Beyond Tachycardia-Induced Cardiomyopathy

Abstract

Background

Tachycardia-induced cardiomyopathy (TICM) is typically reversible with rhythm control, but individual susceptibility remains poorly understood and may reflect genetic predisposition.

Case Summary

A 66-year-old woman with paroxysmal atrial fibrillation (AF) presented with new-onset heart failure. Genetic testing identified a likely pathogenic heterozygous ABCC9 gene variant (c.3892+2T>C), not previously associated with dilated cardiomyopathy or AF. ABCC9 loss-of-function mutations have been linked with cardiac channelopathies and cardiomyopathies. Ventricular function improved with rhythm control and medical therapy.

Discussion

This case illustrates the potential role of ABCC9 mutations in arrhythmia-induced cardiomyopathy beyond pure TICM. Although this variant has not been previously reported in affected individuals, existing models support its pathogenicity. The co-occurrence of prolonged QT, familial AF, and dilated cardiomyopathy underscores the value of genetic testing in cardiac disease.

Take-Home Messages

Genetic testing may reveal causes in atypical or treatment-resistant cardiomyopathies and arrhythmias. This novel ABCC9 variant suggests a genetic contribution to AF-induced cardiomyopathy beyond the expected course of TICM.