Resumen de Encainide reduces heart rate variability fractal dimension among arrhythmic patients who suffered acute myocardial infarct

Jose Luis Hernandez, Eduardo Tejera Torroja, Kiria Valdés Crespo, M Sautié, Carlos Martínez, Luis García Domínguez

• The Autoregressive Dimensional Index (ARDI) was measured in a subset of R-R recordings corresponding to 257 patients from the Cardiac Arrhythmia Suppression Trial (CAST)-study, both before, and during treatment with the anti-arrhythmic drug Encainide (E). Encainide induced an average ARDI increase of 47% (P<0.001, paired t-test). <>A similar analysis with 127 patients treated with Flecainide (F) did not reveal statistical differences related to treatment. Since ARDI is negatively correlated to the Fractal Dimension (FD) of HRV data (Hernandez et al, Electron J Biomed 2004;1:4-15) we conclude that E exerts a reduction in FD among these patients. Since changes suggesting FD reduction are predictive of health worsening and sudden death, our results may provide an explanation for the reported increase in mortality induced by E among CAST patients.

  The lack of effect from F may be in agreement with recent reports suggesting that this drug does not increase the risk of sudden death.