Clinical characteristics, aetiology and occurrence of type 2 acute myocardial infarction.

Background: Cardiovascular diseases are the leading cause of death worldwide. One of the most important diseases in this group is myocardial infarction (MI). According to the universal definition developed by the European Society of Cardiology (ESC), MI is divided into five main types based on its cause. Type 2 MI is secondary to ischaemia due to either increased demand or decreased supply of oxygen (for example due to coronary artery spasm, anaemia, arrhythmia, coronary embolism, hypertension, or hypotension).

Aim: To assess the occurrence and aetiology of type 2 acute MI (AMI), and to describe the clinical characteristics and prognosis of study patients.

Methods: Into a retrospective study, we enrolled 2,882 patients in the Cardiology Department with an initial diagnosis of AMI between 2009 and 2012. Diagnosis of AMI was made based on ESC criteria. In all patients, coronary angiography was performed in order to exclude haemodynamically significant coronary lesions.

Results: Among 2,882 patients hospitalised in the described time period, 58 (2%) patients were diagnosed with type 2 AMI.The mean age of the study group was 67.3 ± 13.2 years; and the majority of the study group, 60.3%, were women. Out of them, 23 (39.6%) patients experienced AMI due to coronary artery spasm, 15 (25.9%) due to arrhythmias, 11 (19%) due to severe anaemia, and nine (15.5%) due to hypertension, without significant coronary artery disease. 42 (72.4%) patients, were diagnosed as non-ST-segment elevation MI, 14 (24.1%) as ST-segment elevation MI, and two (3.5%) as AMI in the presence of ventricular paced rhythm. History of classical cardiovascular risk factors including hypertension, diabetes, dyslipidaemia, family history of heart diseases, and smoking was reported in 42 (72.4%), 14 (24.1%), 23 (39.7%), 24 (41.4%), and 16 (27.6%) cases, respectively. All-cause 30-day mortality rate was 5.2%, and six-month was 6.9%.

Conclusions: Type 2 AMI patients were more often female, and they were more often diagnosed as non-ST-segment elevation MI. The prevalence of classical cardiovascular risk factors in this subgroup of patients was very high. The leading cause of AMI was coronary artery spasm.