Title:

Functional Assessment and Arrhythmia Prediction in Adult Patients with Repaired Tetralogy of Fallot Using a Multimodality Approach

Background:

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. Surgical repair has improved survival into adulthood, but long-term complications like arrhythmias and heart failure remain common. Assessing health-related quality of life (HRQOL) and cardiac function is essential.

Aim:

Assess functional status of adult patients with repaired TOF using a multimodal approach, including myocardial strain analysis via CMR.

Identify predictors of arrhythmia using strain and clinical parameters.

Methods:

Design: Prospective observational study over one year.

Population: Adults (≥18 years) with repaired TOF undergoing follow-up CMR.

Assessments:

Clinical evaluation (NYHA class)

Echocardiography (RV size, function, valve status)

Laboratory tests (BNP, NT-proBNP)

Exercise testing (METs, VO₂ max)

ECG & 24-hour Holter monitoring (QRS duration, arrhythmias)

CMR (volumes, flow, fibrosis, strain analysis of RA, RV, LV)

Outcomes:

Primary: Functional assessment of repaired TOF patients.

Secondary: Detection of arrhythmia and need for further interventions (e.g., ICD or ablation).

Statistical Analysis:

Comparison between arrhythmic and non-arrhythmic groups.

Logistic regression for predictors of arrhythmia.

ROC analysis to determine optimal strain cut-off values.

Ethical Considerations:

Ethics committee approval and informed consent.

Data confidentiality maintained.

• Inclusion criteria:

  • Adult TOF patients who were referred for surgical repair of TOF either valve sparing repair (VSR) or valved conduit (stented valve conduits, freestyle valved conduits, bio-prosthesis, or homograft).
  • Adults (age ≥18 years) with repaired TOF.
  • Undergoing routine CMR for clinical follow-up.
  • Sinus rhythm or known history of ventricular arrhythmia.

• Exclusion criteria:

  • Confounding other congenital defects e.g. AV canal.
  • Significant aortic regurgitation or stenosis.
  • Significant mitral regurgitation.
  • Residual significant major aorto-pulmonary collaterals (MAPCAs).
  • Patients with contraindications to CMR (e.g., pacemakers, severe renal impairment, claustrophobic).
  • Poor-quality CMR images precluding strain analysis.

The study population includes adult patients (age ≥18 years) with previously repaired Tetralogy of Fallot (TOF), who were referred for routine clinical follow-up at least 3 months post-surgical correction. These patients underwent standard evaluations including cardiovascular magnetic resonance (CMR), transthoracic echocardiography, ECG, Holter monitoring, NT-proBNP measurement, and exercise stress testing. Patients were either in sinus rhythm or had a documented history of ventricular arrhythmia. Individuals with other major congenital heart defects, significant valvular disease, or contraindications to CMR were excluded.