Background: Electrical storm (ES) represents a serious heart rhythm disorder. However, the distribution and prognostic impact of coronary artery disease (CAD) in ES is still under debate.

Methods: Consecutive ES patients with implantable cardioverter-defibrillator (ICD) were included retrospectively from 2002 to 2016. Three analyses were applied to characterize ES patients: (I) ES patients without CAD (non-CAD), (II) ES patients with CAD (CAD), (III) results of coronary angiography at the time of ES (immediate coronary angiography). ES patients with CAD were compared to non-CAD ES patients, ES patients with progressive CAD were compared to stable CAD ES patients. The primary endpoint was all-cause mortality at 2.5 years. Secondary endpoints were the composite endpoint of first recurrent ventricular tachyarrhythmias and appropriate ICD therapies, and recurrence of ES (ES-R) at 2.5 years. 

Results: Within a total of 87 consecutive ES patients, 33% had no evidence of CAD. Here, dilated cardiomyopathy (48%) and unexplained ES (21%, unknown) were most common underlying cardiomyopathies, followed by low rates of primary cardiomyopathies and channelopathies. CAD was present in more than two thirds (67%). However, only 52% of all ES patients underwent immediate coronary angiography at the time of ES. Here 84% had CAD, of which 39% revealed progressive CAD with the need of target vessel revascularization (TVR) or cardiac transplantation (n=1). At long-term follow-up, neither the presence (or absence) of CAD (41% vs. 34%; log rank p=0.708) nor progressive CAD (33% vs. 26%; log rank p=0.372) were associated with all-cause mortality, the composite of recurrent ventricular tachyarrhythmias plus appropriate ICD therapies or ES- at 2.5 years.

Conclusions: In ES patients CAD-related cardiomyopathies were more common than non-CAD-related cardiac diseases, accompanied by an underinvestigated rate of coronary angiography despite increasing rates of progressive CAD. Both, CAD and non-CAD had no prognostic impact in ES.