Independent Correlation between Familial Mediterranean Fever under Colchicine Therapy and Tpe Interval, QTc Interval, and Tpe/QTc Ratio Observed on Superficial 12-Lead Electrocardiography

Introduction: Familial Mediterranean fever (FMF) is an auto-inflammatory disorder characterized by recurrent episodes of fever and inflammation, which can lead to cardiac complications, particularly issues with cardiac conduction due to irregularities in ventricular repolarization. This study aimed to investigate the Tpe interval, QTc interval, and Tpe/QTc ratio—key indicators of ventricular arrhythmia—among FMF patients undergoing colchicine treatment compared to healthy controls.

Methods: Conducted as a cross-sectional analysis, the study included 185 participants, with 96 diagnosed with FMF and 89 healthy controls. The researchers assessed cardiac repolarization markers through 12-lead surface electrocardiography (ECG) and collected demographic, laboratory, echocardiography, and medication data during cardiology outpatient visits.

Results: The average age of the control group was 43.2 years, while the FMF group averaged 35.2 years. Notably, the control group exhibited higher prevalence rates of coronary artery disease, diabetes, hypertension, and hyperlipidemia, correlating with their older age. Electrocardiographic findings revealed significant differences between the two groups: the Tpe interval (normal range: 50-100 ms) was longer in FMF patients (110.3 ms) compared to controls (91.4 ms) (p<0.001), while the QTc interval (normal range: 360-440 ms) was shorter in FMF patients (401.4 ms) than in controls (407.5 ms)(p<0.001). The Tpe/QTc (normal range: 0.15-0.25) ratio was also higher in FMF patients (0.27) compared to controls (0.22) (p<0.001). Correlation analysis indicated a positive relationship between FMF and both the Tpe interval (r=0.567, p<0.001) and Tpe/QTc ratio (r=0.594, p<0.001), while a negative correlation was observed with the QTc interval (r=-0.163, p=0.027). In multivariate regression analysis, FMF was independently correlated with the Tpe interval (OR: 17.710; 95% CI: 13.594-21.826, p<0.001), QTc interval (OR: -6048; 95% CI: -11723--0.374, p=0.037), and Tpe/QTc ratio (OR: 0.048; 95% CI: 0.038-0.058, p<0.001).

Conclusion: Despite colchicine therapy, FMF patients may still face an increased risk of arrhythmias. The findings suggest that regular cardiology follow-ups, including ECG evaluations, are a reasonable approach for clinically stable FMF patients.