Three-dimensional cardiac magnetic resonance allows the identification of slow-conducting anatomical isthmuses in tetralogy of Fallot

Kimura, Y.; Wallet, J.; Bouyer, B.; Jongbloed, M.R.M.; Bertels, R.; Hazekamp, M.G.; ... ; Zeppenfeld, K. (2024)

Article / Letter to editor

Background and Aims

Patients with repaired tetralogy of Fallot remain at risk of life-threatening ventricular tachycardia related to slow-conducting anatomical isthmuses (SCAIs). Preventive ablation of SCAI identified by invasive electroanatomical mapping is increasingly performed. This study aimed to non-invasively identify SCAI using 3D late gadolinium enhancement cardiac magnetic resonance (3D-LGE-CMR).

Methods

Consecutive tetralogy of Fallot patients who underwent right ventricular electroanatomical mapping (RV-EAM) and 3D-LGE-CMR were included. High signal intensity threshold for abnormal myocardium was determined based on direct comparison of bipolar voltages and signal intensity by co-registration of RV-EAM with 3D-LGE-CMR. The diagnostic performance of 3D-LGE-CMR to non-invasively identify SCAI was determined, validated in a second cohort, and compared with the discriminative ability of proposed risk scores.

Results

The derivation cohort consisted of 48 (34 ± 16 years) and the validation cohort of 53 patients (36 ± 18 years). In the derivation cohort, 78 of 107 anatomical isthmuses (AIs) identified by EAM were normal-conducting AI, 22 were SCAI, and 7 blocked AI. High signal intensity threshold was 42% of the maximal signal intensity. The sensitivity and specificity of 3D-LGE-CMR for identifying SCAI or blocked AI were 100% and 90%, respectively. In the validation cohort, 85 of 124 AIs were normal-conducting AI, 36 were SCAI, and 3 blocked AI. The sensitivity and specificity of 3D-LGE-CMR were 95% and 91%, respectively. All risk scores showed an at best modest performance to identify SCAI (area under the curve ≤ .68).

Conclusions

3D late gadolinium enhancement cardiac magnetic resonance can identify SCAI with excellent accuracy and may refine non-invasive risk stratification and patient selection for invasive EAM in tetralogy of Fallot.

• Tetralogy of Fallot
• Ventricular tachycardia
• Cardiac magnetic resonance
• Anatomical isthmus
• Risk stratification

• All authors: Kimura, Y.; Wallet, J.; Bouyer, B.; Jongbloed, M.R.M.; Bertels, R.; Hazekamp, M.G.; Thambo, J.B.; Iriart, X.; Cochet, H.; Sacher, F.; Lamb, H.J.; Blom, N.A.; Zeppenfeld, K.
• Date: 2024-05-15
• Journal: European Heart Journal
• Volume: 45
• Issue: 23
• Pages: 2079 - 2094
• DOI: doi:10.1093/eurheartj/ehae268