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Final Program


Program-At-A-Glance

Congenital Track

Virtual Recording

Session: Congenital Track PCHD Oral Session 1: Abstracts

Right Atrial Remodeling as a Predictor of Arrhythmia in Repaired Tetralogy of Fallot: A Multicenter CMR Study

Friday, February 6, 2026
11:20 AM - 11:30 AM  
Location: Americas II & III and Hall 4 (2nd Lower Level)

    Presenting Author(s)

  • Nita Ray Chaudhuri, MD

    Associate professor of Pediatrics
    West Virginia University
    Morgantown, West Virginia, United States

    • Primary Author(s)

  • Nita Ray Chaudhuri, MD

    Associate professor of Pediatrics
    West Virginia University
    Morgantown, West Virginia, United States

    • Co-Author(s)

  • KA

    Kamil Abbas, BSc

    Medical Student
    West Virginia University
    Morgantown, West Virginia, United States

  • Bryan Ho

    Medical Student
    West Virginia University
    Morgantown, West Virginia, United States

  • UK

    Utkarsh Kohli, MD

    Professor of Pediatrics
    Florida Internatinal University, Florida, United States

  • Megan Gunsaulus, MD

    Physician, pediatric cardiology
    Nationwide Children's Hospital
    Columbus, Ohio, United States

  • Tarek Alsaied, MD

    Associate Professor of Pediatric Cardiology
    Dallas Children's Medical Center
    Irving, Texas, United States

  • CM

    Chrsitopher Mascio, MD

    Professor
    West Virginia University
    -, West Virginia, United States

  • DC

    Dhaval Chauhan, MD

    Assistant Professor
    West Virginia University
    -, West Virginia, United States

  • JU

    Jai Udassi, MD

    Professor and Chief, Department of Pediatrics
    West Virginia University
    -, West Virginia, United States

  • MH

    Mehdi Hedjazi Moghari, PhD

    Associate Professor
    West Virginia University
    -, West Virginia, United States

Background: Tetralogy of Fallot (ToF) is a cyanotic congenital heart disease associated with long-term risk of atrial and ventricular arrhythmias. Cardiovascular magnetic resonance (CMR) provides accurate assessment of right atrial (RA) and right ventricular (RV) volumes, as well as the RA–RV coupling index (RACI), which have been linked to life-threatening arrhythmia risk. In this two-center study, we evaluate the predictive utility of RA volume and RACI for arrhythmia risk stratification in patients with repaired ToF.

Methods: We conducted a retrospective two-center study of children and young adults with repaired ToF to identify CMR predictors of atrial and ventricular arrhythmias. RA and RV volumes and function were quantified using CMR and analyzed with Circle CVI42 software (Circle Cardiovascular Imaging, Calgary, Canada). RACI was calculated as the ratio of RA end-diastolic volume (EDV) to RV EDV. Arrhythmia risk was assessed using a validated Importance Factor (IF) scoring system, with IF >2 indicating high risk, as previously described [1]. Receiver operating characteristic (ROC) analysis was used to evaluate the ability of RA and RV metrics, including RACI, to discriminate between high- and low-risk patients. Statistical analyses were performed with JMP Pro (SAS Institute, Cary, NC), with p< 0.05 considered statistically significant.

Results: With IRB approval, 109 patients with ToF were included in this study (Table 1). Patients classified as high-risk (IF >2) demonstrated significantly larger minimum and maximum RA volumes and higher RACI compared with those with IF ≤2 (Table 2). In contrast, RA ejection fraction (EF), RV EDV, RV end-systolic volume (ESV), and RV EF did not differ significantly between the groups. ROC analysis showed that minimum RA volume, maximum RA volume, and RACI were the strongest predictors of high-risk IF score, outperforming other CMR-derived measures (Figure 1 & Table 2).

Conclusion: Minimum and maximum RA volumes and RACI, derived from CMR, are strong noninvasive predictors of life-threatening arrhythmias in patients with repaired ToF. In this population, chronic pulmonary regurgitation frequently results in RV dilation and elevated right-sided filling pressures, leading to RA remodeling and enlargement. This atrial remodeling likely underlies the predictive value of RA measures for arrhythmia risk stratification. Notably, RA volume demonstrated even greater predictive strength than RACI, suggesting that patients with both RA enlargement and RV dilation may be at particularly high risk compared with those who have isolated RA enlargement.

Table 1. Summary of key patient population characteristics from the two-center study. Data are reported as n (%) or median (25th–75th percentile). BTT = Blalock–Thomas–Taussig; CMR = Cardiovascular Magnetic Resonance; EKG = Electrocardiogram; RACI = Right Atrial-Right Ventricle Coupling Index; RV = Right Ventricle; RA = Right Atrium; ToF = Tetralogy of Fallot.

Characteristics of the Study Population from Center 1 (n = 63) and Center 2 (n = 46)

Center

1

2

p-value

Age of Complete ToF Repair (years)

0.54 (0.33-0.96)

0.58 (0.43-0.84)

0.914

Age at CMR (years)

16.36 (12.86, 18.92)

18.50 (12.00, 28.25)

0.277

Sex

 

 

0.491

Male

37 (59%)

30 (65%)

 

Female

26 (41%)

16 (35%)

 

ToF Diagnosis

 

 

< 0.001

Pulmonary Atresia

16 (25%)

4 (9%)

 

Pulmonary Stenosis

47 (75%)

23 (50%)

 

Neither

0

19 (41%)

 

History of BTT Shunt

 

 

0.852

         Yes

9 (14%)

6 (13%)

 

         No

54 (86%)

46 (87%)

 

History of Pulmonary Valve Replacement

 

 

0.554

         Yes

31 (49%)

20 (43%)

 

         No

32 (51%)

26 (57%)

 

QRS duration on EKG (BPM)

134 (108, 150)

135 (128, 156)

0.079

CMR Data

 

 

 

RV End-Diastolic Volume Indexed (mL/m2)

119.1 (94.40, 139.30)

111.30 (95.46, 133,06)

0.404

         RV End-Systolic Volume Indexed (mL/m2)

61.3 (48.72, 73.57)

52.45 (45.68, 73.43)

0.240

         RV Ejection Fraction (%)

49.00 (44.00, 53.00)

49.36 (44.18, 57.22)

0.330

Pulmonary Regurgitation Fraction (%)

39.00 (19.00, 52.00)

43.00 (21.75, 52.25)

0.498

Minimum RA Volume Indexed (mL/m2)

18.50 (12.49, 23.56)

21.09 (14.40, 26.89)

0.092

Maximum RA Volume Indexed (mL/m2)

27.76 (21.85, 37.73)

34.84 (26.93, 45.27)

0.012

RA Ejection Fraction (%)

34.85 (30.38, 45.90)

42.14 (34.07, 48.52)

0.017

RACI (%)

15.18(10.50, 22.19)

17.81 (13.80, 24.60)

0.081

Importance Factor Score

 

 

0.496

>2

8 (13%)

8 (17%)

 

≤2

55 (87%)

38 (83%)

 

Table 2. Results are expressed as median (25th–75th percentile). EF = Ejection Fraction; RACI = Right Atrial-Right Ventricle Coupling Index; RV = Right Ventricle; RA = Right Atrium.

Association of Right Atrial and Ventricular Measurements with Importance Factor Scores

 

Importance Factor (IF) Score

 

≤2

>2

p-value

CMR Parameters

 

 

 

         RV End-Diastolic Volume Indexed (mL/m2)

110.12(95.34, 136.22)

130.25 (94.98, 136.72)

0.246

RV End-Systolic Volume Indexed (mL/m2)

57.80 (45.80, 73.19)

62.98 (49.33, 76.34)

0.380

RV EF (%)

49.75 (44.62, 56.00)

47.50 (43.25, 58.75)

0.997

         Pulmonary Regurgitation Fraction (%)

40.10 (20.50, 52.00)

34.00 (13.75, 57.50)

0.719

Minimum RA Volume Indexed (mL/m2)

18.26 (12.36, 23.92)

27.08 (20.61, 32.76)

< 0.001

Maximum RA Volume Indexed (mL/m2)

29.10 (21.68, 38.86)

38.76 (30.86, 61.14)

0.002

RA EF (%)

39.77 (32.38, 47.84)

34.71 (24.62, 45.57)

0.054

RACI %

15.85 (10.60, 21.98)

20.51 (15.41, 32.00)

0.006

Figure 1. Receiver operating characteristic (ROC) curves for minimum right atrial (RA) volume (A), maximum RA volume (B), and RA-Right ventricle coupling index (RACI) (C) in predicting high-risk importance factor scores (IF>2).