Is it worth changing the tactical approaches to implantation of an artificial pacemaker in patients with acute myocardial infarction in the anterior descending artery basin, depending on the type of atrioventricular block?

Objective: to identify a promising subgroup of patients in the group of patients with acute myocardial infarction and atrioventricular block of II-III degree for implantation of a permanent pacemaker at the earliest possible time.Materials and methods: a retrospective non-randomized study was conducted, which included 124 patients with acute myocardial infarction in the anterior descending artery basin and atrioventricular block of II-III degree. All clinical cases meeting the criteria below were included from a continuous sample of 9687 patients with acute coronary syndrome treated in 2014-2024. Upon admission, all patients were sent to the X-ray room, where coronary angiography was performed, according to the results of which the anterior descending artery was visualized as an infarct-dependent artery and successful revascularization by stenting was performed. Despite the successful revascularization of the anterior descending artery, all patients retained atrioventricular blockade of the II-III degree, which served as the basis for temporary pacing through subclavian access, if there was no restoration of atrioventricular conduction within 14 days, then a permanent pacemaker was implanted. Depending on the type of atrioventricular block, the patients were divided into 2 groups. The AV-proximal group consisted of 58 patients with acute myocardial infarction in the anterior descending artery basin and proximal type of atrioventricular block of II-II degree, the AV-distal group consisted of patients with acute myocardial infarction in the anterior descending artery basin and distal type of atrioventricular block of II-III degree. Atrioventricular blockade of the II-III degree was considered distal with an elongation of the QRS complex of the electrocardiogram of more than 0.12 seconds, and proximal - respectively less than 0.12 seconds.Results: The groups were comparable in all clinical and demographic indicators, with the exception of the frequency of coronary heart disease in the anamnesis, which was more common in the AV-distal group (49 (84.5%) and 64 (97%) in the AV-proximal and AV-distal groups, respectively, p = 0.007; error = 5.9 at 95% confidence interval [1,2;28,4]), and the frequency of AV-conduction recovery in the period up to 14 days from the moment of myocardial infarction, which was significantly higher in the AV-proximal group (48 (83%) and 5 (7.8%) in the AV-proximal and AV-distal groups, respectively, p = 0.001; Recovery = 58.56 with a 95% confidence interval [18.8; 182.8]), as well as the average time of temporary pacing before restoration of AV conduction or implantation of a permanent pacemaker was significantly less in the AV proximal group (7 [5;7] and 14 [14;14] in the AV proximal and AV is the distal, respectively, p = 0.03). When analyzing the complications of temporary pacing, no significant difference was obtained between the groups, except for the frequency of inflammatory skin phenomena in the puncture area and the location of the electrode for temporary pacing (3 (5.2%) and 12 (18.2%) in the AV-proximal and AV-distal groups, respectively, p = 0.01; inflammation = 4.0 [1,1;15]).Conclusion: In patients with acute myocardial infarction in the anterior descending artery basin and distal type of atrioventricular blockade of II - III degree, who underwent successful endovascular revascularization, the chance of AV recovery in the period up to 14 days from the moment of acute myocardial injury is almost 60 times higher than if they had a proximal type of blockade (Recovery = 58.56 at 95% confidence interval [18.8; 182.8]), the risk of inflammatory skin phenomena in the puncture area and the location of the electrode for temporary pacing, which is 4 times higher in the group with distal type of AV block (inflammation = 4.0 [1.1;15]), which correlates with the time of temporary pacing. There is probably a need for more aggressive treatment tactics in patients with acute coronary syndrome in the anterior descending artery basin and distal type of atrioventricular blockade of II-III degree, consisting in early implantation of permanent sources of the rhythm driver from the moment of myocardial infarction.