Type 2 myocardial infarction: Diagnostic features in real clinical practice

Purpose. To determine the incidence of type 2 myocardial infarction (MI) diagnosis (according to the Fourth Universal Definition) and the features of patient management in real clinical practice.

Material and Methods. A retrospective study was performed by analyzing the case histories of 153 patients diagnosed with acute coronary syndrome (ACS). Inclusion criteria were the presence of ACS at admission followed by a confirmed diagnosis of MI during the hospital period according to the Fourth Universal Definition of MI and the age of patients > 18 years. Patients with severe comorbidities affecting the immediate prognosis and/or being an alternative to the diagnosis of MI were not included in the study.

Results. The study showed that emergency coronary angiography was performed in 151 patients (98.7%). A decrease in the renal filtration function in the presence of chronic kidney disease was a contraindication to this study found in 1.3% of cases; 12 (8%) patients did not have coronary artery disease or had stenoses of less than 50%; these patients comprised the group of patients with type 2 MI. While analyzing the results of examination in patients with type 2 MI, ST segment elevation was detected in seven patients (58.4%) according to electrocardiography; ST segment depression was observed in one patient (8.3%); complete left bundle-branch block was found also in 1 case (8.3%), three individuals (25%) did not have any changes in the position of ST segment, but had a negative T wave. Analysis of possible etiological factors in the development of type 2 MI showed the presence of sinus tachycardia in two patients (16.7%), severe sinus bradycardia in one patient (8.3%), fl utter paroxysm and atrial fibrillation with tachysystole throughout the ventricles in two patients (16.7%), and history of atrial fibrillation in one patient (8.3%).

Conclusion. Type 2 MI was diagnosed in 8% of patients with ACS with and without ST segment elevation where cardiac arrhythmias including sinus arrhythmias may be the potential etiological factors. Limited capabilities of assessing the stability of atherosclerotic plaque in the coronary artery including that in the presence of plaque thrombosis represent a significant negative factor for establishing diagnosis in routine clinical practice.

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