This difference became marginally statistically significant ( p = 0.049) when considering the appropriateness of activation, with a significantly higher percentage of inappropriate activations in non-ischemic cardiomyopathies (5.5%) compared to ischemic ones (1.7%), while for appropriate activations, the situation is reversed with 28.7% appropriate activations in ischemic patients and 26.5% in non-ischemic ones.
In the studies on non-ischemic cardiomyopathy, there was no statistically significant difference in mortality between the group receiving optimal medical therapy and the ICD group, although the DEFINITE study showed a trend toward lower mortality in the ICD group (13.8% vs. 8.1%) with a 41% relative risk (RR) reduction, albeit without statistical significance ( p = 0.081).
Similarly, when analyzing only the subgroup with non-ischemic cardiomyopathy, although the number of patients was comparable to the ischemic cardiomyopathy group, the benefit of ICDs did not reach statistical significance, despite showing a positive trend [ 4 ].