The effect of the infarct regions on vulnerability to reentry in two different stages of myocardial infarction

Abstract

Cardiovascular obstruction could lead to myocardial ischemia and myocardial infarction (MI). MI can be further divided into short-term MI stage (several days) and long-term MI stage (several months) with the development of coronary artery obstruction, and the electrophysiological characteristics in these two MI stages vary greatly. At present, there are no relevant studies on the effects of different infarct areas (size and location) on the initialization and maintenance of reentrant waves in these two MI stages. Therefore, this study aims to investigate the differences in vulnerability to reentry between these two MI stages by computer modeling and simulation. Firstly, single cell models, based on the TP06 model were developed in two different MI stages. And simulation results on single-cells showed that the action potential duration (APD) significantly shortened and the resting potential (RP) elevated in the short-term MI stage, compared with that in the normal condition. However, APD prolonged and RP only changed little in the long-term MI stage. When MI areas in 2D annular ventricular tissues were designed with different lengths, widths and positions, the distribution of the vulnerable window (VW) in these two MI stages was investigated. The simulation results showed that the vulnerability of the two MI stages to the length and position of the infarct areas is the same. That is with the increase of the length, VW gradually increased and reached a constant value when the percentage of the length of the MI area reached 50%. And VW was the largest when the infarct area was close to the inner or outer wall. The vulnerability to the width of the infarct area in these two MI stages is different. In short-term MI, VW was the largest when the width of the infarct area was narrow or wide, while in long-term MI, VW was the largest when the width of the MI area reached half of the width of the ventricular wall. In this paper, the effect of the different infarct areas on the initialization and maintenance of reentrant waves in two different MI stages was investigated by computing simulation. This would improve the understanding of arrhythmogenicity in the MI stage and could provide new sights in arrhythmogenic mechanism of MI phases.