We read the article by Demidova et al on the factors predictive of ventricular fibrillation (VF) during reperfusion in patients with acute ST-elevation myocardial infarction (STEMI). In this retrospective study, the authors aimed to describe the clinical factors, which help in early identification of patients at risk for the potentially lethal arrhythmia. Main area of interest was to identify simple electrocardiographic findings useful in early risk stratification in STEMI.

Cardiac arrest, with the VF as an initial rhythm, is one of the complications of acute STEMI. Although a significant progress in the field of myocardial infarction treatment was made, VF still occurs in a significant number of patients. Occurrence of VF is associated with higher in-hospital mortality rate. It is also known that the onset time of VF is also closely related to the mortality rates. We have previously reported a prospective study on the prognosis of patients according to the onset of the VF—before, during, or after percutaneous coronary intervention (PCI). We have showed that the arrhythmia onset is highly dependent of patients’ clinical characteristics. Patients with VF before, during, or after PCI are burdened with different mortality rates because of different mechanisms responsible for VF and different characteristics of patients in the respective groups.

The authors found that the sum of ST-segment deviations in all leads >1,500 μV is an independent predictor of VF and therefore may help in identification of patients at greater risk of death. It is a valuable observation potentially useful in clinical management. One of the potential groups of patients to which the results of the study could be referred is the group with patients considered for implantable cardioverter-defibrillator as prevention of the next arrhythmic event. VF in the acute phase of myocardial infarction is considered as an event secondary to sustained ischemia and during reperfusion as “reperfusion arrhythmia.” For this reason, it is considered that effective reperfusion removes the cause of arrhythmia, and further qualification for cardioverter-defibrillator implantation is carried out as in the primary prevention. It can be considered that the results of the present study support such approach, demonstrating that despite higher in-hospital mortality rate in patients with VF during reperfusion, VF during reperfusion itself had no independent prognostic value for prognosis.

Nevertheless, we have some concerns regarding the methodology of the present study. First, the authors analyze “VF during reperfusion” while providing no definition for this time interval. We can only assume that the study concerns patients with VF in the catheterization laboratory. Therefore, the findings will not apply to all patients with STEMI. Another concern is the way the authors chose the control group. It consists of patients with STEMI with VF who were hospitalized only during 2007, whereas the whole study group includes patients from 2007 to 2012. During that period, a lot have changed in STEMI management, from the availability of new antiplatelet agents and catheterization laboratories, and therefore door-to-reperfusion time, rate of VF, and mortality. Epidemiologic patterns of myocardial infarction and its mortality vary greatly; therefore, it would be more reasonable to choose a more diverse control group. Nevertheless, the study concerns an important topic without much data from the previous studies. Following, better-designed studies should assess if the electrocardiographic findings in patients with STEMI may help to select patients at risk of VF and potentially reduce the risk of death.