Delayed enhancement cardiac magnetic resonance imaging can identify the risk for ventricular tachycardia in chronic Chagas' heart disease.

BACKGROUND

Invasive and non-invasive tests have been used to identify the risk of ventricular tachycardia (VT) in patients with chronic Chagas' heart disease (CCHD). Cardiac magnetic resonance imaging (CMRI) using the delayed enhancement (DE) technique can be useful to select patients with global or segmentary ventricular dysfunction, with high degree of fibrosis and at higher risk for clinical VT.

OBJECTIVE

To improve the identification of predictors of VT in patients with CCHD.

METHOD: This study assessed 41 patients with CCHD [30 (72%) males; mean age, 55.1 ± 11.9 years]. Twenty-six patients had history of VT (VT group), and 15 had no VT (NVT group). All patients enrolled had DE and segmentary ventricular dysfunction. In each case, the following variables were determined: left ventricular volume; percentage of ventricular wall thickness impairment in each segment; and DE distribution.

RESULTS

No statistical difference regarding the DE volume between both groups was observed: VT group = 30.0 ± 16.2%; NVT group = 21.7 ± 15.7%; p = 0.118. The probability of VT was greater in the presence of two or more contiguous transmural fibrosis areas, and that was a predictive factor of clinical VT (RR 4.1; p = 0,04). Agreement between observers was 100% regarding that criterion (p < 0.001).

CONCLUSION

The identification of two or more segments of transmural DE by use of CMRI is associated with the occurrence of clinical VT in patients with CCHD. Thus, CMRI improved risk stratification in the population studied.