Electrical storm (ES) in ICD patients, defined as 3 or more appropriate ICD interventions within a time span of 24 hours, is a medical emergency associated with adverse outcome. However, it is debated if ES is only a marker of progressive near end-stage cardiac disease or an arrhythmogenic entity on its own. Better understanding and prediction are necessary to manage the burden of ES. The goal of this study is to explore the relation between the presence of fragmented QRS and the manifestation of electrical storm in patients with an ICD for ischemic heart disease.
From the UZ Leuven hospitals ICD registry, 50 patients (94% male, 63±10 years, 37.3±14.3 % LVEF at implant) with ischemic cardiomyopathy presenting with ES were identified. Baseline demographics and raw 12-lead ECG data were collected for these patients from implant until storm. As control subjects, 50 patients (94% male, 62±12 y.a.i, 34.2±12.2 % LVEF) from the same registry were included. A set of 6 features derived from the use of Phase-Rectified Signal Averaging (PRSA) were extracted from the 12-lead ECGs recorded at the ICD implantation, and from weeks before ES, leading to 72 features per visit. These features, related to the presence of fragmentation, were compared for the two visits in the groups under study. Statistical analysis was done using the Skillings-Mack test.
None of the features were significantly different for both groups at baseline. However, preliminary results indicate that 14 of them showed statistically significant changes between the first and the last visit for controls. These changes were related to a reduction of the fragmentation observed mainly in leads III, aVR and aVF. This suggests that there is a trend towards favorable remodeling during the follow-up. Further research will focus on the confirmation of this fragmentation considering different outcomes in the patients.