is hemodynamically stable. But, as usual, in the case of any hemodynamic compromise, electrical cardioversion is still the treatment of choice.
Accelerated idioventricular rhythm may occur in the absence of any supraventricular rhythm, or it can occur as a ventricular response to an AV dissociation or block (Figure 4 ).
As you can imagine, the faster ventricular rates in accelerated idioventricular rhythms can lead to more variability in fusion complexes with the dissociated P waves and, also with partially conducted supraventricular complexes.
Accelerated idioventricular rhythms are commonly found in patients having acute myocardial infarctions. They are also part of a set of rhythm disturbances seen commonly after reperfusion has begun during the administration of thrombolytics for an AMI. In this clinical setting, this set of arrhythmias is known as the reperfusion arrhythmias. The reperfusion arrhythmias are typically stable and transient in nature, although they are scary to observe on a monitor. When idioventricular or accelerated idioventricular rhythms appear as reperfusion arrhythmias, they do not require treatment unless they are causing significant hemodynamic compromise.