Abstract 12519: Electrocardiographic Findings and Arrhythmias in Patients With Familial ST-Depression Syndrome

Background: The recently reported Familial ST-depression syndrome is a distinct inherited cardiac disease entity characterized by persistent, non-ischemic ST-depressions and risk of arrhythmias and heart failure. We aimed at further characterizing the features associated with the syndrome. Methods: Retrospective analysis of demographics, electrocardiographic, arrhythmic and imaging data from families with Familial ST-depression syndrome in Denmark. Results: Forty affected individuals (43% men; mean age at diagnosis 49.1 years) from 14 apparently unrelated families with ≥2 affected members were included. Pedigree analyses were consistent with autosomal dominant inheritance in all families. The ST-depressions were most pronounced in leads V4, V5, and II and persisted over time (mean follow-up 9.3 years), i.e. no temporary normalization was seen. The ECG phenotype seemed to develop in pre-puberty. Exercise accentuated the ST-depressions with a maximum difference between rest/stress (mean) of -117μV in lead V5. Six (15%) patients developed ventricular arrhythmias or (aborted) sudden cardiac death, seven (18%) were diagnosed with left ventricular ejection fraction ≤50%, and 10 (25%) developed atrial fibrillation. Seven patients had at least one catheter ablation; five for supraventricular arrhythmias and two for ventricular arrhythmias. Males experienced more arrhythmic endpoints than females (Figure, p<0.01). Surprisingly, in some of the patients the ECG phenotype was tolerated for decades before events occurred. Conclusions: We identified 14 families with the novel syndrome showing autosomal dominant inheritance. The phenotype was associated with arrhythmias, aborted sudden cardiac death, or heart failure in about half of the cases. Families with Familial ST-depression syndrome should undergo cascade screening like in other inherited arrhythmia syndromes.