Intercalated Disc Abnormalities Are Linked to Arrhythmias in Inflammatory Cardiomyopathy

Area of Science:

• Cardiology
• Pathology
• Biomedical Research

Background:

• The connection between intercalated disc abnormalities (IDAs) and arrhythmias in inflammatory cardiomyopathy (ICM) is not fully understood.
• Investigating this relationship is crucial for understanding arrhythmogenesis in ICM.

Purpose of the Study:

• To investigate the link between IDAs and arrhythmias in human ICM patients.
• To compare these findings with a mouse model of experimental autoimmune myocarditis (EAM).

Main Methods:

• Ultrastructural analysis of cardiac tissue from 316 human ICM patients to assess intercellular cleft width (ICW).
• Prospective 24-month follow-up for arrhythmias in IDA-positive (IDA+) versus IDA-negative (IDA-) human subjects.
• Comparison with male mice (n=12) with EAM, assessing ICW and arrhythmias.

Main Results:

• IDA+ patients (22%) exhibited significantly greater ICW and a higher incidence of arrhythmias at presentation and during follow-up compared to IDA- controls.
• IDAs independently predicted major ventricular arrhythmias within 24 months in humans (HR: 3.0).
• Increased ICW correlated with arrhythmias in both humans and EAM mice, with abnormal ventricular electrograms noted in mice.

Conclusions:

• Intercalated disc abnormalities (IDAs) are a shared feature in genetic and autoimmune ICM and are significantly associated with arrhythmias.
• The EAM mouse model shows promise for studying the mechanisms linking IDAs and arrhythmias.
• IDAs may serve as a potential biomarker for arrhythmia risk in ICM.