Use Of Contrast-Enhanced Ecg-Gated MRI of the Heart in Anatomic Prognosis of Risk of Arrhythmias in Patients after Acute Transmural Myocardial Infarction

Aim of the sudy. We did attept to compare directly and quantitatively the local uptake of paramagnetics to myocardium at contrast-enhanced myocardial MRI with results of electrophysiologic study of myocardium, in order to test relationships between myocardial damage and rhythm disorders. Material and methods. The study group comprised nineteen patients with recent transmural myocardial infarc tion. The contrast-enhanced MRI has been carried out in T1-weighted SE mode (by Toshiba Vantage Titan, 1,5Т), with injection of 0,5M contrast paramagnetics ex 2 ml per 10 Kg of BW. Contrast uptake to myocardium has been scored accordingly to classic 17-segment map of the left ventricle. Also topic quantitative study of myocardial electric potential has been carried out using Carto XP system (by Biosense Webster). According to amplitude of electric curve in a specific segment of myocardium the decrease in electric potential was assigned to one of the following degrees: 0 - 1,5 - 8 мВ, area of normal potential; 1 - 0,5-1,5 мВ, transient zone; 2 - 0,05-0,5 мВ, low potential zone; 3 - 0-0,05 мВ, area of “electric scar”, absence of electrical activity.. The Index of transmurality (IT) for the contrast uptake was calculated as ratio of thickness of paramagnetic uptake to overall thickness of myocardium. Results. The IT did depend on the local electric potential of myocardium. In particular in electrically normal segments the IT was 0,072 ± 0,020. In the segment of transient zone the IT was = 0,46 ± 0,046, whereas in low potential area 0,32 ± 0,052. The most prominent damage with IT = 0,66 ± 0,082 was observed in the area of electric scar. The best border vaue of IT that provided separation of electrically normal segments from proarrhythmogenic ones was the IT = 0,27. Pathologic proaarhythmogenic decrease in electric activity was detected with sensitivity = 0,87, specificity = 0,93, and diagnostic accuracy = 0,91. Conclusion. Hencefore we conclude the contrastenhanced MRI of the heart provides additional diagnostic information on arrhythmogenity of specific regions of the left ventricle in patients after acute myocardial infarction.

контрастированная МРТ миокарда, желудочковая экстрасистолия, постинфарктный кардиосклероз, contrast-enhanced MRI of the myocardium, ventricular extrasystolia, postinfarction myocardial scarring

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