From the Guidelines
Idioventricular rhythm after reperfusion is primarily related to the extent of infarction rather than reperfusion itself. The mechanism of idioventricular rhythm after reperfusion involves several key factors, including:
- Intracellular acidosis and ATP depletion during ischemia, which disrupt normal ion channel function, particularly potassium channels 1
- A sudden influx of oxygen, calcium, and other electrolytes into damaged myocardial cells upon reperfusion, creating electrical instability
- The generation of reactive oxygen species during reperfusion, which further damage cell membranes and disrupt normal electrical conduction
- The role of Purkinje fibers, which are more resistant to ischemia than working myocardium, often becoming the dominant pacemakers when the sinus node is suppressed or when conduction pathways are blocked
This accelerated idioventricular rhythm typically manifests as a regular rhythm at 40-120 beats per minute with wide QRS complexes originating from the ventricles. The current guidelines recommend monitoring for arrhythmias, including idioventricular rhythm, for at least 12 to 24 hours after reperfusion 1. If intervention is needed, correction of electrolyte abnormalities (particularly potassium and magnesium) is the first step, followed by antiarrhythmic medications like amiodarone if the rhythm persists and causes instability. It is essential to note that idioventricular rhythm is usually transient and self-limiting, rarely requiring specific treatment unless hemodynamic compromise occurs.
From the Research
Mechanism of Idioventricular Rhythm after Reperfusion
The mechanism of idioventricular rhythm after reperfusion is a complex process that involves the reperfusion of the infarcted myocardium.
- Idioventricular rhythm, also known as accelerated idioventricular rhythm (AIVR), is a ventricular rhythm that consists of three or more consecutive monomorphic beats, with gradual onset and gradual termination 2.
- AIVR is usually seen during acute myocardial infarction reperfusion and can be used as a marker for successful reperfusion in some cases 3, 4.
- However, the relationship between AIVR and reperfusion is not always clear-cut, and some studies have shown that AIVR is not specific for reperfusion and cannot be used as a marker for this event 5.
- The incidence of AIVR during reperfusion has been evaluated in several studies, with varying results. One study found that AIVR occurred in 41% of patients with ST-elevation myocardial infarction treated with streptokinase 3, while another study found that AIVR occurred in 42% of patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention 6.
Factors Associated with Idioventricular Rhythm
Several factors have been associated with the development of idioventricular rhythm after reperfusion, including:
- The extent of myocardial damage: AIVR has been associated with extensive myocardial damage and delayed microvascular reperfusion 6.
- The location of the infarct: The configuration of AIVR may be useful for the noninvasive identification of the infarct vessel 4.
- The timing of reperfusion: Early AIVR has been shown to be a reliable sign of successful thrombolysis 3.
- The type of reperfusion therapy: AIVR has been observed in patients treated with both thrombolytic therapy and primary percutaneous coronary intervention 3, 6.